Figure 1. Great circle paths that match the satellite data after 19:41. (Click on image to enlarge.)
Introduction
In the last post, I presented how the simulation data found on the home computer of Captain Zaharie Shah suggests that the recovered data were from a single flight session on Feb 2, 2014, in which the aircraft takes off from Kuala Lumpur International Airport (KLIA), flies northwest over the Malacca Strait, flies past the Andaman and Nicobar Islands, turns to the south, and exhausts its fuel in the Southern Indian Ocean. The simulated flight could have represented a diversion of flight MH150 from KLIA to Jeddah, Saudi Arabia, which the captain commanded two days later on Feb 4, 2014.
The alignment of data set 10N (the northernmost), 45S1 (just after fuel exhaustion in the SIO), and Pegasus Field (NZPG) at McMurdo Station, Antarctica, suggests that the simulation user might have selected autopilot and used LNAV mode. If LNAV mode is selected, the aircraft follows a great circle path between the starting and ending waypoints of the active leg. This raises the possibility that McMurdo was used as a final waypoint for navigation with the expectation that fuel would be exhausted in the SIO, well before reaching Antarctica.
In this article, I reconstruct flight paths with the assumption that MH370 was flown in automated flight in a similar way as in the simulation session. In particular, I reconstructed flight paths using the following two criteria:
- After 19:41, MH370 was flown in under autopilot, and was following a great circle path in LNAV mode and speed was controlled using the autothrottle.
- In addition to (1), after 19:41, MH370 was following a great circle path that leads to an airport in Antarctica.
What this article does not consider is how drift analyses based on the location and timing of recovered debris from MH370 affects the impact probabilities along the 7th arc. A review of the available drift analyses needs to be considered along with any path reconstruction studies before a new search area can be recommended with any level of confidence.
Flight Paths Along Great Circles after 19:41
Figure 1 shows the path (green) of MH370 as captured by Malaysian civil and military radar. After the last radar capture at 18:22, all we have to help us reconstruct possible paths are the Burst Timing Offsets (BTOs) and Burst Frequency Offsets (BFOs) from communication between the aircraft, Inmarsat’s F1 satellite above the Indian Ocean, and Inmarsat’s Ground Earth Station (GES) at Perth. The BTO values indicate how far the aircraft was from the satellite, and therefore possible locations that satisfy the BTO values form an arc when plotted. Shown in Figure 1 are the arcs at 19:41 (the 2nd arc) and 00:19 (the 7th arc). While the BTO values are indicative of position, the BFO values are indicative of the speed (horizontal and vertical) and track of the aircraft. The BFO nvalues tell us, for instance, that MH370 was traveling south after 19:41, and also tell us the aircraft was in an increasingly steep descent at 00:19.
The radar path ends as MH370 was traveling northwest in the Malacca Strait. Yet we know from the satellite data that the flight ended in the SIO, and the satellite data after 19:41 shows a progression of values consistent with automated flight. The details of how MH370 might have been flown between 18:22 and 19:41 is still the subject of much debate, and it is possible that multiple maneuvers occurred in this time period. (I’ll be presenting some thoughts on this in the next article, benefiting from some new insights.) For now, we start our analysis at 19:41 and don’t consider the time period between 18:22 and 19:41, but also recognize that some of the paths presented below may be eliminated by constraints imposed when the time period 18:22 – 19:41 is considered.
The reconstructed paths starting at 19:41 and ending at 00:19 are shown in white in Figure 1 for paths at a constant pressure altitude of 35,000 ft. Wind and temperature data from GDAS were used to relate Mach number to ground speed. Each path corresponds to a specific track angle at 19:41. (The track angle will in general vary along each path as would be expected along a great circle.) Initial track angles between 162°T and 192°T were considered, and these paths cross the 7th arc over a range of latitudes between 22S and 40S. For each initial track angle, the position at 19:41 was found that minimized the RMS error for the BTO at the times 19:41, 20:41, 21:41, 22:41, and 00:11. (The position at 19:41 was not constrained to fall exactly on the 2nd arc.) The corresponding RMS error for the BFO values at times 19:41, 20:41, 21:41, 22:41, 23:14, and 00:11 was also recorded.
For automated control of speed, two autothrottle modes were considered for the time period between 19:41 and 00:11: constant Mach number, and Long Range Cruise (LRC), in which the Mach number decreases as fuel is burned and the weight decreases. For the time period between 19:41 and 00:11, a speed is chosen so that the aircraft exactly crosses the 7th arc at 00:19 .
The LRC speed schedule also serves as a proxy for ECON speed, for which the speed also varies with aircraft weight. ECON offers better cost efficiency than LRC because the relative value of time and fuel can be adjusted through a Cost Index (CI) parameter, and because the Mach number is adjusted for wind. However, I chose to not consider ECON speed here because the speed profile would be similar to LRC (depending on the CI), and the exact methodology is not generally available to the public for calculating Mach number as a function of weight, altitude, Cost Index, and wind. (Bobby Ulich has just published a model that makes excellent progress in this regard.) If ECON speed had been considered, it is possible that the BTO values for the same of the paths would have marginally improved.
Figure 2 shows the BTO and BFO errors across a range of latitudes for crossing the 7th arc. Some observations are:
Figure 2. Match to satellite data after 19:41 for great circle paths. (Click on image to enlarge.)
- For latitudes south of 34S, the LRC speed is too slow, and constant Mach number results in a better BTO fit.
- For latitudes north of 34S, the speed reduction offered by LRC speed results in a better BTO fit than for constant Mach number.
- For the paths at constant Mach number, the Mach number varies between 0.801 for a crossing at 22S, to 0.842 for a crossing at 40S.
- Constraining the BTO error to less than 32 μs eliminates paths crossing the 7th arc north of around 26.6S.
- Constraining the BFO error to less than 7 Hz eliminates paths crossing the 7th arc south of 39S latitude and north of 28S latitude.
- The minimum BTO error for LRC speed occurs for a crossing of the 7th arc around 33S latitude
- The minimum BFO error occurs for a crossing of the 7th arc of around 35S latitude.
Flight Paths Leading to Waypoints Past 7th Arc
From among the family of reconstructed paths that follow great circles between 19:41 and 00:19, we consider three paths that align with three airports in Antarctica: South Pole (NZSP), Pegasus Field-McMurdo (NZPG), and Wilkins Runway (YWKS). In August 2014, I first considered a path towards the South Pole that might have occurred after a possible landing at Banda Aceh airport (WITT). Although I have long abandoned the possibility of a landing, the scenario of a holding pattern near Banda Aceh followed by a cruise on a due south course remains an interesting possibility. More recently, the path towards NZPG was investigated in a paper I co-authored with Richard Godfrey, and subsequently Richard proposed the YWKS destination in a separate paper.
The three paths to airports in Antarctica are shown in Figure 1 as black lines that extend past the 7th arc. The coordinates as the paths cross the 7th arc are also shown.
Added Nov 10, 2017: Additionally, a fourth path is shown which aligns with 45S, 104E, which are the coordinates from the final data set found on the captain’s home computer. This case is included to represent the scenario where MH370 was flown towards the location where fuel exhaustion was simulated on the captain’s home computer.
The match of the four paths to the satellite data is shown in Figure 2. Of the four, the path to NZSP crosses the 7th arc closest to the latitude where the BFO and LRC BTO errors are at their minimum values. (Lower BTO errors occur for constant Mach paths crossing at more southern latitudes. However, any path requiring Mach numbers faster than LRC is unlikely to have enough fuel.)
More on the Path Towards the South Pole
The flight towards the South Pole is interesting because there are several ways that the autopilot might be used to create this flight. In LNAV mode, a pilot could enter a custom waypoint with a latitude of 90S and any longitude. Or, he could enter the built-in waypoint for the South Pole, which is SPOLE. Or, if it’s available in his waypoint database, he could enter the waypoint for the runway serving the South Pole, which is NZSP. Any of these methods would cause the aircraft to follow a path that closely follows a great circle to the South Pole. Also, if a pilot wanted to reach as far south as possible, a path towards the South Pole using LNAV would be an obvious selection.
Another procedure would be to use TRK SEL mode, with a value of 180° and the NORM/TRUE switch set to TRUE. Although this would produce similar results as the method using LNAV, it is possible that the aircraft could at times deviate from the required track, and the path could deviate from a great circle. For instance, a wind gust or turbulence could momentarily cause the track to deviate. Although the autopilot would correct for the deviation and bring the track back to the target value of 180°T, the error in path that accumulated during the track deviation would not be corrected. By contrast, in LNAV mode, deviations from the great circle path are continuously corrected so path errors don’t accumulate.
There is also close alignment between this path towards the South Pole and waypoint BEDAX. I’ll discuss this more in a future article.
Figure 3 shows an exploded view of the search area, showing the boundary of what was previously searched (yellow), and where CSIRO proposes to search next (green). The new search area extends about 25 NM to the northeast of the 7th arc at 35,000 ft (blue), and about 27.5 NM to the southwest. The three impact sites proposed by CSIRO are also shown, ordered by their priority. In this part of the arc, the width of the searched area is about 19 NM to either side of the 7th arc. The highest priority impact site is 23 NM to the southeast of the 7th arc, and falls within the proposed search area, which extends between 19 NM and 27.5 NM from the 7th arc.
Figure 3. Exploded view of search area proposed by CSIRO. (Click on image to enlarge.)
The path that extends to NZSP (white) is also shown in Figure 3, which runs along 93.7E longitude. At the point of crossing the arc, the width searched was only about 6.5 NM to the northwest and 15.6 NM to the southeast. The fact that this part of the arc was only narrowly searched presents an interesting opportunity to search in the future.
In the future articles, I’ll present more thoughts on how the MH370 aircraft might have been flown between 18:22 and 19:41, and the implications for possible impact sites along the 7th arc.
Update on November 10, 2017
Here is a CSV file with data for the great circle paths, including the position and track at 19:41, position at 00:19, and speed mode. Included are the data for four paths that align with waypoints past the 7th arc. The four waypoints are the South Pole (NZSP), Wilkins Runway (YWKS), Pegasus Field-McMurdo (NZPG), and the fuel exhaustion position from the simulator data (45S, 104E).
Update on November 11, 2017
In Figure 4 below, I have plotted the paths to the four waypoints (NZSP, YWKS, NZPG, 45S) on the same plot that was generated by CSIRO to show the cumulative probability of detection of low-windage debris by the surface search for various impact points along the arc. The calculated probabilities include the drift that might have occurred between the time and location of the impact and the time and location of the search. It can be seen that there are impact points along the 7th arc and north of 33S where the probability of detection is significantly less than 100%, especially if the impact was to the northwest of the arc.
Figure 4. Efficiency of surface search shown with selected great circle paths. (Adapted from CSIRO.) (Click on image to enlarge.)
Update on November 14, 2017
IG Member Brian Anderson has reminded us that “There are a number of RNZAF photos of interesting flotsam (debris), in areas that may now be much more significant. Unfortunately none was ever recovered.” Two of the more interesting photographs are found below. The first photo (Figure 5) is an unknown object that could be part of an aircraft. The second photo (Figure 6) is a field of floating debris.
Figure 5. Aerial photograph (5849) of unknown object on March 29, 2014, at 28.8866S, 96.0844E. (Click on image to enlarge.)
Figure 6. Aerial photograph (5832) of debris field on March 29, 2014, at 28.3927S, 97.7750E. (Click on image to enlarge.)
Both photographs were taken on March 29, 2014, at coordinates not far from where the great circle path to 45S,104E crosses the 7th arc near latitude 28.3S.
In order to determine if these objects are consistent with the expected drift of debris from an impact near 28.3S on March 8, 2014, I used the CSIRO-generated drift results for an impact on the arc near 28S latitude, where the drift model was seeded with objects within an approximate +/- 0.5 deg square area. The drift model results are shown in Figure 7 for the calculated position of debris on March 29, 2014.
Figure 7. Drift results from CSIRO for an impact along the 7th arc near 28S latitude. (Click on image to enlarge.)
The results are shown for low windage debris (red) and high windage debris (green), and should be representative of a range of objects produced by the impact. Both the unknown object and the debris field are found in the general vicinity of where the model predicts objects would drift for the modeled impact location. This makes the possible impact site of 28.3S even more interesting.
@Victor,
Continuation from the previous thread…
Re: “I don’t understand the reluctance to recognize that the OI offer represents an extraordinary opportunity.”
We don’t know what OI’s offer and capabilities are. Fugro, in contrast, is a well-known heavy-weight player in the world of marine surveys. We used their services quite a few times, and they always produced data and reports of excellent quality. But Fugro is expensive compared to other surveyors. OI is a black horse to me, and frankly I wish both OI and Fugro be involved into the search.
Is OI’s contract a lump sum contract or reimbursable? If the former, then what OI’s management is going to do if/when they reach the limit? Declare bankruptcy? Given the length of the arc, this is a pretty high risk. If the latter, then obviously OI will be interested in searching as long as possible. Or are there some timeframes? I guess these points could be a subject of negotiation.
Anyway good to know that things are moving again, and that the OI’s strategy is what I suggested a year ago or more.
With regard to other matter. I found your WYKS route interesting for at least 3 reasons:
1. 172 deg track. This is a key feature of the “radar alerting maneuver” I suggested earlier.
2. Your/Richard’s positions 19:41 are 6.5-6.8N, 93.3-93.4E. My positions, depending on the type of the exit mistake, 93.3-93.5E, 5.2-5.7N. Pretty close.
3. The terminus around 29.7 is within my “compatibility zone” based on my drift study.
The intriguing feature about another route, NZPG, is the terminus at the origin of the “Curtin boom” should it be on the 7th arc. For some mysterious reason the ATBS has completely ignored it. I am only wondering whether you kept this aspect in mind when you suggested respective terminus to OI?
P.S. Why would MH370 be following “a great circle path that leads to an airport in Antarctica”? Logic-wise?
“After 19:41, MH370 was flown in under autopilot …”
So before 18:22 the plane flew a purposeful path, and after 19:41 it flew an even more purposeful path, yet during the one long gap in the coverage (or not, depending on how you want to treat the 18:40 phone event), the plane decided to “loiter”. Fiddle and diddle. Who knows, maybe it did. I wasn’t there. Don’t think you were either.
Were Antartica waypoints in the 9M-MRO navigation database, given the limited amount of memory storage in the AIMS-1 flight maangement system?
@Oleksandr: Have you been following the discussion about OI’s offer? They only get paid if they find the wreckage. They have zero incentive to prolong the search. As for Fugro, they didn’t make an offer of this type. They expect to get paid whether or not the wreckage is found.
@sk999: I disagree with your premise. If the plane was in a holding pattern, it did so for a reason, i.e., the delay was intended once out of Malaysian airspace. Possible explanations have been proposed here. I didn’t speculate in the post as to why a delay might have occurred.
If you have a path and associated scenario that is “purposeful” and meets all the criteria, please present it.
As for memory storage in the AIMS, I’m told that Malaysia Air only manages information on routes and waypoints they fly. Exactly what that means, I don’t know. SIDs and STARs for airports consume a lot of memory, so I can understand why not all are included. Airport waypoint coordinates do not.
@Victor
Your figure 2 above is missing the data for BFO error – M constant.
Victor wrote, “I disagree with your premise”
I did not invoke any premise. I just made an observation.
What is a purposeful path? One where the plane is intentionally directed to go from one point to another – say, in LNAV mode (but other modes are possible) – primarily via waypoints. A route BEDAX to the South Pole via LNAV or True Track is such a route. Many have suggested that portions of the turnback up to the point of last radar contact were flown via waypoints (e.g., KADAX, ENDOR, OPOVI, VAMPI, MEKAR, airwayy N571, …). So there is all this waypoint-to-waypoint travel, but then in the middle for over an hour, the plane fiddles and diddles. It makes you go hhhmmmm….
@Victor
Constraining the BFO error to less than 7 Hz eliminates paths crossing the 7th arc south of 39S latitude and north of 28S latitude.
Your use of an RMS metric for BFO error is questionable. I have beat this drum many times. Even well documented previous 9M-MR0 paths i.e. Figure 5.4 of the DSTG book show that errors larger than 7Hz occur, and that the distribution of errors is not a normal distribution. An RMS metric is inappropriate.
@Victor
Figure 3 a little confusing.
I believe the CSIRO2 and 3 are transposed.
The big red diamond I like too but that is apparently not what CSIRO likes.
@DrB
Thanks a lot for those tables. Impressed again about the amount of detailed work you put into this.
And indeed I’ve got my anwsers on my questions to you.
As expected range is considerably shorter with one engine INOP at FL240 compared to both engines operating FL350 (this is what I had in mind @Paul Thompson).
I see LRC INOP at FL240 falls only 2 minutes short on your endurance/error contraints (00:27/00:25).
And only 4 minutes more than MRC (00:22). Range though is ~300Nm shorter with LRC INOP at FL240.
LRC one engine INOP still looks like a theoretical possibility to me with those figures. Crash area would be ~300Nm north compared to MRC or CI52 as I see it.
Would you exclude LRC INOP based on your findings?
@VictorI
I have wondered about this before and like to bring it up now.
The 45S1 and 45S2 simulator points kind of show a similarity with the final BFO’s; a very steep descent from high altitude without fuel.
With the simulator 45S2 the ‘descent’ is ending at 4000ft.
Am I completely wrong or could it make sence that the end-flight scenario was rehearsed (also).
@VictorI
Interesting new article with ample food for thought & discussion.
I would be curious to know:
– The 19:41 latitudes for the different paths
– The average BFO error graph in addition to the RMS error
Could you perhaps share those numbers as well?
@Victor Iannello:
RE: “ECON offers better cost efficiency than LRC because the relative value of time and fuel can be adjusted through a Cost Index (CI) parameter, …”
What is the value of time on a flight to eternity?
@Niels 1941 lat/long and BFO rms was on the dropbox link
https://www.dropbox.com/s/quhfygiw29edfs2/LNAV%20Tracks.png?dl=0
@Dennis W and path-fitters. Asking my question another way. If there are “equally good” candidate path models (viz BTO error RMS) available as you rotate around 1941, why does the Bayesian pdf have a peak at all?
@DennisW: Your use of an RMS metric for BFO error is questionable
I made observations regarding the RMS BFO error. I showed where the minimum is. I didn’t say I know the plane is there. I still think there are lots of candidate spots.
Your figure 2 above is missing the data for BFO error – M constant.
The BFO errors for the constant M and the LRC cases are essentially the same.
@Paul Smithson: If there are “equally good” candidate path models (viz BTO error RMS) available as you rotate around 1941, why does the Bayesian pdf have a peak at all?
In the Bayesian analysis, they started with the radar position at 18:02 and reconstructed paths with a prior distribution for the manoeuvers that minimizes the number of turns. Any path that requires a “delay” between 18:22 and 19:41 would have a low probability because of the number of manoeuvers it would require.
@Ge Rijn: I don’t think the sim data shows a steep descent.
@TBill: Thank you for finding the error. I had the labels for CSIRO 2 and 3 assigned to the wrong positions. The figure should be correct now.
@sk999 said: So there is all this waypoint-to-waypoint travel, but then in the middle for over an hour, the plane fiddles and diddles. It makes you go hhhmmmm….
Yes, it should make you go “hhhmmmm”. However, the impact sites associated with the simplest of LNAV paths have already been searched without result. That should also make you go “hhhmmmm”. There is an error in the assumptions made in the Bayesian analysis.
Again, I’ll repeat my request that you present your best estimate of one or more paths and the associated scenarios.
@VictorI
Assuming SIM point 45S1 and 45S2 are related as closely as they seem, do you have any explanation/suggestion what SIM point 45S2 with altitude 4000ft could mean?
@Oleksandr asked: I am only wondering whether you kept this aspect in mind when you suggested respective terminus to OI?
I have not suggested a terminus to OI. If asked, I would likely include multiple candidates, some of which are presented above. Frankly, I am open to hearing what recommendations others here might have.
@VictorI
And another question. Why did you put your potential crash area west of the searched area and 7th arc around 34S/93.5E and not east of the 7th arc?
According the final BFO’s at the 7th arc and the simulator runs showing mostly turns to the left after flame out, would it not be more logical your potential crash area would be east to the 7th arc around 34.5S/94E?
@Ge Rijn: I know exactly what it means. In the paper I wrote with Yves, we explained that just before saving the 45S2 data set, the altitude was manually changed from 37,654 ft to 4,000 ft, as reflected in the respective values for the parameters AGL and Altitude. This can be repeated.
@Victor
Your reply to me:
I made observations regarding the RMS BFO error. I showed where the minimum is. I didn’t say I know the plane is there. I still think there are lots of candidate spots.
Actually what you said in your narrative above:
Constraining the BFO error to less than 7 Hz eliminates paths crossing the 7th arc south of 39S latitude and north of 28S latitude.
What you said in your narrative is axiomatically true. My assertion is that the statement is meaningless. My guess is that the 7 Hz comes from the Ashton et. al. Inmarsat paper. Where it is clear that it corresponds to a peak error measured on a particular flight. Not an RMS error associated with that flight. Using an RMS (or peak) BFO error to constrain flight paths cannot be justified. BFO can tell us that 9M-MRO went South after the FMT and dropped out of the sky rapidly at 00:19. Beyond that it is essentially of no value.
@VictorI
On your reply:
‘I know exactly what it means. In the paper I wrote with Yves, we explained that just before saving the 45S2 data set, the altitude was manually changed from 37,654 ft to 4,000 ft’
Yes, but it does not explain (to me) why this was done and what those 45S2 values could mean in relation to 45S1.
I don’t want to bring up old stuff I probably don’t understand well enough. I just wonder.
@DennisW: I fully admit that I don’t know whether or not the BFO error should be used to constrain southern paths. I do know that the DSTG assigned such a large standard deviation to BFO values that it only assured that paths were probable if the plane was flying in a southerly direction starting at some time between 18:28 and 18:40. We know that the NZPG path has a larger BFO error than the NZSP path, for instance. I don’t know if that indicates a preference for the NZSP path.
CSIRO has confidently said that the surface search should have detected debris from an impact north of 33S. I view this statement with an appropriate level of skepticism, but I also don’t assign zero value to it.
@Paul Smithson, VictorI
Thanks, Paul, Victor, to be more precise: I’m interested in the 19:41 positions for all 16 paths, as well as the (arithmetic) mean BFO error (the RMS values are already given in the graph, figure 2)
@VictorI
On your comment:
‘ Frankly, I am open to hearing what recommendations others here might have.’
Frankly, I think the probability of the CSIRO 1/2/3 is quite low probability-wise (and not only). All three being just a few NM outside the searched area would be too big a coincidence imo.
CSIRO/ATSB is holding to a ‘live-line’ here I think.
The area is searched till ~32.75S according a high speed descent crash scenario at 00:19. Nothing has been found.
So something must be wrong with this assumption imo.
Then your discribed flight paths all still assume an uncontrolled end of flight with waypoints or track set just before or after FMT and not altered till fuel exhaust. Still assuming a ghost-flight after FMT or a conscious pilot who just waited for the plane to crash at fuel exhaust..(?)
I think it’s essential (also to OI) to consider the possibility of an all controlled (end of) flight with a certain destination/waypoints set just before or after FMT.
A destination that could serve a possible motivation; to hide the plane and evidence of the one(s) responsible as good as possible.
The best area along the 7th arc with this purpose in mind is just outside the searched area east and west of the 7th arc between 32.5S and 33.5S and 95/96E in the trenches under Broken Ridge.
@Victor
(1) How do we fly LRC in the MS Flight Sim, other than manual changing speed?
All I see is we can set Cost Index or Mach/IAS. Perhaps PSS777 cannot do LRC.
(2) Why is the red diamond in Fig. 3 inside Arc7 (that’s close to where I would put it by descending after Arc5)? You normally have crash past Arc7 by FE (fuel exhaustion) at FL350.
(3) I tend to view matching the 2314 telcon BFO (216 BFO) as a key indicator of path fidelity. However, the 2314 telcon BFO goes off at some point, so I take the steady initial value (216).
It would be helpful to see representative tables of data (including 2314 phone call) maybe one path each for LRC (NZPG) and constant speed (SPOLE path). Frankly I use the data to try to fly the route in FS9 by manually changing winds etc at various points.
@TBill: Not having LRC capabilities is one of the many limitations of the PSS777. If you want to use MSFS as a tool, you would be wise to upgrade to the PMDG777 model on FSX.
@TBill, @Ge Rijn: The only reason that I highlighted the area along 93.7E longitude to the NW of the arc is that the area searched was closer to the 7th arc than the area searched to the SE. The search width was extended to only 6.5 NM to the NW from the 7th arc at 35,000 ft, which is within the error bounds of the location of the 7th arc. For the 7th arc at sea level, the search width was only extended to 2.1 NM to the NW from the arc. It is possible that the aircraft was traveling along 93.7E longitude, and impacted the water at the same coordinates as where it was for the last satellite transmission, but yet was missed just due to noise of the BTO measurement. It’s also possible that during the descent, the plane made a 180° turn and backtracked.
@Ge Rijn: If the steep descent was induced by a steep bank that was in turn caused by the re-start of the left engine, the turn would be to the right, not the left. Also, a 180° turn to the right from an initial 180° track would be closer to the unsearched area than a 180° turn to the left because the arc runs NE-SW.
@Ge Rijn
“I think it’s essential (also to OI) to consider the possibility of an all controlled (end of) flight with a certain destination/waypoints set just before or after FMT.”
I agree with you. There are 3 possibilities
(1) Uncontrolled/Accidental Ghost flight (majority of proposed paths)
(2) Controlled/Intentional Ghost Flight (Victor/Richard)
(3) Intentional Live Pilot Flight
Many feel it was either (2) or (3) above, but especially Option (3) is under-represented. Part of the rationale for not considering Option (3) is that it is a “Wild Card” hard to say where the crash site it. But it is conceivable that the live pilot actions were after Arc5 and they were not too extreme, in which case we should not ignore those cases.
Another way to say it, I think we can show close to exact math to BTO/BFO with intentional flight. So far all of the rigorous path prognosticators refuse to show us that case. My 180S CTH case pretty much meets all, but I am not putting myself in the rigorous path prognosticator (RPP) category. I am in the Not Ready for Prime Time Path Prognosticator category.
@Ge Rijn
P.S.- Yet another way to say it, I view Arc5 to Arc6 somewhat similar to Arc1-Arc2…that is to say they were some intentional maneuvers, presumably less drastic between Arc5 to Arc6, but also with potential to save fuel (eg; long desacent).
@TBill: I don’t think I ever said whether I believe there was a pilot alive at 00:19, and I prefer to not use the term “ghost flight” because it has been used to mean many things, as has the term “death dive”. A steep descent at 00:19 could have occurred with or without pilot input. What I think is unlikely is that a steep descent was followed by a long, controlled glide.
@VictorI
On your comment:
‘CSIRO has confidently said that the surface search should have detected debris from an impact north of 33S.’
I like to remind to the fact debris was detected north of 33S.
The flaperon sized/shaped piece detected was photographed but never recovered. It was later explained by bloggers as an aircraft pallet which makes you wonder still. There was never an official explanation.
Anyway that specific piece was drifting there in the middle of nowhere but right near the area and time MH370 is now assumed to have crashed.
@Victor
“due to noise of the BTO measurement”
I just got slaughtered last thread asking if there could be some BTO error.
I fly FS9 PSS777 to be consistent with what ZS might have seen. I realize PMDG is fantastic almost pro simulator. So far I am happy with constant Mach simulations.
Have you ever tried to match a MH370 path with PMDG 777? I assume we have some errors like impact of winds, shape of Earth etc.
@VictorI @TBill
A ‘ghost flight’ implies to me there was somewhere after FMT no one alive anymore, at least no pilot to control the plane.
This makes a big difference with possible pilot input at an end of flight scenario.
Indeed the steep descent and a high speed nose down impact could be initiated by a pilot too without a glide after.
But the big difference with a ‘ghost flight’ is the impact area could have been selected.
@TBill: All reasonable people understand that there is noise on the BTO measurement.
I don’t think it is useful for me to simulate paths after 19:41 using the PMDG777 model, except for the end-of-flight. It is too cumbersome to incorporate temperature and wind fields, for instance and the simulations take too long. (Time acceleration introduces errors.) On the other hand, it is very useful for simulating the flight before 19:00, including FMC programming, speed modes, turns, descents, and holds.
re: @TBill
As an original member of the IG and a proponent of the
“rigorous path prognosticator (RPP) category” approach, I have not been willing to throw my hat in the ring again, despite having some opinions on the subject based on further simulations.
The continued leakage of scraps of information and inferences derived therefrom is significant as the lack of transparency by governmental authorities (which is typical of all governments) encourages too much speculation.
There are apparently enough simulations that have merit so as to encourage entrepreneurs to undertake further searches and the proposed search areas take into account many of the suggestions made by the IG and contributors to this blog.
That the search will continue is the best news I have heard in a long time.
Sid
@Victor said “Yes, it should make you go “hhhmmmm”. However, the impact sites associated with the simplest of LNAV paths have already been searched without result. That should also make you go “hhhmmmm”. There is an error in the assumptions made in the Bayesian analysis.”
Yes. That is what has been the most frustrating and led to many conspiracy theories (one of which may turn out to be the truth, who knows…) But I do appreciate seeing this comment. It should be straightforward, but some haven’t been able to say it: the plane was not found in the highest probability areas (based on prior analysis). It is either not there (very high probability) or it was missed in the search (exceptionally low probability). I hope they find it this time. This is an unimaginable tragedy, a puzzle of epic proportions, and a potential threat to air safety globally. Praying for a stroke or two of luck to go with the genius from you all.
Separately, I recall something about the quicker and better search possibilities with OI from your previously in-depth report on their search technology. Am I recalling right? They will need it to zig zag all over finding the plane or (sadly) dispensing with the CISRO sites quickly.
Final comment on all the secrecy. I know some people can’t stand not to be told people’s sources. It does appear unseemly at times (thus some of the angst that flashes between IG members and others). It is very frustrating. And it does mean data/info cannot be scrutinized properly. But it is also in the nature of things, not just MH370…sometimes there are good reasons for it. Sometimes just an imagined sense of importance and ego in controlling the information. But, either way, it shouldn’t be a shock to folks that some people like to keep secrets. I hope it has not in any way impeded the work done by many here (IG and others). We will know one day as everything ends up in the sunshine sometime. I advise all to keep calm and constructive.
More searching is great news. Praying for the best.
@VictorI,
In response to your question on my endurance predictions, they all assume Air Packs are ON all the time until MEFE. If you turn the air packs OFF at 18:29, the endurance is increased by about 6 minutes.
@sk999,
You said: “You first state, “I updated the CI = 52 speed schedule based on matching the MH370 Flight Plan and MH371 ACARS data.”
You then state, “HERE is a paper demonstrating MH371 was flown with Cost Index = 52.”
Is there there circular reasoning here?”
No. The conclusion that MH371 was flown at CI = 52 has nothing to do with a fuel model. It is based on the excellent consistency of the air speeds between MH371 and the MH370 Flight Plan (which we know used CI = 52) as a function of equivalent sea-level weight Wo.
As a separate issue, I modified the CI = 52 speed prediction of my model at low weights in order to be consistent with both sets of data.
Many thanks Victor for an excellent post!
@DrB On the previous post you asked some questions:
1. What are the flight levels?
I tried altitudes between 18,000 feet and 36,000 feet. The 3 LNAV tracks were all computed at 35,000 feet.
2. How do you handle the effects of headwinds/tailwinds in computing ground speed?
SQRT(POWER(‘Calculated Air Speed (knots)’,2)+POWER(‘Predicted Wind Speed (knots)’,2)
−(2×’Calculated Air Speed (knots)’×’Predicted Wind Speed (knots)’×COS(RADIANS(Diff))))
Where Diff is ‘Instantaneous Track (degs True)’−’Predicted Wind from Direction (degs True)’
3. Are you using the GDAS temperature data in computing the TAS?
Yes
4. Have you figured the fuel consumption for any of these routes?
Yes, the fuel consumption is re-calculated every 15 seconds.
5. Are you assuming a constant Mach from 19:41 until fuel exhaustion?
I have tried various speed schedules, the 3 LNAV tracks were all calculated using LRC mode.
6. What is your justification for fitting a 3-digit Mach number? After an extended Hold, why would a pilot select a 3-digit Mach using the MCP?
The tracks were calculated using LRC mode (19:41 0.815, 20:41 0.807, 21:41 0.799, 22:41 0.791, 00:11 0.780). This is not pilot input, in this case,
7. How many waypoints are entered to define the course from 19:41 until MEFE? Which ones?
Just one ultimate waypoint NZSP, YWKS or NZPG.
The start points at 19:41 are chosen from the best fit:
https://www.dropbox.com/s/h8olw7w4moaauux/2nd%20Arc%20Limits.pdf?dl=0
8. Which BTO times are you using to compute the RMS of the residuals?
19:41, 20:41, 21:41, 22:41 and 00:11.
@Ge Rijn,
You said: “I see LRC INOP at FL240 falls only 2 minutes short on your endurance/error con(s)traints (00:27/00:25). . . . Would you exclude LRC INOP based on your findings?”
I used a 2-sigma criterion (± 8 minutes), and LRC INOP (at +10 minutes long) was just outside that limit. I wouldn’t exclude it, but is seems to be of a rather low probability.
@Victor “I have not suggested a terminus to OI. If asked, I would likely include multiple candidates, some of which are presented above. Frankly, I am open to hearing what recommendations others here might have.”
Very early on it was suggested MH370 went out into the Andaman Sea, came back towards Banda Aceh then round below Sumatra and ditched around 10S 108E. This required a PIC for at least most of the flight and only one more waypoint than the flights from ISBIX to the Antarctic.
Surely this is not unreasonable particularly in light of the motive that has been well canvased here and despite no whistleblower having come forward.
@TimR: A crash 100 NM off the southern coast of Java should have produced debris in Indonesia, which never occurred. It also makes no sense that the plane would run out of fuel after such a short distance was traveled with so many airports that were reachable.
You believe you have inside information that the disappearance was the result of a political negotiation that was unsuccessful. I ask you again to reveal more details or your information will continue to be ignored.
@Victor
Poor choice of words on my part, when I said I got “slaughtered” it was my sense of humor. I am most happy to hear a suggested location inside Arc7 at the red diamond. So as far as Arc7 deviations we have (a) +-5.3 nm error bar, (b) altitude adjustment per BTO calcs, and (c) anything else (noise?).
@Sid
Thank you for the perspective, it is very interesting to me.
@Paul,
@Dennis W and path-fitters. Asking my question another way. If there are “equally good” candidate path models (viz BTO error RMS) available as you rotate around 1941, why does the Bayesian pdf have a peak at all?
Not ignoring you, Paul. I just had to let my thoughts settle relative to your question. My opinion is that Bayesian analytics were inappropriate for MH370 flight path modeling. The priors assumed were just that – assumed, and not based on any relevant sampled data i.e. previous 9M-MRO flights were not representative of a diverted flight. Bayesian analytics only work well with relatively solid priors.
@Victor
One possible explanation for Shah’s SIM flight:
Firstly, I don’t believe he was planning to fly toward McMurdo Station until fuel exhaustion. The distance from Kuala Lumpur to the turn back 30NM in front of DOTEN, and back to latitude N7.5 was judged by Shah to be roughly equivalent to the distance MH370 would be flying from Kuala Lumpur to IGOGU, and the FMT on 8th March. He used the SIM flight into the SIO to obtain the distance he could travel at a constant Mach, on the Jedda fuel allocation. He would then be able to work out a rough estimate of the distance he could fly into the SIO from IGOGU at similar constant Mach on MH370, taking the proportionate difference in fuel load between MH150, and MH370 (estimated, from previous flights) as a multiplier.
He could then draw an arc centred on IGOGU, radius equal to the estimated distance applicable to MH370, draw a second line for sunrise at takeoff plus 7.5 hours. Where the two line cross is the point to aim for IF he wanted to synchronise fuel exhaustion with sunrise.
Thus he would have simulated the MH370 flight, using the MH150 flight, would have left no trace of the proposed MH370 flight on his simulator, and laid a false trail in the direction of McMurdo.
@IG
Based on previous (acrimonious)discussions relative to the OI offer, I am convinced that you know what the offer is. Your comments betray that familiarity.
My current opinion relative to the “snag” is that Malaysia wants to architect a fee based on time and materials i.e. the fee would depend on the area searched as opposed to a fix fee. This structure would avoid the embarrassment of a windfall by OI. Of course, OI would then be in the position of acting like a Fugro, except without any guarantee of getting paid.
Looking at the Fugro effort, my conclusion is that they received about $100M (USD) for searching 120,000 km^2. A simplistic ratioing (ignoring the fixed startup costs) puts the equivalent value of 36,000 km^2 searched at roughly $25M to $30M. Close to my previous estimate.
@Victor “A crash 100 NM off the southern coast of Java should have produced debris in Indonesia, which never occurred. It also makes no sense that the plane would run out of fuel after such a short distance was traveled with so many airports that were reachable ……. I ask you again to reveal more details or your information will continue to be ignored.”
I accept no debris is strange but not unexpected considering the direction of flow up close to Java.
Its not such a “short distance travelled” in that it is the same time in the air as the other proposed flights.
My hands are tied. I am sure you would well know that confidences need to be kept.
This is a valid flight path, despite not meeting the apparent requirement of being an uncontrolled flight after ISBIX.
From 19:41 onwards the BTO’s accurately fit right through to the ditching and the BFO’s are a reasonable fit up to 22:41.
@Tim R
Victor, is correct. We need more. If you cannot provide it, you are relegated to the “whacko” category. Of course, that includes the IG based on recent discussions.
@DennisW
I also sense something, but that’s way better than nothing happening.
@Victor
I am curious as to why you put that red circle on the “2nd Arc Limits” slide, indeed, why you titled it that way at all.
I first assumed that you were plotting the start points for the three destinations, and were thus effectively saying “these are the maximum limits of the aircraft on the second arc” that should be considerd. If that were the case, there would be no need for the red circle at all, so why did you plot it ?
Just looking at it, it appears to be centered on either Nilam or Radar End, and the radius of the red circle from either would presumably be estimated ground speed times the time interval from either position until 19:41.
Could you:
(a) nominate the centre point and time, and
(b) nominate the effective ground speed used for the radius, and
(c) nominate the actual iintersection points (north and south) with the 19:41 second arc, and
(d) explain why you plotted it.
@Rob
Re: The Captain’s sim flight as an exercise in fuel planning.
The simulation program used by the Captain models a B777-200LR, an airplane with a higher empty weight, different wing and more powerful engines to the B777-200ER. Does that sound like the sort of tool you would employ for an exercise in fuel planning?
Moreover, we know from Victor’s and Yves’ paper that the fuel used on the recovered flight differs significantly from a recreation of what was ostensibly the same flight. The recovered data shows a 45% discrepancy to recreated fuel usage at 5N increasing to nearly a 65% discrepancy at 10N. Whatever the Captain was simulating/modelling it is highly unlikely that it was related anything even vaguely connected to fuel planning.
@TBill
“I also sense something, but that’s way better than nothing happening.”
I agree. Resuming the search is good thing. I remain pessimistic relative to the outcome. The area defined by the Iannello and Godfried McMurdo path is where the aircraft is, IMO.
Not to say that that the IG is not in the whacko category.
@ventus45: The second arc is the locus of points corresponding to the measured BTO value at 19:41. The starting locations for the great circle paths fall near (but not exactly on) that arc. Each starting track angle that I considered corresponds to a different starting latitude. As you change the starting track, the 19:41 position rotates around the arc. The starting positions at 19:41 don’t converge to a single point, if that is your question.
@Oleksandr
“P.S. Why would MH370 be following a great circle path that leads to an airport in Antarctica? Logic-wise?”
Conjecture of course but here is one possible reason- DOTEN to NZPG cuts nicely around Indonesian FIR air space boundary. This could have been important if the target hijack flight was e.g. MH150 hitting DOTEN at an earlier time of day when radar was operating. Various other implications if this theory fits the reason.
@sk999
“Were Antartica waypoints in the 9M-MRO navigation database, given the limited amount of memory storage in the AIMS-1 flight management system?”
Not a big limitation right? I use 78S67 oceanic waypoint shortcut for NZPG. With a little more complexity, any pin-point on the globe can be entered as a waypoint.
There are only 2 Waypoints actually on (or very close) to the 2nd Arc: VOCX and ISBIX.
The aircraft speed required from 18:28:14 UTC to be on the 2nd Arc at 19:41:03 UTC is:
(1) 173.8 knots for VOCX.
(2) 353.1 knots for ISBIX.
Most likely, neither case was a non-stop direct flight track:
(1) For VOCX the speed is too slow and hence your loiter theory.
(2) For ISBIX the direct route passes right over the tip of Sumatra and, if Indonesia’s radar was active, it would be seen as a threat.
But with an indirect route around Sumatra, ISBIX is reachable without a loiter.
This makes a small preference for NZSP above NZPG in my view.
On top of the “No Loiter” argument, you have outlined above the ease of entry for the NZSP option into the navigation system.
I favour the hot spot priority order:
(1) CSIRO.
(2) NZSP.
(3) YWKS.
(4) NZPG.
@Andrew. In a post on Sep 1st at 3:58 AM I asked you for an estimation of the internal diameter of the fuel line from the APU DC fuel pump to the APU. You kindly obtained an answer, at 8:14 PM on the same day, “I’m told the outside diameter of the APU fuel line is one inch (25.4mm – forgive me I was brought up on metric). If we say the inside diameter is 20mm……”
In thanking you for that I commented, “I assume they mean outside diameter net of the shroud in the forward section.”
While looking into another fuel question I have delved again into this. The attached 3 pages are applicable to the -200ER (the AMM manual pages on the -300ER are identical). Page 127 depicts a flexible rubber and kevlar line inside a shroud. Also from the sense of the description on page 126 and the diagram on page 123 the shroud extends over the whole length of the flexible line.
For that line to hold sufficient fuel for the APU to power the 7th arc log on it would need to hold a minimum 4.4 lbs, 2 kg, of fuel. For that it would need to be of at least 10mm internal diameter and that supposes all fuel in it would be drawn through by the APU. Yet should the 25.4 mm line you refer to in fact be the shroud, if you scale from that on p127, the outside diameter of the flexible line is less than 10mm. One would expect that type of tubing to have appreciable thickness.
Do you have access please to a -200 or -300ER parts listing which might specify the internal line diameter? Alternately could I again prevail upon you to ask your tech gurus whether they can confirm the flexible line’s external diameter is 25.4 mm or close to?
https://www.dropbox.com/s/t0y366qqakaqnwi/APU%20fuel%20line.pdf?dl=0
@ALSM. The meanwhile please lie back and think of England.
@Oleksandr: You might be interested in this new article that (in a very simplified way) discusses the data collected by the Cape Leeuwin hydrophone station as it relates to MH370. Neither of the two relevant signals is (statistically) close to the 7th arc.
@Paul Smithson
Re “@Dennis W and path-fitters. Asking my question another way. If there are “equally good” candidate path models (viz BTO error RMS) available as you rotate around 1941, why does the Bayesian pdf have a peak at all?”
I don’t class myself as an accomplished path-fitter, however it seems to me that the DSTG “hotspot” was determined as much by the assumed range of possibility cruising speeds on autopilot (as advised by Boeing) as it was by the BTO errors. The IG found the same thing when they modeled BTO/BTO RMS errors, first for LRC
cruise, and then updated for CI51 ECON; the effect was simply to shift the 7th arc crossing point a hundred or so NM further west. If I’m wrong on this, hopefully Richard will clarify. The range of paths are also limited by the endurance on the available fuel. Hence the peak at S38.
The orientation of the 2nd arc serves to constrain the 19:41 crossing point, in the east-west direction, if you don’t consider the loiter scenario, which the DSTG analysis didn’t.
The DSTG analysis did allow for changes in direction at each crossing, but found that a straight path was preferred, which for me at any rate prompts one of those “hmmmm” moments. The BTO rings turn out to be particularly amenable to straight line paths, suggesting to me that the plane most probably flew in a straight line after FMT.
If this wasn’t what your original question was asking at all, then please pardon my intrusion.
@Rob
Maybe even more the range of paths is depending on which altitude the plane was flown most of the time till the 7th arc.
F.i with a drop in altitude from FL350 to FL300 the range decreases with ~150Nm according @DrB’s ‘endurance/range table’ in two engine operative speed modes. Decreasing further when altitude drops further.
As far as I’m aware no one still knows at which altitude the plane flew most of the time till the 7th arc.
~150Nm is about 2 degrees latitude which is quite a lot when you want to define a search area.
@Rob said: The DSTG analysis did allow for changes in direction at each crossing, but found that a straight path was preferred
The posterior distribution shows a preference for straight paths because of the prior distribution they used for the number of manoeuvers. For instance, a delay of an hour, be it a holding pattern or excursion, would have required many manoeuvers of a particular type, and would be improbable because of the distribution assigned to the number of manoeuvers. The prior distribution was based on a study of a commercial flights, where planes tend to fly in near straight lines. There is no reason to believe that MH370 was flown like a typical commercial flight. People don’t seem to understand this. They jump to the conclusions without investigating the assumptions.
@Richard
I am in general agreement with your search area priorities. I would say:
(1) NZSP (or 180S CTH)
(2) CSIRO
(3) NZPG
(4) YWKS
Re: your ISBIX discussion – note that ISBIX to NZPG seems to go directly over Dordrecht hole area, which I see as one possible flight strategy. If so, I assume the pilot got to ISBIX late or had less fuel than expected, and knew that Dordrecht was non-reachable.
Therefore the alternative strategy I see is 180S to deep water beyond Broken Ridge due south of ISBIX, BEDAX, and OK, add VOCX.
NZSP (South Pole) I see as 180S CTH. I believe there is a visible wind impact in the data. which means the “Fig 3 red diamond” could be offset from Victor’s to center around 94.2E. I also think they need to be looking inside Arc7, whereas the lofty FL350 Arc7 is a little unfair (it shifts the search zone more outside Arc7).
@Richard
I favour the hot spot priority order:
(1) CSIRO.
(2) NZSP.
(3) YWKS.
(4) NZPG.
Thx. I was going to ask you about that. Personally, I have difficulty with the CSIRO hotspot.
The CSIRO claims relative to the air search are a bit annoying to me. The air search in the area they are “discarding” was started nine days after the aircraft went missing. I have no experience in ocean air searches, but people I have talked to out of Moffett AFB claim that significant dispersion and sinking would have occurred in that time frame.
The NZPG terminus that you and Victor modeled would be my first choice since there is actually an “evidentiary” pointer to it.
@DennisW: Two questions:
1) For 26.9S (NZPG path), how far along and across the 7th arc would you search, and why?
2) If not at 26.9S, where would you search next?
@Victor
I would assign equal boundaries to LNAV (along the arc) and BTO (orthogonal to the arc), +/- 40km each. Search area ~ 6400 km^2. Not much different than the 10000 km^2 assigned by OI (which I also think is a reasonable choice, BTW).
After that I would do the same for NZSP simply based on the ease of using it as a waypoint.
@DennisW: Would you consider searching a narrower width between the hotspots?
@Victor
Yes, that also makes sense IMO.
This, is a very interesting paper.
https://www.nature.com/articles/s41598-017-14177-3.pdf
I can’t help but notice, that E2 (see Figure 4 in the paper) is virtually due south (180 True) of UPROB.
The distance from UPROB to E2 is approximately 2,656 Nm.
At an average 480 knots GS, leg time = 332 minutes = 5 hours 32 minutes.
The event Time @ E2 is calculated to be between 00:25 and 00:31.
So, the time at Uprob would be between 18:53 and 18:59 (for 480 knots GS to E2).
Position E2 obviously does not gell with either the 6th or 7th Arcs, so, for the moment, ignore them.
Position E2 obviously would be impossible to reach for any FMT near Ache off the Radar / Lido slide, so, for the moment, ignore them.
Position E2 is however, within reach of a Southern FMT, at, or in the vercinity of, Uprob, which can be reached coming off a path from the 17:52 phone call at Penang, via Medan and Merim.
@Paul Onions,
I will answer as many of your questions as I can.
You said: “. . . what is the expected fuel remaining at Igari? Is this higher than the estimate in the Factual Information report?”
At IGARI near 17:22 UTC my Fuel Model V5.4 indicates 42.1 tonnes of fuel remaining. The revised Factual Information in Section 1.6.5 gives an estimated 41.5 tonnes (but no details of how this was done). Since we know that the ACARS fuel report was 43.8 tonnes at 17:07, the Factual Information estimate was for (43.8-41.5) = 2.3 tonnes in 15 minutes or 9,200 kg/hr. Frankly, that estimate cannot be correct. For instance, at LRC at FL350 and +10C the fuel flow at 17:07 at 218 tonnes total weight is only 6,934 with PDA = 1.5%. My best estimate is (43.8 – 42.1) = 1.7 tonnes in 15 minutes, or 6,800 kg/hr averaged between 17:07 and 17:21.
You said: “If the aircraft maintained CI52 and was 6nm south of Penang at 1752:35, where would the aircraft be at 1825:27? Would it be starting its turn at Nilam towards Sanob and exposing its Right High Gain Antenna?”
The ground speed using CI52 during this part of the route is too low to match the military radar track. At FL340 the TAS at CI52 is 483 knots, whereas my best estimate is about 498 knots +/- 5 knots. At M0.84 at FL340, the TAS is 297 knots, and this is what I use. This corresponds to the maximum operating Mach. Wherever they were going, they were in a hurry.
The aircraft location at 18:25:27 depends on the maneuver performed at about 18:22 (a 15 NM right SLOP, or possibly a turn to the right, or possibly a deceleration and a turn. Victor and I are studying this maneuver independently. Whatever the maneuver was, we do know the aircraft was near the 18:25:34 BTO arc (it is more accurately located than the 18:25:27 BTO arc).
You said: “And if it flew Nilam-Sanob-Banda Aceh, and then maintained HDG True, where would it end? Would it be the Bayesian Hotspot?”
I have never been able to fit an acceptable CTH route through Banda Aceh. I have found a good fit passing just west of IGOGU. If you go to my pubs list HERE and click on the link for 9 January 2017 you can find the details. This route ends on the 7th Arc at 34.75S. This location is in the northeastern lobe of the Bayesian probability function.
You said: “Is there fuel remaining at 7th arc? If yes, could APU have been on, resulting in the aircraft being past hotspot? Or the left engine was still operating with inoperative Left GCU and Backup Converter and the aircraft is within 100 NM radius of hotspot?“
Using my CTH route at 257 KCAS at FL350, estimated MEFE is at 00:29. This is a bit too long. Having the APU running might eliminate this issue, but then how do you explain the SDU reboot at 00:18? My understanding is that if the APU were running at MEFE, the SDU would not reboot, and therefore no transmissions would have occurred at 00:19. If I understand this correctly, the SDU reboot means that the APU could not have been running when MEFE occurred. In addition, if a restart of the left engine occurred, it must have been brief (less than several minutes and probably very much shorter than that).
@DrB
1. I agree that the Factual Information report estimate of fuel remaining at Igari (41.5t) is too low. It should be 42.2t.
2. Primary Radar is not very accurate when compared to Secondary Radar, especially at long range. The Primary Radar screen shot shown at Lido Hotel has time stamp of 1813:16 for Vampi. Thus from south of Penang to Vampi is 171 NM in 20.6833 min equals 496 knots groundspeed. Subtract the ~13 knot tailwind and TAS is 483 knots. Project this forward and 1825:27 is start of Left turn at Nilam towards Sanob, at the exact time when the Right High Gain Antenna is finally exposed to the satellite!
3. I get a really good fit with CTH through Banda Aceh from Sanob ending at Bayesian Hotspot.
4. APU already on, then left engine fuel starvation leads to momentarily depowering of Left main AC bus as the left engine spools down (yes this is different to what happens normally) Autopilot remains engaged, aircraft porpoises further south.
5. It is possible that Left GCU and Backup converter are both inoperative, such that Right IDG is supplying all the power to the main AC buses. When right engine failures, APU autostarts, creates log on, but left engine is still operating. Projectory of flight path is greater.
@Paul,
You said: “@Dennis W and path-fitters. Asking my question another way. If there are “equally good” candidate path models (viz BTO error RMS) available as you rotate around 1941, why does the Bayesian pdf have a peak at all?”
@Rob,
You said: “The BTO rings turn out to be particularly amenable to straight line paths, suggesting to me that the plane most probably flew in a straight line after FMT.”
The reason there are multiple solution for straight paths is that the satellite motion during the flight was quite small compared to the aircraft motion. Each “arc” of constant BTO is centered at the sub-satellite point (assuming a spherical Earth). Therefore, if the satellite were stationary, BTO would, in fact, provide zero information on the initial route bearing. There would be, in this case, complete rotational symmetry in the arcs, and only the BFO would provide very coarse information regarding the route bearing. Fortunately, the satellite moved during the flight, displacing the arc centers. Thus the arcs are not “parallel” (more accurately, concentric) to one another. This displacement of arc centers is what allows more precise determination of route bearing. In this particular case, a “straight” path was initially found to fit the BTOs quite well, and that led to initial (high-speed) estimates of endpoints in the 39S area. If you slow down, as needed to avoid excess fuel consumption, the straight solutions rotate counter-clockwise to the points Victor has shown. The errors in BTO are sufficiently large as to accommodate a straight path over a wide range of bearings (about 20 degrees) – and thus we see numerous solutions. The DSTG Bayesian analysis was weighted to favor fewer turns, and thus, its probability peak was at 38S and was quite broad. We also know the aircraft is unlikely to be located there because of the unsuccessful search.
Now, in the case of curved paths, the “eccentricity” (i.e., non-concentricity) of the arcs is much more constraining on the route bearing, with the result that there are very few solutions (perhaps one or two at most, I think). You can visualize this by shifting the centers of the arcs in your mind and noting the strong impact on arc-to-arc separation.
This non-concentricity effect does not imply one or the other solution is more likely to be correct. It does mean that for straight paths, other independent information, such as assumed waypoints, must be supplied in order to generate a precise 7th Arc location. For curved paths, no other assumption is required. The only curved-path solutions identified to date are very narrow indeed along the 7th Arc (a fraction of a degree). In that respect they have the advantage of not requiring an addition assumption regarding bearing.
@DrB said: The aircraft location at 18:25:27 depends on the maneuver performed at about 18:22 (a 15 NM right SLOP, or possibly a turn to the right, or possibly a deceleration and a turn. Victor and I are studying this maneuver independently.
If the aircraft was not following N571 after 18:22:12, it gets harder to predict what occurred. We have to consider changes in speed, track, and vertical speed to match both the BTO and BFO values. And more than one change in track might have occurred. If the speed was constant, the plane turned right to around 320° and was descending at about 600 fpm. If the plane was flying at constant altitude, it turned right to around 307° and decelerated to 372 kn (GS). Similarly, the BFO values at 18:40 are matched with various combinations of track, speed and vertical speed. What occurred between 18:22 and 19:41 is not at all straightforward to determine.
@Paul Onions said: APU already on, then left engine fuel starvation leads to momentarily depowering of Left main AC bus as the left engine spools down (yes this is different to what happens normally) Autopilot remains engaged, aircraft porpoises further south.
You have said many times on this blog and on Twitter that a transfer of power for the left bus from the IDG to the APU causes a momentary loss of power and a reboot of the SATCOM. On the other hand, we know that the SATCOM is designed to ride through this interruption of power. Your evidence seems to be PMDG777 simulations you have run. I have explained that you can not used MSFS to study transients that occur over a sub-second time interval.
Do you have any new evidence which supports your assertion?
This is a flight path further North that has a pilot in control til the end or at least til late in the flight
MH370 reached cruise altitude on route to Beijing, turned back over Malaysia and proceeded up the Strait of Malacca.
Say passed NILAM on way out into the Andaman sea.
Turned back towards Banda Aceh.
At say NOPEK turned towards BEDAX.
At BEDAX a decision was made to go South in a loiter off the coast of Sumatra.
Turned towards ISBIX.
Crossed the 19:41 BTO at 4°22N on a heading of 181°.
Reduced speed slowing through 19:41 to 370 kts and maintained this.
The speed at 19:41 was approximately 410 – 420 kts.
At ISBIX turned towards Cocos Islands.
Used a FBT at PCCNG onto a heading for Christmas Island.
MH370 could have ditched in the area from 8°S to 10°S near the 7th arc.
There was a possibility of disruption on the flight deck from near Cocos Islands onwards.
This could have meant there was no turn at Cocos Islands leading to overflight and continuing to a ditching further South as far as 22°S near the 7th arc.
From 19:41 onwards the BTO’s accurately fit right through to the ditching and the BFO’s are a reasonable fit.
In summary, MH370 could have ditched in the vicinity of the 7th arc anywhere from 8°S to 22°S with a more likely range for the ditching 8.5°S to 9.5°S.
@Victor,
Re: “You might be interested in this new article that (in a very simplified way) discusses the data collected by the Cape Leeuwin hydrophone station as it relates to MH370. Neither of the two relevant signals is (statistically) close to the 7th arc.”
Thanks for sharing this link. As I see @ventus45 shared full version, but I did not dive into details yet.
First impression is that E1 area is surprisingly close to the 7th arc, so frankly I don’t understand your comment that it is not. Just assume that the error in determining distance is twice higher than the authors claim.
Secondly, it is indeed close to the point I indicated around 1.5 years ago based on the intersection of the 7th arc with the ‘curve’ of possible sources based on HA01 and RCS data (for example, see my TN-ATT-Rev1.0 note).
Thirdly, Crivelli’s paper nearly confirms that Alec Duncan’s hypothesis about a possible origin near Maldives was wrong. Initially I stated this based on my analysis of Duncan’s plots, but at that time I faced groundless resistance.
Fourthly, water temperature affects sound speed, and this could contribute to a larger error (one would need to accurately take into consideration 3D temperature to eliminate errors associated with this effect).
Fifthly, waves generated by a seabed impact may also propagate in the seabed, not only in the water. This may affect the overall ‘picture’.
@TimR,
Re: “In summary, MH370 could have ditched in the vicinity of the 7th arc anywhere from 8°S to 22°S with a more likely range for the ditching 8.5°S to 9.5°S.”
No, it could not. 17°S is a firm threshold based on a number of drift studies and the barnacle forensics. More realistic multi-criterion northern boundary is 25°S.
@Oleksandr: The best estimate of the impact is about 535 km from the arc. That is well beyond range error.
On the other hand, if the range is wrong, the bearing might still be correct. Extending a path from HA01 over the range of angles of 301.6 +/- 0.75, and the acoustic path crosses the arc very close to the NZPG path. A plane turning left after the final satellite transmissions would put the impact site closer to the middle of that range.
This could be very interesting evidence.
@Victor,
Re: “The best estimate of the impact is about 535 km from the arc. That is well beyond range error”
My estimates show approximately 350 km from the center of E1 area (24.9S, 98.1E) to the 7th arc (26.87S, 100.87S) based on the plot in Crivelli’s paper. How did you get 535 km?
While I do not agree with underlying hypotheses leading to the suggested areas, I believe the crash site might be in one of them. Here are my thoughts with regard to the search priority:
(1) ‘NZPG’ zone: define a segment of the arc at its intersection with the acoustic signal ‘curve’.
(2) ‘YWKS’ zone: I think the whole segment from 28 to 30.5S is ‘suspicious’, but it is a lot larger compared to the ‘NZPG’ zone.
(3) ‘CSIRO’ zone: put it on a shelf.
(4) ‘NZSP’ zone: put it in a dust bin.
@Oleksandr “…….17°S is a firm threshold based on a number of drift studies and the barnacle forensics. More realistic multi-criterion northern boundary is 25°S.”
According to an article in the German newspaper Kieler Nachrichten, scientists from the GEOMAR-Helmholtz Institute for Ocean Research in Kiel completed a detailed drift analysis of their own in collaboration with colleagues in Great Britain
This study was done soon after the flapperon was found.
“We have traced back almost two million ‘virtual’ particles over a period of 16 months and 95% of all the particles tracked pass just below Java.”
These were unbiased calculations provided by qualified people without overt pressure being applied to comply with the official doctrine of a ghost flight into the SIO.
http://www.geomar.de/index.php?id=4&no_cache=1&tx_ttnews%5btt_news%5d=3972&tx_ttnews%5bbackPid%5d=185&L=1
@TimR,
Re: “According to an article in the German newspaper Kieler Nachrichten, scientists from the GEOMAR-Helmholtz Institute for Ocean Research…”
GEOMAR did not consider wind in their study. I believe this is a primarily reason why their result is dramatically different from the results of a dozen of other drift studies. If you wish, you can compare it with MeteoFrance, which is also a reverse drift study, and it includes wind/no wind plots.
@Oleksandr Here is another drift study that shows a high probability that debris originated up towards Java
Météo France, the French national meteorological service.
After running hundreds of thousands of simulated drift trials under varying assumptions, Pierre Daniel, the author of the Météo France study concluded that if the piece floated as its Lepas population suggests, that is to say submerged, then it couldn’t have started anywhere near the current seabed search area. Its most likely point of origin would have been close to the equator, near Java at latitudes from 9S to 23S.
http://031c074.netsolhost.com/WordPress/wp-content/uploads/2016/05/Pierre-Daniel-report.pdf
@TimR,
Have you read my comment above? What does Danil’s report show for the scenario where wind was included?
@Victor, Dr B, Dennis W.
There are several reasons that I err towards an early turn, essentially over Banda Aceh. One of these is that if you fit a third order polynomial to the BTOs ring 2-7 or even 2-6, and use this to predict “what would BTO have been at 1825, 1828 if it was produced by the same pattern as produced 2-6”. The answer is that it predicts a value very close (within about 100 microsecs) of values observed 1825-1828. Even closer when you strip out the delta satellite-Perth element. To me, this suggests to me that if 2-6 was a “straight course” then that straight course should lead back nearly to 1828, not a long ways west of it.
Does that mean anything to you, or just serendipity?
:
1) There’s a plausible accident-scenario reason for doing so [if, like me, you are wedded to that line of thought]
2)
\
@Paul Onions,
You said: “The Primary Radar screen shot shown at Lido Hotel has time stamp of 1813:16 for Vampi.”
I don’t know where you get that time stamp. I have looked long and hard at the Lido images, and all the labels near VAMPI are unreadable to my eyes.
You said: “I get a really good fit with CTH through Banda Aceh from Sanob ending at Bayesian Hotspot.”
Please post the details so others can evaluate it.
Your point about the right engine IDG possibly powering the left AC Bus at right engine shutdown is interesting, but I am not knowledgeable in this area. Perhaps Andrew and Victor might provide their opinions on this scenario. If something like that happened, and if there was sufficient fuel to continue operating the left engine for about 7 minutes longer, as expected, then why did the IFE not log on at 00:21 since the aircraft should still have been in controlled flight and the APU should still have been running then?
oops. sorry for the orphans at the bottom. incomplete edit again. past my bedtime.
@Paul S
I reproduce your third order predictive fit, but I am struggling to understand what that means relative to a flight path. I need to noodle that some more I guess.
@DrB
You can see the time stamps on Victor’s earlier blog article about Lido
http://mh370.radiantphysics.com/wp-content/uploads/2017/03/LidoImageTimestamps.png
@TBill
I believe that was added to the graphic by a third party, and not included in the slide shown at the Lido Hotel.
@PaulS
“There are several reasons that I err towards an early turn, essentially over Banda Aceh. One of these is that if you fit a third order polynomial to the BTOs ring 2-7 or even 2-6, and use this to predict…”
…Paul what are your other reasons? in case that one does not work out? I await the responses otherwise you or Dennis have to show me the calcs. It has been suggested BFO would be a straight line for straight path, but I do not agree with that either. I think you have a certain trend incoming towards the satellite, and then moving away from it (after about 19:50).
@ Paul
I don’t think the 3rd order polynomial argument is solid proof of a straight flight from 18:xx. The same polynomial can also show that the derived BTO at IGARI would also fit quite nicely, and we know pretty conclusively that the path wasn’t straight from there.
I remember discussing the polynomial question with you a couple of years ago in relation to some other potential flight paths.
On the otherhand constructing the 3rd order polynomial in this manner does illustrate a couple of other points, i.e. one can derive the time of closest approach to the sub-satellite position, and then with a bit of spherical geometry one can estimate the average ground speed between 19:41 and 20:41 [assuming the path is relatively straight].
It is also possible, in my view, to reverse engineer the BTO for a hypothetical position at some time earlier than 19:41, say 19:01 [but not as early as 18:28] and then assuming this position to also sit on a relatively straight path, determine it’s location. One is left then with a lesser time interval to ponder over, i.e. the time between 18:28 and say 19:01, and to try various track and path options that will fit the geometry.
Of course, we don’t know that the path was indeed straight from 19:01, but it does provide an interesting possible point to help fill in the time gap.
@Brian. I’m not still banging that old drum.
In this case, I’m pointing out that backward extrapolation of a low order polynomial curve fitted to the BTO values 1941 onwards turns out to be a very good predictor of BTOs at 1825-1828. These are most certainly not the same as BTOs at position IGARI or even straight path from IGARI southward.
@VictorI
Assuming one of those routes was taken (NZPG, NZSP, YWKS) those locations had to be deliberately and purposefully selected by a pilot who knew there was not by far enough fuel to reach those destinations.
It makes no sence imo a pilot makes such a decision without a specific reachable destination in mind.
This destination was maybe somewhere near along one of those great circle routes within fuel range.
But if he selected one of your routes/waypoints he could as well have selected a direct route/waypoint to/near the destination he had in mind.
This makes more sence imo.
Why select NZPG, NZSP or YWKS if you know you cann’t reach them anyway?
After all the planning and effort/risk at- and after IGARI?
Imo if you take those three routes seriously you have to assume the flight was planned from beginning till end. Am I right here?
And imo if so, he must have had a specific end-destination in mind also.
Maybe along one of those routes. But more probably imo a selected waypoint near one of those routes he knew he could reach with the fuel on board.
Just flying to NZPG, NZSP, YWKS till fuel exhaustion makes no sence in a well planned scenario which it shows all the signs of imo.
@Ge Rijn: If the pilot wanted to remain in LNAV mode following a great circle without reaching a route discontinuity, he would need to select a final waypoint that was with certainty beyond the point of fuel exhaustion. NZPG, NZSP, and YWKS are possibilities. The sim data is consistent with NZPG as the destination. If traveling as far south as possible (after a delay) was the objective, then NZSP is a viable candidate. We don’t know what the intention was for the flight south, nor how he implemented that intention. I think flying towards a distant waypoint remains a viable candidate. I don’t dismiss other possibilities.
@Paul Smithson: The BTOs might follow a progression back to 18:25, but the BFOs do not. To consider a path with no major turns or changes in speed starting before 18:25 requires us to reject the radar data so that the position is much further north on the arc at 18:25 and traveling to the south. We also need to impose a climb at 18:28 to match the BFO. Considering that there are (many) paths matching the satellite data that are also consistent with the radar data, it is hard to justify rejecting the radar data.
It is noteworthy that the progression in BTO you see starting at 18:25 is related to the observation that the satellite declination (latitude) and the BTO seem to be related, i.e., the minimum of one is close to the maximum of the other. I’ve thought a lot about this, and I have no explanation other than it’s a coincidence. I know you’ve also studied this in the past.
Let me make a more generalized statement about coincidences. We’ve all studied the sparse data in so much detail that we recognize patterns that we often use to support particular scenarios. Some examples are the alignment of sim data points with McMurdo Station; the relationship of satellite declination to the BTO; and the identification of satellite images that support a particular drift model. Since flight paths that make use of these patterns suggest different impact points, we know they can’t all be correct. The challenge is to identify which patterns are likely to be correlated and not just coincidental. On this matter, there is considerable debate.
@VictorI
I also think flying towards a distant waypoint like NZPG (or the others) remain viable candidates but only because one of them brought him near to his specific destination before final fuel exhaustion.
Entering a direct waypoint to a near specific destination within fuel limits along those routes makes more sence imo.
There would be no route-discontinuity till after this final waypoint.
To me it just makes no sence why a pilot would enter NZPG, NZSP or YWKS and then wait for hours till fuel exhaustion and the plane to crash considering all the other information and what happened before ~18:40.
Imo there must have been a specific end-point/area if NZPG, NZSP, YWKS or another route was chosen.
@Ge Rijn
To me it just makes no sence why a pilot would enter NZPG, NZSP or YWKS and then wait for hours till fuel exhaustion and the plane to crash considering all the other information and what happened before ~18:40.
I am with Victor on this issue. Since the terminus on the 7th arc coincides with fuel exhaustion, I don’t see how it could have been a premeditated destination. The fuel models developed by DrB, Victor, Boeing, and others are not at all trivial. I doubt Shah could have predicted fuel exhaustion with sufficient accuracy for it to be aligned with a particular 7th arc location.
@Victor
It’s worth noting, you would have noticed, that MH150 scheduled takeoff time is mid afternoon local time. And would there be a 3 man flight crew for an 8.5 hour flight?
@Ge Rijn
@DennisW
re. “to me it just makes no sence why a pilot would enter NZPG, NZSP or YWKS and then wait for hours till fuel exhaustion and the plane to crash considering all the other information and what happened before ~18”
Dennis, I’m also with you and Victor on this issue.
@DennisW
If all planned he knew the amount of fuel he had available.
If too much before reaching his destination he could have loitered for a while to burn fuel (which is common to do before an expected crash landing) or jettison fuel at the end to avoid possible explosion and fire on impact.
And detection from space and a large debris field.
If Shah was at the controls he would have known exactly what his range was.
The 7th arc is only the outcome not an intention.
@Ge Rijn
The 7th arc is only the outcome not an intention.
I agree with that. I don’t think that there was any intended terminus.
@DennisW
You point out the difference in thoughts quite well.
The intended terminus defined the 7th arc outcome imo.
Not the other way around which makes no sence.
@Ge Rijn
I am relatively comfortable with the following:
1> Shah diverted the plane for a specific reason (not suicide).
2> There was a loiter West of Penang related to 1> above.
3> The specific reason did not work out.
4> Shah pointed the plane South per the rehearsal on his simulator.
5> The plane ran out of fuel and plunged into the ocean per Exner.
6> The surface search was started after the debris dispersed/sank.
@Ge Rijn: You are right. It makes no sense. Antarctica was not his destination.Without an intended terminus setting a true track would have been easier.
@Ge Rijn @DennisW @Rob
I agree partially with Ge Rijn. For example, instead of SPOLE, the pilot could enter a intermediate waypoint such as 3294S. This tells you if you have enough fuel to get over the Broken Ridge. No reason a pilot could not switch to oceanic waypoints temporarily to get fuel estimates. One hypothetical purpose for Z’s simulation work could be to get a feel for manual waypoints.
I personally use the shareware add-on “Flight Sim Commander”, which puts my FS9 flight path on Google Earth as I fly, so I can target features such as Broken Ridge. Then I can shift over to SkyVector once I see what I am doing.
The reason I do the Google Earth overlay is that, early on I adopted someone else’s hypothesis that the flight logic may have been to ditch in a deep. mountainous hard-to-find location.
If it was “Z did it”, I see at least two explanations:
(1) Suicide with intent to decoy on flight path and hide crash site, in which case the simulator may give clues as to the out-and-back decoy plan
(2) Per Dennis some kind of plot, in which case a hold pattern makes sense
In reality I mostly go with Option#1 as I have adopted Ewan Wilson’s book Goodnight Malaysian 370 as my hypothesis, and I merged that hypothesis with another book saying hiding in the undersea mountains was a possible strategy.
@DennisW:
RE “The plane ran out of fuel and plunged into the ocean per Exner.”
Why did he rehearse fuel exhaustion twice on his simulator?
@Rob
“It’s worth noting, you would have noticed, that MH150 scheduled takeoff time is mid afternoon local time. And would there be a 3 man flight crew for an 8.5 hour flight?”
Yes probably 3 pilots to Jeddah. You know they added 2nd later Jeddah flight, right? that one was at nite, but pretty sure it would been several hours earlier than MH370 getting up Malacca Straits, so radars might have been more active.
@TBill
No, I didn’t realise it was a night flight, and Victor was too polite to embarrass me by pointing it out. Three man crew would have made it much more difficult, if not impossible for Shah to hijack MH150 in the way he hijacked MH370.
Which prompts the question “what was the object of the exercise, choosing MH150 to simulate two days before he sat in the left hand seat on the real thing?” What aspect of the SIM exercise did he want to check out or verify on an actual flight? If no one can come up with a persuasive operational reason for why he needed to do it, then we are left with “to lay a false trail” as the most probable.
This is a very important issue as far as the search is concerned. If the object of the exercise was to lay a false trail, then it would give us an insight into Shah’s thinking as he formulated the plan. To be more specific: 1) it would suggest he assumed primary radar would reveal his route up the Malacca Straight, after the event (ie when the military got round to checking the radar). 2) He was planning to let the outside world know that he flew until fuel exhaustion with the 2nd logon event. 3) He knew we would probably deduce that he had flown into a remote part of the SIO.
@TBill
Continued: The idea was to give the impression that he had originally planned to hijack MH150, but during the flight, was thwarted for some reason. He subsequently succeeded with MH370
@TBill
Continued (2) The idea was to give the impression that he had originally planned to hijack MH150, but during the flight, was thwarted for some reason. When he succeeded on the second try, with MH370, the simulator would show us where he was intending to fly.
@Oleksandr
Why did he rehearse fuel exhaustion twice on his simulator?
The first simulation was to see how he would react to a nose wheel explosion.
@TBill
In reality I mostly go with Option#1 as I have adopted Ewan Wilson’s book Goodnight Malaysian 370
Hard to put “reality” and “Option#1” in the same sentence.
Wilson’s book was written and published before the flaperon was found, and before the information on Shah’s simulator was generally known. Wilson’s book is generally regarded as cheap shot to make a few bucks.
A suicide scenario cannot be reconciled with a loiter. The loiter is needed to explain the ISAT data between 18:25 and 19:41 as well as the absence of wreckage in the primary search area.
@DennisW
Talk about cheap shots. The only new evidence since Sept_2014, that was not discussed in Wilson’s book is yes the debris, which is consistent with his scenario.
“A suicide scenario cannot be reconciled with a loiter.”
Sure it can. Turning left at Banda Aceh is a very strange flight path, does not seem very likely to me. You are campaigning for your scenario. It would however be interesting to hear from Ewan Wilson if his views have changed.
@TBill,
You are campaigning for your scenario.
Definitely not. I could actually not care less what anyone thinks about my suggestions relative to MH370.
@Victor,
Earlier I asked you: “How did you get 535 km?”.
Either I am missing something, or there is a mistake in the full paper, link to which was posted by @ventus45.
Extract from the full paper:
“E1: 301.4 ± 0.4°, 1900 ± 200 km from HA01, centred at −23.662°, 96.676°”
Now compare it with Figure 4 in the same paper. The center of E1 zone is clearly around 25S, not 23.6S. Furthermore, the distance from HA01 to −23.662°, 96.676° is 2100 km, not 1900 km. It appears that the figure is consistent with the claimed distance of 1900 km, but the reported center of E1 area is not.
What do you think?
@Oleksandr
I also could not reconcile the propagation times in the paper with the speed of sound in salt water. Of course, the time of the E1 event is not compatible with the termination of the flight.
@Oleksandr: I averaged the coordinates of the HA1 sensors to get -34.891540,114.14130, and used the bearing of 301.6 +/- 0.75 to determine the 7th arc crossings. I did not use any data from the figure.
@Rob
Hard to say. It could be argued the simulator cases were indeed intended for a Jeddah flight plan, and so that is why the plan was later modified for the MH370 flight.
@Dennis,
Re: “The first simulation was to see how he would react to a nose wheel explosion.”
I think you confused me with Gysbreght, who asked relevant question.
But generally I think your list is a total mess:
1> Shah diverted the plane for a specific reason (not suicide).
Ok as an assumption.
2> There was a loiter West of Penang related to 1> above.
Here nonsense starts. What kind of loiter? What do others do during this time? You mentioned negotiations – by what means? What kind of negotiations? Any political claimants would attempt to attract as much media as possible. Money? Why did he need to go to the Malacca Strait for such a purpose, why take such a risk? At least 4 radars were supposed to track him there; how would he know that all of them would fail? Why did he need to switch off the SDU? Why did he need to switch it on again? Why was the first BFO in 18:25 login sequence correct? Why would he fly manually up to Penang?
3> The specific reason did not work out.
Ok. Then what? He was upset and decided to kill 200+ innocent people?
4> Shah pointed the plane South per the rehearsal on his simulator.
This is equivalent to suicide. Why South? To meet antipode of Santa Claus? Why would he need rehearsal for this?
5> The plane ran out of fuel and plunged into the ocean per Exner.
What is to do with Exner? If a plane runs out of fuel, it plunges, per Sir Isaac Newton.
6> The surface search was started after the debris dispersed/sank.
I am not sure what you tried to say. The flaperon, RR fragment were still floating, as we know. The engines would have sunk. Mangosteen would get rotten. Then what?
@Victor,
Re: “I averaged the coordinates of the HA1 sensors to get -34.891540,114.14130, and used the bearing of 301.6 +/- 0.75 to determine the 7th arc crossings. I did not use any data from the figure.”
So, what center of E1 area did you assume in your estimation? And what are your coordinates of the 7th arc crossing?
But this does not address my latest question with regard to the paper: the authors stated 1900 km from the center of E1 to HA01, while I am getting 2100 km if I use the position indicated by them.
@Oleksandr
3> The specific reason did not work out.
Ok. Then what? He was upset and decided to kill 200+ innocent people?
When a negotiation fails you have to carry out the “what if” in order to establish credibility for future negotiations. Like an employee walking into my office and threatening to quit without a raise. My reaction was always to dial for an exit interview with HR. Plus that, it was fun to fire an engineer.
4> Shah pointed the plane South per the rehearsal on his simulator.
This is equivalent to suicide. Why South? To meet antipode of Santa Claus? Why would he need rehearsal for this?
Not at all equivalent to suicide. Simply making good on the threat.
5> The plane ran out of fuel and plunged into the ocean per Exner.
What is to do with Exner? If a plane runs out of fuel, it plunges, per Sir Isaac Newton.
Agree. Simply recognizing that Exner has been strongly associated with this end of flight physics.
6> The surface search was started after the debris dispersed/sank.
I am not sure what you tried to say. The flaperon, RR fragment were still floating, as we know. The engines would have sunk. Mangosteen would get rotten. Then what?
Simply pointing out that expectation of finding a significant debris field after nine days of elapsed time is not realistic.
@Dennis,
Re: “I also could not reconcile the propagation times in the paper with the speed of sound in salt water. Of course, the time of the E1 event is not compatible with the termination of the flight.”
In this regard I am always implying seabed impact, not surface impact. I have not heard any strong argument against it. Of course E1 is compatible with such an event. Right now the question is whether the center of E1 is 350 km away from the 7th arc, or 530 km.
@Oleksandr
In this regard I am always implying seabed impact, not surface impact. I have not heard any strong argument against it. Of course E1 is compatible with such an event. Right now the question is whether the center of E1 is 350 km away from the 7th arc, or 530 km.
OK. That could well be compatible with the time and propagation speed.
@Dennis,
Re: “When a negotiation fails you have to carry out the “what if” in order to establish credibility for future negotiations. ”
Has he succeeded in establishing credibility for future negotiations?
Re: “Not at all equivalent to suicide”
Is not steering the plane to where no landing place exist equivalent to suicide?
@Oleksandr
Has he succeeded in establishing credibility for future negotiations?
Absolutely, IMO.
Is not steering the plane to where no landing place exist equivalent to suicide?
Of course not. Suicide is a completely different notion in the context of, by way of example, a suicide bomber or a kamikaze pilot. You are sacrificing your life for a cause. Not committing suicide due to some personal emotional issue. You should know better than that. You are word-smithing.
@DennisW If your scenario is true, Z must have known that failure was a very real (likely) outcome. Would he not have left something behind that would establish his intentions to others? He would have known that while the Malaysian officials may be dishonest, they are not stupid. They would be able to divert blame unless there was something concert to implicate them. As it stands now, they do not seem to be any worse off.
What did Z accomplish? A very bad plan executed by an apparently very careful man?
Except for that consideration, I think your scenario fits the ‘facts’ (radar data, satellite data, debris, behavior of the Malaysians, …). But I suspect there some big pieces of the puzzle missing (and perhaps a few false pieces in the pile).
@Gysbreght,
You said: “@Ge Rijn: You are right. It makes no sense. Antarctica was not his destination.Without an intended terminus setting a true track would have been easier.”
I agree. A magnetic track is even easier to set than a true track.
@Shadynuk
Yes, all well said, IMO.
According to the paper, the hydrophones at HA01 are arranged in a triangular shape spaced by around 2000 m and located at the following coordinates:
Channel 1: latitude −34.89299, longitude 114.15398, depth 1385 m = 4,543 feet
Channel 2: latitude −34.89848, longitude 114.13385, depth 1473 m = 4,831 feet
Channel 3: latitude −34.88316, longitude 114.13608, depth 1419 m = 4,654 feet
My Eye Fitted / Plotted “Centroid” of the array is:
Centroid: latitude -34.82344, longitude 114.14284, depth (google earth)1273 m = 4,176 feet
See Image:
https://www.dropbox.com/s/unu8a32rxr2i4ui/CTBTO%20HA01%20Location.png?dl=0
@ventus45: See my coordinates for HA01 above. Your latitude is incorrect. Perhaps you have a typo.
@TBill: I looked at the case where 45S,104E was entered as the final waypoint, which is which is close to the coordinates for simulator data sets 45S1 and 45S2. The crossing of the 7th arc is around 28.3S. This seems like a candidate path. Perhaps McMurdo was entered as the destination in the simulator session, but the coordinates 45S,104E were extracted from the session and used for MH370.
@Victor
I don’t know how thw wrong latitudes got in there (I was cutting and pasting from a list) but a major boo-boo none the less.
I hope this one is correct !
https://www.dropbox.com/s/0r01qvvyxq59v3i/CTBTO%20HA01%20Location.png?dl=0
@Victor
A lot is being built around the contention that 10N and 45S1 are joined directly despite a number of factors that suggest that that may not be the case. For instance, it appears that none of the other data points are joined directly; 2N to 3N requires a left turn off the runway heading and routes via at least one intermediate waypoint; 3N to 5N routes via an intermediate waypoint and requires a subsequent right turn; 5N to 10N ostensibly routes via at least three different intermediate waypoints and requires something like four separate changes of track.
Further, as you know, the airplane’s heading at 10N is 255.5°. As others have picked up on before, that makes 10N “unusual” in that the airplane’s headings at the preceding data points are consistent with where the airplane appears to go next; 2N is aligned with the runway heading, 3N is aligned with R467 and 5N is aligned with VAMPI. Not so 10N, when you extend 255.5° from 10N it does not take you to 45S1, it takes you pretty much directly to Katunayake/Bandaranaike International Airport at Colombo (VCBI), Sri Lanka.
Accordingly, we might well ask, was VCBI an intermediate point between 10N and 45S1?
As you’re probably aware, VCBI is not only an en-route alternate for traffic crossing the Bay of Bengal, INOP flying time from it together with Chennai (VOMM), India, Medan (WIMM), Indonesia and Phuket (VTSP), Thailand define the ETOPS segments of flights crossing the Bay of Bengal. Interestingly (or otherwise), 10N is very, very close to the WIMM/VCBI Equi-Time Point (nil winds), being 640 nm to VCBI and 648 nm to WIMM. (10N is also quite close to the WIMM/VOMM ETP being about 615 nm from VOMM.) The WIMM/VCBI ETP is an important consideration for ETOPS across the Bay of Bengal; it is referenced in two MAS B777 ETOPS simulator training exercises. Coincidentally (or otherwise) the Captain had been the Type Rating Examiner for ETOPS simulator training (ETPS77S6) on 16 January and was rostered to do so again on 13 February (ETPS77S1). In fact he was rostered on as the Type Rating Examiner for significant block of simulator training (5 sessions over 9 days) commencing on 8 February. That might raise the possibility that he was reviewing simulator training rather than MH150.
Any old how, in looking for any other indications that the airplane may have been heading to VCBI from 10N rather than directly to 45S1, I started looking at the sim data again and stumbled across the “Avionics.0” section. The data labels and values from 2N are as follows:
[Avionics.0]
CommlACtive=122.950
CommlStandby=118.000
Comm2Active=119.900
Comm2Standby=121.700
NavlActive=113.40
NavlStandby=110.60
OBS1=338
Nav2Active=113.40
Nav2Standby=109.60
0BS2=315
Transponder=1200
ADFActive=353
ADF2Active=281
ComTransmit=l
ComReceiveBoth=False
AudioNavlListen=False
AudioNav2Listen=False
AudioMarkerListen=False
AudioDmeListen=False
AudioAdfListen=False
AudioAdf2Listen=False
I’ve inferred that the labels Comms1 and Comms2 probably equate to VHF L and VHF R, Nav1 and Nav2 probably equate to VOR L and VOR R and ADF and ADF2 equate to ADF L and ADF R.
I’m guessing that all of the 2N values are “default” values as they seem to correlate quite nicely with what you’d expect for the airplane’s first flight out of Boeing’s Everett plant at Seattle;
Comms1Active 122.95 Unicom SEA
Comms1Standby 118.00 D-ATIS SEA
Comms2Active 119.90 Seattle Tower
Comms2Standby 121.70 Seattle Ground
Nav1Active 110.30 ??
Nav1Standby 110.60 PAE VOR/DME (PAINE)
Nav2Active 116.80 SEA VOR/DME (SEATTLE)
Nav2Standby 109.60 TCM VOR/DME (McCHORD)
Transponder 1200
ADFActive 353 RNT (RENTON)
ADF2Active 281 HPK (PARKK)/SZ (SEATTLE PARKK)
When you review the settings across the captured data points you find that while the Comms and ADF selections do not change, interestingly (and perhaps instructively), the Nav1Active and Nav2Active settings do, and for the most part, they make “sense” for the airplane’s location, as detailed below:
3N
Nav1Active 114.70 which is the VBA VOR/DME (BATU ARANG)
Nav1Standby 110.60 Default
Nav2Active 109.50 I haven’t been able to identify this one yet
Nav2Standby 109.60 Default
5N
Nav1Active 113.00 MDN VOR/DME (MEDAN)
Nav1Standby 110.60 Default
Nav2Active 116.20 VPG VOR/DME (PENANG)
Nav2Standby 109.60 Default
Then we come to 10N which, bear in mind, sees the airplane pointed at Colombo;
10N
Nav1Active 116.90 PUT VOR/DME (PHUKET)
Nav1Standby 110.60 Default
Nav2Active 114.10 KAT VOR/DME (COLOMBO)
Nav2Standby 109.60 Default
That makes me suspicious that VCBI had been selected as the destination airport on the Arrivals Page (doing so should invoke the Procedure Autotuning function for the Navigation Radio Page and select the arrival airport VOR/DME). However, because virtually nothing related to this bloody mystery is not conjectural, 114.1 is also the frequency for the VPL VOR /DME at Langkawi (WMKL).
45S1 is perhaps equally as curious;
45S1
Nav1Active 113.40 BAC VOR/DME (BANDA ACEH)
Nav1Standby 110.60 Default
Nav2Active 113.40 BAC VOR/DME (BANDA ACEH)
Nav2Standby 109.60 Default
I’m not sure how you get both Nav channels tuned to the same NAVAID but those settings are interesting.
Any old how, if you join all those breadcrumbs (viz 10N – VCBI – WITT – 45S1) you end up with a distance of around 4640 nm, and that distance has got to be a reasonable fit for exhausting the 62,700 kgs of fuel that the airplane had onboard at 10N.
So, a couple of questions arise;
Does the PSS B777 sim program model the real airplane’s FMC VOR autotune function? Or do NAVAIDs need to be tuned manually?
In the course of your and Yves’ recreation of a flight connecting 2N, 3N, 5N, 10N and 45S1/2, did you happen to note/record the Nav1 and Nav2 settings?
@Mick Gilbert
That is very interesting.
I am particularly curious about the 5N settings.
5N
Nav1Active 113.00 MDN VOR/DME (MEDAN)
Nav1Standby 110.60 Default
Nav2Active 116.20 VPG VOR/DME (PENANG)
Nav2Standby 109.60 Default
Why set MEDAN VOR/DME on Nav1 Active, when it is presumably behind you, and you (presumably) have no intention of flying “over” Sumartra in the first place ? It does seem a bit odd, without a “reason”.
Perhaps Victor and Yves’ could recreate the flight connecting 2N, 3N, 5N, 10N and 45S1/2 AGAIN, and SAVE ALL the Nav1 and Nav2 settings ?
@ventus45
The reason that navaids that are off track (and even “behind” you) is relatively straightforward. As has been explained to me, enroute the FMC autotune function will select in-range navaids for best position orientation (it uses the data to compare with the airplane’s calculated position). Where there are a number of navaids to choose from, the FMC will select ones that are separated by about 90° in bearing as that gives you the best resolution of your current position. 5N to MDN is 180° and to VPG is 085°; they are almost ideally located for the purpose of a positional fix.
@ventus45
Apologies, that first sentence should have read “The reason that navaids that are off track (and even “behind” you) are selected is relatively straightforward.”
@Mick. That’s very interesting. Does the frequency 113.4 tell us which radial that is? And does that make sense as a fly-by last auto-tune?
@Paul Smithson
Paul, if there’s radial/directional data buried in there somewhere I can’t spot it. Without understanding how the PSS B777 Professional flight sim program models the airplane’s actual FMC navaid autotuning function it’s difficult to infer much about flybys, overflys, etc. The dual selection of BAC at 45S1 is curious though. If the airplane flew 10N to 45S1 direct with the autotune function operating I would expect to see 114.1 (CC88 COCOS ISLAND) as a tuned value.
In the post above, Victor Iannello said:
“After some email exchanges with the ATSB, I was surprised to learn that the ATSB has additional data values from the recovered flight files that were omitted from the data sets that were provided in the RMP report. In particular, there is a section of the flight files in which the date and time of the simulation session are stored. These data values tie the date of the simulation to February 2, 2014. Also, the time values show that the chronological order of the data sets matches a flight departing KLIA, flying over the Malacca Strait, continuing past the Andaman Islands, turning to the south, and exhausting fuel in the SIO, in the same order that the progressively depleting fuel levels suggest. The time values also indicate that the flight session lasted for about one hour. This confirms that the position and fuel levels were modified during the simulation, just as Yves Guillaume and I had concluded in our paper.”
The distance from KLIA at 2N, via 3N, 5N, 10N to 45S1 is about 4250 NM, about 9 hours of simulated flight time. I don’t think the simulator session that lasted little more than one hour involved simulated flight between those locations. Rather, the airplane was positioned at those locations, fuel levels and other flight parameters were manually changed and .FLT files were saved. About nine minutes per saved .FLT file.
An interesting question is how the player could have known that location 45S1 was close to a great circle path between location 10N and McMurdo. In all files the [Autopilot.0] field indicated the autopilot was not engaged, and the [ATC_Aircraft.0] field indicated 0 waypoints with 0 next waypoints.
@Mick Gilbert: First, regarding the heading at 10N, as you know, the plane was turning as indicated by the 20° bank. What we KNOW is that the plane did not roll out of the turn at that point. Therefore the heading had to be greater than 255.5°. I have no idea why people continue to extend the path in this direction and expect it to have meaning.
I would be amazed if the pilot was adjusting the navigation frequencies. He would have to go to a screen in the CDU and make changes. There’s no reason to do this. As people here have explained many times, navigation occurs using three sources: GPS, inertial, and nav radio. At any one time, whichever is considered most accurate is used, which is typically GPS. Radials are NOT flown, for instance. And it doesn’t matter if the nav aid is behind or ahead of the flight path.
I would be very surprised if the nav radio frequencies selected by the FMC are related to a future waypoint. They are selected by the proximity to available nav aids, not the destination selected. And I am not even sure the values you report have any significance because there might be other values in the PSS section of the flight files (not part of the fragments we have) that are the true indications of what nav aids are autotuned. I’d have to check to be sure.
Yes, I have saved the data sets when I recreated the sim flight. At some point, I might go back and check, but I see no indications that links anything to Colombo. And if the plane was moved ahead along the path the way I suspect, the nav aid might not reflect the current position, but where it was before the move.
@Mick Gilbert
@Victor Iannello
Thanks for explaining the VOR/DME selection criteria.
@Gysbreght said: Rather, the airplane was positioned at those locations, fuel levels and other flight parameters were manually changed and .FLT files were saved.
Yes, I have been saying this for a year.
An interesting question is how the player could have known that location 45S1 was close to a great circle path between location 10N and McMurdo.
As explained multiple times before, the path from the flight plan appears in the MAP window. The user would simply move the icon forward along the path.
In all files the [Autopilot.0] field indicated the autopilot was not engaged, and the [ATC_Aircraft.0] field indicated 0 waypoints with 0 next waypoints.
As explained multiple times before, those values in the Autopilot.0 section of the flight file are meaningless as they are superseded by values in the PSS section of the flight file, which we don’t have.
@Mick Gilbert said: If the airplane flew 10N to 45S1 direct with the autotune function operating I would expect to see 114.1 (CC88 COCOS ISLAND) as a tuned value.
Not if the plane was close to BAC before it was moved forward on the path to 45S1.
@Victor Iannello: “As explained multiple times before, those values in the Autopilot.0 section of the flight file are meaningless as they are superseded by values in the PSS section of the flight file, which we don’t have.”
The ATSB says it has received four complete and two partial data captures. Are the ‘complete’ captures then incomplete .FLT files?
@Gysbreght: I don’t know whether or not the flight files the ATSB have are as truly complete as they believe. Either way, I’d like to get what they have, as they have more information than what is available publicly.
@Victor
Well I guess that it’s just one more of those uncanny MH370 coincidences that at 10N the airplane is pointing with uncanny precision at Colombo and has Nav2 tuned to the KAT VOR at Colombo!
Re: “I would be very surprised if the nav radio frequencies selected by the FMC are related to a future waypoint. They are selected by the proximity to available nav aids, not the destination selected.”
Then prepare to be very surprised, I guess. Short response; it depends. Long response, per the FCOM:
“FMC autotunes VORs for procedure flying and route operations. The FMC also tunes related DMEs. The tuning status displays are:
• P (procedure autotuning) – FMC selects navaids for approach or departure procedure guidance.
• R (route autotuning) – FMC selects navaids on the active route. The navaid is the previous VOR or a downpath VOR within 250nm of aircraft position.
• A (autotuning) – FMC selects a navaid for best position orientation.
• M (manual) – VOR is manual–tuned. Manual–tuning takes priority over FMC autotuning. Deletion of a manual–tuned frequency returns system to autotuning.”
That’s the real world. The question remains, how does the PSS B777 Professional flight sim program model that?
Re: “ And if the plane was moved ahead along the path the way I suspect, the nav aid might not reflect the current position, but where it was before the move.”
My thoughts exactly. In fact I think you can get a sense of how the simulator session may have played out by looking at the navaid settings and the fuel quantities. If the 10N navaids are in fact PUT and VPL (rather than KAT) then I suspect that the airplane was somewhere between TASEK and NILAM when it was dragged to 10N. If it had been west of NILAM then VPL would most likely have been dropped and replaced by BAC due to the range. When you then consider that only 1,740 kg of fuel was burned between 5N and 10N, the airplane probably wasn’t even all the to VAMPI before it was dragged.
More broadly, there is this persistent and mistaken belief that everything from one simulator session is somehow meant to be representative of one flight. That is not how simulators are used in commercial aviation. One simulator session typically incorporates a number of different exercises that are most assuredly not representative of one flight. For example, in just one of the sim sessions that the Captain examined on there is an engine malfunction on start-up, an engine failure on take-off, an engine restart, a TCAS alert during the climb out, a stall, and a continued climb to cruise followed by an emergency descent … and that’s just the first half of the session! That’s not meant to be representative of a one real flight.
The fact that the recovered data shows that the airplane was being dragged from point to point (which means that fuel burn is ignored) rather than “flown”, either in real time or by using time acceleration, is a fair indicator that we are not looking at one complete flight but rather something that may have been a series of exercises. If nothing else, the fact that the airplane was dragged means that the sim session was essentially useless as a fuel planning exercise.
@Victor
Just by the bye, at 10N you’ve got an airplane with a gross weight of 242,586 kg at FL400 in a 20° banked turn! Is that even possible? 242.6 tonne on a -200LR (-300ER) wing at FL400 strikes me as problematic in level flight leave alone in a 20° AOB turn. Did you replicate those conditions on the recreated flight?
@Mick Gilbert: I did some quick checking using the FLT files I saved from the simulator recreation, and also I just performed some other tests. The recreation was performed using FS9/PSS777 many months ago. I am hesitant to re-run tests using the PSS777 because I am now much more familiar with the FSX/PMDG777 model, but if necessary I could, or @TBill can.
First, the navigational frequencies in the saved file for 5N correspond to the values in the sim file 5N. Recall, we know that the position was not changed prior to the save for this data set, so that’s good.
Secondly, when I use the PMDG777 to fly the sim coordinates, as VAMPI is approached, the VORs (L and R) switch from VPL (114.10) to PUT (116.90). That indicates to me that before the user moved the plane to 10N, it was near VAMPI, as the DME is around 130 NM for both the VORs. There is nothing to suggest that the frequency is related to a navigational aid near COLOMBO.
@Mick Gilbert: Just by the bye, at 10N you’ve got an airplane with a gross weight of 242,586 kg at FL400 in a 20° banked turn! Is that even possible?
I just did it in the PMDG777 at M0.84. Unfortunately, I didn’t record the turn when I ran the PSS777 flight. But remember, we don’t know whether the altitude was changed along with the position just before the save at 10N.
In any event, your work on the radio frequencies was interesting, but it confirms what we already knew: the plane was moved along the path before the save. There is no evidence of a detour to Colombo.
@Mick @Gysbreght
FS9/PSS777 has no problem making those turns…I probably did it hundred times. The main implication I see are:
(1) that 10N turn probably did not start exactly on the LAGOG to DOTEN line…probably the aircraft was moved by hand to that area *or* the true path was more like DUBTA to DOTEN, whereas DUBTA is definitely a common waypoint on the Jeddah route.
(2) Given the N10 turn was 255 degrees, then 10N is not the exact upper point of the trend line to NZPG. The exact upper point of the trend like to NZPG, when the aircraft comes out of the turn, could be more like 10.5N, 90E. This is turn could suggest NZIR or NOBEY as alternate end points.
(2) FS9 is very interesting and somewhat unpredictable on how it makes turns, so one would have to hit on exactly the way ZS did it. FS9 is repeatable, but things like saving the case can apparently change how it does the upcoming turn. Of course simulation speed 1x,2x,4x,or 8x also impacts the curve.
(4) I know nothing about radio frequencies, so that is something Victor or someone has to help on. Tell you what, Victor and Yves did a quite thorough job…I have trouble seeing anything they missed, and I am trying pretty hard to gleen more out of it.
@Gysbreght
You should see from the prior FS9 screen shots I provided that the flight path route is the thick white line. I have recently done a take-off with Victors McMurdo route so I could see the forward path to NZPG, and I made the flight path peak at 10N so I could see when the turn hit 10N exactly. Previous to that I had the Jeddah route highlighted, which was a less useful guide.
Wow if ATSB has complete file, then they have a ton of missing data such as waypoints, time/date of flight and basically could answer all of the questions we are struggling with.
@Mick Gilbert: I explained that the heading is meaningless during a turn. In fact, the one thing we know is that it was NOT heading for 255.5° after roll-out of the turn. I also explained that the navigational frequency is related to Langkawi, not Colombo, which I repeated by flying near VAMPI. The NAV2 frequency indicates the active VOR, which was Langkawi just before VAMPI.(The procedure frequency is autotuned as the airport is approached.) If you want to ignore these facts and believe that the data somehow lines up with Colombo, I won’t try to persuade you further.
@Ocean Infinity followers
For the first time (to my knowledge) a fee has been publicly divulged.
http://www.thesundaily.my/news/2017/10/26/ocean-infinitys-offer-search-mh370-still-being-studied
As I suspected, the fee is not fixed (as initial reports would lead one to believe), but apparently activity based in some manner.
@TBill:
Thank you for reminding me of the files you sent back in November 2016. Yes, I see the white line on the MAP page.
At the time you also sent some .FLT files. Interesting that the [ATC_Aircraft.0] field indicates 6 waypoints and WaypointNext=1.
@Dennis,
Re: “As I suspected, the fee is not fixed”.
I had little doubts that negotiations were about the structure of a fee, but not about definition of ‘success’. How to monitor progress and man-hours if the fee is not fixed?
@Victor @Andrew
“… I looked at the case where 45S,104E was entered as the final waypoint, which is which is close to the coordinates for simulator data sets 45S1 and 45S2. The crossing of the 7th arc is around 28.3S. This seems like a candidate path. Perhaps McMurdo was entered as the destination in the simulator session, but the coordinates 45S,104E were extracted from the session and used for MH370.”
…with all my MH370 work, I find I use oceanic waypoints a lot. For example, let’s say instead of SPOLE the pilot used 180S CTH. Now if I put a waypoint in the FMC such as 3294S, and I press the PROG(ress) button on the CDU, it gives me fuel remaining to waypoint 3294S even though I am still using 180S CTH as the A/P flight mode, and not really flying exactly to 3294S. I am curious if that works on real B777?
So Victor I tend to look for oceanic waypoints closer to the end point, such as for example 2698S for the McMurdo case. If I was just trying to key in distant NZPG I would use (eg; in SkyVector) 78S67 for NZPG and 78S69 for NZIR.
@ventus45,
@Victor,
These minor errors in the coordinates of HA01 are of order of 1 km. I was talking about 200 km discrepancy. Where is the center of E1 zone?
@Oleksandr: As I said, I don’t know. It’s too far off the 7th arc to matter.
@Oleksandr
How to monitor progress and man-hours if the fee is not fixed?
I don’t see how it is possible with Ocean Infinity.
@Gysbreght
…and that was before I started using the PSS777 which extends the FLT files data quite a bit. But even if ATSB just had the full FS9 portion of the FLT files, that could be very important.
@TBill: It might be that the ATSB, or whoever else analyzed the sim data, compared the recovered file fragments to the flight files produced by FSX/PMDG777, not realizing that the FS9/PSS777 flight files are longer because of the PSS section. I suspect that they don’t have the full flight files, but that’s just my guess.
Ocean Infinity demonstrates performance at 5200 m, setting a record for multiple AUVs.
More here.
@Dennis, Oleks:
How to monitor progress and man-hours if the fee is not fixed?
I don’t see how it is possible with Ocean Infinity.
Seems ‘effort’ would be scalable to effective drone-hours/area searched.
Or am I missing your joke, Dennis?
@ikr
No joke, Ikr. In the case of Fugro they had imaged terrain as a measure. The scans needed to pass certain quality metrics to qualify. In fact, Fugro was not bashful about commenting on the difficulty. In the case of Ocean Infinity, I do not believe that is the case. No mention has been made of terrain mapping. It may well be that Ocean Infinity has methods other than visual examination to detect debris signatures, and then follow up optically. I really don’t know what their algorithms are. Simply measuring AUV hourly activity would not be a measure of coverage area or quality.
Hopefully, when an award is made we will get the details.
@Victor
” It might be that the ATSB, or whoever else analyzed the sim data, compared the recovered file fragments to the flight files produced by FSX/PMDG777, not realizing that the FS9/PSS777 flight files…”
Have to wonder if they are missing a lot like addon programs for flight planning and Google Earth linkage, magnetic table updates etc. PSS777 waypoint and airport data bases which are easy to edit for waypoints and airports you want to see but that they left out.
@Victor,
Re: “It’s too far off the 7th arc to matter.”
I strongly disagree. 150 km is not too far bearing in mind all the uncertainties.
@Oleksandr
My apprehension is your assumption of an ocean floor event. It is clear from the linked paper that it was based on the assumption of a surface event. Not saying you are wrong. What I am saying is that I don’t know. The sea water propagation speeds associated with the paper do indicate a significant depth.
@Dennis,
The paper suggests this method works for landslides and earthquakes. I did not have time to study it in detail, but if that is true, why not seabed impact?
@Dennis:
OK, I see where you’re coming from. My sense is that if this were a poker game, Malaysia and OIs interest would be divergent. OI is taking a high risk and wants the chance of a lucky hand. But OI, I think, is in here to sell their technology, so they’ll settle for a higher risk, moderate return strategy. As far as I can see, Malaysia wants to save face — if OI scores two weeks in, on their first priority, Malaysia won’t look like chumps. So let them require so many sea-days + so many vehicle hours. And let OI set the quality of coverage to what their models say is rational. Perhaps 99+% in areas that have high possibility, and 95% or less, steaming from one hot spot to another. We should be happy that Fugro didn’t do that — but assuming this is the last best chance [with present technology], I’d say let OI follow the evidence rather than filling out a data field.
As far as quality of
@Ikr,
The problem is not in Fugro, but in their advisers. What would you change: advisers or contractors?
I doubt that OI has technology that is significantly superior to Fugro’s as I have not heard anything about them except self-advertising. Remains to be seen.
@Oleksandr: If the uncertainty in position is so high, then only the bearing matters. That was my point, although I question whether even the bearing provides useful information. People much more knowledgeable than me in this area are diving into this pretty deep.
@Oleksandr: What I thought was self-evident about OI’s technology is it offers speed and economics. The season for searching in the SIO is short, and the cost of seabed scanning is driven by the cost of the host vessel. Six sensor vehicles in the water for a single host vessel should be very advantageous.
@VictorI
The details of the recent press releases are actually fairly nuanced. Cut paste below from a linked article.
link:
https://www.nst.com.my/news/nation/2017/10/295340/search-missing-flight-mh370-may-cost-us70-million
“Ocean Infinity has offered to provide the search missions on a ‘no cure – no pay’ basis (payment depends upon success and the recovery of property),” he said.
Ab Aziz added that the negotiation also touched on other aspects, including payment terms and schedule, such as whether the fee will paid after the actual wreckage of the plane is found.
The negotiation will also require that the wreckage is certified to be MH370 by the plane’s manufacturer, Boeing.
The terms “success depends on recovery” and “whether fee will be paid after the actual wreckage is found” suggest that Malaysia wants to pay on actual recovery of specific items (presumably the recorders).
Likewise third party certification by Boeing will almost certainly require the recovery of something.
Ocean Infinity would seemingly need to insist on being the party responsible for recovery (hence, the higher than anticipated fee of $70M) since their payment would presumably be coupled to a recovery of some sort.
@David
Re: “Do you have access please to a -200 or -300ER parts listing which might specify the internal line diameter? Alternately could I again prevail upon you to ask your tech gurus whether they can confirm the flexible line’s external diameter is 25.4 mm or close to?”
I don’t have access to the IPC. I was told the external diameter of the APU fuel supply line is 1 inch, or 25.4mm. That does not include the shroud.
@TBill
Re: “Now if I put a waypoint in the FMC such as 3294S, and I press the PROG(ress) button on the CDU, it gives me fuel remaining to waypoint 3294S even though I am still using 180S CTH as the A/P flight mode, and not really flying exactly to 3294S. I am curious if that works on real B777?”
If 3294S is the active waypoint, then the FMC fuel prediction will be based on a direct track to that waypoint regardless of the AFDS mode that is engaged. The fuel prediction will only be accurate if the aircraft is actually tracking towards that waypoint. If the aircraft is not tracking towards the waypoint, then the FMC will keep updating the fuel prediction based on the current distance to the waypoint, groundspeed, etc.
@Victor
Thank you for checking those navaid values and how the PMDG sim program models the autotune function. It appears that after 5N the airplane was probably flown, either in real time or under time acceleration, for a distance towards VAMPI that was consistent with the fuel burn between 5N and 10N (1,740 kg or around 15 or so minutes) and then dragged about 500 nm. That suggests that the airplane was possibly dragged to 10N before it had reached VAMPI.
Thank you also for confirming that the sim allows a 20° AOB turn at a gross weight of 240-odd tonnes at FL400. In real life that would be towards the limits of the airplane’s performance (the LRC maximum operating altitude at ISA+10 for the -200LR is about FL380 at that sort of weight).
@Andrew. Thanks for that confirmation.
@Mick
I don’t recall anyone questioning the similar turn at IGARI as far as being too close to aircraft performance limits.
@DennisW: I don’t know the financial details. I am hearing that things continue to move forward in a positive way. I hope that means a signed deal in short order.
@VictorI
I have the same sense relative to a deal. Attorneys are frequently not helpful in getting a deal done. I think only details remain. I don’t sense anything big blocking the way.
@Victor
@Mick Gilbert
Re: “@Mick Gilbert: Just by the bye, at 10N you’ve got an airplane with a gross weight of 242,586 kg at FL400 in a 20° banked turn! Is that even possible?
I just did it in the PMDG777 at M0.84. Unfortunately, I didn’t record the turn when I ran the PSS777 flight. But remember, we don’t know whether the altitude was changed along with the position just before the save at 10N.”
That’s interesting. The -200LR FCOM shows that the LRC maximum operating altitude at ISA+10 is about 37,300 ft at 243T, providing a 0.3g margin (approx 40° AoB) to initial buffet. The FMC MAX altitude displayed on the VNAV page is based on the same margin, so it should show approx FL373. It’s theoretically possible to do a 20° AoB turn at FL400, but the aircraft would be well above the MAX altitude and very close to the buffet. That’s certainly not something anyone would do in everyday operations! As you said, perhaps some of the parameters were changed.
@TBill
Re: “I don’t recall anyone questioning the similar turn at IGARI as far as being too close to aircraft performance limits.”
That’s a bit like comparing apples and oranges. MH370’s weight at IGARI was about 217T. In the -200ER, the LRC maximum operating altitude at 217T and ISA+10 is about 40,400 ft, well above MH370’s initial cruise level of FL350. The aircraft could have done a steep turn and not run into problems due to buffet or lack of thrust!
@Paul Onions.Your 24th Oct, 2:32 pm to Dr B.
“5. It is possible that Left GCU and Backup converter are both inoperative, such that Right IDG is supplying all the power to the main AC buses. When right engine failures, APU autostarts, creates log on, but left engine is still operating. Projectory of flight path is greater.”
The ATSB had this modelled by Boeing (p8, Search and Debris Examination Update). It says, “In an electrical configuration where the loss of engine power from one engine resulted in the loss of autopilot (AP), the aircraft descended in both clockwise and anti-clockwise directions.”
What I believe has not been raised before about this is that loss of autopilot, from AC loss, would result in failure of the AC powered main engine boost pumps for a minute pending the APU coming on line.
During that time if it had been the right engine still operating that would be reliant on fuel supply through its gravity feed.
Were it the left engine still operating (ie with IDG and back up gen off line) that engine would be supplied also initially by gravity. The APU DC pump would not have started to supply the APU during its autostart. That requires both that there is no pressure in the left engine fuel manifold and that the APU selector is at ‘start’ or ‘run’, whereas it would be ‘off’. Without that the APU in starting would need to draw fuel from the left main tank through its (stopped) DC fuel pump there.
The pump would cut in to supply the engine if and when the engine’s fuel manifold pressure dropped past nil*, that is suction overcame pressure due to gravity. In so doing, by happenstance it would then supply both the engine and APU. However the pump’s supply is limited to just 3150 lb/hr (1430 kg/hr) and the engine at power would need to supplement this through gravity feed. The APU draw off, by its gear wheel pump, is likely to increase that engine gravity supply requirement a little (130 lb/hr based on the ATSB’s 2.2 lb/min).
(*most likely there is also an RR engine rpm stipulation but my manuals do not cover that)
With fuel low in both tanks how much air might be sucked**in through the gravity supply by either engine still running is conjectural and whether that might cause that engine to flame out: restart at altitude can be problematic. Were there no relight or it did not last, the engines would shut down at 35% N3. However as to the left the APU pump, if it had started it would not shut down with the engine since a feature it has which will leave it selected is that it is now running.
(**Leaving aside entrained air, which should have been drawn out by then).
Bear in mind that the oddities and complexities of all this are a result of this being reaction to circumstances naturally not foreseen in design and certification: unpiloted fuel exhaustion.
Without pilot or autopilot during this minute and with uncertain engine happenings the aircraft might have rolled, yawed, or pitched, which too might complicate fuel supply; and aircraft trajectory thereby.
There are numerous uncertainties here.
Simulator verisimilitude achieved by Boeing and sufficient?
@TBill
Regarding the turn at IGARI, 220 tonnes (more than 20 tonnes lighter) at FL350 (5,000 feet lower) for the -200ER (as opposed to the -200LR) is well within the performance envelope, even for bank angles well beyond 20°. On the other hand, you may recall that talk of a climb to 45,000 feet at IGARI was quickly hosed down as being beyond the capability of the airplane.
Para 7. I say, “However as to the left the APU pump, if it had started it would not shut down with the engine since a feature it has which will leave it selected is that it is now running”.
Please replace with, “However as to the left, had the APU DC pump started it would not now be shut down with the engine. Since the APU is now running the pump will remain selected”.
@David
“Bear in mind that the oddities and complexities of all this are a result of this being reaction to circumstances naturally not foreseen in design and certification: unpiloted fuel exhaustion.”
Yes, I agree with the above, except that I would have said “piloted fuel exhaustion”.
@Rob. If a pilot were assumed I would have had a lot more to say.
However the final BFOs suggest there would be little effect on search width. These unpiloted possibilities are not as constrained by the BFOs as by simulator outcomes, and since we have little information on the simulations currently they are lesser constraint.
However where the 7th arc log-on was, piloted, is thrown to the winds. Course and speed changes, step climbs blurring endurance and range, flicking switches, re-engaging the autopilot, selecting APU on….
@David
Re: “What I believe has not been raised before about this is that loss of autopilot, from AC loss, would result in failure of the AC powered main engine boost pumps for a minute pending the APU coming on line.
During that time if it had been the right engine still operating that would be reliant on fuel supply through its gravity feed.
Were it the left engine still operating (ie with IDG and back up gen off line) that engine would be supplied also initially by gravity. The APU DC pump would not have started to supply the APU during its autostart. That requires both that there is no pressure in the left engine fuel manifold and that the APU selector is at ‘start’ or ‘run’, whereas it would be ‘off’. Without that the APU in starting would need to draw fuel from the left main tank through its (stopped) DC fuel pump there.”
The APU DC fuel pump should start as soon as AC power is lost and the boost pumps stop. ELMS uses the signals from the AC boost pump pressure switches to determine if there is pressure in the left engine feed manifold. Once ‘no pressure’ is sensed, the P310 EEU sends the DC pump command signal to start the pump and the isolation valve command signal to open the isolation valve. The aft boost pump is located ‘upstream’ of the fuel suction bypass valve.
@Andrew. Thanks for that. However the point that the pump will not be automatically selected on autostart still stands, I take it.
Either way, the APU pump will not necessarily protect the left engine from flame out through air drawn down the gravity feed outlets with thin fuel coverage that supply supplementing the APU DC pump; and of course will not have any effect on susceptibility of the right engine. I remember you saying earlier that the gravity outlets would be bare with quite some fuel remaining, which would increase risk of flame out of these engines during that minute to certain if so.
OK
@David “However where the 7th arc log-on was, piloted, is thrown to the winds. Course and speed changes, step climbs blurring endurance and range, flicking switches, re-engaging the autopilot, selecting APU on….”
David, I quite agree. But, putting myself in the pilot’s shoes (even though not myself a pilot, just an informed bystander) I personally would just keep unnecessary procedures to a minimum. I’ve reached the end of the flight, “I’m confident no one knows where I am, and reasonably confident no one will ever know where I am. I’m going to let the SDU go through a depower- repower- logon cycle to show the folks back home I kept going until the fuel ran out, then I’m just going to glide her down on RAT power, go as far as the potential/kinetic energy store will allow, then get her under the waves with the minimum of fuss”.
@David
Why am I so confident there was a pilot in control? It’s because the debris tells me so.
@Mick Gilbert,@TBill, @Andrew: You are taking this 20° turn too seriously. When the plane was moved to 10N, I suspect the altitude was also increased to 40,000 ft. You are seeing a snapshot before the simulation was re-started. The flight may or may not have been stable. The vertical speed of 3,570 fpm was induced by the change in parameters and re-start, as I’ve explained before. This also is unstable, and will cause the speed to drop because of the limited thrust at this altitude.
As for MH370’s climb to 45,000 ft at IGARI, a zoom and climb could have temporarily reached this altitude, although I doubt this happened.
@all
It’s all still about scenarios without pilot control at the end.
Imo this makes no sence at all still, regarding the whole flight and information we have.
It has brought us and no one else anywhere near the plane.
If OI takes this lead also they will maybe miss their potential goal only based on a ‘ghost scenario’.
This would be very limiting imo. I sure hope they don’t make the same mistakes DSTG/ATSB have made based on those ‘ghost flight’ assumptions.
To me it’s obvious a ditch-like controlled impact must have occured.
The flaperon and outboard flap section speak very clear language among many other pieces.
IFE must have been shut OFF long before impact.
The pilot had complete control over range, fuel, engines, APU, AC/DC power supply at choice.
Ignoring this obvious possibility has again the potential of limiting the OI search effort.
While those ‘ghost scenarios’ all staying close to the 7th arc left nothing.
We’ve seen the results till now.
Nothing. Another approach is needed imo.
@Ge Rijn
I don’t think the failure to find the aircraft has anything at all to do with a misinterpretation of the observables. The solution has been under constrained from the get-go. Where is a clairvoyant when you need one?
@Victor
“@Mick Gilbert,@TBill, @Andrew: You are taking this 20° turn too seriously”
You could be correct, but I know a lot about making turns in FS9 now.
@Ge Rijn
“To me it’s obvious a ditch-like controlled impact must have occurred.”
Apparently Larry Vance has a new book coming out to say that too, if I got that right.
@DennisW
I agree based on the sence it was all about finding the plane based on those observables at that time!
No debris was found yet before 7-2015. And this changed everything.
DSTG/ATSB never adjusted their search effort accordingly while they had plenty of time and information to do so.
Certainly after more debris got found.
To me it’s not about clearvoyance but about reasonable thinking.
The plane has not been found in a 120.000km2 priority area based on the assumption of a ‘ghost flight’, an uncontrolled high speed descent and impact.
So something else must have happened.
@Ge Rijn: Surely you realize after contributing here for many months that there are many areas close to the arc that have not been searched that are allowed by the satellite data. The priority zone was based on certain assumptions in DSTG’s Bayesian analysis that may not be true. A long glide after fuel exhaustion is just one of many possibilities. Many believe the other possibilities are more likely.
As for Larry Vance, the last time he was making statements for the media, he never bothered to explain how a long glide is consistent with the increasingly steep descent that the BFO data suggests. Rather, he said the satellite data cannot resolve altitude. What he neglects to say, either out of ignorance or because he deliberately cherry-picked evidence to promote his theory, is that while the BTO and BFO data are not sensitive to altitude, in fact the BFO is highly sensitive to vertical speed. That’s how we know the plane was in a steep descent.
@TBill
I read the article with Larry Vance. I’m on his views from the get go (and even before soon after the disappearance on a Dutch blog).
But it’s not about having those same views to me at all.
I would find it very disappointing if OI would discard this possibilities of an intended destination and glide towards it.
@DennisW
“I don’t think the failure to find the aircraft has anything at all to do with a misinterpretation of the observables”
So what do you think the failure and the waste of 112.47 million US dollars (Malaysian Govt. estimate, Feb 2017) tax payers money was due to? Was it due to the ATSB wanting or persuading themselves to believe the IG’s unpiloted impact? Was it due to political pressure from on high, the same political pressure that also prevented disclosure of confidential information, on pain of a prison sentence?
More importantly, will Ocean Infinity, presumably a company with shareholders, now be foolish enough to waste a wedge of their own money on a continued misinterpretation of the observables? If Ocean Infinity follows the ATSB’s flawed analyses and draws a blank, it will positively deter any further search efforts.
Will they take a step back and take independent aviation expert advice before committing their hard earned money and reputation? Will they, for example insist on an independent aeronautical engineering analysis of the debris? The usual, tried and tested procedure of an air accident investigation is to assemble the parts (where and if available)on the floor of a hanger, in their respective locations on the airframe and see what can be deduced. I would venture to say that if were done with the MH370 debris, an uncontrolled, high speed, nose down impact would be shown the door. They might be able to see if the ATSB’s story hangs together. Possibly, they might smell a rat.
The Malaysian MOT Safety Investigation Team are due to publish their final report by January next year. I wonder what their conclusions will be? My guess is they will say the condition of the debris does not permit any definite conclusions to be drawn other than: 1) It confirms that MH370 ended up in the Southern Indian Ocean. 2) The impact was evidently of high energy, ruling out a controlled, soft ditching with flaps extended. What a travesty that will be. Will Ocean Infinity be gullible enough to believe them? I sincerely hope not.
@Ge Rijn
If there was an intended place to “ditch” I am not sure how the pilot would have done that, dive-in vs. glide. I tend to feel we have to give priority to Arc7, equal opportunity to inside and outside of Arc7 to a certain error bar, unless new data comes forward to suggest a specific long glide crash location.
@VictorI
We still don’t know if the steep descent continued after the 8 sec. snapshot. Maybe an active pilot pulled out after and set a glide towards a destination intended.
Maybe the 4000ft from 45S2 was a set pull-out limit in the simulator?
It does not have to have been a long glide. It could have been just outside the searched area. In fact it must have been for the plane wasn’t found there.
Just to put a managable constraint on possible search width I would like to advise to OI to take at least 50 miles on each side of the 7th arc.
The final BFO’s only tell a possible snapshot, thats all.
Not enough to draw definite conclusions from imo.
@Rob said: Was it due to the ATSB wanting or persuading themselves to believe the IG’s unpiloted impact?
Let’s get our facts straight. Members of the IG early on suggested that the BFO was consistent with a high speed descent. Later, after more analyses using data not available to the public, Ian Holland (DSTG) and others agreed.
I am not aware of any statement from the IG that says the end-of-flight was unpiloted. I know I have said that there may have been a banked descent with no pilot input, or a nose-down pilot input. Either way, the increasingly steep descent is not consistent with a long glide. I’ve yet to hear a sensible reason for why a pilot would follow a 15,000 fpm descent with a long glide.
@Victor Iannello:
“I’ve yet to hear a sensible reason for why a pilot would follow a 15,000 fpm descent with a long glide.”
Are you serious?
@VictorI
Your comment; ‘Either way, the increasingly steep descent is not consistent with a long glide. I’ve yet to hear a sensible reason for why a pilot would follow a 15,000 fpm descent with a long glide.’
It’s ofcourse hard to give a reason but the plane was not found between ~39S and ~32.7S near the 7th arc where it was expected to be found.
A reason?
There must be one for the plane was not found where it was expected on previous assumptions.
It must have flyed out of that area some way.
@ROB
So what do you think the failure and the waste of 112.47 million US dollars (Malaysian Govt. estimate, Feb 2017) tax payers money was due to?
Starting an underwater search based on the analytics. The decision makers knew or should have known the uncertainties involved.
The analytics themselves have never been shown to be flawed.
@Ge Rijn: I think any possible latitude should be searched to around 25 NM from the arc. As you can see in Figure 3 above, at some latitudes, the arc was only searched to 6.5 NM from the arc, which was not far enough. Perhaps we simply disagree on what that width should be. I think a search to 120 NM is hard to justify.
@Victor
Actually, as I believe ALSM pointed out a while ago, the Arc7 in Fig. 3 is skewed to high altitude, so the actual amount of Arc7 searched inside could even be less than 6.5 nm, could be 2 nm. So I like what I think Richard said was define Arc7 at say 17,500 ft so it’s in the middle of the possible range.
@VictorI
I think a width of search with a radius of ~50 miles is sensible depending on where you start and to include all possibilities.
If you start from (f.i.) ~33S on the 7th arc expanding outwards till ~35S and 32S then ~50 miles would be a managable limit in my view.
Covering ~30.000km2 from around a centered starting point could lead to finding the plane well within those 30.000km2.
Nothing gained, nothing lost regarding a possible glide and ditching.
When the plane gets found near the 7th arc according a high speed, descent scenario it would be splendid all the same.
My concerns are OI rejecting the possibility of a controlled glide after a steep descent too.
@TBill: You have to be a little careful. Yes, the 35K ft arc is about 5 NM outside of the sea level arc. But the possible distance between the last transmission and the impact also reduces if the transmission occurred at lower altitude. You have to consider both these effects.
@Ge Rijn: I agree w/ Victor, who stated: “I’ve yet to hear a sensible reason for why a pilot would follow a 15,000 fpm descent with a long glide.” In fact, I haven’t heard any reason why that might have happened, sensible or not.
Given that:
1. 9M-MRO reached FE ~00:17:30
2. 9M-MRO was descending at a rate of ~5,000 ft/min 2 minutes later at 00:19:29
3. 9M-MRO was descending at a rate of ~15,000 ft/min 8 seconds later at 00:19:37
4. There was no IFE logon at ~00:21 as expected
5. There were no other transmissions received after 00:19:37
…it is reasonable to conclude that:
a. an extremely high rate of descent began within seconds of FE
b. 9M-MRO’s vertical acceleration by 00:19:37 was ~0.68g
c. given a & b, 9M-MRO must have already descended 10-20k ft feet by 00:19:37
d. even if a pilot intentionally caused b, given c, that pilot could not possibly have levelled out and glided more than 30-40 nm. A continuation of the steep descent is far more likely, even if a pilot was in control.
Although 30-40 nm is perhaps a worst case max glide distance assuming a live pilot, the totality of the evidence and prior cases suggests that 9M-MRO is actually much closer to the 7th arc, probably within ±10nm of the “true 7th arc”. The true 7th arc is known to ±5.3 nm (due to BTO noise) and the altitude uncertainty adds about another ±2 nm to the true 7th arc uncertainty, so a reasonable 7th arc width to search is ±18 nm.
Most will recall, but some might wonder why the search width NW of the arc should be the same as the width SE of the arc (~18 nm each). The reason is that all the simulations of an uncontrolled descent indicate that a quasi spiral descent should be expected. In other words, the aircraft tends to descend in a increasingly tight circular track. The heading at 00:19:29 is unknown, but given that FE took place 2 minutes earlier, it is entirely possible that 9M-MRO was already headed east or even north at that time. Thus, both sides of the arc need to be searched with equal areas.
FTR, Larry Vance is an ignorant fool on MH370. His theory has been soundly discredited both by ATSB and numerous outside experts.
Some interesting information on how Ocean Infinity (OI) intend to operate their fleet of AUVs (link below). They will operate in tight formation in a single area, it seems. I had wondered if they would be assigned separate areas (perhaps adjoining) but a closer formation allows the support vessel to remain close to all the AUVs.
https://oceaninfinity.com/ocean-infinity-reaches-5000-meters-with-six-hugin-auvs-operating-simultaneously/
Currently, Seabed Constructor is operating several hundred kilometres to the west of the Azores, where the ocean depth is recorded as greater than 5000m, as would be required for the test being performed (map below). Ship positions are S-AIS data from fleetmon.
https://www.dropbox.com/s/5i3rdqdxn52c1w8/27-10-17-map1.jpg?dl=0
The ship movements from 00UT on the 17th Oct to 00UT in the 21st Oct are shown in the map below. The points where the ship was indicated by the S-AIS data as stopped are shown – the ship has to stop to deploy or pick up an AUV. The pattern of movements and stops suggests the AUVs were deployed in the eastern marked area and then recovered in the western marked area.
https://www.dropbox.com/s/eponnr7w2qyexnv/27-10-17-map2.jpg?dl=0
@ALSM,
Why do you spread false information again:
2. 9M-MRO was descending at a rate of ~5,000 ft/min 2 minutes later at 00:19:29
3. 9M-MRO was descending at a rate of ~15,000 ft/min 8 seconds later at 00:19:37
?
After that you again make conclusions based on your assumptions. That is silly.
Oleksandr: 2 and 3 above are true, and you know it. ATSB agrees with the statements. Victor agrees. Don agrees. Richard agrees. Bobby agrees. In fact, almost everyone that understands the math agrees. Why are you spreading more false statements?
@Richard Cole
Thank you for keeping up detailed AIS tracking with Seabed Constructor. This map shows the ship’s manouevres while working close to the Azores on Sep 10 before moving off north to the N43W27 area in the mid-Atlantic.
BFOs 00:19 cannot be deemed as a reliable indication of RoD until the mystery of the first BFO in 18:22 logon sequence is solved.
@ALSM,
“2 and 3 above are true, and you know it. ATSB agrees with the statements. Victor agrees. Don agrees. Richard agrees. Bobby agrees. In fact, almost everyone that understands the math agrees. Why are you spreading more false statements?”
Yours 2 and 3 might be true, or might not be true. I don’t know. There are several explanations, but not enough data. If you take BFOs 00:19 “as is”, you are dealing with an event of less than 1:1000 probability. Not talking that we are yet to see the simulations, which can reproduce such a high average acceleration. Sorry, I am not buying it regardless what the IG members think.
Oleksandr: And you also believe ATSB’s assessment is wrong? Please!
Oleksandr said: Not talking that we are yet to see the simulations, which can reproduce such a high average acceleration.
I provided you with the video of a simulation that shows how this acceleration might occur. Independent of whether there are some shortcoming in the model at transonic speeds, to say that the acceleration and vertical speeds are not physically possible is just plain false.
Oleksandr: And it’s not just Victor’s desktop sim (which is quite good, BTW). It’s Boeing’s many EOF simulations on their engineering simulator, my EOF trials in the UAL B777-200 Level4 simulator, and ATSB’s assessment of all the available EOF information. (Thanks again to PM for arranging those simulations.)
Regarding the simulator we used…
Manufacturer: Thompson
Model: 700-200
Year of manufacture: June 1997
Level: D
Configuration
AutoThrottle: Under control of FMS in ECON Mode.
CI=50
ZFW (Zero Fuel Weight): 395,000 lbs
Fuel at 1707 (ACARS reported): 96,500 lbs
Fuel at end of flight: 200-800 lbs per tank, depending on scenario
CG: 28%
Altitude: 35,000 (for most of the simulations)
TAS @ IGARI: 471 kts
Wind Velocity at 38S: 57 kts
Met Direction at 38S: 240 degrees (direction from which the wind is blowing)
Heading at 38S: 186 degrees
Track at 38S: 179 degrees
If I were in charge of selecting the search locations, I would hire our host, along with the IG and a few other contributors to this blog. Perhaps they would also have access to additional data.
A question: Others have calculated speed around 498 KTAS over the last 20 min of the radar. As DrB said the PF was in a hurry. I have no reason to dispute this. (Is this speed supported by a standard setting?) However, right around 18:22 the PF reduces the speed for the remainder of the flight. Why was that done:
To meet the BTO?
To meet the BFO?
To meet the Endurance?
Also, around this same time, the AES re-boots.
Could it be that someone other than the PF after IGARI is the PF around MEKAR? That might explain the changes made around 18:22-18:28. A struggle ensues but both become victims to hypoxia after a southern destination is entered.
I see some still use LRC to calculate endurance and/or range. @Andrew has stated that this setting is rarely used. It has to be another setting that also reduces speed as the a/c gets lighter.
@Victor,
“I provided you with the video of a simulation that shows how this acceleration might occur. Independent of whether there are some shortcoming in the model at transonic speeds, to say that the acceleration and vertical speeds are not physically possible is just plain false.”
Have you read my comment carefully? Where did I state that it was physically impossible?
I recall your scenario shows about 15 percents lower average acceleration compared to MH370. I think it could be significant in this context. I would like to see the same or higher accelerations than the one derived from BFO data. How frequently do you hit these extreme values?
Finally, almost everyone outside the IG does not believe in such a remarkable coincidence of the logon and the beginning of a rapid descent.
@ALSM,
As I mentioned, I was unable to derive acceleration from your transcript. Can you show that you achieved the same order of average downward acceleration lasting for 8 seconds as derived from BFO?
At the moment I lean to think that the second last BFO was subjected to the overshot of similar magnitude as demonstrated in Holland’s paper. That eliminates high acceleration, various coincidences, etc. In other words the plane was already falling at high RoD when the logon 00:19 occurred.
@ALSM,
“And you also believe ATSB’s assessment is wrong? Please!”
Yes, the ATSB did many mistakes. Why would I be sure they are correct this time, especially in light of certain remarks they did in their report?
Oleksandr: You stated: “If you take BFOs 00:19 “as is”, you are dealing with an event of less than 1:1000 probability.”
1:1000!!! What? That is another totally false statement. The probability is at least a number greater than 50%, if not 95%.
The probability that the plane was descending is virtually 100%. It was already out of fuel for 2 minutes, right? The probability that the BFO values were accurate to 250 Hz. Thus, it is virtually certain 9M-MRO was accelerating downward as described ad nauseum.
Let’s return to something worth debating.
Oleksandr: You stated: “If you take BFOs 00:19 “as is”, you are dealing with an event of less than 1:1000 probability.”
1:1000!!! What? That is another totally false statement. The probability is at least a number greater than 50%, if not 95%.
The probability that the plane was descending is virtually 100%. It was already out of fuel for 2 minutes, right? The probability that the BFO values were accurate to ±50 Hz is GT 99%. The vertical speed signal in BFO space was GT 250 Hz. Thus, it is virtually certain 9M-MRO was accelerating downward as described ad nauseum.
Let’s return to something worth debating.
@Victor
You are right. The final BFOs do present a problem for the extended glide camp.
I’m close to wearing out the grooves on my favourite record. I’ll turn it over and see if I can get to like the B side.
@ALSM,
“1:1000!!! What? That is another totally false statement. The probability is at least a number greater than 50%, if not 95%.”
This is absurd. Where have you been for so long time? If you assume BTO and BFO independent, and that the abnormalities in the BTO and BFO were caused by unrelated reasons during 00:19 and 18:25 logons, then the estimated probability of such an even would be around 1:3000 if I recall correctly. Pure Inmarsat data.
I see no point to further discuss your erroneous beliefs and your circular logic.
But please don’t present them as a given fact.
@Lauren H,
You asked some good questions.
You said: ” A question: Others have calculated speed around 498 KTAS over the last 20 min of the radar. As DrB said the PF was in a hurry. I have no reason to dispute this. (Is this speed supported by a standard setting?)”
This one I can answer. Mach 0.84 at FL340 is a standard speed setting that matches the radar track speed. CI52 is too slow at this weight. I think it is more likely that M0.84 (Mmo) was used instead of LRC.
You also said: “However, right around 18:22 the PF reduces the speed for the remainder of the flight. Why was that done: To meet the BTO? To meet the BFO? To meet the Endurance?”
Since the air speed was already at maximum, any change in speed would be a reduction. I think if you had asked either pilot about BTO and BFO they would have had no idea what you were talking about, so those don’t make sense. Personally I don’t think endurance factored into it either. One reason does, and there may be others (such as simply restoring a “standard” speed like ECON), and that is to slow down for a Hold. Unfortunately, we don’t know how far the slow-down was in the hour after 18:22; we only know the average speed through 00:17 was reduced. Otherwise the fuel would have been exhausted well before 00:17. It is possible the speed reduction was just to ECON with CI = 52, since that provides sufficient fuel economy to reach 00:17 with power, but it could have been much larger for a period of time (not more than an hour), followed by a higher-speed cruise. I think that there is likely to be a connection between the speed change(s) and the route followed. I would certainly expect them (speed and route) to be compatible, and most likely turns or racetracks occurred in conjunction with (not independent of) speed changes.
You also said: “Also, around this same time, the AES re-boots.”
I don’t think it is coincidence that, within a period of a few minutes of the power restoration to the SDU/AES, it is almost certain that a speed change or a turn (or both) occurred. In my mind, these are correlated elements of a changed strategy.
You also said: “Could it be that someone other than the PF after IGARI is the PF around MEKAR?”
I think the events then (near 18:22) indicate a changed strategy. I suppose that could involve a change in PF.
You then said: “That might explain the changes made around 18:22-18:28. A struggle ensues but both become victims to hypoxia after a southern destination is entered.“
That is possible, but lack of human control is only demonstrated by (or perhaps I should say consistent with) the data from 19:41 to 00:19. If there indeed was loss of human control, I think that occurred between about 18:39 and 19:29. For the 1-hour Hold scenario, you need a PF to get out of the Hold at about 19:29, so no pilot actions are required after that time to explain that route. For the scenario with a much earlier FMT, probably just before 18:40, you need a way to produce a southern route (possibly a 180-degree CTH or, perhaps more likely a CMT, which is nearly identical in this case). That heading/track command now appears more likely to be an intended route, instead of an unintended EOR/Route discontinuity error. In that case the command would have been executed close to 18:40. That is a little more than 10 minutes after the flurry of activity near 18:22. Perhaps TRK/HLD of 180 degrees was entered, with the NORM/TRUE switch in its usual NORM position, so that attention could be temporarily diverted elsewhere than to the flight deck, or possibly just to steer the aircraft away from land.
@DrB
Re: “This one I can answer. Mach 0.84 at FL340 is a standard speed setting that matches the radar track speed. CI52 is too slow at this weight. I think it is more likely that M0.84 (Mmo) was used instead of LRC.”
Mmo is M0.87 in the B777-200ER. I’ve never heard of M0.84 being used as a ‘standard’ speed, except that it approximates LRC when the aircraft is flying at the optimum altitude for the weight.
@David
Re: “However the point that the pump will not be automatically selected on autostart still stands, I take it.”
The autostart case isn’t specifically mentioned in the manuals, but it’s my understanding that ELMS also sends the DC pump command signal during an autostart if there is no pressure in the left engine feed manifold. It would make little sense to command the DC pump to run for a normal APU start or while the APU is running, but not do the same for an autostart, given that it would be far more important to ensure a successful start in the latter case. I’ll try to find some more information.
@Andrew. “It makes little sense…” Yes though as you know the manual does include specific criteria that the selector must be “in START or ON” position.
I must say that if the ATSB and others reckon the APU can draw fuel without the DC pump at altitude and with the aircraft in a dive it makes little sense to me why it is there for the APU at all.
Nevertherless, accepting that is the way of it, returning to your logic I think the rationale for APU auto-start is to support twin flameouts by assuredly getting the left engine reignited in a hurry on AC loss. I had not noticed the distinction between ‘left engine manifold’ and ‘left engine feed manifold’ that you pointed out. With the APU DC pump being started automatically at twin flameout there is no need for it to be selected on at auto-start if that is just what it its for.
If so there is no need for your further inquiry, though I must say that does not explain the “while the APU is running” other criterion. However, that might be because it might be selected off prematurely otherwise.
Assuming that there was a hold or other deliberate maneuvering around the FMT 18:22 – 18:40 time frame, which involved speed changes for some reason, would it be reasonable to consider what would happen if the auto throttle was disengaged at that time for that sequence of events, but, for whatever reason, was not re-engaged afterwards ?
If some speed was set along with a heading or course or waypoint, what would the aircraft do as it flew south with some fixed, but arbitrary power setting ?
Would it slowly “drift climb” as weight reduced with fuel consumption ?
@Dr B. The outcome so far of the discussion above on the possibility that an engine failed when the other had its IDG and back up generator off line can be simplified. Assuming that the PDA difference applies (no cross feed, no ancillary load imbalance) the engine failing first would be the right. If the left then flamed out as the boost pumps went off line the consequence to range and endurance would be that the left would shut down shortly after the right, ie with fuel left in the tank.
So in that scenario range and endurance would be shortened compared to the left engine failing when providing AC power.
That supposes the APU DC pump supply would be insufficient to keep the left engine from drawing air through the left tank’s gravity outlet pending boost pump restoration a minute later by APU generated AC.
This is a hypothetical to the extent it would need to be accompanied by a rationale as to why the left IDG and back up generators would both be selected off. That is not obvious.
Dr B. Third line. To, “….no ancillary fuel imbalance” please add, “…favouring the right”.
@Victor @ALSM
“You have to be a little careful. Yes, the 35K ft arc is about 5 NM outside of the sea level arc. But the possible distance between the last transmission and the impact also reduces if the transmission occurred at lower altitude. You have to consider both these effects.”
Hard for me to calculate, but I agree with whatever the “average Arc7” is we need to search equally both sides of it.
Since Item (4) we did not hear IFE logon at 00:21, that seems to agree with one hypothesis of mine the that sharp descent perhaps
(funny behavior of my keyboard or website)
Cont’d
Since Item (4) we did not hear IFE logon at 00:21, that seems to agree with one hypothesis of mine the that sharp descent perhaps started lower altitude such as FL100 possibly lower.
@ventus45: With A/P engaged and ALT HLD selected, the aircraft would not drift up in altitude if thrust were held constant.
Tbill: regarding altitude at 00:19:37…please see my statement at October 27, 2017 at 1:45 pm, item “c”.
@Andrew,
Thank you for correcting the value of the maximum operating Mach. I wonder then, if M0.84 is not a ”standard speed”, why Boeing went to the trouble of providing a specific fuel flow table for it?
Here are the Machs and TAS values for various flight levels at LRC using the estimated average weight from 17:22 to 18:22 (213 tonnes and +10C):
FL330 (TAS 486 kts) (M0.817)
FL340 (TAS 490 kts) (M0.828)
FL350 (TAS 493 kts) (M0.836)
FL360 (TAS 493 kts) (M0.841)
FL370 (TAS 493 kts) (M0.841)
FL380 (TAS 493 kts) (M0.840)
The estimated air speed over the radar track is 498 +/- 5 kts. This is consistent (at the -1-sigma level) with LRC at FL350-380. If one wants to assume an even flight level was used heading west, then you get FL360 or FL380. I would say that FL340 at LRC is not very likely (but possible). The Mach needed for 498 KTAS is M0.841 at FL340 and increases to M0.849 at FL380. At FL360 the speed is about 285 KCAS, but I don’t know why a fixed KCAS would have been used.
My conclusion is that we have three possibilities for the radar track speed setting:
1. LRC at FL350-380 (and more likely at FL360/380)
2. M0.84-0.85 at FL340-380 (set via MCP)
3. ECON with Cost Index ≫ 180
Can you suggest other options or opine which of these might be more likely to have been used?
@ventus45
Re: “Would it slowly “drift climb” as weight reduced with fuel consumption ?”
No, as per Victor’s comment. If the thrust were held constant with the AP and ALT (or VNAV ALT) engaged, the speed would slowly increase as the aircraft’s weight decreased.
@David,
The impact of no additional L engine run time after R engine flame-out is about 7 minutes of INOP range and endurance.
Another argument against this scenario is the fact that the average (radial) speed between the 00:11 and the 00:19 Arcs shows a marked drop. The speed reduction would not be this large, in my opinion, if both engines had operated from 00:11 until 00:17:30. In other words, the 6th and 7th Arcs are too close together to be consistent with no speed change until after 00:17:30.
@DrB
Re: “I wonder then, if M0.84 is not a ”standard speed”, why Boeing went to the trouble of providing a specific fuel flow table for it?”
The FCOM performance data is primarily intended for use in the case of a dual FMC failure. In that sense, I guess you could call M0.84 a ‘standard speed’ that the crew might use, but it’s faster than the typical ECON speeds used by airlines these days and there is certainly no requirement to fly at M0.84 in the event of a dual FMC failure. Indeed, many airlines tailor their FCOMs and some include the LRC tables but not those for M0.84.
Re: “The estimated air speed over the radar track is 498 +/- 5 kts.”
I assume you’ve already taken the wind into account when you determined the estimated air speed from the observed ground speed? If so, I would say that option 2 is the most likely, followed by 1 or 3. A speed of M0.84-0.85 would be consistent with someone who wanted to fly faster than normal, but not flat out at Mmo.
@ventus45
Just to expand on Victor’s and Andrew’s responses to your question about a disengaged autothrottle, if the “other deliberate maneuvering” you contemplate involved a change of altitude and that change had been commanded using the Flight Level Change (FLCH) function then the airplane would hold its speed and ascend gradually as fuel was burned. You’d see something like a 3,500 – 4,000 ft ascent over the course of the flight into the SIO.
@Andrew,
Yes, I took the tailwind into account in figuring the air speed from the ground speed across the radar track.
I’m a bit confused about M0.84. By calling it a “standard speed”, I really just meant that it was easily and directly settable. I understood from your first response that it was not normally used, but in your second response you indicated it was more likely to be used than LRC. Did I understand you correctly to mean that, if you wanted to speed up a bit from ECON (with CI = 52), that you would set M0.84 or M0.85 rather than selecting LRC or simply increasing the Cost Index to several hundred? Why (or under what circumstances) would a relatively small speed increase (only 2-3%, or less than 2 minutes over the next hour) be done at all?
@DrB. Thanks. Yes I follow. APU start is the datum.
@Victor
I don’t know about taking that 20° AOB turn at 10N too seriously, I was really just curious with regards to what it might mean and how the sim program modelled performance towards the edge of the airplane’s envelope.
What is becoming increasingly apparent is that what we are seeing with regards to the simulation airplane’s orientation at 10N (the 20° AOB left turn coming through 255.5° at FL400) is more likely a representation of what the airplane was doing on the previous segment of the simulation (the segment that falls between 5N and VAMPI) rather than what it is doing after being dragged to 10N. The proposition is at least in part supported by both internal and external factors, specifically and respectively, the “inherited” navaid settings and the fact that TBill can’t recreate a plausible turn off N877 that passes through 10N on the correct heading.
A few more inferences arise:
1. Sometime after 5N (and, if fuel burn is considered, most likely before reaching VAMPI) the simulation airplane most likely commenced a 20° AOB left turn off a heading greater than 255.5°.
2. On the basis that from the Malacca Strait (GUNIP) to the eastern Indian coastline (RINTO) N571’s track falls only between 286° – 311°, if the simulation airplane ever reached N571 at VAMPI, it left it again
3. The absence of a disparity between the “Altitude” (=+040003.30) and “AGL” (=40003.327639357369) in the 10N data set means that the simulation airplane was most likely at FL400 before it was dragged to 10N.
4. 10N most likely has no relationship to a deviation from a flight along LAGOG N877 DOTEN. There is, in fact, no evidence that the simulation airplane was ever on N877 (or N571 for that matter).
That makes depictions of the simulation “path” as travelling along N571 and N877 and of the turn at 10N as part of an FMT towards 45S1, quite fanciful (or, at the very least, very highly speculative). Further, it all calls into question whether the simulation relates to MH150.
@DrB
Re: “By calling it a “standard speed”, I really just meant that it was easily and directly settable.”
I thought you meant the crew might set M0.84 for a specific purpose, the same way they would set M0.82 for severe turbulence penetration, for example. There is no specific reason to set M0.84 except:
a. it approximates LRC at optimum altitude, and
b. there happens to be M0.84 performance data in some operators’ FCOMs.
Re: “Did I understand you correctly to mean that, if you wanted to speed up a bit from ECON (with CI = 52), that you would set M0.84 or M0.85 rather than selecting LRC or simply increasing the Cost Index to several hundred?”
Yes, but only because it’s very easy to ‘open’ the MCP speed window and wind it up to a specific speed. The LRC/increased CI options would require the pilot to select LRC or a higher CI, see what speed resulted, then perhaps make another change if the resulting speed wasn’t deemed to be appropriate. In practice, however, any one of those three methods could be used to increase speed; there’s not much between them. It would also be possible to set a specific speed (eg M0.84) in the FMC.
Re: “Why (or under what circumstances) would a relatively small speed increase (only 2-3%, or less than 2 minutes over the next hour) be done at all?”
On a ‘normal’ flight it might be done because of an ATC requirement to maintain separation with another aircraft, or to arrive at a particular waypoint at a specific time. In the context of MH370, however, who knows? In reality a small speed increase doesn’t make a heck of a lot of difference over the course of an hour, as you noted, except that it ‘feels’ a bit faster.
@Victor Iannello:
Ventus 45 said: “If some speed was set along with a heading or course or waypoint, …”
Where did he say that ALT HLD was selected?
Just curious how long my post will be “awaiting moderation” this time.
[VI: If this site were not moderated, it would be quickly overrun with trolls, spam, and disruptive comments. If you are not satisfied with the moderation here, you should consider contributing elsewhere.]
@ALSM. About search width, confidence in that depends on;
• the ATSB final BFO interpretation being correct and if it is;
• there being no glide or straightening of the descent spiral predicted by Boeing that would take the aircraft beyond distances based on unpiloted descent simulations. In other words, whether a pilot was present or not would make no difference, and;
• the simulations are valid representations of the aircraft behaviour with no pilot input, and;
• confident deductions as to search widths can be drawn from the simulations.
My judgement like yours and many others is that the prospects of the first two proving sound are high.
The others are weaker.
As you know the ATSB has said, “Simulations that experienced a descent rate consistent with the ranges and timing from the BFO analysis generally impacted the water within 15 NM of the arc”.
Following the first dot point, those which are inconsistent with those ranges and timing are irrelevant. So BFO compliance is effectively a selection tool of scenarios, as distinct from scenarios in any way ‘proving’ the BFOs.
In that context two issues which remain unclear are:
• what specific scenarios should receive no further consideration and is that consistent with other evidence?
• How valid are the simulations? In turn about this:
1. Which simulations other than those specially asked of Boeing most recently have been included? I think Gysbreght mentioned there were just one or two among those which met the criteria: not much of a sample.
2. Does ‘timing’ above mean the 8 secs between the BFOs or the time lapse after such as APU start/RAT deployment to the BFOs; or both?
3. What account was taken of the possibility of a break in communication with the satellite in steep bank or spirals?
4. What was the prospect of in-flight aircraft break up in any tight spiral or pull up, which might scatter debris into more than one site, as per MH17?
5. The ATSB says also that, “flight simulators are unable to accurately model the dynamics of the aircraft’s fuel tanks……” It adds that if unusable fuel, “resulted in APU start-up, it would re-energise the AC buses and some hydraulic systems. This could affect the trajectory of the aircraft. Similarly, the left and right engines may also briefly restart, affecting the trajectory”.
Since 5. was not included in the simulations does that not invalidate them?
I do not think that a search width conclusion can be drawn in view of that, as apparently has the ATSB/SSWG. Besides, lack of answers to 2, 3 & 4, vitiate validity further. Finally, noting the apparent sample size, there can be little confidence anyway in the actual results.
This joins other implicit probability assessments such as the position on the 7th arc and the assumption of no pilot, even if that quite probably is sound. My own intuitive multiplication of all the implicit probabilities of these results in a low one overall.
I see the simulations as being the weakest link, based on what has and has not been disclosed about them. It is also the issue that appears most open to potentially rewarding work.
Meantime, the search goes on (or I hope it will) but I think the outcome as it stands now will depend more on luck than it should.
PS About why a pilot would follow a 15,000 fpm descent with a long glide you say, “In fact, I haven’t heard any reason why that might have happened, sensible or not.”
I have mentioned that a pilot might have lost control at high altitude as control power was reduced during the time the RAT was deployed, that continuing until the APU happened to come on line. Or he might have tried a zoom climb, stalling and again losing control. As to the second, how that would meld with recovery lower down I could not say but then a pilot at that stage may not be consistent.
Maybe, “…or not” but there it is.
@Andrew. Wanted to check one thing with you, if I may. Is ECON descent speed always the same KIAS for a given cost index or does it vary depending on aircraft weight (or any other factors). What I’m trying to understand is: if the aircraft were “stuck” in VNAV ALT without having initiated descent and speed on ECON descent KIAS, would you expect the speed to change over the next 5+ hours, assuming no pilot inputs?
@ALSM RE YR comment of October 27, 2017 at 1:45 pm:
“a. an extremely high rate of descent began within seconds of FE”
Do you consider 5000 Ft/min an “extremely high rate of descent”? And do you mean seconds before 00:19:29?
“b. 9M-MRO’s vertical acceleration by 00:19:37 was ~0.68g”
Based on your numbers the average b. vertical acceleration between 00:19:29 and 00:19:37 was ~0.68g. If the vertical acceleration is assumed to be constant, then the rate of descent must have started to increase 2.4 seconds before 00:19:29
“c. given a & b, 9M-MRO must have already descended 10-20k ft feet by 00:19:37”
The steady rate of descent power off at cruise altitude is about 2000 ft/min. Between FE and 2.4 seconds before 00:19:29 the airplane would have lost 4000 ft or the equivalent in total energy. In the next 10.4 seconds the average rate of descent was (2000 + 15000)/2 = 8500 ft/min and the altitude would have reduced by 8500/60*10.4 = 1473 ft. The altitude at 00:19:37 would then be about 5500 ft less than at FE. The speed would have increased, and the excess speed couyld be converted back to altitude in the recovery. That recovery could be effected in the next 10.4 seconds and 1473 ft of altitude after 00:19:37.
“d. even if a pilot intentionally caused b, given c, that pilot could not possibly have levelled out and glided more than 30-40 nm. A continuation of the steep descent is far more likely, even if a pilot was in control.”
Your first sentence has been debunked above. I don’t share the opinion you express in the second sentence. If the purpose of the steep descent was to (re)gain airspeed, it is unlikely to have continued after 00:19:37.
@Gysbreght said: Where did he say that ALT HLD was selected?
He didn’t say the aircraft was in ALT mode (which would be entered if HOLD was selected). He did ask about a condition in which the plane was maintaining a heading or was flying towards a waypoint. That implies the A/P was engaged. With the A/P engaged, both roll and pitch are controlled. If the plane was not in a descent or climb, that implies it was in either ALT or VNAV ALT, as @Andrew said. If in either ALT or VNAV ALT, for a constant thrust, as fuel is burned over time, the weight decreases, the pitch decreases, the induced drag decreases, and the plane increases its speed, as @Andrew said.
@ventus45: Here’s one way a drift up in altitude might occur while the A/P is engaged:
1) The A/P and A/T are both engaged and altitude is steady in ALT or VNAV PTH modes.
2) The A/T is disconnected by unarming both engines.
3) A higher altitude is selected in the MCP window and FLCH is selected.
4) As fuel is burned, the plane will slowly drift up in altitude.
Note that for this scenario to occur, the pilot would have to manually select a higher altitude in the MCP.
[VNAV ALT was changed to VNAV PTH in (1)]
@Victor Iannello, @Andrew:
Ventus45 also said: “… consider what would happen if the auto throttle was disengaged at that time for that sequence of events, but, for whatever reason, was not re-engaged afterwards ?”
Can you have VNAV ALT with the autothrottle disengaged?
@Gysbreght asked: Can you have VNAV ALT with the autothrottle disengaged?
@Andrew: Please jump in if I have something wrong.
The quick answer is “yes”.
First, VNAV ALT implies that the VNAV altitude and the MCP selected altitude are different. Without the difference in selected altitudes, constant altitude is maintained by the A/P in ALT or VNAV PTH modes.
If the A/T is disconnected by flipping down the two A/T ARM switches to OFF, A/P modes are not inhibited, and the A/T will remain disconnected.
If the A/T is disengaged with the A/T ARMed, changing the pitch mode will automatically engage (wakeup) the A/T, which can then be manually disengaged, although the A/T will wakeup as required to protect against exceeding envelope limits.
@Paul Smithson
Re: “Is ECON descent speed always the same KIAS for a given cost index or does it vary depending on aircraft weight (or any other factors).”
The ECON descent speed varies a small amount with weight, but the main factor is the cost index.
Re: “…if the aircraft were ‘stuck’ in VNAV ALT without having initiated descent and speed on ECON descent KIAS, would you expect the speed to change over the next 5+ hours, assuming no pilot inputs?”
The ECON descent Mach no. is normally the same as the ECON cruise Mach no. The FMC will enter the descent phase at T/D, but if the aircraft fails to descend it will continue to maintain the Mach no. and won’t transition to the ECON descent ‘speed’ (ie KIAS). I suspect the FMC will recalculate the Mach no. as the weight decreases, but I’m not sure – I’ve never flown more than a few minutes past T/D!
@Victor Iannello:
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Anybody interested in my comments should be aware that they appear on the blog after some delay.
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@Gysbreght
@Victor
I agree with Victor’s comments. In short, all VNAV modes are available without the autothrottle.
@Victor Iannello, @Andrew:
Thank you both for your replies on VNAV ALT
@ALSM
I accept the 0:19 BFO’s represent a very high speed descent in those 8 seconds till 0:19:37. And it makes a strong case for that descent rate continued till impact within ~15Nm of the 7th arc.
But imo no one can be completely sure yet at which altitude this 8 seconds descent event took place and what happened after 0:19:37.
Then there is the conflicting information regarding the debris. Particularry the flaperon and outboard flap piece.
They show no substantial leading edge damage but mainly trailing edge damage. A high speed nose down impact is impossible if those pieces seperated on impact.
There is still no conclusive evidence (published..) on how those pieces seperated.
Imo the debris (particularry the flaperon and outboard flap section) show clear signs of a ditch-like impact and the final BFO’s show signs of a high speed nose down impact.
Two very conflicting sets of information that are still not resolved.
My take on a wider search width is to include both possibilities as long no conclusive evidence has been presented for one of both scenarios.
~50Nm on each side of the 7th arc would limit chance of failure if this uncertainties still exist when OI starts searching.
And they could (and would I guess) work inside out from the 7th arc from areas not searched yet.
If the plane then not gets found within ~15Nm between ~32S and ~36S they’ll know some kind of glide had to be involved and they would have given themselves room to search beyond ~15Nm.
I think it would be ‘stupid’ if OI would limit themselves only to a high speed nose down scenario within ~15Nm of the 7th arc at this stage.
Too much conflicting evidence still.
Than it’s better to include both possibilities from the get go imo.
@Ge Rijn: You propose that the search extend to 50 NM from the arc without considering that it will restrict the distance searched along the arc. Ultimately, limited resources and time dictate a balance based on probabilities and judgment. As for not searching north of 32S, that seems arbitrary. Further north better explains some evidence, such as the timing of the “Roy” discovery at Mossell Bay and the lack of debris on the shores of Western Australia.
@VictorI
I admit ~32S is a latitude limit based on my own assumptions.
I would surely support an initial search along the 7th arc from ~35S till ~30S within ~15Nm. But as you say choices have to be made.
The several forward drift studies give uncertain and sometimes conflicting outcomes. North of ~30S drifters arrive a year too soon at Reunion and Madagaskar. @MPat’s study shows none of the 177 historical drifters (over 20 years) that passed the search area above 36S reached WA.
‘Roy’ had many big barnacles still attached when first found in december 2015 and it was the most distance piece ever found so far. So this piece sets a ~time marker of ~20 months drifting from the crash site.
North of ~30S this piece should have arrived much earlier imo.
I see the importance of searching along the 7th arc up to ~30S but not with the exclusion of a possible glide after a steep descent.
The ATSB based their search mainly only on the latter and failed to find the plane.
I won’t like to see OI taking the same assumptions the ATSB did and limit their search within ~15Nm of the 7th arc anywhere.
@Mick
“4. 10N most likely has no relationship to a deviation from a flight along LAGOG N877 DOTEN. There is, in fact, no evidence that the simulation airplane was ever on N877 (or N571 for that matter).”
Not sure about LAGOG, but DOTEN sure does seem to be the waypoint the sim study was heading towards. One could imagine that is consistent with a Jeddah route diversion…not sure if heading to DOTEN would be part of a hypothetical MH370 strategy.
@Ge Rijn: I won’t like to see OI taking the same assumptions the ATSB did and limit their search within ~15Nm of the 7th arc anywhere.
My guess is that OI will extend the search to 25 NM or so from the arc, based on the 25,000 km2 priority area recommended by CSIRO.
Hi @Andrew. I thought that if you are in ECON cruise and programme an approach, that descent would occur at ECON speed descent. I’d further understood that the switch to ECON speed, denominated in KIAS, occurs as soon as you reach T/D; and that the switch to VNAV ALT occurs as soon as deviation from vertical path has surpassed threshold. So that if you go past T/D you very soon end up in VNAV ALT at a KIAS speed of around 272kts. Is all of the above incorrect?
@Paul Smithson
My apologies, you are correct for the case where the cruise level is around FL350. I was thinking of a higher level cruise, where the aircraft’s CAS at the ECON cruise Mach no. is less than the ECON descent CAS. In that case, the aircraft will initially descend at a Mach no. equal to the ECON cruise Mach no. until the CAS catches up to the ECON descent CAS at the CAS/ Mach transition altitude.
For the FL350 case, if the ECON descent CAS is 272 kt and the ECON cruise Mach no. is more than about M0.80, then the CAS in the cruise will be more than the ECON descent CAS. In that case, the FMC will calculate a level deceleration segment at T/D and the aircraft will reduce speed from the ECON cruise Mach no. to the ECON descent CAS while in level flight. Going back to your original question, the last sentence in my previous reply still stands, I suspect the FMC will recalculate the [ECON descent CAS] as the weight decreases, but I’m not sure – I’ve never flown more than a few minutes past T/D!
@Andrew: A couple of weeks ago, Paul Smithson asked me many of the same questions he is asking you, and I performed a simulation of his test case. Among other things, I was surprised to find that the ECON DES speed did not vary with weight. We looked at a descent into WITT in which the MCP altitude was not changed after T/D, which produced some interesting behaviors. I sent you an email with the results.
@Victor
My guess is that OI will extend the search to 25 NM or so from the arc, based on the 25,000 km2 priority area recommended by CSIRO.
I am more interested in the trade-offs between detection of debris than the imaging of debris. Fabricated objects will generally have a much higher reflectivity than objects created by nature. When I gaze at the mountains surrounding my ranch there are many “specular” reflections that leap out at you from various man made objects – cell towers, radio repeaters, abandoned vehicles, old propane tanks,…and many other things. It has to be true that the sound energy reflected off of aircraft debris would behave in a similar manner. I have not seen (nor have I read) anything about the trade-offs relative to scanning at lower resolution (wider swath width) and looking for reflection peaks and subsequently investigating such events at higher resolution. My guess is that the scan coverage could easily be doubled or more by exploiting this effect.
@DennisW: Yes. OI’s mission is to find parts of MH370, which should be “acoustically hard”, and not to map the seabed. That will probably make the data that is generated less useful, but it should also reduce the cost and improve the speed of scanning.
@Victor
Excellent.
@Victor
I would also like to know the results of your descent into Banda Aceh (WITT) experiment.
Have you ever tried it from 6 nautical miles south of Penang with a diversion programmed to Banda Aceh (WITT) via Vampi-Mekar-Nilam-Sanob-BAC-route discontinuity at FL350/Econ Cost Index 52 cruise with Auxiliary Power Unit on and unresponsive crew?
Where was the aircraft at 1825:27 in the above example? Was it turning left at Nilam and exposing its right High Gain Antenna mounted on the right side of the fuselage?
Where did the aircraft end in the above example? Was it beyond 40 nautical miles past the Bayesian Hotspo
What was the speed profile passing Banda Aceh if your destination in the FMC is Banda Aceh? Was it 272/240/272 KIAS?
What was the speed profile passing Banda Aceh if after the route discontinuity your destination is still Beijing? Was it Econ cruise profile: Mach 0.82 reducing to M0.78?
@Victor. Scanning through I had missed Gysbreght’s 7:12 AM post and came across it by chance, which has happened before.Perhaps you could draw attention to release of delayed posts?
@Paul Onions: No, I haven’t repeated your test.
@Victor
@ventus45
Victor, in your 7.58am response to ventus45 with respect to the fixed thrust setting caused by a disengaged autothrottle giving rise to a gradual ascent in FLCH, you say,
“Note that for this scenario to occur, the pilot would have to manually select a higher altitude in the MCP.”
I don’t think that is correct. You don’t have to select a higher altitude in the MCP just a different altitude (higher or lower) using FLCH.
Using FLCH switches the AP mode to “speed-on-elevator” and it remains in that mode until the target altitude is reached when it then reverts to “path-on-elevator”. As the name suggests, in “speed-on-elevator” mode the AP controls speed using pitch via the elevator and ascents/descents are controlled using thrust typically via the autothrottle. Without the autothrottle engaged and absent pilot intervention, there’s no change to thrust and therefore no change to altitude but the AP remains in “speed-on-elevator”. Over time the airplane becomes lighter as fuel is burned, the fixed thrust setting means that it will tend to fly faster which the AP promptly corrects by pitching the nose up slightly and you get an ascent. It is a very gradual process. In the case of MH370 had the airplane been in “speed-on-elevator” mode with a disengaged autothrottle at the IGARI turnback then the total change in altitude over the ensuing 7 hour flight is only about 4,000 feet (a smidge under +10 fpm).
As an aside, failure of either autothrottle servo motor (ASM), the small electric motors that physically move the thrust levers to command changes to thrust, will cause the autothrottle to disengage. The circuit breakers (2.5 amp) for the Left and Right ASMs are mounted on the P11 Overheard Circuit Breaker Panel on the flight deck.
@Mick Gilbert: I don’t think that’s correct. With A/P engaged, with or without the A/T connected, a climb won’t exceed the altitude in the MCP window, even when in FLCH SPD mode.
To test this in the PMDG777, I went to level flight, SPD, HDG HLD, ALT at FL340, M0.84. I then disconnected the A/T, set altitude in the MCP to 33000 ft, selected FLCH, which was shown in the FMA as [Blank], HDG HLD, FLCH SPD. I then gradually reduced the fuel. As the weight fell, the angle of attack reduced and the speed increased. The altitude remained constant at 34000 ft. Essentially, it behaved just as in ALT mode. I then did the same experiment except I changed the MCP altitude to FL350 instead of FL330. Now when fuel was reduced there was a gradual climb which stopped at 35000 ft.
If you have documentation that says with the A/P engaged you can climb and exceed the altitude in the MCP window, I’d like to see it.
@Victor
@Paul Smithson
Re: “I was surprised to find that the ECON DES speed did not vary with weight.
I have not come across equivalent guidance from Boeing, but the Airbus publication Getting to Grips with the Cost Index suggests that the aircraft weight has a negligible effect on the ECON descent speed. This page shows that the ECON descent speed for the A340 only varies by about 3 kt for the weight range 160-190 tonnes with CI=50. I guess the B777 FMC uses the predicted weight at T/D to calculate the ECON descent speed and that value is then frozen once the aircraft enters the descent phase.
“We looked at a descent into WITT in which the MCP altitude was not changed after T/D, which produced some interesting behaviors. I sent you an email with the results.”
Thanks for your email Victor. I was surprised to see the target speed increase back to the ECON descent speed as the aircraft headed further away from the active waypoint (CF17). I know Paul mentioned that behaviour earlier in the discussion, but it’s not something I have seen previously. The FMC obviously keeps monitoring the vertical profile as the aircraft flies away from the active waypoint. The target speed seems to revert back to the ECON descent speed once the distance from the active waypoint is sufficient to put the aircraft above 10,000 ft if it were flying the ideal descent profile.
@Victor
Victor, as you can see here with regards to pitch modes, the B777 FCOM states,
“FLCH SPD (active) – pushing the MCP FLCH switch opens IAS/MACH window
(if blanked). Pitch commands maintain IAS/MACH window airspeed or Mach.” (my bolding).
What was displayed in PFD pitch flight mode annunciation when you ran that test?
@Victor
Further to the above, if you think about the logic of FLCH process for a descent, as soon as you press the FLCH switch after selecting a lower altitude you are exceeding the altitude in the MCP window.
@Mick Gilbert: Please read what I wrote. I said that the A/P would not allow a CLIMB above the MCP altitude (when not near overspeed, of course). It also won’t allow a DESCENT below the MCP altitude (when not near stall, of course). It doesn’t matter whether the altitude is changed using VNAV, FLCH, or V/S, or whether the A/T is connected or disconnected.
You asked what the pitch mode annunciation was. I already told you it was FLCH SPD. It remains in FLCH SPD until the MCP altitude is captured, which won’t occur if the altitude is set lower than the current altitude and the weight is reduced, all while holding thrust constant.
Rather than reduce the weight, the same effect can be observed in a more pronounced way by increasing the thrust. So we start at FL340 in ALT mode, disconnect the A/T, set the MCP altitude to 33000, hit FLCH, and manually increase the thrust. Rather than climb and maintain the MCP speed, the plane will increase in speed and hold altitude, unless the MCP altitude is increased past 34000, and then only until the MCP altitude is captured.
@Victor
Thank you for your response, Victor. Have you read the FCOM description for FLCH SPD? Apart from the reference already provided there is this (B777 FCOM, Automatic Flight – Controls and Indicators, pp.4.10.8-4.10.9) ;
“Flight Level Change (FLCH) Switch
Push –
• selects FLCH SPD pitch mode
• FLCH SPD pitch mode displays in green (active) on PFD flight mode annunciation
• when IAS/MACH window closed, it opens to the FMC target speed, if valid. If not valid, the IAS/MACH window opens to the current speed
• when IAS/MACH window open, it displays command speed
• when changing from TO/GA to FLCH, IAS/MACH window displays highest value of current speed or selected speed
• AFDS pitch holds selected speed. When selected altitude captured, pitch flight mode annunciation changes to ALT
• A/T operates in THR, followed by HOLD mode in descent. When selected altitude captured, A/T mode changes to SPD
• A/T advances or retards thrust levers to provide 500 FPM vertical speed for each 1000 feet altitude change
• AFDS attempts to reach the MCP selected altitude within two minutes if able with available thrust. Otherwise, A/T uses IDLE or CLB thrust to reach the MCP selected altitude
• with a higher altitude set in the altitude window, reference thrust limit changes to CLB when CRZ displayed or to CON with an engine inoperative.”
The behaviours that you are describing for the simulation program are not consistent with the behaviour described in the FCOM, specifically that when FLCH SPD is selected “AFDS pitch holds selected speed.”. I can’t add anything to what Boeing has written about their airplane.
@Victor
On an entirely separate and very much sadder note, Australian aviation journalist, Ben Sandilands, lost his lengthy fight against cancer last Friday evening. I know that Ben followed and often reported on proceedings from your blog (and before it, from Duncan’s). Ben was very much an “old school” journo, sometimes he wasn’t right but he was always forthright. He will be missed.
@Mick
I can’t add anything to what Boeing has written about their airplane.
Of course, Boeing was represented in the SSWG as was the manufacturer of the AES (who said nothing about overshoot transients).
These discussions are getting very old and very silly to me. It is a classic example of “when you are a carpenter, the whole world looks like a nail.” Good grief people, move on with your lives miserable as they may be.
Do we think we are smarter than the manufacturers of the equipment? Do we think the manufacturers are part of a plot to make the airplane disappear?
@DennisW
Has Ami had you splitting wood again?
@Victor
Regarding our discussion on the A/P not allowing a CLIMB above the MCP altitude, you are correct. I had misinterpreted a prior separate discussion on the matter. My apologies.
@Mick Gilbert asked: Have you read the FCOM description for FLCH SPD?…
I understand quite well how FLCH works. I also understand how MCP altitude constraints work, which you seem to neglect.
@Mick Gilbert: Regarding our discussion on the A/P not allowing a CLIMB above the MCP altitude, you are correct. I had misinterpreted a prior separate discussion on the matter. My apologies
Thank you. I’m glad we reached agreement.
@TBill
I said, “10N most likely has no relationship to a deviation from a flight along LAGOG N877 DOTEN. There is, in fact, no evidence that the simulation airplane was ever on N877 (or N571 for that matter).”
You said, “Not sure about LAGOG, but DOTEN sure does seem to be the waypoint the sim study was heading towards. One could imagine that is consistent with a Jeddah route diversion … ”
Mmm … Can you explain your rationale please, Bill? “Heading towards” implies it was “coming from” somewhere. The previous data point is 500 nm away and a track between the two doesn’t align with DOTEN.
More broadly, I think that there may be a marked difference between the way many of us conceive of how simulators are used and how a senior commercial pilot and Type Rating Examiner, such as Captain Shah, might actually use one. Many of us think each simulator session is representative of one flight (take-off, climb, cruise, descent, landing), typically either rehearsing a flight to come or recreating one that has taken place. That’s not necessarily how flight crew members, particularly instructors/examiners, might approach a simulation session. In many cases simulation sessions for commercial pilots, particularly during training, are a series of exercises, often quite unrelated (eg a TCAS alert and avoidance maneuvering followed by a stall at 5,000 feet followed by an accelerated climb to FL350 followed by recovery from a dual engine failure). For qualified flight crew, six monthly proficiency checks and twelve monthly Line Operational Simulations (LOSs) are normally constructed around “one flight” scenarios whereas six monthly recurrent training sessions tend to fall into the “series of exercises” category.
If we look at the six data points from the Captain’s flight simulator with a “one flight” mindset then that is what we see, one continuous flight from Kuala Lumpur terminating in the Southern Indian Ocean. If we look at the data points with a “series of exercises” mindset we might see something else, three or possibly four separate exercises, separated by the airplane being dragged from one location to another. I’m not saying that one perspective must be right and the other, by corollary, must be wrong, I’m just saying that there are different ways of viewing that sparse data set.
@Mick Gilbert: If you think a TRE would use the FS9/PSS777 to practice exercises of the type you mentioned, you are sorely mistaken. The fidelity for simulating abnormal conditions is not close to being realistic, nor does it have complete checklists that a trained pilot would follow. The FSX/PMDG777 is much closer to behaving as documented in the FCOM, but even that model has some important limitations. For instance, when I used the PMDG777 to simulate fuel exhaustion, I had to manually do things like force a failure to secondary mode and inhibit the IDGs from powering the AC busses at idle spool speeds. Any 777 pilot would be very aware of the obvious limitations of either aircraft model, but especially the limitations of the FS9/PSS777.
@Mick
Has Ami had you splitting wood again?
Stacking and chain saw work. Ami has been doing all the splitting.
We are all saddened by Ben Sandiland’s passing. Ben dared to ask questions about the disappearance of MH370 that few others were willing to ask. He continued to passionately contribute even while he battled cancer. He was a reader of this blog, and through his column, he helped some of us reach a broader audience. Rest in peace, Ben.
Read his articles often. No sign he was battling a fight like this in between. Great respect.
The unbearable lightness of being comes up in my mind.
R.i.p. for him. At least he and his friends and family knew what was coming I suppose. All the victims of MH370 deserve the same. To rest in peace and acceptance. The plane must be found.
Otherwise no closure will be possible for those deseaced and the loved ones left behind.
Read his articles often. No sign he was battling a fight like this in between. Great respect.
+1 Ge Rijn
Especially the respect part – a model for what a journalist should be.
@Victor. Contract negotiations re wreckage finds.
There is the possibility of an in flight breakup from a spiral, pull up or pitch up. I have mentioned MH 17 in this context: two main debris sites, well separated. That resulted from a fuselage break, the main front section ‘gliding’.
The Silk Air 737 ended in a very high speed descent only because a pilot applied full manual down trim beforehand then held the nose down. Otherwise it would have pitched up, according to Boeing.
If MH370 were in a spiral, speed becoming excessive, most likely the pitch up would translate to a tightening spiral then break up. If not in a spiral, then a pitch up (or piloted pull up) could lead likewise to a break up. (If not the aircraft could recover and possibly fly some distance, with phugoids… but that is another issue).
If MH370 broke, that might well be at a wing, but not necessarily: it could be the fuselage, the tail coming off. That could lead to well separated debris fields, the recorders ending up well away from the main wreckage.
Because the ultimate outcome would be beyond aircraft limitations it would not be apparent during simulations. However an ALSM simulation resulted in a spiral that when analysed evinced high g. That I think is relevant, despite no simulations envisaging tank residual fuel.
IMO the Silk Air analysis by Boeing is likely to be relevant to the 777, meaning the above is not just a hypothetical, to be left in the ether as hitherto. A mid air breakup, the front section not necessarily hitting the sea nose down, could help explain some ambivalent characteristics of the debris.
@David: Yes, I agree that finding the main debris field will be challenging.
@Victor
I did not say that Captain Shah was practising any of those non-normal items. I provided the example of a sequence of non-normal items (taken from an actual B777 flight simulator training session) to illustrate how typical simulator training sessions are constructed. The point that I was making is that the approach taken by commercial pilots, in particular instructors/examiners, to flight simulation sessions is much broader than the simple “one session = one flight” perspective that underpins the join-the-dots interpretation of the Captain’s simulation data. In short, there is more than one way to interpret the data.
The simple fact of the matter is that there is insufficient data to conclude that the data points are from a single complete, contiguous and coherently constructed flight, they might just as likely represent three or four separate exercises, separated by “dragging”, that are completely unrelated. That is the virtue of simulation programs, they allow the user to undertake multiple disparate exercises in one session.
We can say with reasonably high confidence that the simulation airplane was “dragged” from one location to another on multiple occasions during the simulation session. Moreover, we know that the “dragging” process is not constrained; the simulation airplane can be “dragged” from one point to anywhere else on the globe completely independently of its path at the originating point. Thus, there may be no relationship whatsoever between the location from which the simulation airplane was “dragged” from and where it was “dragged” to. Suggesting that there is a path or route between two locations under such circumstances is at least misguided and quite possibly wrong.
Had the user wanted to model one continuous and related flight the option of using the time acceleration function was available. Using time acceleration models fuel usage and preserves the relationship between two points, “dragging” does not.
Accordingly, the depiction of a “simulator path” connecting the various data point locations as being a route taken by the simulation airplane sits somewhere between inference and speculation. To illustrate such a path as following N571/N877, when there is no evidence that the simulation airplane was ever on either of those airways, is even more highly speculative.
Additionally, the fact that there is no evidence that fuel usage was modelled accurately between the data points supports the possibility that the simulation session is more likely a sequence of separate, and possibly unrelated, exercises. With evidence of such little regard to fuel usage, it is not unreasonable to infer that the simulation session was not a fuel planning exercise nor was it meant to model an actual flight, such as MH150. Further, given your experience that the far more sophisticated PMDG simulation program fails to accurately model airplane systems behaviour on fuel exhaustion, it is probably not unreasonable to also infer that the less sophisticated PSS simulation program would not have been used for that purpose.
@Mick
That relevancy of the simulator data lies in the SIO data points. Does not matter how or if the data points were connected (dragged or contiguous) or not. How in the world can you possibly ignore the SIO data points regardless of how they might have been created?
You are asymptotically approaching the whacko category.
@Mick Gilbert: Time acceleration is not as perfect as you might believe. First, even at 16X time acceleration, dragging is much faster. Secondly, time acceleration, especially around turns, causes flight instability on the PSS777, which anybody that has actually used the program understands.
There was a time not so long ago that a number of people did not even believe the sim data sets were all from a single session, and I received a lot of unkind comments for suggesting they were. There were claims that the points were cherry-picked among thousands, the chronological order could not be determined, and the simulation could have been performed months before the shadow volume data of Feb 4. Of course, this completely ignored the fact that the sim data sets were found grouped together in a single shadow volume with no other flight data. This made them unique, as I have said for many months.
With the additional information from the ATSB showing that the time stamps for the data sets were Feb 2, chronologically ordered according to the flight path, and all timestamps within an hour, we know the data sets are from a single session. But now, you propose that although it was a single session, the data sets might represent multiple flights since this is what pilots do with simulators.
We don’t know for sure why the captain was practicing fuel exhaustion exercises deep in the SIO, and why he chose to save a series of data sets with consecutive positions at KLIA, the Malacca Strait, the Andamans, and the SIO, and with progressively decreasing fuel levels. The likely explanation is that points are related to each other and represent a single flight, irrespective of whether the position and fuel levels were manually advanced during the flight, and irrespective of whether we know the exact path between the positions. We can’t definitively prove that the points represent a single flight, but in my book, it is by far the most obvious explanation. And it would be an extraordinary coincidence if the sim data sets were not related to MH370.
@Victor
@DennisW
You will note that I have never contended that the SIO data points are irrelevant. Nor have I suggested that the “multiple exercises” (as opposed to the “single flight”) perspective is antithetical to malicious intent; the two are not mutually exclusive.
What I principally have a problem with is supposition, interpretation and inference being presented as fact. First and foremost in the supposition as fact category is running a string around the map pins and saying, “That’s the flight path.” Not only wouldn’t I bank on it, I’d bet against it. Worse still is depicting WMKK B446 GUNIP VAMPI N571 LAGOG N877 DOTEN as the “Simulator Path”.
Then there’s the contention that the turn at 10N represents the turn towards 45S1. It is now reasonably clear that the simulation airplane was in a 20° AOB left turn when it was dragged to 10N from somewhere after 5N (and probably before VAMPI). That means that the turn may not even be (and I would argue, probably is not) relevant to 10N, its relevance is to a position 500 nm away from 10N (where, just by the bye, it would have the simulation airplane turning towards Banda Aceh).
I also have a problem with invoking the user fiddling with fuel levels to explain what would otherwise be premature fuel exhaustion at 45S1 if flown directly from 10N. You don’t need to invoke fiddling with fuel levels to explain the data at 3N, 5N or 10N; “fly (and burn) and drag” or “drag and fly” can easily explain the data at those points. Fuel exhaustion at 45S1 suggests either one or more intermediate, uncaptured points (a possibility that the ATSB alludes to) or fuel exhaustion elsewhere with the airplane being dragged to 45S1 in that condition.
Victor, what is the basis for your saying that it is a fact “… that the sim data sets were found grouped together in a single shadow volume with no other flight data“? There is no dispute that the RMP’s Flight Simulator Analysis report states that, “All these coordinates are found in a single Volume Shadow file
Information (VSI) named {OOd7ef6c-8bcb-1Ie3-b3f7-ee8a9181afad} {3808876b-c176-4e48-b7ae-04046e6cc752} dated February 3, 2014.” but I’ve yet to see any reference to there being no other flight data in that VSI.
As to the history of the Captain’s flight simulator data, up until 12 October 2017, when you released the information passed to you by the ATSB that the simulator session lasted for about one hour, the chronological order of the data files could not be determined. Up until only a couple of weeks ago any suggestion that all the data files were contemporaneous was pure conjecture.
Further to the information provided to you, in response to an email from me, the ATSB has stated,
“All files except the final (partial) file contained a [DateTimeSeason] field which contains values for Day, Year, Hours, Minutes, Seconds, Season.
The files with the field had the common values of Day=33, Year=2014 and Season=Winter
The [DateTimeSeason] field in the files indicated 15:26 to 16:38 (hh:mm).”
Now, while I strongly suspect that all the data points were created in one session, the fact that five of the six data points are timestamped within a period of 72 minutes does not eliminate the possibility that they were created over more than one session. The individual time stamps for each data point are what is needed.
As to your question do I “… propose that although it was a single session, the data sets might represent multiple flights since this is what pilots do with simulators“. No, what I propose is that the data sets might represent multiple activities or exercises that may or may not be related to one another. That proposition is not solely based on “this is what pilots do with simulators” but because that is what the data suggests.
Dennis, if I do happen to be categorised as “Whacko” I do hope that I manage to scrape into the “Respected” subcategory.
@David, report from Adam Harvey of ABC News has the following paragraph:
“Deputy Transport Minister Datuk Ab Aziz Kaprawi said that cabinet ministers had agreed “to prepare a special allocation to the Ministry of Transport amounting to between US$20 million up to US$70 million if MH370 aircraft wreckage is successfully found within 90 days”.
It’s the “within 90 days” that made me sit up. A bit optimistic, I’m thinking, considering the challenge ahead, onforseen operating difficulties, weather etc.R
@Rob. Thanks. For those who would like to read the article:
http://www.abc.net.au/news/2017-10-30/mh370-search-us-company-promised-millions-for-trace-of-flight/9100818
25000 sqkm as per the ATSB as I read it. Why a time limit at all is unclear. Maybe that stipulation instead should read to start within 90 days of contract? Similarly the 25000 may be a minimum requirement?
Australia to contribute just ‘technical assistance’, unspecified. China contribution nil?
Do not know of Adam Harvey or how well informed.
Quoting ‘Deputy Transport Minister Datuk Ab Aziz Kaprawi said […] if MH370 aircraft wreckage is successfully found within 90 days”.’
Kaprawi has repeatedly been behind the curve on detail but mention of 90 days, and that payment is being made through MoT/MY, is significant.
Malaysia’s previous search contracting, with Go Phoenix & Phoenix International during 2014-2015, was exercised through Petronas and DRB HICOM.
That previous arrangement, under the auspices of the two companies’ CSR activity, perhaps permitted more flexibility by contracting in the commercial realm while, ultimately, the government paid in the form of tax incentives that encourage CSR work. At the outset of the Phoenix International deployment on Go Phoenix, in Oct 2014, a Petronas exec stated Petronas had commintted funding through to Feb 2015 at which time they’d “sit back & think again”. They did continue to work until Jun 2015.
Governments can’t do flexibility in contracting. It’s fixed scope plus change control.
ATSB’s requirement of Fugro was 200km² per day for which two boats, each with one deep-tow vehicle, were deployed. 25,000km² over 90 days requires 277km² per day. I suspect Adam Harvey is ‘cobbling’ numbers together without any substantial coherent analysis, the focus of his headline is the ‘prize‘, disregarding the effort expended in attempting to attain it.
@Mick Gilbert: We are not going to agree, and I’ll let you get in the last word. I think you downplay the most obvious of scenarios, while you think I ignore other likely possibilities. Readers here can decide for themselves.
@David, @Don Thompson: Some quick math. The 25,000 km2 priority area extends to about 32.6S latitude on the arc. If the search continued along the arc to the north of this point with a continuous width of +/-25 NM (+/- 46.3 km), each degree of latitude searched along the arc corresponds to about 12,780 km2. For instance, a search from 32.6S up to 26.6S latitude would require 76,673 km2 beyond the initial 25,000 km2. Starting south and working towards the north extends the season of favorable weather.
It would be very interesting to know what a realistic expectation is for the coverage per day.
@ALSM: You may have missed my comment of October 28, 2017 at 7:12 am because it was “awaiting moderation” for several hours. Therefore I’ll post it again. I’ve also expanded the text with additional explanations in case the original was not sufficiently clear, and corrected typos.
RE YR comment of October 27, 2017 at 1:45 pm, let’s get the facts right:
“a. an extremely high rate of descent began within seconds of FE”
Do you consider 5000 Ft/min two minutes after FE an “extremely high rate of descent”? And do you mean seconds before 00:19:29 rather than “within seconds of FE”?
“b. 9M-MRO’s vertical acceleration by 00:19:37 was ~0.68g”
Based on your numbers the average vertical acceleration between 00:19:29 and 00:19:37 was ~0.65g. The vertical acceleration at 00:19:39 may have been greateer or less than 0.65g if it varied in that time interval. Since a certain deflection of the control column commands a certain vertical acceleration (by virtue of the B777 fly-by-wire pitch control law) it may well have been constant in that time interval. If the vertical acceleration is assumed to be constant, then the rate of descent must have started to increase from about 2000 ft/min to about 5000 ft/min 2.4 seconds before 00:19:29.
“c. given a & b, 9M-MRO must have already descended 10-20k ft feet by 00:19:37”
The steady rate of descent power off at cruise altitude is about 2000 ft/min. Between FE and 2.4 seconds before 00:19:29 the airplane would have lost about 4000 ft or the equivalent in total energy. In the next 10.4 seconds the average rate of descent was (2000 + 15000)/2 = 8500 ft/min and the altitude would have reduced by 8500/60*10.4 = 1473 ft. The altitude at 00:19:37 would then be about 5500 ft less than at FE. If a pilot can command a downward acceleration of 0.65g by pushing the control column forward, he can just as easily command an upward acceleration of 0.65g by pulling the control column rearwards. Recovery from the steep descent could therefore be effected in the next 10.4 seconds after 00:19:37, and requires also 1473 ft of altitude. So at 10.4 seconds after 00:19:37 the airplane could be back at a steady rate of descent of 2000 ft/min at an altitude of about 7000 ft less than at FE, but at a higher speed. Since the excess speed can be converted back to altitude, the manoeuvre would have negligible effect on the glide distance available at FE.
“d. even if a pilot intentionally caused b, given c, that pilot could not possibly have levelled out and glided more than 30-40 nm. A continuation of the steep descent is far more likely, even if a pilot was in control.”
Your first sentence has been dealt with under c. above. I don’t share the opinion you express in the second sentence. If the purpose of the steep descent was to (re)gain airspeed, it is unlikely to have continued unchanged after 00:19:37.
@Mick
Dennis, if I do happen to be categorised as “Whacko” I do hope that I manage to scrape into the “Respected” subcategory.
Yes, of course.
@VictorI
I imagine some priorities could be made also.
The CSIRO 1/2/3 high priority regions actually cover a relatively small area. If those are searched first and the plane is not found there I think the latest CSIRO theory can be abandoned and there would be no urgence to search the rest of the CSIRO area till ~32.6S.
OI could f.i. decide to search north near along the 7th arc starting form ~32.6S after those CSIRO 1/2/3 priority areas.
If then nothing is found still they could choose to search in more width at a certain area along the 7th arc.
I mean essentially OI could split those 25.000km2 up in different areas that don’t have to be connected.
This would give them flexability also if new information surfaces.
Maybe other debris get’s found during the search or conclusive evidence comes forward on how specific debris seperated.
Just searching that 25.000km CSIRO area would be too limited and a recipy for failure I’m affraid.
We already know MH370 is not near the 7th arc till ~32.6S.
It hasn’t been a direct plunge from 00:19 onwards at ~15.000ft/min RoD till impact. Otherwise the plane was found in the searched area.
@Ge Rijn: Just searching that 25.000km CSIRO area would be too limited and a recipy for failure I’m affraid.
When you hear reports that only the CSIRO-recommended area of 25,000 km2 will be searched, either that is said either out of ignorance, or to deliberately spread false information. There has been an incredible amount of false information about both the plans for the search and about Ocean Infinity.
@VictorI
I trust you know more than I do about OI and their plans. Kind of reassuring. I have only the common media on this.
Does the 90 days stick? Or is this also ingnorance or false information?
It seems a very short time to me considering OI and no one else have ever done this before.
@Rob
It’s the “within 90 days” that made me sit up. A bit optimistic, I’m thinking, considering the challenge ahead, onforseen operating difficulties, weather etc.R
The 90 day statement is not news. It was made in an article which appeared last Friday (10/27).
https://themalaysianreserve.com/2017/10/27/govt-expected-spend-additional-us70m-search-mh370/
Lots of weirdness being reported relative to the OI search “discussion”:
1> 90 days?
2> payment on recovery?
3> third party verification?
At this point I think we would be well-advised to ignore the journalism relative to OI.
DennisW said: At this point I think we would be well-advised to ignore the journalism relative to OI.
@DennisW, @Ge Rijn: I certainly wouldn’t assume that it is 100% factual.
@Victor
Even the payment range of $20M to $70M has not been explained at all.
To simplify, it appears there are just two categories of people in the world:
1. Whackos – those with whom DennisW disagrees.
2. Non-whackos – those with whom DennisW agrees.
This makes it easy to figure out which category you are in.
@Gysbreght
Re: Your October 30, 2017 at 8:22 am post:
“@ALSM: You may have missed my comment of October 28, 2017 at 7:12 am …”
I did not miss your original post. It was your typical diversionary nonsense, not worthy of serious a reply. Trying to pick fights over things like the exact numerical value of the acceleration (0.65 vs. 0.68 gs) or the correct adjective to characterize a 5000 or 15,000 ft/min descent rate is not in anyway relevant to the topic, which was, the best estimate of the 7th arc search width.
@ALSM: “… a 5000 or 15,000 ft/min descent rate is not in anyway relevant to the topic, which was, the best estimate of the 7th arc search width.”
My point exactly. The best estimate of the 7th arc search with can not be inferred from the descent rates at 00:19:29 and 00:19:37.
@Gysbreght: You tell the tale of two pilots:
1) The incompetent pilot who gives a nose up input after fuel exhaustion and causes the plane to stall and eventually reach a high descent rate of 15,000 fpm.
2) The proficient pilot that expertly recovers from a high descent rate and glides the plane for many miles at an efficient descent angle.
How do you reconcile (1) and (2)?
@Mick
That is interesting time stamp info for the simulator runs. Are you saying that is recent info to you from ATSB? Should we be asking for more data from the runs? (which we may or may not be privy to, but at least we would know the response).
As far as the time stamp, that would appear to be the date/time of the simulator cases, however, for some reason if I create a new case in FS9 right now today, my FS9 flight time setting is defaulting to 11-Oct-2017 for some reason. One can of course change to any Time/Date. Seems the Date/Time, if it was instead intentionally set, would be roughly consistent with the of arrival at 45S1 assuming MH150 take off that day.
@Victor Iannello: “How do you reconcile (1) and (2)?”
I don’t have to. The descent rate of 15000 ft/min could result from the recovery from a stall, or from a surprised over-reaction to an unexpected stall warning (stick shaker). Pushing the nose down then pulling it up again does not require an expertly proficient pilot. Either an inexperienced or an experienced pilot could have done this, although I am leaning toward the former.
Now consider a proficient pilot, seven hours after high-jacking the plane at IGARI, after nearly six hour flying at roughly constant speed and altitude, on headings roughly due south, only awaiting fuel exhaustion before pushing the nose down to end the flight as quickly as possible. Does that make sense?
@Gysbreght: After a double engine flameout, there is absolutely no way that a proficient pilot would provide a nose up input (which would be required) and get to stick shaker speed. Nor is a recovery from a 15,000 fpm descent followed by an efficient glide as trivial as “pushing the nose down then pulling it up”. That would be a challenge even for an experienced pilot.
(@Andrew: Do you think a novice could easily accomplish this?)
As for your example of a pilot waiting hours until fuel exhaustion and then pushing down the nose, I don’t know if that occurred or not, but it certainly is within the skill set of a 777 captain.
@Victor Iannello: “After a double engine flameout, there is absolutely no way that a proficient pilot would provide a nose up input (which would be required) and get to stick shaker speed. “
Andrew’s simulation showed that the plane left to itself would come quite close to stickshaker speed after a double flameout.
“Nor is a recovery from a 15,000 fpm descent followed by an efficient glide as trivial as “pushing the nose down then pulling it up”. That would be a challenge even for an experienced pilot.”
I’m sure you would not find it difficult at all if you tried it in your simulator.
@Victor Iannello: “a pilot waiting hours until fuel exhaustion and then pushing down the nose, (…) certainly is within the skill set of a 777 captain.”
The captain’s “skill set” is not the issue.
@DrB
You omitted the largest category – “don’t care”.
@Gysbreght said: Andrew’s simulation showed that the plane left to itself would come quite close to stickshaker speed after a double flameout.
The case you cite was for a single engine flameout, A/P still engaged and maintaining altitude as the speed reduced. For a double flameout with no pilot input, the A/P would disengage, the control mode would degrade to secondary mode, and the plane would descend at the trim speed.
I’m sure you would not find it [recovery from a 15,000 fpm descent] difficult at all if you tried it in your simulator.
Your certainty is misplaced. It’s challenging, as I said. It’s hard to keep the wings level, and it’s easy to rip the wings off the plane on the recovery.
@Victor Iannello: “The case you cite was for a single engine flameout, A/P still engaged and maintaining altitude as the speed reduced.”
Thank you for the correction. The airplane came close to the stickshaker before the second flame-out and stabilized at just 4 kt above the stickshaker speed until the second flame-out. The point is that at that point the pilot may have become aware of the situation and over-reacted to it.
@Victor
@Mick
@ventus45
@Rob
Re: Simulator Cases
>>For those interested in MH150 Time Tables, there are two documents.
(1) From the appropriate MAS timetable Booklet
Flight MH150 was 15:15 Take off until 18-Jan-2014 (Days 1 34 6 )
Flight MH150 was 15:15 Take off 19 to 27-Jan-2014 (Days 1 34 67)
after 27-Jan-2014 the MH150 time table was modified per below announcement:
(2) Malaysia Airlines Increases Jeddah Service in Feb / Mar 2014
“Malaysia Airlines from 28JAN14 to 29MAR14 is adding 2nd daily Kuala Lumpur – Jeddah service, on board Boeing 777-200ER aircraft. Reservation for the new MH168/169 service is now open.
MH150 KUL1145 – 1600JED 772 D
MH168 KUL2230 – 0245+1JED 772 D
MH169 JED0500 – 1835KUL 772 D
MH151 JED1730 – 0705+1KUL 772 D
MH169 begins from 29JAN14 until 30MAR14.
From 30MAR14, MH will operate 1 daily flight as MH168/169, which means the oneWorld member shifting operational schedule to night-time departure from KUL.”
>>I default to Victor re: potential significance, but it would appear that the 15:26 time in the saved simulator case is close to the 15:15 take off time prior to the schedule expansion on 28-Jan. At the moment I am thinking the Time/Date in Microsoft Flight Sim is shown as the last saved case, but I need to do some testing to verify that.
@TBill: “At the moment I am thinking the Time/Date in Microsoft Flight Sim is shown as the last saved case, but I need to do some testing to verify that.”
i your verification tests, could you also look into what happens to the Time/Date if you use the fast-forward option? Does the Time fast-forward or not?
Gysbreght: When you deliberately quote people completely out of context to mislead readers, you make a fool of yourself. You should be ashamed.
You stated at October 30, 2017 at 1:39 pm:
——————-
“@ALSM: “… a 5000 or 15,000 ft/min descent rate is not in anyway relevant to the topic, which was, the best estimate of the 7th arc search width.”
“My point exactly. The best estimate of the 7th arc search with can not be inferred from the descent rates at 00:19:29 and 00:19:37.”
——————-
That is another of many lies by omission. My complete sentence, which you butchered, was:
“Trying to pick fights over things like the exact numerical value of the acceleration (0.65 vs. 0.68 gs) or the correct adjective to characterize a 5000 or 15,000 ft/min descent rate is not in anyway relevant to the topic, which was, the best estimate of the 7th arc search width.”
In context, it is clear I had no intention whatsoever to say what you claim I said. Of course 5000 or 15,000 ft/min descent rates are very important in estimating the search width. I have no doubt you are 100% aware I was referring to your ridiculous argument that my use of the adjective “extreme” to describe the 15,000 ft/min descent rate somehow discredited the whole thread of logic.
@ALSM: My out-of-context quote was of course deliberate and ‘tongue-in-cheek’. My apologies if that upset you.
Your reply limited to the first point addressed in my comment just for completeness and for the purpose of the more significant aspects I raised later my comment ignored what I was trying to bring across. That is that those 8 seconds do not define what could have occurred in the 20-odd minutes of descent that lay ahead.
@TBill
Good work TBill. And wise of you to default to Victor on significance of the 15:26 SIM time.
CORRECTION: Please read “… later in my comments”.
@Victor
Ron is a typo. There is no Ron, trust me. There is only a Rob. My mobile has autocomplete syndrome
@DennisW
“Lots of weirdness being reported relative to the OI search “discussion””
Apologies Dennis for making something out of nothing with the 90 days thing. I don’t mind being associated with weirdness but if you should ever put me in the whacking camp with those other unfortunates, it would send me over the edge.
@Rob
No fear. You are pure of heart. BTW, I do think the 90 day thing is significant. I have no idea what it could mean in the search/payment context.
Gysbreght asked: could you also look into what happens to the Time/Date if you use the fast-forward option? Does the Time fast-forward or not?
Of course time accelerates when the time acceleration option is selected.
@DrB – A while back, someone posted the idea that the initiation of a SLOP caused the 18:22 radar return. That means we have 3 major changes around this time:
A change in direction
A change is speed
Turning the AES back on
This would indicate a change in strategy (unsuccessful negotiations, etc.) or a change of control from one person to another. It’s also possible that the original PF regained control later on but didn’t disable the AES. The change in control is one of the few explanations for the AES reboot. I wonder if the escape hatch could be breached after an hour or so?
A few of us had calculated a weight of 210 mt (so 35.6mt fuel) at 18:22. How accurate is this using your fuel model?
As for all of the calculations, I wonder about the accuracy of the following:
The FCOM gives methods for determining the “break-even” speed. In other words is it worthwhile to change altitude for a reduction in head winds? That suggests that the winds can vary with altitude (plus they gust and seem to change direction often). If we do not know the flight level during the entire flight, how sure can we be of the winds? Even your 6 kts tolerance could be 30 kts over a 5-hour flight. Correct?
I believe you found that the temperature was 10°C above Standard and this would have an adverse effect on fuel consumption. Does it make sense that the temperature could maintain this offset over the entire flight?
@Victor
We may not agree on interpretations of the data but surely, if we want readers to decide on a truly objective basis, we can agree on the importance of clearly separating fact from assumption, inference and supposition.
@Victor Iannello: Thank you for clarifying the time acceleration option. Does that mean that the time actually spent in that February 2 simulator session could be considerably less than the 1:12 hh:mm between the time stamps?
@TBill
Re: “That is interesting time stamp info for the simulator runs. Are you saying that is recent info to you from ATSB?”
Yes. Subsequent to Victor’s revelation of the roughly one hour “session” time on 12 October I wrote to the ATSB requesting further details. The 15:26 to 16:38 (hh:mm) information was provided to me in their reply.
“Should we be asking for more data from the runs? (which we may or may not be privy to, but at least we would know the response).”
I have; to date I have not received a response.
Now, to explore your observations on timestamping, are you saying that the timestamps might likely refer to the “simulation time” (ie the simulated time of day for the simulated flight) rather than the actual real world time (ie the time at which the user is actually sitting at the PC)? I had (perhaps rather naively) assumed it would be the later.
@Gysbreght: It’s possible that time acceleration was chosen for short periods of time and the actual time passed was less than the duration suggested by the timestamps. We also know that the simulation was paused and parameters were changed, which would have increased the time passed. If the user was moving the position forward, there would be little reason to accelerate time, and there would be reasons to not do it.
@TBill: I think you will see that if you create a flight using Free Flight, the simulation time will default to the current time. There are other conditions where the time defaults to the current time when the program starts. Try it.
@Victor
OK, yes if you start out in the CREATE NEW FLIGHT then you get today’s date. If you run another case first, you get the date of that last case. Of course, the user can change the default TIME/DATE to any time/date.
@Victor Iannello: “It’s possible that time acceleration was chosen for short periods of time and the actual time passed was greater than the duration suggested by the timestamps. “ (My bolding).
Did you mean less rather than greater?
To make a judgment on time acceleration versus time spent in pauses one would need access to the time stamps of the individual locations. I asked the ATSB for those time stamps but their reply indicated only the first and the last. Perhaps worth another try?
@Mick @Victor
“Now, to explore your observations on timestamping, are you saying that the timestamps might likely refer to the “simulation time” (ie the simulated time of day for the simulated flight) rather than the actual real world time (ie the time at which the user is actually sitting at the PC)?”
Yes I believe the info you quoted is the “simulated date and time” of the flight, for example, if I save a case and had set a time in 2014, it shows 2014, or in the future, I could save a 2018 case. As Victor points out, when you create a new flight, the Time/Date default setting is today’s date, or alternately as I found the default time/date can also be populated a prior case you ran. So there is a possibility the first file was saved at approximate real time.
What we would need, that I do not know if we have, is the date/time of the FLT file save.
Another point of interest.
The [DateTimeSeason] field of the recovered files indicated 2 February 2014; 15:26 to 16:38 (hh:mm). On the day the simulation was conducted the PIC was on a rostered day of leave. The following day the PIC was rostered to fly from Kuala Lumpur to Denpasar, Bali and return the same day.
The Shadow Volume that contained the recovered file fragments was dated 3 February 2014. To save the recovered fragments of deleted Flight files in the Shadow Volume on 3 February 2014, the computer must have been operating and an application must have been writing new files to blocks of disk space that had been allocated to the previously deleted files.
Odd.
@Gysbreght
As far as time acceleration in FS9:
The main thing I have noticed is the observed turn radius is wider as you go faster sim rate, and also you can overshoot and make ugly wide turns with oscillations. So I always try to take turns at 1x. Any serious work, if I am working up a real flight path, would have to be verified in 1x speed. Also I always try to move back to 1x before saving a case.
Other than turn radius and general loss of stability, as far as I know the clock and other functions operate well in accelerated time.
@Victor. You say of a piloted recovery in your simulator”…and it’s easy to rip the wings off the plane on the recovery”. Literally or do you mean exceed the flight envelope? What indicates that please?
Pilot black out possible?
@David: High g-loads on wings.
@Gysbreght said: To make a judgment on time acceleration versus time spent in pauses one would need access to the time stamps of the individual locations
No. Neither time acceleration nor pausing has an effect on the relationship between position and simulation time. Manually changing the position does.
(I changed “greater” to “less” in a previous comment.)
@Victor
@Gysbreght
Re: ”After a double engine flameout, there is absolutely no way that a proficient pilot would provide a nose up input (which would be required) and get to stick shaker speed. Nor is a recovery from a 15,000 fpm descent followed by an efficient glide as trivial as “pushing the nose down then pulling it up”. That would be a challenge even for an experienced pilot.
(@Andrew: Do you think a novice could easily accomplish this?)”
I didn’t respond earlier as it was way past bedtime in my part of the world.
Let’s say a low speed event did occur at some point. The recovery from such an event doesn’t normally require an extreme nose-low attitude. However, a novice pilot (or even a startled experienced pilot) might disconnect the autopilot (if it were engaged) and ‘shove the nose down’, causing the rate of descent to increase rapidly over a short time interval. If the speed was low at the beginning of the upset, then a novice pilot might still be able to effect a recovery if the duration of the upset were short and the speed brakes were deployed during the recovery. Unfortunately I don’t have a simulator at hand to try it out.
As Gysbreght noted, the aircraft speed stabilised just above the stickshaker during the simulator experiment. I think he has a valid point that a startled or novice pilot might over-react, as described above. However, that is difficult to reconcile with the estimated one-minute time interval between the second flameout and the log-on request at 00:19:29. One minute is an awfully long time to sit there and do nothing, assuming the low speed was recognised immediately after the autopilot disengaged following the second flameout.
@TBill
@Victor
@ventus45
@Rob
Regarding the mooted MH150/151 MH168/169 schedule changes.
Bill, I don’t think that those changes were ever implemented. When I skim the historical departure/arrival information for January – March 2014 I don’t see any change to the departure time for MH150 (scheduled departure 1515 MYT) and I can’t find any records for MH168/169 at all.
@Mick
Interesting…
@all,
HERE are two MH370 models – one for BTO and one for BFO. Just click on the link in my pubs list for 31 October 2017 to download a macro-enabled EXCEL file.
You can input the aircraft coordinates, flight level, and temperature deviation, and the BTO model calculates the true altitude and the Calibrated BTO value. There are 21 lines of inputs if you want to compute an entire route. As an example, I put in the values from my CTH route fit dated 2017.02.27.
You can also input the true course, ground speed, and Rate of Climb for each line, and the BFO model computes the Calibrated BFO values.
I also included in one table all the available BTO and BFO data from Inmarsat. For the BTOs, the table shows the “raw” reported values and adds the corrections needed in some cases to generate the “Calibrated” BTOs (which are then directly comparable to the model predictions). I also listed the errors for each BTO based on the DSTG guidance.
The table also includes the “raw” BFOs from the Inmarsat data logs. The first correction is for the channel-dependent bias values. The second correction is for the 16 Hz self-calibration step applied at 00:16. The third correction listed is my estimate of the SDU OCXO warm-up transient correction. Adding all three corrections to the raw BFOs gives the “Calibrated” BFOs. I also estimated the BFO errors by summing in quadrature the noise and drift error, the transmit channel calibration error, and the estimated OCXO transient error.
I included some notes in the data worksheet that explains the corrections and error estimates for BTO and BFO.
@Lauren H.,
You said: “@DrB – A while back, someone posted the idea that the initiation of a SLOP caused the 18:22 radar return.”
In my opinion the radar contacts continued until 18:22:12 and then stopped because the radar maximum range of 250 NM was reached.
You also said: “A few of us had calculated a weight of 210 mt (so 35.6mt fuel) at 18:22. How accurate is this using your fuel model?”
My fuel model predicts 209.45 tonnes at 18:22.
You said: “If we do not know the flight level during the entire flight, how sure can we be of the winds?”
We can’t be sure. What I try to do is find a flight level that, in conjunction with the wind and temperature data, gives an acceptable fit to the BTOs/BFOs and also matches the known endurance within the error in my fuel model. That fit synthesizes tailwind errors and, for constant-heading routes, crosswind errors which I add to the GDAS values. I expect those wind errors to match the GDAS errors if the route is the correct one.
You said: “Even your 6 kts tolerance could be 30 kts over a 5-hour flight. Correct?”
No. The GDAS data gives temperature, wind speed, and wind direction every 3 hours at 1 degree spacing in latitude and longitude, and at several pressure levels corresponding to typical cruise altitudes. I interpolate over all these parameters to get a best estimate along the route. However, the wind errors do not accumulate over time, so your 30 kts is not appropriate. 5.7 kts is the only precise, published measurement of the GDAS RMS wind error. The temperature error is probably < 1C.
I assume the GDAS wind readings over time at a single location have the same error as spatially independent readings made at the same time (both 5.7 kts RMS).
You said: “I believe you found that the temperature was 10°C above Standard and this would have an adverse effect on fuel consumption. Does it make sense that the temperature could maintain this offset over the entire flight?”
No, the temperature deviation is only near 10C near FL350 when close to the equator. At greater latitudes the temperature deviation shown by the GDAS data drops to 9C at 22S, 6C at 33S, and 3C at 34S. The declining temperature deviation means that less fuel is burned late in the flight, and the KTAS at a given Mach is also declining with time.
@Victor. “High g-loads on wings”.
The simulator indicates that or is that an impression?
RE: “…and it’s easy to rip the wings off the plane on the recovery”
One of the shortcomings of a simulator is that the user doesn’t feel the g-forces acting on the real airplane.
Returning to the Shadow Volume:
It is odd that nothing is known about the files that were saved on the simulator on 3 February 2014, nor of the time of day that the Shadow Volume was created on the day the owner was rostered to fly from Kuala Lumpur to Denpasar, Bali and return the same day.
Hi Dr.B. You have been busy! It is a great help to have this index of papers, some of which I am now seeing for the first time.
23 Oct. paper on predicted fuel/range with fuel model 5.4.
This is a tremendously useful summary of candidate speed modes and altitudes filtered by predicted fuel endurance. I had hoped that it might have a somewhat more “discriminatory” conclusion but it appears that there is still a surprisingly wide range of options that are compatible with observed endurance.
Is your MEFE for both engines pooled with PDA1.5% or time of final fuel exhaustion (R)? If the latter, please conform PDAs used for R/L for the purpose of the model.
Please also confirm your assumption on speed/altitude between 1720 and 1829 that underpin your assumed “starting fuel load” at 1828.
I couldn’t see in your tables the “southern latitude limits” [mentioned at the end] that are associated with each scenario.
Dr B. In the above, might it also be useful to list/summarise the range of constant M or KIAS speeds that are endurance compatible over a range of altitudes?
@Victor Iannello: “Neither time acceleration nor pausing has an effect on the relationship between position and simulation time.”
Thank you for your comment. I’m interested in the spacing between the time stamps, i.e. were they about equally spaced, or were some close together with larger gaps between others?
@Gysbreght: We don’t have individual timestamps.
@Gysbreght said: It is odd that nothing is known about the files that were saved on the simulator on 3 February 2014, nor of the time of day that the Shadow Volume was created on the day the owner was rostered to fly from Kuala Lumpur to Denpasar, Bali and return the same day.
Shadow volumes are automatically created by Windows 7 during periods of inactivity, and usually with a spacing of a week or more. If the captain’s computer was running while he was away, it would be a candidate time to create a shadow volume.
@David: There is an option to display the g-loading on the wings as the simulation proceeds. Without gently pulling back, the g-loading exceeded 3.5. This also assumes the flight control mode is secondary, where there is no envelope protection.
If I have time, I will create a video showing this, although I don’t know a realistic sequence of events to simulate. The stick shaker speed is reached after a single engine flameout, A/P engaged, and holding altitude, at which time the nose would automatically drop, and a steady, stable descent is achieved, all with the A/P engaged. If the pilot intervened and lowered the nose, the rapid descent would not have been timed with the log-on at 00:19, which we believe occurred some time after the APU started following the second engine flameout. There is a timing inconsistency of 2 minutes or more, depending on how long the last engine continued to run after reaching stick shaker speed.
@Victor Iannello: “Shadow volumes are automatically created by Windows 7 during periods of inactivity, and usually with a spacing of a week or more.”
I couldn’t find that on the Microsoft site. Can you provide a reference?
If it is true, then what is saved in the Shadow Volume at the time it is created?
Correction to my October 30, 2017 at 10:34 pm comments.
The last paragraph should read:
…that is difficult to reconcile with the estimated two-minute time interval between the second flameout and the log-on request at 00:19:29. Two minutes is an awfully long time to sit there…
That makes it even more difficult to reconcile!
@Victor
Re: “Without gently pulling back, the g-loading exceeded 3.5.”
Just curious, but do you recall the maximum speeds that were achieved with both the high-g and ‘gentle’ manoeuvres?
@Andrew: I would say it is two minutes or more, depending on how long the last engine continued to run after reaching stick shaker speed.
@Andrew: If you have an interest, I will make a video. However, I need to know exactly what scenario I am simulating. Previously, I simulated a dual flameout, and raised the nose to get to stall, then lowered the nose to reach high descent speeds, then recovered. I think is an unlikely series of events.
@Victor
Re: ” I would say it is two minutes or more…”
Yes.
Re: “If you have an interest…”
No, I was just curious.
@DrB
Thank you!
>Why not include the 23:14 Sat Call time slot?
>I like the path end point 34S, 94.15E
Earlier Victor posited “It would be very interesting to know what a realistic expectation is for the coverage per day.”
I expect that the six Hugin AUVs should cover 600km² per day, taking recovery cycles into consideration. The side scan sensors employed by Ocean Infinity’s Hugin AUVs are of similar specification to those deployed with Fugro’s autonomous and towed underwater vehicles: all are Edgetech systems operable at 75/410kHz “full spectrum CHIRP” side scan sonar mode.
Thanks to “TBill”, it now seems that:
MH150 Departed KUL at 11:45am local (UTC+8) = 0345UTC and arrived JED at 1600 = 4:00pm local (UTC+3) = 1300UTC.
This is a flight time of (1300 – 0345) = 0915 = 9hrs 15 minutes.
MH168 Departed KUL at 22:30pm (UTC+8) = 1430UTC and arrived JED 02:45am (UTC+3) = 2345UTC.
This is a flight time of (2345 – 1430) = 0915 = 9hrs 15 minutes.
So, a normal flight time of 9:15 can be assumed, plus mandatory diversion and holding reserves, would give an endurance of nearly 11 hours, so let’s say 11 hours.
11 hours endurance for MH150 (departure 0345 UTC) gives fuel exhaustion at 1445 UTC.
11 hours endurance for MH168 (departure 1430 UTC) gives fuel exhaustion at 0130 UTC.
Note that sunrise at 45S 104E on 4th Feb 2014 was 22:04 UTC.
Obviously MH150 was not a viable flight to reach 45S at or just before dawn, but MH168 certainly was, with 3.5 hours of fuel to spare.
So, for a 1430 UTC departure for MH168, there is only an available flight time interval of (2204 – 1430) = 0734, ie, 7 hours and 4 minutes to reach 45S 104E at dawn.
There is only one realistic flight path that meets that mission requirement, to arrive at dawn.
Using 480 knots TAS as the average ground speed nil wind yardstick, the route is:
WMKK (1430 UTC) – GUNIP (21 min 1451 UTC) – TASEK (32 min 1502 UTC) – MABIX (62 min 1532 UTC) – 45S104E (7h06m 2136 UTC) – YPPH (9h03m 23:33 UTC).
There are two very interesting points about this flight path.
The first is that the flight path Mabix to 45S104E crosses L774 at a point 41Nm NE of UPROB, only 77 minutes into the flight (at 1547 UTC) 15 minutes past Mabix. I will come back to this later.
The second is that the flight can comfortably reach YPPH via 45S104E in 9 hours and 3 minutes, the same time almost as the scheduled 9 hours and 15 minutes flight for MH168 to OEJN JED Jeddah, with standard reserves.
The question must therefore seriously arrise, did Z in fact actually plan for MH168, instead of MH150, with the intention of having himself re-rostered from MH150 to MH168 ? As a very senior captain, he would have more than enough “pull’ to do that, even at pretty short notice, should he have chosen to do so.
Indeed, it is also very interesting to consider the track from Tasek to Mabix, from a “radar” point of view, assuming Z was really wanting to “drop off the scope” so to speak.
The interesting new “fly in the ointment” here, may well be Mick Gilbert’s recent observation, that apparently MH168 never flew. Is it possible therefore, that Z’s “initial plan” was for a flight, that as things turned out, became “The Flight that never was” in more ways than one ?
But, if we take the lesson of the sim data to be that in all probability the intention was in fact to ditch at dawn, then it is a simple matter to apply the same rationalle to the circumstances he faced at Penang, at 17:52, on MH370.
The time available to fly south to dawn from there was his crucial issue. He had no time to go northwest up the Mallacca Strait. He had to fly across Sumatra, and had planned to anyway, through a civil ATC radar black hole, which also turned out (so we are told) to be a military radar black hole as well.
In the context of MH370, it is worth noteing, that Penang (17:52 UTC) direct to Mabix is 346Nm in 44 minutes approximately, arriving at approximately 18:36 UTC.
Similarly, and alternatively, Penang (17:52 UTC) to 41Nm east of Uprob on L774 is only 41 Nm further, at 387Nm in 49 minutes approximately, arriving at 18:41 UTC.
Interesting timeing for a southern FMT, for both cases.
@Mick @Victor @Gysbreght
Re: MH150 on 4-Feb-2014, isn’t it unusual that ZS flew Denpasar round trip on 3-Feb and then Jeddah on 4-Feb?
Mick- I assume you confirm 4-Feb-2014 MH150 flight was 15:15 Departure? Amy further info such as flight path?
[VI to Gysbreght: If you complain one more time about the way this site is moderated, you will be banned.]
@TBill
“Especially for you” Hopefully this link works for MH150 on 4th Feb 2014
http://de.flightaware.com/live/flight/MAS150/history/20140204/0715z/WMKK/OEJN/tracklog
@Ventus45
“But, if we take the lesson of the sim data to be that in all probability the intention was in fact to ditch at dawn, then it is a simple matter to apply the same rationale to the circumstances he faced at Penang, at 17:52, on MH370.
The time available to fly south to dawn from there was his crucial issue. He had no time to go northwest up the Malacca Strait. He had to fly across Sumatra, and had planned to anyway, through a civil ATC radar black hole, which also turned out (so we are told) to be a military radar black hole as well.”
Sorry but I must be missing something. At Penang at 17:52 MH370 had enough fuel and enough time to proceed up the Malacca Strait, turn south at IGOGU at 18:37 onto a heading of 186 and continue on a great circle until fuel exhaustion, AND arrive in time for sunrise. I agree with you on one thing: it is quite plausible that Shah planned to synchronize fuel exhaustion with local sunrise.
@TBill: I don’t see anything unusual in the rostering of ZS. Perhaps Andrew could answer.
@Victor Iannello: Is it permitted to inform readers that my delayed comment has appeared?
[VI: Comments that I deem to be informative, collegial, sincere, and relevant are permitted.]
@Don Thompson
Seabed Constructor has finished its current swing testing the six OI AUVs and is moving off to the Bahamas. No sign yet of it returning to its earlier ports of call in the UK, or deploying closer the MH370 search area.
@Joseph Coleman
Thank you so much Joseph! I certainly had you in mind. You saved me $$, amd I know @ventus45 is looking for that data
OK well that estimated path looks like DUBTA on P574 sky vector to me pending overlay on SkyVector. So I am saying the Simulator case was possibly DUBTA divert to DOTEN, and possibly the 15:26 time in the sim studies was inserted as realistic take off time for Flight MH150.
@ventus45, @TBill
Concerning the announcement you have quoted, dated Aug 2013, referring to the seasonal introduction of MH0168.
An MH0150 typical departure from KUL was 07:35UTC (15:35MYT) arriving JED 16:20UTC (19:20 local), that’s ATD/ATA.
MH0168 was announced as an additional seasonal service, to operate only 28JAN14 to 29MAR14. Its departure from KUL would have been 17:15UTC (23:15MYT) arriving JED 02:45UTC (05:45 local).
However, according to the November 2013 MAS timetable MH168 never made it as an operational service.
Hi Richard,
Thank you for that information. I’d checked earlier but missed it leaving the assumed trials area.
@Don Thompson
Doesn’t the Nov-2013 MAS Time Table seem to show MH150 changing to the proposed new departure time on 28-Jan-2014? but it seems like that change did not happen either.
TBill,
The timetable for 01 Dec 2013 thru 29 Mar 2014 contradicts the August 2013 announcement of the MH168 additional daily service KUL/JED during February and March 2014.
The recorded actual times of departure/arrival for MH150 KUL/JED after 28th Jan 2014 contradicts the timetabled KUL departure of 1145MYT, it remained as 15:15MYT
It appears MH168 did not make it onto the schedule during the period of interest.
@Don Thompson
Agreed!
@Paul Smithson,
You said: “Is your MEFE for both engines pooled with PDA1.5% or time of final fuel exhaustion (R)? If the latter, please conform PDAs used for R/L for the purpose of the model.”
I compute the L and R PDAs and use them separately to predict L and R engine fuel consumptions and flame-out times. The values are shown at the bottom of the table “Output Parameters” on the “Endurance Model” worksheet (0.45% L and 2.55% R).
You said: “Please also confirm your assumption on speed/altitude between 1720 and 1829 that underpin your assumed “starting fuel load” at 1828.“
For the endurance/range plot, I assume the period from 17:22 to 18:29 (Leg #2) was flown at M0.84 and FL340, as shown in the “Input Parameters” table in the “Endurance Model” worksheet.
You said: “I couldn’t see in your tables the “southern latitude limits” [mentioned at the end] that are associated with each scenario.“
The “southern latitude limits” are not listed explicitly in this table, but you can compute them if you want by using the polynomial equation shown at the top of the figure entitled “Range from Earliest FMT Position to 7th Arc” in the “Endurance vs Range Plot” worksheet. This uses the post-18:29 Range shown in the table in the same worksheet. You can also estimate the latitude limit by simply reading the curve in the figure. The southern latitude limits are also plotted in the MEFE/Range figure at the top of this worksheet.
Later you said: “Dr B. In the above, might it also be useful to list/summarise the range of constant M or KIAS speeds that are endurance compatible over a range of altitudes?”
Good idea. I’ll explore those two options and post my results later.
[Gysbreght is banned.]
@Victor,
@Gysbreght,
Re: “Gysbreght is banned.”
Gents, come on. Sometimes discussions are getting hot, often we have disagreements, but as long as they are not turning into personal attacks or fights of gut feelings, I think they should not be banned.
@Gysbreght,
Sometimes it is better to let it go.
@Victor, please don’t become JW-II. You know that your blog is unique, and it is focused on the science and engineering. I think Gysbreght has provided many valuable thoughts and analytics, so I sincerely hope you will calm down and take a right decision only after that. It is easy to break, but difficult to repair.
@TBill
Regarding MH150 on 4 Feb 14.
Yes, Flight Stats says it departed at 1514 MYT, one minute before its scheduled time of 1515 MYT.
Regarding the Captain’s cluster of flights on 3 – 6 Feb 14.
Such clusters were unusual but certainly not unique. He had two not dissimilar clusters in mid-2013.
6 Jun 13 – MH102/103 – KUL-DAC-KUL
8 Jun 13 – MH2 – KUL-FRA (Early AM departure, duty starts late PM 7 Jun 13)
9 Jun 13 – MH3 – FRA-KUL (Arrives KUL early AM 10 Jun 13)
6 Jul 13 – MH851/850 – KUL-DPS-KUL
7 Jul 13 – MH190 – KUL-DEL
8 Jul 13 – MH191 – DEL-KUL (Arrives KUL early AM 9 Jul 13)
Andrew is undoubtedly far better placed to comment on the vagaries of rostering.
Thinking loud. 18:25:27 BFO. If Holland’s curves always exhibit such a monotonic behaviour as presented in his paper, then BFO 18:25:27 could potentially be explained by a rapid descent occurring simultaneously with the SDU boot-up, and subsequent recovery 7 seconds later. Of course, such an explanation does not eliminate the elements of coincidence, but at a glance it appears to be physically possible.
@Tbill
@Mick Gilbert
http://uk.flightaware.com/live/flight/MAS150/history/20140204/0715zZ/WMKK/OEJN
According to this, Gate departure was 15:14 and take off was 15:29
@Tbill
@Mick Gilbert
http://uk.flightaware.com/live/flight/MAS150/history/20140204/0715zZ/WMKK/OEJN
According to this, Gate departure was 15:14 and take off was 15:29
Rob says:
October 31, 2017 at 12:35 pm
@Ventus45
“But, if we take the lesson of the sim data to be that in all probability the intention was in fact to ditch at dawn, then it is a simple matter to apply the same rationale to the circumstances he faced at Penang, at 17:52, on MH370.
The time available to fly south to dawn from there was his crucial issue. He had no time to go northwest up the Malacca Strait. He had to fly across Sumatra, and had planned to anyway, through a civil ATC radar black hole, which also turned out (so we are told) to be a military radar black hole as well.”
Sorry but I must be missing something. At Penang at 17:52 MH370 had enough fuel and enough time to proceed up the Malacca Strait, turn south at IGOGU at 18:37 onto a heading of 186 and continue on a great circle until fuel exhaustion, AND arrive in time for sunrise. I agree with you on one thing: it is quite plausible that Shah planned to synchronize fuel exhaustion with local sunrise.
@Rob
I wrote that before going to bed in the early hours after a long day. I have just had 7 hours sleep and one coffee while reading the posts since.
You are not missing something.
It is I who forgot to put in what is a crucial point in my view, and it is this.
The sim is telling us that he wanted to get to 45 South.
He chose 45S in the first place for a very specific reason in my view.
That reason, was to get into the circumpolar current to ensure there was next to no chance that any debris would ever wash up anywhere that it would be found, recognised, and recovered, and give the game away.
The plan was “to vanish”.
So, my reasoning is this.
From Peneang at 1752 he had fuel remaining for (00:17 – 17:52) = 6 hrs 25 minutes, which equates to remaing range of about 3,080 Nm.
Getting to Mabix (direct) would take him until 18:36 and he now has fuel remaining for only (3080 – 346) = 2734 Nm. Even going due south from Mabix only gets him to 42.5 S, still 2.5 degrees latitude or 150 Nm short of his “goal” or target.
Alternatively, going via Medan direct to 41 Nm East of Uprob on L774 gets him closer to his goal.
Getting there costs him 49 minutes and 387 Nm. He now has fuel for (3080 – 387) = 2693 Nm. Going due south, that gets him to about 43.6 South, now only about 85 Nm from 45 South, which is well within glide range.
But, on the night of the 7th / 8th March, the terminator for his “new” fuel exhaustion time of 00:17 has moved west, so he will burn a few miles getting there, but no many, and he still ends up well south of 40 in theory.
So I think the only solid thing we can infer from the simulator, is that his initial PRIMARY goal was ditch at sunrise. His SECONDARY goal was to do that as far south as possible, preferably at 45S or further, if he could make it, but anything south of 40 would be acceptable.
If he had flown from Penang to Igogu, he would arrive there at 17:52 + 00:46 = 18:38 UTC for 375 Nm, leaving him a range of (3080 – 375) = 2705 Nm. Even if he then flew due south, that gives him 45 degrees of latitude range, from Igogu at 7.5 N, which means he ends up at only 37.5 South at best, which puts us pretty much rite back to square one, where we have been looking for three and a half years, with no result.
If we accept that the simulator is telling us that 45 south was most probably the goal, coincident with sunrise, for the ditch, then quite clearly, N571 and all that it entails, is “out the window”.
@Oleksandr
Interesting.
Tangential note.
There has been a feeling expressed here that interest in MH370 amongst the general public has waned to the point that it no longer cares. I have thought that way too. On occassion I give talks to various audiences on MH370, always replete with lots of slides and narrative. By now, three years after the event, I figured that the story had run its course. Today, I gave a very informal talk without slides, just draowing maps of Malaysia on a chalk board. The audience was what I would call a scientific general public. The interest was intense. Afterwards, I attended a completely unrelated function. Two people, one a very well know scientist and a former division head at the NSF, the other a former director of a major national laboratory, both expressly regretted having missed my talk. I had clearly captured their attention.
Conclusion – the interest may be latent, but it is still there.
Have slides, will travel.
@all,
HERE is a new Version 5.5 of my fuel model that now includes endurance and range estimates for the cases of constant Mach and constant KCAS after the earliest possible FMT. Just click on the link in my pubs list for 31 October 2017 to download a macro-enabled EXCEL file of Fuel Model V5.5.
Here are the cases with acceptable endurance (within 8 minutes of 00:17 UTC):
M0.84 None
M0.82 FL370-410
M0.80 FL350-410
M0.78 FL340-360, FL410
M0.74 FL310-320
275 KCAS FL250-330
250 KCAS FL390-400
You can compare all the results in the new Range versus Endurance plot. I also added the southern latitude limit to the summary table.
@Don Thompson
On rechecking Seabed Constructor’s course and declared arrival time, destination is the Freeport in Bermuda (not the one in the Bahamas). Much closer to the area it has been working.
Dr B. Many thanks. That is really useful.
@Victor. “I don’t know a realistic sequence of events to simulate”. No, not in the way of MH370 descent replications, what with software limitations at flight extremes and the ‘unawareness’ of tank residual fuel in this and all simulators.
However about the pilot recovery instance you describe, the ‘g’ gives a general measure of the loadings on the aircraft when pitching up, pilotless. The NTSB in the 737-300 Silk Air investigation said of that dive, (which I take as wings level), without the use of nose down trim, or large control column forces and inputs, “the airplane would have initiated a return to a nose-up attitude due to its inherent stability.”
That sounds similar, yet both appear inconsistent with your June BFO replication. There, at the end, without a spiral and at high speed the aircraft showed no sign of pitching up.
Any thoughts?
@Ventus45
Thanks for explaining. I have a clearer picture now. I’m with you on the sunrise, and the advantage of reaching the circumpolar current, However, I am going to stay with the Malacca Strait route, following the FIR boundary, FMC at 18:37 in the vicinity of IGOGU and crossing the 7th arc at about S37.7, E89 (close go the DSTG hotspot) particularly as DrB’s fuel model indicates that constant Mach 0.81 at between FL350 and FL390 would have sufficient endurance.
If Shah wanted to get as close as possible to the circumpolar current, and the argument for it is persuasive, he would have needed every ounce of his gliding skills to do it. There is the problem posed by the final BFO’s. But bear in mind he was flying into the northern fringe of the Southern Jetstream and encountering a significant headwind as fuel exhaustion approached. If he had been cruising at say 40,000ft, a dive to a lower altitude after fuel exhaustion could make sense. He would be gaining kinetic energy at the expense of potential, and reducing the headwind component.
Do you catch my drift? Pardon the pun.
@David: I’m not sure I understand your question. The only way I produced the BFO values was with either a banked descent or nose down input. With wings level and no pilot input, a damped phugoid would develop, with the initial amplitude dependent on the initial conditions.
@DrB: That’s really useful. It’s too bad the DSTG in their Bayesian analysis did not constrain speeds in a more realistic way.
@All: With preparations for the re-started search ongoing, now is the time to succinctly express your views about where to search after the initial 25,000 sq km.
@Rob
What I understand from @DrB’s numbers max. reachable latitudes depend on where the FMT was.
He took the earliest possible FMT at 18:22. Straight from there max. reachable latitude towards the SP would be a lot farther south than a FMT later on at say 7N and maybe a loiter of some kind included after 18:22.
I think it’s not likely the FMT took place at 18:22 and so the max. reachable latitude from there is not likely either.
If I misunderstand this I’m glad to hear.
@VictorI
On a simulation-proposal I was thinking about ChinaAir 006 again. This 747 plunged vertically from 41.000ft to 9.600ft where the pilot pulled out with 5.1G’s strain on the plane.
I know it’s not quite comparable for this plane had engines working but I assume the pilot did not use engine power to recover from this dive.
I imagine it could be usefull to see how this pilot managed to recover from a same kind of descent rate/dive as MH370 seems to have made without distroying the plane.
@Ge Rijn: I didn’t say it was impossible to successfully recover from a high rate of descent. I said it would be challenging, and not as easy as simply pulling the nose up, as one person implied.
@victor. My question stemmed from your comment to Gysbreght:
G: “I’m sure you would not find it [recovery from a 15,000 fpm descent] difficult at all if you tried it in your simulator.
V: “Your certainty is misplaced. It’s challenging, as I said. It’s hard to keep the wings level, and it’s easy to rip the wings off the plane on the recovery”.
It was the recovery ‘g’ there I was talking about, which later you described as, “Without gently pulling back, the g-loading exceeded 3.5.” ie a pitch up as I understood it, without pilot input.
@DrB: Regarding your calculations of the maximum southern latitude for various scenarios, some questions:
1) For the 1 hour hold + LRC calculations, at which position did you start the flight south?
2) Did you consider roll modes and compatibility with the BTO (or BFO) values? Or were great circle paths considered without regard to the BTO?
Thank you.
@David: Now I understand the confusion. I meant that with pilot input, it was necessary to pull up slowly. Pulling up rapidly produced high g-loads.
@Victor. Thanks. I see now.
In the 737 Boeing simulator software from the report, “the
nonlinear mathematical software has been validated up to Mach 0.87, and extrapolated using computational data up to Mach 0.99”.
It is unclear at what Mach this, “nose-up attitude due to its inherent stability” would apply to the 737 but in MH370’s case a deal later than would apply at early recovery from the BFO descent rates anyway I would think.
@VictorI
I know you did not say it was impossible but it would be challenging to pull the plane out of such a descent rate.
ChinaAir 006 shows this was surely not simply done by just pulling the nose up. They had to level the plane first to the horizon which was not visible till 11.000ft and then pull out. They accomplished this within ~1500ft (11.000ft to 9500ft) from a nearly straight spiral dive to horizontal/level agian.
All engines had flamed out early in the high speed descent btw.
They restarted after leveling out at 9.500ft.
I would be curious how MH370 would have behaved in same kind of circumstances and what would be needed to level the plane and pull it out in time.
Would this be possible regarding the descent rates the BFO’s show and what altitude space would be needed?
A replicated simulation with a B777-200 could give some more insight I’m thinking.
@David, @Ge Rijn: Again, if there is interest, I can run a test case. I need to know exactly what we are simulating. For instance, the airspeed at the time of recovery will greatly impact the wing loading.
@VictorI
I like to add ChinaAir 006 shows an incident where a plane the size of a B777 virtually runs out of pilot control at high altitude with engines flaming out shortly in the dive-descent. It’s mainly on it’s own and free falling till 11.000ft when the pilot can see the horizon and can level out again.
From 41.000ft till 11.000ft it is in fact an unpiloted plane.
So possible similarities with MH370’s end-flight scenario can be made imo.
I just think a comparing simulation with the available MH370 data could give more insight in possibilities (and impossibilities) regarding MH370.
@GeRijn
I think you are possibly misunderstanding the situation.
Firstly, although I am yet to pore over DrB latest endurance figures, I believe he takes FMT to be nominally at 18:29, not 18:22.
I’m glad you asked out the endurance question. I have already established to my own satisfaction that if MH370 flew at constant M0.81, at FL350, then it would comply with the BTO, ie cross the arcs at the right times, an ndd reach the 7th arc at S37.6, E89.1, at UTC 00:19:30, IF it had enough fuel to make the journey. DrB’s latest results suggest that it did have enough fuel, give or take a few minutes.
So what I’m now saying iro the M0.81 constant Mach great circle from IGOGU to S37.6, E89.1: “If it looks like a duck, quacks like a duck itand walks like a duck, it probably is a duck”.
We now have a reason why Shah glided as far south as possible; to get a close to the circumpolar current as he could, (credit to Ventus45 for that idea)
It makes S35 look less and less likely.
@VictorI
I sure would be interested ofcourse in the simulation I propose (and other simulations too ofcourse).
I answered before your latest comment…
ChinaAir006 reached VMO speed in the dive and pulled ~5G’s in the pull out. The plane just survived but loosing landing gear doors and parts of the elevators..
Maybe that’s a limit for a simulution?
Maybe it’s an idea to let the plane (MH370) spiral out of control after flame out at ~30.000ft asif no pilot was at the controls and then try to recover before ~9000ft?
@Rob: So what I’m now saying iro the M0.81 constant Mach great circle from IGOGU to S37.6, E89.1
My calculations say that to cross the 7th arc at 37.6S latitude on a great circle, BTO constraints require a speed of around M0.83 at FL350 starting at a latitude of around 0.4S at 19:41. There would not be sufficient endurance at this speed.
Can you please show you arrived at 37.6S latitude at this (M0.81) speed?
@Rob
You’re right about the 18:29 instead of 18:22 as a most early FMT @DrB mentioned. Sometimes those close numbers get mixed up a bit by me. Awfull ofcourse but in this case not quite relevant imo.
I’ll await @DrB’s anwser to @VictorI’s question few posts back on this subject.
@Rob
The endurance/range issue was initiated by me but @Paul Smithson picked up on that further for he stated there was no significant difference between them while I was arguing there was. There the discussion started on this issue.
I’m glad @DrB picked up on this so detailed and pointed out range and endurance are two quite different factors.
You can circel for 7 hours and not make much range at all.
But this is the beauty of discussion.
@sk999
“Conclusion – the interest may be latent, but it is still there.
Have slides, will travel.”
Thank you for that perspective. To gather support for the search, we should have an MH370 speakers list, and use your slides. Perhaps Malaysia realizes that dropping the search would not solve the problem in the public eyes.
Technical BFO question sk, I was reading some of your 2014 posts and you had offsets that you added to the BFO’s. Are you still doing that? or have the BFO numbers been updated such that no offsets are needed?
@GR. Yes, you were quite right (and I was wrong) that the one-engine range is not better while the endurance is. Having said that, I do understand the difference between the two.
@Rob. 37S is still on the N side of the large borderline area between SIO gyre and circumpolar proper. If you come down there debris ends up on S Aus and NZ. In absence of anomalies due to local eddies, this holds all the way through to about 45/46S. So “aiming for the circumpolar current” won’t cut it, in my view.
@VictorI
Your comment:
@All: With preparations for the re-started search ongoing, now is the time to succinctly express your views about where to search after the initial 25,000 sq km.
With all latest evidence and indications (simulator, debris, drift analysis etc) I think it’s essential OI takes a deliberate goal into account the PIC took the plane and wanted it to vanish with the at least possible evidence. He succeeded till now.
This motivation has to be taken into account.
Just outside the CSIRO priority area east and west of ~32.6S there are deep trenches. Especially to the east. The pits there are ~6000m deep.
This region has to be searched imo.
All signs are the flight was a planned one with a necessary calculated end imo. A deep trench would serve all those objectives.
@sk999
Conclusion – the interest may be latent, but it is still there.
Curious post relative to “scientific interest”. My experience has been almost the polar opposite – I found very little interest from the get-go. Most of the people I know who have worked in navigation and understand time of arrival and Doppler looked at the issue long enough to understand it (about 10 minutes) and the data we have to work with, and said the solution was indeterminate, and that it was a waste of time to screw around with it. That was my conclusion as well, but being retired I had nothing better to do.
Reality has come home to roost. We have no convincing analytics relative to a precise location after more than three years and a lot of looks.
@Victor
“@All: With preparations for the re-started search ongoing, now is the time to succinctly express your views about where to search after the initial 25,000 sq km.”
I assume the 25,000 sq km includes the green space in Fig 3, which I support because I think that should have been the first place to search.
After that I would simply continue up Arc7 in the same manner. It is OK if they jump around to certain “hot spots” eg; 26.9S, but the idea would be to cover Arc7. They should NOT skip the hard part of Broken Ridge. I feel Inmarsat made an enormous contribution defining Arc7, and that effort deserves follow-up.
Miscellaneous points:
> I have an issue with the *assumptions* in the models (Bayesian/fuel) to help define the search area. The reason Arc5 to Arc6 is hard to fit could be due to pilot actions (due to sunrise, winds, sat calls, etc) and descent/slow down/change of track/fuel saving steps, are all possible there, in addition to late FMT after 18:40 (which we tend to say is “loiter”). I assume an open-minded Bayesian model just says somewhere on Arc7, but if there could be an “un-opinionated” model, then it could be useful to have model predictions.
> @ventus45 has a good theory about 45S circumpolar currents, which helps give the ZS simulator cases a possible end-strategy. But I do not currently feel MH370 had enough fuel to accomplish that. So there must have been an alternate strategy, and I feel 180S past Broken Ridge at 33-35S has many of the same attributes as 45S. I am currently trying see if I can import the NASA Perpetual Ocean data to Google Earth (someone did this mapping already), so I can see if there are logical flight paths to the ocean currents as known in 2014.
@Victor
Re “My calculations say that to cross the 7th arc at 37.6S latitude on a great circle, BTO constraints require a speed of around M0.83 at FL350 starting at a latitude of around 0.4S at 19:41. There would not be sufficient endurance at this speed.
Can you please show you arrived at 37.6S latitude at this (M0.81) speed?”
Victor, I’ll be happy to do that for you tomorrow, when I can get to a PC. I’ve had a rather busy day and am getting in some much needed “quality time” with myself, walking along the river Medway, in the heart of the Kent countryside. I hope that doesn’t sound too pretentious, I wasn’t meant to. 😊
@Paul Smithson ” 37S is still on the N side of the large borderline area between SIO yre and circumpolar proper. If you come down there debris ends up on S Aus and NZ. In absence of anomalies due to local eddies, this holds all the way through to about 45/46S. So “aiming for the circumpolar current” won’t cut it, in my view.”
Paul, isn’t that being just a bit picky?
Let’s say that he actually got to S38 in the middle of the “hotspot”. Then a 100Nm glide would get him closer to S40, wouldn’t it? A glide would explain why the ATSB couldn’t find him. A flight path parallel to the sunrise terminator would solve the problem of synchronising fuel exhaustion with sunrise.
What’s not to like, apart from the revised CSIRO drift studies? I have little faith in them myself, considering how they seem to have been made to support the ATSB after they failed to find the aircraft where they assumed it would be.
The ATSB told me in late 2016, that S40 was possible, according to CSIRO.
Then there’s the previously discussed evidence from the debris,
@Rob
A glide would explain why the ATSB couldn’t find him. A flight path parallel to the sunrise terminator would solve the problem of synchronising fuel exhaustion with sunrise.
What’s not to like, apart from the revised CSIRO drift studies?
A great many things can explain the ATSB failure to find the aircraft. Why settle on your explanation? Why even bring it up? It does nothing to favor your hypothesis.
What’s not to like is the absence of debris in WA, and the incompatibility of your terminus with the simulator data. Why not pick a terminus compatible with both? Seems like a much stronger argument to me.
…and so it goes…
http://www.themalaymailonline.com/malaysia/article/not-true-mh370-search-mission-to-continue-next-year-transport-minister-says#m6wVeAfoLMD7D67t.97
As I said, it is senseless to speculate at this time.
@DennisW said: As I said, it is senseless to speculate at this time
Yup.
@TBill – As an alternative to Victor’s McMurdo, I really like continuing the track away from MEKAR and then turning to a CMH or CTH of 180° south. Could it be possible that any speed and/or direction change necessary to meet the BTO & BFO data is due to the winds?
A reprint of my 10/01/2014 post:
Per the ATSB report, Inmarsat used the March 7, 2014, BFO data to predict the flight paths of MH021 and MH009. Presumably, they were able to calibrate their BFO model to the known actual location of each of these flights. At the point where these flights crossed the 7th Arc, their predictions were off by 145nm and 200nm, respectively.
Is there a reason why current models are believed to be more accurate?
In using the sim data to correlate the accident flight, might it be possible that ZS had planned to divert the Feb. 4 flight to Jeddah but changed his mind somewhere along the Straight of Malacca and later chose MH370?
@Lauren H asked: At the point where these flights crossed the 7th Arc, their predictions were off by 145nm and 200nm, respectively. Is there a reason why current models are believed to be more accurate?
Any specific location is based on other assumptions such as the navigational mode and whether there were pilot inputs. The DSTG model used a prior distribution for number of manoeuvers that biased the results towards favoring straight paths. Any prediction is only as good as the underlying assumptions, including prior distributions.
@Lauren
In using the sim data to correlate the accident flight, might it be possible that ZS had planned to divert the Feb. 4 flight to Jeddah but changed his mind somewhere along the Straight of Malacca and later chose MH370?
I think a planned diversion on a flight to Jeddah is unlikely for a couple of reasons:
1> A three man flight crew.
2> The diversion from IGARI provided an extra hour of negotiating time. A negotiation could only be started after the diversion was known and verifiable. A Jeddah flight removes that extra hour.
People here who think Shah committed suicide and wanted to find the best “hiding place” for the plane in the nooks and crannies of the SIO are in the pathetic category. As are the various mechanical failure affectionados. The plane was diverted for a reason. Some day that reason will come to light.
A diversion on a flight to Jeddah simply does not work.
Oleksandr says:
“Sometimes discussions are getting hot, often we have disagreements, but as long as they are not turning into personal attacks or fights of gut feelings, I think they should not be banned.
@Victor, please don’t become JW-2. You know that your blog is unique, and it is focused on the science and engineering. I think Gysbreght has provided many valuable thoughts and analytics, so I sincerely hope you will calm down and take a right decision only after that. It is easy to break, but difficult to repair.”
As a longtime silent reader, I’d just like to echo Oleksandr’s thoughts, which reflect mine.
What I like so much about your blog, Victor, is
(1) its calm, informational, scientific, factual nature, largely void of personal attacks
(2) that unlike JW you don’t censor thoughts that are different from your own, but instead you are very tolerant and allow a very free flow of discussion and information, which makes your site an extremely interesting one with a large spectrum of theories and investigative approaches. Thank you for that.
I think (2) creates a positive conversational atmosphere (unlike @JW),
which leads to –> people collaborating instead of attacking each other,
which leads to –> (1).
In the early days, JW was like that, too. But then he started becoming evermore authoritarian and ban more and more people (for nothing else than differing opinions, honestly) until almost noone from the early days was left. Luckily you started your blog, so that most of the homeless JW contributors could find a new home, provided by you. Your work is an important part of finding MH370.
I don’t know what Gysbreght wrote (since you redacted it) and don’t want to get into your way, Victor, but I just hope that in the future you won’t go down the same path as JW. It started in the same way.
@Lauren H
I used M0.84 until Arc5 where I see a slow down and descent. But I was using uncorrected standard air temp, so that’s one thing I’d need to go back and fix. (I previously shared a preliminary 180S CTH path from ISBIX).
Mathematical basis: if you put the Arcs 3/4/5 on Google Earth, you are looking for the place where a vertical (180S) line has the same speed between Arc 3 and 4 and between Arcs 4 and 5. There is no exact place where the speed is equal for strictly vertical lines, but due to the winds, the Arc 3 to 4 line is actually a little slanted.
@Victor
The DSTG model used a prior distribution for number of manoeuvers that biased the results towards favoring straight paths. Any prediction is only as good as the underlying assumptions, including prior distributions.
Yes for sure. A Bayesian analysis is meaningless without solid priors. Why the DSTG took this approach without any solid priors (previous scheduled flights do not count as meaningful priors) is a mystery to me as is their statistical approach to the BFO characterization from previous flights.
My SO (PhD EE MS Math) happens to be an excellent mathematician (unusual for a PHD EE) with over a decade of GPS industry experience (in the trenches not working a budget). She looks at me like I have just fallen out of a tree when I am working on MH370.
@DennisW “Reality has come home to roost. We have no convincing analytics relative to a precise location after more than three years and a lot of looks”.
As a Dennis “Whacko” I came up with a location three years ago that had nothing going for it except that it was under pilot control and fitted the BTO’s perfectly.
Every time I raise my head above the parapet I get knocked back and yet I have frankly not seen anything more convincing.
I can only continue to make my case because an unbiased observer would, in my opinion, have to acknowledge it has as much merit as anything else that has been put forward.
@Perfect Storm: There is a minimum level of decorum required for collegial discussion. When somebody has been repeatedly warned and cannot meet that requirement, and in fact chooses to deride the minimum process of review, it is time to make a change. I could cite specific instances, some very recent, of disruptive behavior. However, I think there are more valuable things to discuss.
@TimR
I have not kept a list relative to the whacko category. I actually view it in the same light as autism. We are all affected by it to some degree. The clinical attention to it has served the raise the frequency of diagnosis. Not the actual prevalence of it (despite what my Cali anti-vaxxer friends believe). The recent wave of sexual harassment revelations is another example of the same affect. I expect to be accused of it any day now.
@DennisW
It is a privilege to be rated by Dennis as a “whacko”.
I wear it with pride, it is a badge of honour.
@DennisW “What’s not to like is the absence of debris in WA, and the incompatibility of your terminus with the simulator data. Why not pick a terminus compatible with both? Seems like a much stronger argument to me.”
Dennis, I don’t believe you’re naive enough to think Shah would leave any really useful evidence on his SIM hard drives. The data he left accidentally on purpose on his computer was intended to show us that he was toying with the idea of taking a plane into the SIO until the fuel ran out, flying in LNAV. The smoke without the gun.
And the no debris on WA shores argument is based on supposition, not science. Before the flaperon a arrived at Reunion, CSIRO were predicting that debris should be make landfall in Indonesia. When that was shown to be nonsense, they publicly admonished themselves for being so inept. The “expert” drift modelers have their methods, but the Indian Ocean obviously has it’s own, and it’s keeping it to itself.
CSIRO have now been able to pinpoint a number of prospective termini, with unparalleled precision! I rest my case on he drift modeling fiasco.
@Rob
You are taking the simulator data to the next level of abstraction. That is a dangerous thing to do, IMO.
I agree CSIRO has a checkered history relative to the drift analytics, but just about everyone concurs with the WA location for debris originating as far South as you hypothesize.
@Dennis,
Re: “Interesting.”
Yea, that is interesting. My estimates show the downward velocity component of 30 m/s (5900 fpm) required to explain the difference of 131 Hz (=273 Hz – 142 Hz). I think it is quite realistic to recover 30 m/s speed over 7 seconds. But I am sure, ALSM will not like this explanation.
@Oleksandr
Yes, I nominally use 4Hz per m/sec. I don’t have any experience on the recovery time.
@Rob,
“ to think Shah would leave any really useful evidence on his SIM hard drives”
What gives you the impression that Zaharie had a depth of knowledge of Windows 7, the NTFS filesystem, and its arcane file system state recovery capabilities, in order to accidentally, on purpose, delete files but leave breadcrumbs? You’re implying professional system administrator level knowledge.
“ no debris on WA shores argument is based on supposition, not science”
You’re drifting into unfounded opinion there.
“ CSIRO were predicting that debris should be make landfall in Indonesia”
It was not CSIRO staff but GEMS, engaged as one of six contributors to AMSA’s initial drift work, who made the error that resulted in the call for debris observation on Indonesian shores.
“ pinpoint a number of prospective termini, with unparalleled precision”
Next time you’re out at the mouth of the Medway, look to the north-east 330km towards Den Helder, NL, visualise a swathe 75km wide (Sheerness to Stansted): that’s the precision. Don’t forget, the ‘X’ is a similar distance out from port as from Sheerness to Trondheim, Norway.
@Ge Rijn,
You said: “I think it’s not likely the FMT took place at 18:22 and so the max. reachable latitude from there is not likely either. If I misunderstand this I’m glad to hear.:
Yes, apparently you did misunderstand. To clarify, what I have said is the following:
1. There is no evidence for a turn after passing VAMPI and before 18:22:12.
2. The BTOs and BFOs between 18:25-18:28 do not allow a southward FMT during this time period.
3. The earliest possible FMT southward would therefore be at ~18:29.
4. The earliest possible FMT southward would also reach the southern latitude limits I calculated assuming a great circle path thereafter.
5. FMTs later than 18:29 or which follow curved paths cannot reach as far south as a turn at 18:29 followed by a great circle path.
@Richard Cole
According to VTS Bermuda, Seabed Constructor due in Thu at 0700 and departing again, Fri 1600.
DennisW says, “My experience has been almost the polar opposite – I found very little interest from the get-go.”
It is hard to predict where a person’s interests lie. I once flew into somewhere to give the talk, and on the way out of the airport started telling the taxi driver why I was there. He was all ears. Totally fascinated. Asked a ton of questions. Became my personal taxi driver for 3 days. Best taxi driver I ever had.
Presentation matters. If you try from the start to flog the ATSB, you will lose your audience. I just try to present the facts as we know them. No finger pointing. It seems to work.
@VictorI,
You said: “@DrB: Regarding your calculations of the maximum southern latitude for various scenarios, some questions:
1) For the 1 hour hold + LRC calculations, at which position did you start the flight south?”
Good question. The answer is that for all cases I used the same position for the start of the southbound path as the estimated aircraft position at 18:29 (7.18N 95.68E). For the case of the 1-hour Hold, my calculated range assumes there was no racetrack flown, and both the Hold speed and LRC were consecutively flown along the same great circle. The range for a 1-hour leg at Holding speed at FL200 is about 309 NM from the initial descent, so you can subtract that from my indicated total range for that case to get a range for the case where the racetrack was flown at the 18:29 location. If the racetrack is flown farther out to the northwest (near VOCX), then the range south will be further reduced by the extra path from 18:29 to the racetrack position. There will be some small errors still remaining because the great circle southward would start from a slightly different position. It’s pretty straightforward to estimate where that occurs on the 7th Arc using my BTO Model. Just find the net range (= my total range less 309 NM and less the distance from the 18:29 position to the racetrack position). Then find the location on the 7th Arc where that range from the racetrack position matches the calculated net range. You can solve this iteratively by picking an approximate latitude, then adjust the longitude by trial and error to get a Predicted BTO = 18,400 at 00:19:29. (As an aside, it is interesting that the 00:19:37 BTO has a smaller error than the one at 00:19:29.) Next find the distance between the racetrack position and the 7th Arc position (with BTO = 18,400). Iterate this process until the calculated distance equals the net range. Then you know the southern latitude limit for a Hold at a fixed position.
You also asked: “2) Did you consider roll modes and compatibility with the BTO (or BFO) values? Or were great circle paths considered without regard to the BTO?
In calculating the southern latitude limit, I only considered range along a path following an orthodrome (great circle). I did not consider other roll modes, nor did I consider consistency with BTOs or with BFOs, nor did I consider tailwinds. The impact of tailwinds is expected to be rather small since the winds were primarily from the east or from the west. The major wind effect is to curve the post-FMT path eastward for constant heading navigation modes.
@ventus45
@Rob
@Paul Smithson
I agree with Paul regarding the Antarctic Circumpolar Current and the unlikely association between it and 45S1 from the recovered simulation data. It is generally accepted that the northern boundary of the ACC is defined by the eastward flow of the Subantarctic Front. In the Indian Ocean that is found no further north than (and generally much further south of) 48°S.
In the recovered simulation data, at 10N in the Andaman Sea the simulation airplane had more than enough to fuel to reach well south of 48°S. The fact that the flight appears to terminate at 45°S is antithetical to targeting the ACC.
With regards to trying to glide to the ACC from even the southernmost point of the fuel constrained 7th arc, not even World Gliding Champion Sebastian Kawa could have gotten the airplane anywhere close. Moreover, if there had been any prior study of the ACC (and you’d expect that there would have been if it was geographical goal of the whole exercise) then it would have become apparent that just missing to north is worse than missing by a long margin with regards to where and when debris is likely to come ashore.
@sk999
Could be an age thing as well. In the “valley” you are pretty much irrelevant at 40 or so.
@DrB: Thank you, although some may have thought you matched the BTO/BFO data between 18:28 and 00:19 when you reported reachable southern latitudes.
Here is one of @sk999’s presentations.
What the Malaysian Transport Minister says. Another version. Now a 5000 sq km aim.
https://www.msn.com/en-my/news/national/malaysia-hoping-to-re-launch-mh370-search-mission-in-january/ar-AAuj7y3
@David: Ignore it. OI will search at least 25,000 sq km. As some reports said, the contract with OI is being negotiated by a group headed by Azharuddin Abdul Rahman, the Director General of the DCA. Prime Minister Najib can of course kill the deal, irrespective of other negotiations. We’ll just have to wait to see whether things go forward.
Here’s a video of what Transport Minister Liow Tiong Lai actual said.
Additionally, reports say that with the technical investigation completed, the focus will be on the criminal investigation, with a report expected next year. I’d be surprised if that adds to what we already know.
DennisW,
I am well over the age of irrelevance. However, I do have a finger on the pulse of many who are under. Make no mistake – MH370 does get their attention. At least down to age 25. If not under.
R.E. “the valley”. Today I guess it means “silicon”. Back many years ago, it meant “San Fernando”. Thirty years from now it will mean … who knows?
It used to be that irrelevance kicked in at age 30. Where did this 40 come from? Age inflation, methinks.
@All
With respect to the subject of “public interest” in MH370.
I have noticed, that among my friends and associates, that the level of what I will call “active” interest has dropped off to zero, but surprisingly, the level of “passive” interest, both among them, and in the wider community, is still very much alive and well, but only if they are “prompted” by some event, ie, if it “pops up in the news”.
By that I mean, that my friends and associates know of my deep interest, since it was a daily subject of conversation up until the end of the search early this year. Since then, they don’t ask me about it any more, or only occasionally, and I don’t tell them what is currently going on (for example, here in this forum), unless asked, but they know I am still burning many hours daily on it. They sort of consider it to be an obsession of mine, indeed, when it does come up, they refer to it, not as MH370, but as “Pete’s plane”.
Recently, within the last few months, I have, on reflection, had three interesting experiences of this.
(1) David Mearns.
David Mearns was in Australia a short while ago, for the HMAS Sydney aniversary memorial ceremonies. As most of you would know, he found HMAS Sydney. He was interviewed on morning TV a number of times and was also doing “book signings” of his latest book “The Shipwreck Hunter” whilst he was here. (I managed to secure a signed copy for myself, and I recommed it, it is a fascinating read). What was interesting though, was that in his TV interviews, he made a point of raising, and talking about MH370, how it was unacceptable that the search had been abandoned etc, that it must be found, and he more than strongly hinted that he stands ready to help, but did not go any further with that. The level of interest from the interviers seemed to be both high and genuine. Later that day, when I arrived at the club, the first thing people said to me was, “hey – did you see that shipwreck guy on TV this morning”, followed by, what happens now, is “he” going to go and look for it, etc.
(2) Charts.
I had obtained some genuine navigation charts (both marine and aviation) of the Indian Ocean for doing some plotting. The trouble was, that they were physically “too small” for what I wanted to do. I wanted them “blown up”, if possible. I consulted one of the guys at the club who is a building inspector of some sort. He deals with plans and blueprints etc on a daily basis. He came in to the club after work about 6pm, as he usually does, so I button holed him. After discussing it for a while, he said “lets have a look”. Since I had the charts rolled up in the back of the car, I went outside and got them. We unrolled them, and spread them out on the pool table. All of a sudden, or so it seemed, we had a crowd form. In the end, I had to give a little “off the cuff” lecture on what this was all about. The upshot, surprisingly, was that those who were NOT previously aware of my work, were the ones who seemed most genuinely interested. So, MH370 is still there in the public mind, not on the surface perhaps, but not far below, let’s say at periscope depth. Anyway, after people drifted away, Mark pulled out his mobile and made a couple of calls. Eventually he came up with a printing company that does some work for him, who he said has a very large scanner that could take these charts, and could do what I wanted. So, now armed with a contact name and number and an address of this place, not too far away at Arncliff, I headed off next day to see what could be done.
(3) Printing Company.
I arrived at the printing company just after lunchtime. I walked in with the charts rolled up and presented at the front counter, which was unattended. I had a look around, it is a small private company, only half a dozen staff as it turned out, but there were printing machines of all types, some quite large, with lots of activity going on. Eventually, one of the staff saw me, and came over to the counter. After the initial “hello” formalities, I began to explain what I wanted. Within seconds, before the end of the opening sentence actually, “so you are the guy Mark told us was coming – come in – let’s have a look”. It turned out that they know Mark quite well, having done work for him for years. Over the course of the next hour or so, they scanned the charts to a very high resolution DPI wise, and brought them up on the computer. The software they have is amazing, and the woman doing it is a wizzard. Anyway, with me perched over her shoulder, we moved the charts around to select the areas of interest, and made new files of those sections, and enlarged them to the max for the printers, which then did the job. We went over to the printer selected, and waited for the first one to slowly come out. It was a very large, very impressive machine. I asked her how much. She smiled, and simply said, “heaps”. As the first one came out, slowly, I was more than impressed with the quality of it. After examining it closely, I decided to proceed with the others, full well knowing that I would be shelling out quite a bit, but I “bit the bullet anyway”. About this time, the “boss” came in from somewhere, and she explained to him who I was and what we were doing. As the prining was done, we examined them as they came out, one by one, and as they were all perfect as far as I was concerned, they were placed on top of each other on a large bench, and at the end, rolled up. During this process, there was time for a discussion of my project, and they did seem genuinely interested, to the extent that when it came time to “work out the bill”, the boss said that since it was a “private” effort, for a good cause, well ……..he hummed and harrred for a bit, and then came up with a price, which was about one third of what Mark had suggested (at commercial rates) I might be up for. I was more than happy with that !! Basically, I think he really only charged me for the materials, and not for their time or expertise.
So the point is, people at large, still do care about it, and some are even willing to assist in some small ways, as this small company did for me. It seems that there is a little bit of a modern day “Titanic” feel to it, in the public mind.
On the subject of the sim and 45S.
Even the ATSB indicates that they take the sim data as “indicative” of an “intent”. The real question is, was there really any “intent” in Z’s mind to begin with, and if so, what was that “intent” ? There is a wide range of views on both of those.
Looking at it now, it is all very well for many to dismiss 45S as a realistic planning intent, based on what we now know about the Indian Ocean and drift studies and all that.
But ask yourselves, idividually, what did “you” know about the SIO, it’s currents and all that, back in February 2014 ? Does anybody want to put their hand up, as an “expert”, back then ? Deafening silence.
When I first looked at it, my prior knowledge was close to zero, and I live down here, and dad was a yachtie (although I was not, any more than I had to be, which was limited to within sight of solid ground !). My initial look into it started with google, you look at the simple charts first. They all show the gyre and the main currents fairly simply. If you are a pilot, not a sailor, and you look at them with an “intent” in mind, for an idea of where to go, the first and second and third looks all tell you the same thing, south of 40 will do nicely, 45 would be better. If that is all he did, research wise, the sim has to be taken as a clue (in my view).
@Victor. On the video he did say at 2:04 that, “the three countries involved in the search wanted to narrow it down to 5000 sq km”.
Separately there has now been a Ministry statement also:”International reports claiming the MH370 search could resume next year is (sic) untrue…”
https://audioboom.com/posts/6450153-ministry-clarifies-mh370-search-report
A reasonable explanation of the apparent contradictions, allowing for interpretation, is that statements that the search WILL go ahead are premature, since Australia and China have not yet been consulted and a contract has not been finalised.
@David: It would make no sense for OI to search only 5000 sq km. Don’t believe it. I suspect the contradictions on the status are occurring because the technical personnel within DCA are making progress on the negotiation and want to proceed, but in the end, this will be a political decision.
[Other comments redacted at Dennis’ request.]
Back to 370, I don’t have a good feeling about it. The Malay activity with Ocean Infinity is confused at best. It seems they are falling back in line with their tri-partite partners. I don’t see a resumption of the search as likely.
@TBill,
You asked: “Why not include the 23:14 Sat Call time slot?”
I just posted a new version 1.1 of my BTO/BFO Models that includes the 23:14 phone call. By the way, you can add as many lines to the calculator as you want by just selecting the cells in the bottom row and copying them downward. The time order does not matter.
With repect to the charts I mentioned above.
In case anyone wants them so that they can get them professionally printed out locally, I have uploaded them to dropbox, but be warned, they are huge files.
File 1 – Is a cropped section of a marine navigation chart = 96 Megabytes.
https://www.dropbox.com/s/lubu640whepirgd/SIO-1.pdf?dl=0
File 2 – Is a cropped section of a aviation navigation chart = 113 Megabytes.
https://www.dropbox.com/s/vnucapuxn0vjrxq/SIO-2.pdf?dl=0
@DrB
Thank you! I was just looking at the worksheet in some detail. I was particularly noticing the +4-Hz offset you are adding to sat calls BFO, as I was not aware some folks are post-adjusting some of the BFOs.
@ventus45
Re: “Even the ATSB indicates that they take the sim data as “indicative” of an “intent”.
Really?! Where have the ATSB used the words” indicative” and “intent” together with regards to the recovered flight simulation data?
@Victor
I can not download @sk999’s presentation that you linked, and the audio is so low it is almost inaudible. Is there another way to get it ?
@Mick Gilbert
https://www.atsb.gov.au/media/5773565/operational-search-for-mh370_final_3oct2017.pdf
In discussing the simulator data on Page 99, they say:
“There were enough similarities to the flight path of MH370 for the ATSB to carefully consider the possible implications for the underwater search area.”
If that doesn’t indicate “indicative” and “intent”, what does ?
The ATSB did not put that comment in just for fun.
@DrB
Thanks for explaining your max. latitude from 18:29 to me and @VictorI.
I see I inderstood you well. I only mistakenly put 18:22 in my post instead of 18:29 which I corrected few posts later to @Rob who pointed me at the mistake.
All clear about your max. latitude thoughts now.
@TBill.
You said: “I was particularly noticing the +4-Hz offset you are adding to sat calls BFO, as I was not aware some folks are post-adjusting some of the BFOs.”
Yes. It was apparent early on from the raw BFOs that the transmitted frequencies varied by a few Hz among the different channels in the SDU. For an example, see Table 10 on page 41 in my Addendum 5 from November 2015. The first publication of which I am aware is the paper by Hyman and Martin in December 2014. Mike Exner also contributed significantly to understanding this effect.
Tbill:
ATSB used only a subset of the R channel BFO observations because it was evident different channel types (R, T, C) had slightly different BFO Bias Values. We want to use all the BFO observations from all channels. So, several of us in the IG worked to calibrate all of the channel types using all 597 available observations. It turns out the C channel BFO Bias is estimated to be ~4 Hz lower than the R channel bias(~150 Hz), thus C channel BFO Bias= ~146 Hz. Thus, to compare R, T and C channel BFO values directly, it is common to normalize the values to be the R channel equivalent. For C channel BFO values, that means adding 4 Hz to make them R channel equivalent. Calibration values for all channel types and channel units available here: https://goo.gl/tCWTp6
@ventus45
Normally, “inverted commas” are used to show a direct quotation, that is referencing the specific words used in context. The ATSB used neither of those words.
“If that doesn’t indicate “indicative” and “intent”, what does ?”
Well, that should be self-evident; actually using the words “indicative” and “intent” would be a good start.
@Victor. Don Thompson says, “I expect that the six Hugin AUVs should cover 600km² per day, taking recovery cycles into consideration”.
Ten days production, plenty more than that for preparation and transit time. Unrealistic as you say to both parties: risk, overheads to OI, incommensurate reward to cover those risk and overheads.
However what he has said is troubling for other reasons. What is the nature of this contract? If the contractor offers a reward contract, isn’t the extent of his searches up to him to decide when enough is enough, so long as there is no dawdling?
Besides, again from this 25000/5000 business it sounds almost as though the tripartite countries are prescribing search areas, in which case implicitly they could be accepting some responsibility for their prescriptions/advice.
Maybe the Malaysian public service is, like others, intent on precluding public (and political) uproar over value for money should the wreckage be located in a couple of days using the search information and resources provided by governments, not just Australia but also the SSWG internationals.
The press would bear down. What? $50 million for 2 days work based on others research? What is our government doing gambling and not getting its money’s worth?! A paid for search would have cost considerably less! It was obvious it was there. Etc.
Perhaps the size of the reward will increase with the area searched.
Turning though to suggestions you sought as to the search area, I put myself first in Oliver Plunkett’s shoes. In principle start at the highest probability areas and work down, quitting when probability gets too low, though with some gain from the publicity and equipment proving. Keep things simple.
To define that more, some back-of-the-envelopes. Plan on 85 days of searching this coming season @600 sq km/day, say 50,000 sq km. Part A would be the 25,000 ATSB search area but review that with ATSB/SSWG as to balance of overall probabilities with Part B, the 25,000 left. That roughly would allow a run up to 28deg and a run back, searching 7½ miles (12 km) each side of the arc, 6 AUVs of 8 down, each with 2000m swept width. 600 sqkm/day at 3knots say, (5 km/hr, 60 sq/km), 10 hrs effective sweeping a day. Adjust targets as experience is gained.
Note this does not discriminate in priorities up the arc because most likely there is insufficient reason from conjecturals to chop, transit and restart. Also aerial and surface search outcomes are of little consequence, their runs commonly being very widely spaced and the debris having drifted during the delayed start. If priorities are about equal, give some priority to getting in early the run directions which weather might make awkward later.
If at the end any time is left over, use it on the then highest probabilities remaining.
Have a taxi ferry on standby to transport people and heavy items. Air drop parts.
Have the option of extending by a season should your shareholders choose.
Note for the tripartites. All search information to be disclosed by OI and placed under public ownership. All advice by the ATSB to be for information only. Make sure there is no use of this just for publicity and proving, then cessation at shareholders’ behest: the required search area should be the 25000 minimum (unless found part way through that).
@Victor. I left off the heading of the above, “The 5000 sq km search aim statement”, though a bit late.
The below is on the simulator sequence you offer to take a look at.
The ATSB says of the most recent Boeing simulations, “In some simulations, the aircraft’s motion was outside the simulation database. The manufacturer advised that data beyond this time should be treated with caution”. They have not said where the database limits are. They also say, “Some simulated scenarios also recorded descent rates that were outside the aircraft’s certified flight envelope”. They do not say whether the simulation outcomes of those are to be trusted. They have said also that the simulations do not include the effects of APU and engine starts even though an APU start is central to the 7th arc explanation.
In view of this I think an outcome from home simulators when working in these fields might be misleading yet much of my interest lies in those esoterics. So I can propose no sequence in those fields which to me would be useful, though thanks for the offer.
Also on pitch up, when Boeing advises caution with 777 motion simulation outside the database I assume they allude to insight they have similar to the 737. The Indonesian investigation of the Silk Air crash did not accept Boeing’s view of aircraft behaviour outside flight testing.
However, in both instances there is no more expert assessment available than theirs nor is there likely to be, so that should be the default view with the 777. What I am getting at is that lack of any allusion by Boeing to 777 pitch up dumps a bucket of cold water over my assertion that it might behave like the 737. I note also the EgyptAir flight 990 Boeing 767 pilot did not need nose down stabiliser trim to hold the nose down. So my postulation about pitch up now looks shaky.
@ALSM, @TBill: I think the bias for the C-channel is different as we have no data on the ground to use for calibration. What Mike has done is to assume a linear fit of the other BFO values to infer a bias for the C-channel. Doing this makes the BFO fit at 23:14 a measure of the BFO linearity for a given path.
@DennisW: Please do yourself (and your former employer) a favor and review your comments before you post them.
@David wrote:
“6 AUVs of 8 down, each with 2000m swept width. 600 sqkm/day at 3knots say, (5 km/hr, 60 sq/km), 10 hrs effective sweeping a day. Adjust targets as experience is gained.”
Only six AUVs (and ASVs) deployed on Seabed Constructor. I will suggest the effective side scan swath is less than 2000m, more like 1600m to allow for overlap with adequate resolution. Fugro’s original intent was to survey 2000m swathes but it was reduced to an average of 1700m. Your speed and mission duration estimates are too high & too low, respectively: halve the speed and double the duration.
I understand that the Edgetech equipment employed by Fugro on their deep tow vehicles and the AUV was capable of comparable performance but the AUVs were used for higher resolution infill work so less range.
OI’s Hugins are similarly equipped, I don’t expect any significant performance difference per vehicle in wide area survey.
@David, @Don Thompson: I’ve heard mention that the scanning profile will be optimized for finding the debris field rather than seabed mapping. I imagine this could result in more economical scanning compared to what Fugro was doing.
@Tbill, @VI Re C channel BFO bias:
My intent above was not to defend the method used to derive the channel dependent bias, but merely to explain why Bobby made the 4 Hz adjustment.
The BFO channel dependent bias estimates were derived in the fall of 2014. As Victor noted above, the C channel bias was estimated from the 23:14 data as shown on the last page of the following, published in Dec 2014 by me. https://goo.gl/S454AY.
The estimate does depend on an assumption that there was no change in altitude at the time, and the linear trend. I still think those assumptions are reasonable given the full record. That said, the C and T channel bias differences vis a vis the R channels do not have much impact on any of the important questions.
@ALSM @Victor @DrB
“The estimate does depend on an assumption that there was no change in altitude at the time”
That’s why I am so tunnel-vision focus on it…without the correction, I had come to the conclusion of a descent starting at maybe 22:50 (twilight).
Thanks to all for the explanation.
By the way, also note the values start jumping around about half-way through the reading period. So I tend to use the initial value (216). My interpretation of the mini-upset is a little turbulence in the high winds below 22S. Other thoughts?
Bad markup above, only first para should be in emphasis.
@Victor
@DennisW: Please do yourself (and your former employer) a favor and review your comments before you post them.
Good point. This whole endeavor has me spun up badly.
@DennisW: If you are so “spun up” that you are making injurious statements about you and your employer, it’s time to take a break.
@Victor wrote: “optimized for finding the debris field rather than seabed mapping”
Certainly, any search has to be optimised to find the debris field. Given that the debris field will be scattered it may be feasible to comb, rather than mow, each sector. By comb, I imply that survey of an area might involve interlaced sweeps, leaving gaps to incrementally work to 100% (or the deemed maximum) coverage.
The equipment must be operated in a mode that is capable of discriminating potential objects in a debris field. That is where I expect similarity between Fugro’s configuration and OI’s.
@Don Thompson: I wasn’t referring to the search pattern. Rather, since the search is for hard objects with significant acoustic signatures, might this allow the sweeps to be either wider or at a higher speed?
Don: I agree. Combing, rather than mowing, could effectively double or triple the search rate, depending on the estimated size of the debris field.
@VictorI
Here are the calcs I promised you yesterday, applicable to constant Mach 0.81 great circle.
The following calcs apply to the IGOGU/ISBIX/7th arc great circle that crosses the 6th arc at S36.60, E89.24, and the 7th arc at S37.62, E89.08. Calcs assume the aircraft flew at a constant altitude of 35,000ft until right engine fuel exhaustion.
Distances and arc crossing coordinates obtained from Moveable Type Scripts online Vincenty calculator for WSG84 ellipsoid.
The great circle distance between IGOGU and the 6th arc is measured at 2,651.5Nm, the corresponding journey time 5.5625hrs (5hrs, 33.75mins) measured from the mid-point time of FMT 18:37:15*. When a time averaged 2.2Kts headwind is factored in, the airspeed works out at M0.81, ie. 476.67Kts + time averaged 2.2Kts headwind = 478.87, divided by 590.50 = M0.81. (590.50Kts is the estimated average value for Mach 1 between IGOGU and the 6th arc, for estimated average temp 42.5C at 35,000ft altitude).
* Between completion of initial turn-back manoeuvre at approx 17:25 and last radar contact at 18:22, the aircraft flew at a relatively constant airspeed M0.84. Between 18:22 and arriving at the FMT mid point (estimated time 18:37:15), the airspeed is assumed to have gradually reduced from M0.84 to M0.81.
When calculating the average airspeed for each leg of the IGOGU/ISBIX/7th arc great circle I found that, assuming it flew at a constant altitude of 35,000ft, the aircraft maintained an almost constant Mach 0.81 throughout its journey south, subject to the limits of accuracy of the wind speeds and temperatures determined from the earth.nullschool.net global map of windspeeds and temperatures. applying specifically to altitude 34,000ft, for the date/time in question – via link on Brian Anderson’s paper “Determining the Mid- Flight Speed of MH370, 20/03/2015, Duncan Steel website.
IGOGU to 2nd arc: 512Nm, 480Kts average groundspeed, 1.8Kts average tailwind = Mach 0.808 (Mach 1=592Kts, Temp -41C) 2nd arc crossing point S1.0, E93.53.
2nd arc to 3rd arc: 478.7Nm, 478.7Kts average groundspeed, 1.6Kts average tailwind = Mach 0.806. (Mach 1=592Kts, Temp -41C) 3rd arc crossing S9.0, E92.7.
3rd arc to 4th arc: 488.6Nm, 485.6Kts average groundspeed, 4.6Kts average tailwind = Mach 0.812. (Mach 1=592Kts, Temp -41C) 4th arc crossing S17.09, E91.82.
4th arc to 5th arc: 480Nm, 479.6Kts average groundspeed, Zero average head/tailwind = Mach 0.81. (Mach 1=592Kts, Temp -42C) 5th arc crossing S25.06, E90.87.
5th arc to 6th arc: 692.2Nm, 461.5Kts average groundspeed, 13.5Kts average headwind =Mach 0.81. (Mach 1=586.5Kts ave.for leg, Temp -46C ave.for leg) 6th arc crossing point S36.6, E89.24.
6th arc to 7th arc: 61.5Nm, 434Kts average groundspeed, 33Kts average headwind = Mach 0.804. (assuming Mach 1=581Kts, Temp -50C, at altitude 35,000ft. However, aircraft would have been descending)
Perhaps interesting to note that a 100Nm (17:1 ratio) piloted glide initiated nominally at 35,000ft at MEFE, 14Nm prior to crossing 7th arc, and maintaining the same heading, would have terminated at approx S38.9, E88.9 when taking estimated headwinds into account, or 15Nm outside the southern boundary of 120,000sq.km. search area. For comparison, a 13:1 ratio glide would have terminated just inside the search area. Possibly a case of so near yet so far.
@VictorI – Originally, it was decided that pilot input after the FMT would give a search area so large it could take 10-20 years to complete a search. The only things that have changed since then is the recovery of debris and elimination of the previously searched areas. Has that changed the “no pilot input” assumption?
@Lauren H: Now we have a higher level of confidence that the final BFO values indicate a progressively steep descent. Regardless of whether there was pilot input, that suggests the impact was not far from the arc.
@Don Thompson. With 6 AUVs down there be at least one in transit and another being charged, maybe 2 depending on charge rate. Then there are repairs and replacements. More than 8 I would say to support the 6 deployed for 3 months, though I had read that they already had 8. Not just the items of course but the stowage for them. Likewise the surface vessels.
Some more idle thoughts. I imagine they would run staggered, not abreast, a replacement starting behind that being withdrawn. It would be awkward if running staggered interfered with their efficiency, time being lost reforming an abreast formation.
Then there is the like withdrawal and need for back up of the surface vessels.
Sea states present and predicted could affect AUV recovery times and damage rates. If caught out by weather do you put them all in loiter? What of the surface vessels? Put them in mother’s lee?
Their trials will have given them clues how to do all this but getting it all fully and efficiently operational might take a couple of weeks.
Re combing as opposed to mowing.
I don’t like the combing idea. I think the logic is flawed.
If the aircraft ditched, the debris field is the 4 corners size of the aircraft, say 80 by 80 metres.
If the aircraft went in nose first, the debris field should be relatively compact, like AF447’s debris field, which was small, only about 200 by 600 metres.
I think mowing with confirmed swarth edge overlaps is essential.
@David,
Six Hugins are deployed on Seabed Constructor, undoubtedly the ship carries spare parts. AUVs, and ASVs, 7 & 8 have been described as a separate package to be deployable on ships of opportunity.
The Hugin battery packs are swapped rather than recharged in-situ, endurance depends on speed but 72hrs is possible for side-scan sonar survey. Operational methods remain to be seen in detail but the AUVs will operate simultaneously during a mission.
Two stingers launch & recover the AUVs off the ship’s stern, directly from a purpose built, covered, hangar. The ASV LARS (launch & recovery system) operates with the ASV alongside the ship, each LARS is designed and built to launch and stow three ASVs. Many photographs have been uploaded to sites such as Marine Traffic since July, when trials began, showing the working configuration. The ship is presently in Hamilton, Bermuda, after working two areas in the mid-Atlantic over the last four weeks.
Sure, sea state and weather will dictate operations, but that’s what forecasting is there for.
@Don. As of June 15th they had 8 AUVs as 8 USVs and presumably they could get these all stowed, if not more, if they expect to have 6 down continuously.
http://subseaworldnews.com/tag/ocean-infinity/
@Don. Sorry. Overlapped.
@Victor,
I have assumed that the AUV operations for side-scan sonar survey will be conducted in similar configuration to Fugro’s work, the ‘state-of-the-art’ hasn’t progressed significantly. The Hugin’s Edgetech side-scan sonar operates at two frequencies to optimise cross-track range and resolution, while delivering a compromise along-track resolution. Fugro elected to operate at 75kHz for a 1600m cross track swathe and 410kHz for near range detail. That configuration, in turn, dictates the AUV speed and along-track resolution. 75kHz and 410kHz are the extremity of choices available.
Appendix D of ATSB’s Operational Search/Final Report summarises Fugro’s results. Debris fields and a lone object were discriminated, albeit lying on seabed that provided good contrast (high backscatter).
The Kraken SAS sensors are not spec’ed to deliver the range achievable with side-scan.
Of course, there’s the possibility that an undocumented, ground breaking, technique has been developed that exploits MBES, over a wider swathe than side-scan, to discriminate man-made objects on the seafloor …
@Don. Impacts on initial securing will be the main limit to acceptable sea states IMO. Yes if the seas remain benign and the USVs can be refuelled and serviced without grappling the damage rate would be minimised.
You have more faith in SIO weather predictions though than do I and with likely recovery times of USVs and benign conditions needed for that there might be little scope for taking chances.
With battery exchange, if quick and easy, recharging AUV downtime is overcome though there is transit and recovery time still for AUVs and transit and refuelling of USVs. I have my doubts that staggering would overcome that or would be efficient.
Also I think expecting to keep on line a total of 12 vehicles for 3 months say without needing to replace any, including during repairs, would be optimistic.
Thanks for that info. Obviously and necessarily I post when far from being fully informed and am really indulging in some mind clearing, though ceasing that for now.
@David,
On 4th Sept, ASV Global posted on social media that ‘build of the final Ocean Infinity SeaWorker ASVs is well underway’ together with a video.
There are only six deployed on the host vessel at this time.
@Don. Thanks. Maybe they will increase that, or they have a secret recipe.
A correction to my earlier please. By “weather predictions” I should have included sea state predictions. Seas come from wind, fetch and time, but swells of course can be independent and from a distance.
@ventus45
IF the aircraft ditched do you not think at least one engine would have detached as it skimmed across the waves? Wouldn’t the main fuselage drift before sinking and then not sink vertically to the bottom?
At least three recovered fragments originate from an engine inlet cowl and a cowl door, that suggests that engine debris was created at impact.
@Don. Late final. ‘Simultaneous’ as the recipe. Maybe. I have had a look, though getting off topic.
https://www.dropbox.com/s/9glvhnn6lr426nh/Simultaneous%20vs%20serial%20AUV%20deployments.docx?dl=0
@David @Don Thompson
Imo it’s all about the assumptions.
If the plane made a high speed nose down impact the plane was smashed in small pieces scattered along the seafloor.
Biggest pieces would probably be remains of the engines and landing gear.
High resulution scanning would be needed closer to the seafloor with a smaller width taking more time.
If the plane ditched or made a ditch-like impact (extreme like AF447) there would be much bigger pieces or even the hull with wings attached in a small area.
No need for a very high resolution scanning.
Three to six meters of resolution would be enough which would save a lot of time imo.
@Ge Rijn
My understanding is that the requirement in the Fugro search was to detect (with high probability) an engine-core sized target at the edge of the 1.6km wide sonar scan. This was presumably the assumed worse case of a very high-speed sea impact that shattered the airframe. A target of this size was dropped to the seabed just off Fremantle and used occasionally for testing. I doubt the requirement for the OI work would be much different since a high-speed impact cannot be ruled out, and that Fugro requirement seems a minimum for that situation.
“made a ditch-like impact (extreme like AF447)”
When AF447 impacted the Atlantic Ocean the last recorded FDR values showed a vertical speed of -10,912 ft/min, a ground speed of 107 kt, pitch attitude of 16.2 degrees nose-up, roll angle of 5.3 degrees left. Not even remotely “ditch-like“.
Assumptions, yes, but those based on credible and plausible reasoning, not “imo”.
@Richard Cole
I agree a high speed impact cannot be ruled out. But imo a ditch-like impact cann’t be either.
Maybe it’s a idea to make high resolution scans close to the 7th arc first relating to high speed impacts and lower resolution (and less time consuming) scans beyond those regions after.
@Don Thompson
That’s why I called AF447 an ‘extreme ditch’.
Result was a relatively small debris field on the ocean floor with big pieces of fuselage, wings and engines close together.
Easy to spot with three to six meters sonar resolution.
@Ge Rijn
“Easy to spot with three to six meters sonar resolution.”
Really?
The successful deep ocean search for AF447 operated Remus 6000 AUVs with side-scan sonar operating at 120kHz so as to ensure adequate discrimination of a likely target at a maximum range of 700m. The Airbus debris field straddled the overlap of two adjacent passes by the AUV. The seabed in the area was abyssal plain. That was fortunate as the sonar backscatter from the debris field contrasted well against the uniform return from the seafloor. Discrimination is not a simple ‘pixel’ based resolution issue.
This presentation delivered by Jan Ingulfsen at a recent conference in Perth, WA, might help illuminate some of the points @David & I discussed above.
@Don Thompson: Thanks for finding that and sharing it. I think advanced technology that drastically reduces the cost of a wide search area offers hope that we can find MH370.
@Victor
Re: ZS Sim Cases
I wonder if Yves has any ideas about to prevent the >90 deg turn over shoot we see in FS9/FSX? I am finding the turn thru 10N may have an unusual quality. Pending fine tuning, it is the exact correct place to start a very sharp >90 deg turn that ends exactly on the DOTEN to NZPG great circle without over-shoot or under-shoot.
@Victor
I think advanced technology that drastically reduces the cost of a wide search area offers hope that we can find MH370.
“Hope is the currency of the poor.” – Cesare Maestri. Probably the best climber in the history of the world.
Sorry, I could not resist. I know “hope” is all we have at the moment.
@DrB, Your fuel model is proving extremely useful, particularly the Endurance v Range table. I had been working on what I thought was a promising candidate path, a great circle, constant M0.81 at FL350, with FMT at IGOGU at 18:37 and crossing the 7th arc at S37.6 but I can see from the table that FL350 has insufficient range to reach latitude S37.6.
However, I notice that M0.82 at FL380 meets the desired range and MEFE time requirement very closely. Range requirement from 18:29 to MEFE at 00:17 is 67NM (estimated) to IGOGU, plus 2,651NM to 6th arc crossing at latitude S36.6, plus 47NM to MEFE at 00:17 = 2,765NM. By comparison, from the table the range for M0.82 at FL380 is 2,774NM from the 18:29 point, and MEFE is 00:16. It could be that ground-speed of M0.82 at FL380 is comparable to ground-speed at M0.81 at FL350, (assuming the same windfield) because the lower temperature at the higher altitude has the effect of increasing the Mach number, for the same ground-speed. Is that a reasonable assumption?
I know that S37.5 has been searched already, that the final BFOs indicate a rapidly accelerating descent rate between 00:19:29 and 00:19:37, and the latest drift results run counter. But the BFOs represent an 8 second snapshot, and if a piloted glide had begun at 38,000ft, a steep descent at one point should be considered less unlikely perhaps?
All,
I am trying to understand better just what factors drive the DSTG’s various solutions and what happens as assumptions are relaxed.
As an initial investigation, consider Bayesian Methods, Figure 10.3, top. This figure shows the probability distribution in final latitude along the 7th arc using the BTO data alone. Surprisingly, there is a
well-defined narrow peak centered around -39.2 deg latitude (plus another one at -36.7 – presumably magnetic track routes.) How can that be? If we consider the BTOs from 19:41 to 24:11, they can be fit with either an LNAV or true track route with constant Mach, but the starting location is ill-constrained. (More specifically – even though the satellite was moving and thus the “ping rings” are not concentric, one can pick any starting latitude from 0 to 20 degrees, and the fits are all essentially identical.)
The DSTG started it modeling at the 18:01:49 position. If one is free to choose the speed and heading at that point up to the FMT, a second speed and heading after the FMT, and the time of the FMT, there is a 1-dimensional family of routes that match all the BTOs (including the ones from 18:25-18:28). For reasonable speeds both before and after the FMT, there is a spread in the final latitude ranging from -37.5 to -40.2 deg.
Why is the DSTG distribution in final latitude so narrow? It is because the DSTG imposed two additional constraints – the speed and heading were constrained to be close to the values that its filter had output for the 18:01:49 point based on the primary radar data up to that point (Figure 4.3 – 508 knots ground speed and 289 deg true heading.) Formally, it used these values as “priors”, with stdev of 17 knots and 1 deg respectively (Table 8.3). Now, I am not running Monte Carlo’s like the DSTG, but if I make a least squares fit with these free parameters and priors, I find a final latitude of -38.8 deg with a stdev of 0.6 deg. This latitude is still 0.4 deg North of the DSTG value, but the stdev is small, in agreement with the DSTG result.
The time of the FMT is 18:36, in agreement with (but not at all driven by) the BFO of the 18:39 phone call. However, all is not well. The BFO residuals are big (5.5 hz stdev). The time that the final radar position is reached (whether my value or that of B. Ulich) is approx. 18:23:38, more than 1 minute later than what the Lido Hotel radar image showed.
Comments welcome. More to come.
Minor edit – “Table 8.3” => “Table 8.2”
@Don Thompson
With lower resolution scanning I did not mean 3 to 6 meter p/pixel but to scan with minimal resolution to find 3 to 6meter (and bigger) objects.
The main idea is to scan possible high speed impact areas along the 7th arc with high resolution and areas beyond/outside those areas with lower resolution to save time and money.
For if the plane is not found in the possible high speed impact areas it probably made a ditch-like impact with much bigger pieces remaining close together on the seafloor.
@Rob,
I am glad you find the Endurance Model useful. I wanted to allow people to try various scenarios on their own, and I am glad you are doing that.
You said: “It could be that ground-speed of M0.82 at FL380 is comparable to ground-speed at M0.81 at FL350, (assuming the same windfield) because the lower temperature at the higher altitude has the effect of increasing the Mach number, for the same ground-speed. Is that a reasonable assumption?”
The TAS is shown in the Fuel Flow Model worksheet. If you put in M0.81 at FL350 and +10C, the TAS is 477 kts. At FL380 the same TAS gives M0.815. So, yes, that is a reasonable assumption, that a higher Mach in colder air gives the same TAS.
You also said: “But the BFOs represent an 8 second snapshot, and if a piloted glide had begun at 38,000ft, a steep descent at one point should be considered less unlikely perhaps?”
A piloted descent at 15,000 fpm does not seem reasonable or likely to me, but I am not a pilot. I am quite convinced that the two final BFOs accurately indicate the RODs at 00:19.
@sk999,
Regarding the DSTG analysis, you said: “Surprisingly, there is a well-defined narrow peak centered around -39.2 deg latitude (plus another one at -36.7 – presumably magnetic track routes.). . . . However, all is not well. The BFO residuals are big (5.5 hz stdev). The time that the final radar position is reached (whether my value or that of B. Ulich) is approx. 18:23:38, more than 1 minute later than what the Lido Hotel radar image showed.”
My first solution back in July 2014 was at 39S at a constant track and constant speed. You are correct that the BFO errors there are a problem because their standard deviation is too large. Even worse, they have a mean which is not close to zero. That indicates there is a systematic error in the course southward, and both these issues are resolved for courses close to 180 degrees.
Despite much looking, I have never gotten a magnetic track solution at S36.7. I don’t think a peak there is a magnetic track route. More likely it is a slower straight path.
I am surprised by your computed time for the last radar position. 18:23:38 seems awfully late. Could you please explain the method you used to derive this time?
@DrB
Even worse, they have a mean which is not close to zero.
I told Victor I was done posting, but your statement above demands a comment. Why in the world would you think the BFO errors should have a zero mean? You have made this assertion before. It is just plain wrong. Does a random walk have a zero mean? Does figure 5.4 of the DSTG book have a zero mean? Were you asleep when ergodicity was discussed in your stats class?
@Don. With PAX capacity of 102 (less I suppose the search staff, ie other than ship’s crew), plus lift from 6000m and ROVs, maybe Seabed Constructor could do wreckage recovery; if equipped with some bits and pieces the ATSB mentions in its Operational Search report. There might need to be some USV offloading for deck space. A part of contract discussions maybe, together with the site survey and information needed before starting the recovery?
This was a presentation to unstated Perth WA attendees I notice, not at the ATSB’s Canberra but I suppose that unless there was another presentation they went across.
Various interesting practical points like the effectiveness of the hook-up gathering ‘funnels’ on the USVs with falls blowing and swaying about and the USVs rolling, pitching and heaving are of interest but must work quite well, in limited seas anyway.
It is worth them pointing out a relationship between telemetry/data transfer and distance and also the challenge of timely processing of the data, given its quantity. However why they would depict USV at the p13 distances they do not make clear. I assumed the ship would be in the middle with USVs abreast. Perhaps her underwater noise might be a reason why not?
I note for the first trial (p25) they describe area vs time, the outcome being almost 200 sq km/day, which is also the average over the “last month”. Both presumably had the various gaps that would come with trials.
Their use of the word ‘simultaneous’ applies to the searching being 6-at-once I think, not whether they are recharged/refuelled in a search halt (as distinct from serially). There look to be (p26) 2 AUV recovery doors, allowing for recovery and battery exchange in pairs, applicable to both the ‘one hit’ and serially.
There must be a high potential demand for deep ocean searches to warrant the level of expertise, investment and enterprise at work here and I suppose competitors will be committed likewise. What will search capability in 10 years look like???
Bobby Ulich,
Much thanks for your commentary. My spouting r.e. magnetic track to -36.7 was just a conjecture – I didn’t study it one iota, so it could be wrong.
R.E. time to last radar position, what I do was to assume a constant Mach starting at the 18:01:49 position and continuing up to the FMT, the exact value of said Mach being found by least squares. I then plucked off the time when this particular path passed the longitude of the last radar point. Remember, I am just trying to recreate something close to what the DSTG did – I’m not representing that it is what actually what happened.
@sk999 said: another one at -36.7 – presumably magnetic track routes
@DrB said: Despite much looking, I have never gotten a magnetic track solution at S36.7. I don’t think a peak there is a magnetic track route. More likely it is a slower straight path.
Or a slower path with another turn or two.
@DrB, Excellent work on the Fuel modeling. Thank you for sharing. Please check the following Version 5.5 model data points against your source data.
Workbook Tab [LRC INOP FF] ( 80FL, 270 MT)
Workbook Tab [Holding INOP FF] (200FL, 140 MT)
Workbook Tab [CI=52 FF] (270FL, 180 MT)
Cheers, Tom
@sk999. Bless you. I was hoping that someone with the requisite skills could properly address my earlier incredulous enquiry on how, exactly, the DTSGs probability peak should be so clearly defined, yet Victor’s BTO and BFO RMS error curves appear to provide a gigantic and nearly equally-good spectrum of candidate paths from 19.41ff. Since all parties appear to be in full agreement on the BFO and BTO interpretation methodology, the only reason for such a difference must lie with DSTG’s priors – as Victor has pointed out. I’m not entirely convinced that this is wholly down to a model bias towards fewer turns. If I understand them correctly, their point is rather that with reasonable priors a solution can be obtained with a single manoeuvre. Other solutions are also possible, but they require multiple changes in track/speed. And in the absence of a sensible reason for supposing the more complex solutions to be credible, a parsimonious solution is preferred. I’ll be following closely the discussion among experts on this topic as I am yet to be convinced that DSTG’s clearly-defined PDF peak is a mirage.
@VI and sk999 re bi-modal peak in PDF. If memory serves, I think that there reason behind this result was clearly explained but I can’t recall the details. Something to do either BFO uncertainty intervals or how much weight is put on veracity of 1822 vs taking 1802 as the LKP?
@Paul
If memory serves, I think that there reason behind this result was clearly explained but I can’t recall the details. Something to do either BFO uncertainty intervals or how much weight is put on veracity of 1822 vs taking 1802 as the LKP?
So why not look up the details? What is wrong with you people?.
@David
“presentation to unstated Perth WA attendees”
The PDF is hosted by SUT, the (Australian) Society of Underwater Technology). The site also hosts the October conference agenda, etc.
The cone-bullet latch mechanism you note on the ASVs is also typical for ROVs. You’ll note that the AUV hangar includes cradles for six Hugins, two of which are the launch and recovery ‘stingers’.
@Dennis W. I’m simply pointing out where to find the answer so that the person asking the question can go and look it up for themselves.
Alright Dennis. Since I’m in neighbourly mood this fine morning, the answer to the bimodal or not is found in Bayesian methods, figure 10.3 page 87. Using BTO only, you get a bimodal PDF with one peak at 39S and a second at 37S. With BFO included you get more of a single peak at 38 with a bit of a shoulder at 36S.
It’s also worth noting that probability north of 34S is practically zero in both cases, and 35S is practically zero on the “BTO only”. When BFO is included, 35S lies on the tail of the PDF with relative frequency of about 0.07 (about a fifth of the peak value).
Here is a short video showing the final sea trails of the Unmanned Surface Vehicles (USVs) that Ocean Infinity is using on Swire’s Seabed Constructor.
The DSTG in their Bayesian analysis considered these kinds of manoeuvers: changes in course, changes in speed, and changes in altitude, where each change of a given type is considered to be one manoeuver, and the time between manoeuvers is described by a Poisson distribution.
I have long believed that another manoeuver that should have been considered is a holding pattern, which could be described by a random variable indicating the duration in that pattern. When you consider that holding patterns are automated, holding patterns are commonly found as part of “normal” commercial flights, and holding patterns are also common in “abnormal” commercial flights, such as when the crew in an emergency situation is assessing and controlling conditions while in the vicinity of a suitable airport, it seems there is ample justification for including a manoeuver of this type.
Of course, I also believe the possibility that the plane was descending during the sat call at 18:40, and the FMT occurred afterwards. In the time since I described that possibility in a previous post, I’ve done additional work that suggests to me that rate of change of the BFO during this descent would be less than previous models suggest.
I think that if you allow these two possibilities (descent at 18:40 and holding pattern manoeuver), and you eliminate trajectories crossing the 7th arc further south than around 36S based on previous search data, you would see a posterior distribution that is relatively flat up to around 26N latitude, as the curve for BTO error shows in Figure 2 above. That doesn’t help us define hot spots, but it does justify a fairly large search area.
An animated clip showing how the Denith designed LARS operates with the C-Worker ASVs.
All,
Slight correction to above post r.e. BTO-only solutions. Turned out I was using constant airspeed, not constant Mach. Switching to the latter, I now get best fit for LNAV mode going to latitude -39.1, which matches Figure 10.3, top. Turn is a minute earlier – 18:35.
The second peak in Fig 10.3, top might be true heading routes. I can get a decent fit that turns at 18:39 and goes to -36.6 provided I incorporate wind errors. The final latitude depends on altitude, since winds are involved; this particular run used FL280 and Mach 0.758.
@Victor
Bottom line for search zone model – stick with Arc2 as the starting point and it is possible the only arcs that might be without pilot input are Arcs 3-5, and even that assumption I would give up on if necessary.
@TBill: I think solutions where no pilot input is required after 19:41 (or sooner) are preferred. The flight between 18:22 and 19:41 is much less likely to be automated.
@sk999. Thanks for that. Your 39.1S route in LNAV with turn at 18:35 is not going to be fuel feasible, I suspect. What does your fuel model say?
@Victor. Agreed. Would have been nice if the modelling had permitted a holding pattern in the mix of possibilities since this appears to be the chief means by which more northerly terminus becomes a decent path fit. I recall Dr B was running models to reach the 35S area but I’m not sure if he found a path model that produces a good fit without inclusion of a holding period?
I wonder if they (DSTG) might consider re-running the models with that variant and seeing if the PDF it produces indicates any clear peaks. I shouldn’t think that would be a terribly time-consuming or costly thing to do with the modelling they have already done?
testing
@Victor,
“I think solutions where no pilot input is required after 19:41 (or sooner) are preferred. The flight between 18:22 and 19:41 is much less likely to be automated.”
Ironically I arrived to this idea 3 years ago, but I was heavily criticised for pursuing it.
These days my thinking is concentrated on triangular patterns with descent. A wrong exit would result in the heading of approximately 172 deg. At the moment I have 4 such patterns, which fit 18:22-18:41 data.
Perhaps Andrew could tell whether repeated triangular patterns can be used for some other purpose besides indication of navigational or radio failures.
BTW, I believe 23:14 BFOs provide strong indication that the plane was flown in one of the three possible constant heading modes (true, magnetic or hygroscopic), all being subjected to the wind.
@Oleksandr said: Ironically I arrived to this idea 3 years ago, but I was heavily criticised for pursuing it.
I certainly don’t recall criticizing it since I considered a loiter followed by a BEDAX-SouthPole path since July 2014.
@Victor,
I did not mean someone specifically, but in general.
General consensus was that the FMT took place between 18:25 and 18:40, wasn’t it?
@Victor
re my great circle constant M0.81: I’ve just remembered that I was using ground miles as per the Vincenty calculator for the calcs, rather than air miles. ie miles covered at altitude. the additional distance from IGOGU to the 7th arc is 4.5NM for FL380. And a 7th arc at 38,000ft would be further south than the 33,000ft arc. I seem to remember reading in an INMARSAT paper, that they assumed the arcs to be nominally at 10,000 metres altitude, although I’m not sure if that figure is still used for calculating the arc positions. If the 6th and 7th arcs are 2NM further south, then the total distance from 18:29 to MEFE becomes 67.5NM (estimated) from 18;29 to FMT at IGOGU, plus 2,658NM from IGOGU to the 6th arc, plus 47.5NM from the 6th arc to MEFE at 17:30 = 2,773NM. Compare this to DrB’s 2,774NM for M0.82 at FL380. There’s more, M0.81 at FL350 equates approximately to M0.82 at FL380; average TAS for the journey south is now increased to 480Kts from the previous 478.69Kts, which equates to average M0.813. Now using the simple conversion factor I borrowed from DrB (ref his previous post to me) to convert Mach at FL350 to Mach at FL380, you multiply by 0.82, and divide by 0.815, and get M0.818, or very close to M0.82.
Thus the distance covered at constant M0.82,FL380 turns out to be within 1NM of the IGOGU/ISBIX/7th arc great circle distance, and the MEFE time is within 1 minute. An exceptional result. One should remember that DrB has gone to great lengths to ensure his fuel model for MH370 is as accurate as possible. It is a fuel model for those specific engines and the specific atmospheric conditions on the night. This cannot be dismissed as a coincidence. This has to be none other than the actual flight path.
@Oleksandr said: General consensus was that the FMT took place between 18:25 and 18:40, wasn’t it?
Before the search of the first 60,000 sq km failed to find the wreckage, and before any debris was recovered from Eastern Africa, an impact along the 7th arc at around 38S was the consensus, corresponding to an FMT between 18:29 and 18:39.
@Rob: By my calculation, a great circle path crossing the 7th arc at 37.5S requires a speed of M0.828 at FL350 to match the BTO data, which is well above the M0.81 you have calculated.
@Victor
Could you possibly show me your calcs?
@Rob,
Where, in your calculations, do you account for the wind. It has a significant effect in more southerly latitudes.
@Oleksandr
“BTW, I believe 23:14 BFOs provide strong indication that the plane was flown in one of the three possible constant heading modes (true, magnetic or hygroscopic), all being subjected to the wind.”
What is your logic about 23:14? I tend to agree there could be a wind/turbulence effect at some point in time the BFO jumps from steady 216 up to 220-222 with bouncing around. I like 216 as the base point.
@Brian Anderson
Re wind calcs, probably best if I send you the relevant section of my earlier post to Victor. You can then see how the wind was accounted for for each leg. I took the wind values from the earth.nullschool map linked to your “Calculating the Mid Flight Speed” paper. I took multiple readings along each individual leg, then averaged them to get a single wind speed/direction for each leg. Same for the temperatures. Here is the relevant section:
“When calculating the average airspeed for each leg of the IGOGU/ISBIX/7th arc great circle I found that, assuming it flew at a constant altitude of 35,000ft, the aircraft maintained an almost constant Mach 0.81 throughout its journey south, subject to the limits of accuracy of the wind speeds and temperatures determined from the earth.nullschool.net global map of windspeeds and temperatures. applying specifically to altitude 34,000ft, for the date/time in question – via link on Brian Anderson’s paper “Determining the Mid- Flight Speed of MH370, 20/03/2015, Duncan Steel website.
IGOGU to 2nd arc: 512Nm, 480Kts average groundspeed, 1.8Kts average tailwind = Mach 0.808 (Mach 1=592Kts, Temp -41C) 2nd arc crossing point S1.0, E93.53.
2nd arc to 3rd arc: 478.7Nm, 478.7Kts average groundspeed, 1.6Kts average tailwind = Mach 0.806. (Mach 1=592Kts, Temp -41C) 3rd arc crossing S9.0, E92.7.
3rd arc to 4th arc: 488.6Nm, 485.6Kts
average groundspeed, 4.6Kts average tailwind = Mach 0.812. (Mach 1=592Kts, Temp -41C) 4th arc crossing S17.13, E91.82.
4th arc to 5th arc: 480Nm, 479.6Kts average groundspeed, Zero average head/tailwind = Mach 0.81. (Mach 1=592Kts, Temp -42C) 5th arc crossing S25.12, E90.87.
5th arc to 6th arc: 692.2Nm, 461.5Kts average groundspeed, 13.5Kts average headwind =Mach 0.81. (Mach 1=586.5Kts ave.for leg, Temp -46C ave.for leg) 6th arc crossing point S36.6, E89.24.
6th arc to 7th arc: 61.5Nm, 434Kts average groundspeed, 33Kts average headwind = Mach 0.804. (assuming Mach 1=581Kts, Temp -50C, at altitude 35,000ft. However, aircraft would have been descending)”.
I have since found, from Dr Bobby’s endurance table, that M0.81 at FL350 has insufficient range, but that M0.82 at FL380 appears to have exactly the required range and endurance.
However, according to Victor, the overriding problem with this particular constant Mach path is that it does not comply with the BTO. I find that a bit surprising, but then I admit I’m no expert on path fitting.
Curiously, Bayesian Methods Fig 10.3, bottom, “with BFOs,” has a broader distribution than the top, “without BFOs.” Why does adding data cause the distribution to broaden? A guess is that the top plot was not generated with all degrees of freedom in the model turned on, while the bottom plot was.
Next exercise – suppose I only consider the data (BTOs and BFOs) from after the FMT. I will assume that the plane followed a constant LNAV route at constant altitude and Mach starting just before 18:40 up to the end of the flight. What can we say?
I have four free parameters – the starting latitude, longitude, heading, and speed. (I’ll take a starting time of 18:38, just before the 1st phone call.)
The DSTG report assigned errors of 29 microsec to the BTO (with a couple of values higher) and 7 hz to the BFO. Given those errors, I find that the best-fit starting coordinates are 8.6N, 94.3E, and a best-fit end latitude of -36.9 deg. However, these values are very poorly constrained, and the 1-sigma error on the final position (measured along the 7th arc) is 3.4 degrees. Note also that the best-fit starting coordinates are well beyond where the aircraft could have flown by 18:38 (and curiously is near the 19:12 NW point, although that should be regarded as a coincidence.)
Final exercise. What if I include the data from before 18:38 along with the starting position and priors assumed by the DSTG, as I previously did for the BTO-only case? I end up at -38.4 degrees, with a small error – only 0.23 deg. For comparison, a true track ends up at -37.9 deg.
The overall spread in the final distribution must come from combining at least three individual narrower distributions (1 each for LNAV, true track, and true heading) plus accounting for other elements that have been left fixed here – different altitudes, variable winds, etc.
@TBill,
Re: “What is your logic about 23:14? I tend to agree there could be a wind/turbulence effect at some point in time the BFO jumps from steady 216 up to 220-222 with bouncing around. I like 216 as the base point.”
When I developed a so-called CTS flight model (already outdated) I noticed that wind pattern ‘centered’ around 96S, 22S, FL200-FL250 was just right to alter ground velocity to fit the BFOs in 23:14 cluster. Even the trend during the 2nd call was reproduced correctly. I observed the same effect in later models, where I managed to connect 19:41-00:19 section to 18:22 radar position via triangular patterns.
I guess the same is applicable to CMH models. I am currently looking at that issue, but perhaps @sk999 can already comment on it.
In summary, nothing to do with the turbulence; just the plane needed to fly through such a wind pattern in the mode, which could alter track angle.
@Victor,
“Before the search of the first 60,000 sq km failed to find the wreckage, and before any debris was recovered from Eastern Africa, an impact along the 7th arc at around 38S was the consensus, corresponding to an FMT between 18:29 and 18:39.”
Exactly.
My 3-year old prediction that the FMT did not occur during this interval was based on simple logic: the plane was actively piloted till 18:22; some unorthodox actions, which resulted in the SDU logon 18:25, were in process. How could the plane become unpiloted in just 5-15 minutes?
@VictorI
You wrote: “@TBill: I think solutions where no pilot input is required after 19:41 (or sooner) are preferred. …”
What are your arguments to support this thought / statement?
(If you look in detail to the BTO/BFO data as @TBill is doing, I also find there are some indications for “maneuvering” still going on between 19:41 and 20:41. However: given the unclear BFO errors, not something we can say with certainty.)
@Kenyon,
I checked the three cases of Fuel Flows you mentioned. The first one was a dyslexic typo I made in manually transcribing the Boeing table.
The second one seems to match the Boeing table. Perhaps you might explain why you thought there was a problem with it. Be sure to use the Flaps Up table value.
In the third case, there was an incorrect entry which I have fixed.
LRCINOP FF FL80, W 270 tonnes: Was FF 8,436, Corrected to 8,346
Holding INOP FL200 W 140 tonnes: Was FF 3,780, Appears correct
CI=52 FL270 W 180 tonnes: Was FF 2,566, Corrected to 2,891
These two corrections are included in a newly posted V5.6 fuel model. You can use the same link as before.
Thanks for pointing these things out, Tom. You have a keen eye.
@VictorI
At the beginning of this thread I indicated I am interested to know the 19:41 latitudes of the sixteen great circle paths you have analyzed (fig. 1, fig. 2). Would it be possible to share those?
@DennisW,
You said: “Why in the world would you think the BFO errors should have a zero mean? You have made this assertion before. It is just plain wrong. Does a random walk have a zero mean? Does figure 5.4 of the DSTG book have a zero mean?”
Actually, yes it does have essentially a zero mean. Here is why:
1. The mean of the BFO Probability Density Function of BFO errors shown by DSTG in Figure 5.4 is listed immediately above the figure in Table 5.1
2. The mean observed BFO error was between 0.10 and 0.27 Hz. That’s VERY close to zero.
3. To quote the DSTG on the previous page, “The mean BFO error was close to zero in all cases . . . .”.
4. Therefore, the expected value of any size ensemble of BFOs is also within a few tenths of a Hz from zero.
5. Therefore an ensemble with a mean significantly different from zero (say several Hz), is possible but is less likely than an ensemble with a near-zero mean.
I think you were asleep when you read the DSTG report.
Ocean Infinity. A couple more on how it all works:
AUV storage (including hoists), launch, recovery:
https://spark.adobe.com/video/z8cksY38bal7z?w=_2913
AUV innards:
https://spark.adobe.com/video/4e6XIf5pGDBJL?w=_5634
@Paul Smithson,
You said: “I recall Dr B was running models to reach the 35S area but I’m not sure if he found a path model that produces a good fit without inclusion of a holding period?”
Yes, I have found a CTH route ending at 34.75S that uses a single FMT without a Hold. I published this in January 2017. A link is in my pubs list, and a PDF can be found HERE . This route is an excellent fit to the satellite data, except that the endurance is a few minutes too long using my new fuel model. Another issue is why a pilot would set the NORM/TRUE switch to TRUE at MH370 latitudes.
A more likely possibility, in my view, is a 180-degree Constant Magnetic Track. This closely mimics the CTH route and perhaps it is a more likely setting. My first attempts gave good (but not perfect) results fitting a CMT route using a 2014 magnetic declination table. Now we know 9M-MRO used a 2005 table. I have these 2005 data, and I will see if that improves the fit. The end point won’t move much.
@Oleksandr
Not convincing re:2314 without a plot or something so show it. At some point the 2314 BFO reading sequence instantaneously went from steady, to jumping around a bit.
@Dr B Thanks for posting the link to your path. I’ll take a closer look.
I recall you saying previously that CMT looks similar to CTH and I was surprised. I thought that CMT bends quite a lot more than CTH (in the last 1-2 hours) but I guess I must be wrong. I’m using a modified version of Barry’s model that offers CMH but not CMT as a mode so I can’t actually simulate it. Could you post the .kmz of the two tracks so that we can see them side by side?
@TBill,
I’ve just taken a fresh look at my old CMH model. My prediction was indeed correct: BFOs 23:14 also agree well.
I guess I know why the DSTG missed this batch of routes:
“An initial Mach number was selected
from a uniform prior between 0.73 and 0.84; this was chosen on the basis of expert advice to ensure that the required flight endurance is achievable.”
My experiments show corresponding Mach of 0.70-0.71, so the next task will be quite delicate: the existence of a CMH route depends on fuel.
@TBill,
Re: “Not convincing…”
I posted plots and tables quite a few times… including recently. You may also check my CTS note (rev 02.12.2015), where you can see what wind does around 23:15.
I don’t have plots for CMH models (yet), as I abandoned this class of models long time ago. I believe effect is similar.
@DrB
“Now we know 9M-MRO used a 2005 table.”
How do we know that? I have been using 2005 table ever since ALSM said ATSB intimated that to him a while back. But I also use circa. 1995 mag tables as that was the FS9 default, and sometimes I use 2017 to bracket.
You will find 2005 harder to fit, I would think, as it is more curve.
@Oleksandr
Re: “Perhaps Andrew could tell whether repeated triangular patterns can be used for some other purpose besides indication of navigational or radio failures.”
I’m not aware of any other purpose. I’ve already given you my view on the likelihood of MH370 flying a triangular pattern; I really don’t think it has ‘legs’ (if you’ll pardon the pun).
Bobby Ulich,
The DSTG discussion regard the BFOs in general and Table 5.1 in particular is quite confusing, and I am usure of what it really means.
The text discussing Fig 5.4 (the BFO residuals for the Mumbai-KL flight of Mar 2, which is what DennisW frets over), states as follows:
“The residual error is clearly not zero-mean, and the mean varies with time.”
The bias value used for this plot was derived from on-tarmac measurements. The DSTG then goes on to say:
“The potential variations were incorporated by modeling the BFO bias as an unknown constant with a prior mean given by the tarmac value and a standard deviation of 25 Hz.”
In other words, the in-flight BFO bias was basically forced to give zero mean aside from a slight “tinting” introduced by the prior.
What, exactly, does “Mean BFO error” in Table 5.1 refer to? Mean of what relative to what? Are the on-tarmac residuals relative to a bias determined by the on-tarmac values themselves, and the in-flight residuals relative to a slightly tinted bias? Any insight would be welcome.
On a related note, the DSTG had no example of a cold restart of a SATCOM while in flight. Will the BFO bias come back to its original value? It is worth noting that the BFO bias offset for MH371 was 25 hz bigger than that for MH370 (pre-IGARI).
@Victor: I am deeply appreciative of the efforts of those who work tirelessly, intelligently, and endlessly to uncover MH370’s true fate. And I continue to appreciate your efforts in particular; in the hypothetical that the ISAT data we were fed is, despite clear appearances, authentic, it is always useful to nail down the Bayesian pdf of possible impact points.
Re: “best fit ending at 34S”:
1) in your analysis, you’ve chosen to fit BTO and BFO values for 6 arcs from 19:41 onward – not 3, as the JIT did in April of 2014. If you had been heading up the JIT – and had to decide how many arcs to fit paths to – would you have chosen 6, or 3?
2) I can happily wait until the post with which you’ve teased us, but hopefully this is something you can let slip: for this best fit path, at what precise coordinate is it at 19:41?
I also reiterate (and hopefully focus) my polite request for the names of all the people from whom you’ve received data you’ve used to shape your theories and models since March 8, 2014. As we all know, the likelihood of this data being suspect grows with each passing day, and is something the “discovery” of deep sea “wreckage” is unlikely to quell.
Even if one illogically sets at zero the possibility that something is amiss, here, proper data sourcing is the heart of good science. I’m interested mostly in the Météo and RMP “leaks”, but a comprehensive list of full names and titles of all “data” used as inputs to all of your advertised models works best – it would minimize the amount of my pestering you’d have to endure. Thanks in advance.
In other developments:
Re: hydro-acoustic study to which you referred last month: have you read any public response from Dr. Alec Duncan? In a critique he emailed me (originally sent to the journal’s editor), he was characteristically diplomatic and open-minded – but still left me with the strong impression there was limited rigour to this new science, and limited value to the experiment.
He also agreed with me that the likelihood the Scott Reef and Leeuwin sound blips were of the same event was somewhere in between how Senator Watling’s committee characterized it (0%) and how the ATSB’s final report characterizes it (100%). I have promised not to divulge his own gut feel on the likelihood, but all who actually read his Scott Reef work can see for themselves that he basically stays on the fence. So neither the Senate Committee nor the ATSB are properly characterizing the work. It is bizarre to me that they would each slant the science in opposing directions. Throw it on the pile of rabbit holes down which we’ve been coaxed over the years…
@TBill,
ATSB has confirmed to me that 9M-MRO used 2005 magnetic variation (declination) tables. They are unsure of the exact day of the year used. I am using 1 January 2005.
@Paul Smithson,
I have previously posted a plot a long time go that shows what you want. You can get it HERE .
There are 3 plots in this file. The first plot shows the wind vectors along the southern route.
The second plot shows CTT, CTH, and CMT route fits I have done. The CTH and CMT are essentially identical down to 22:41, and then the CMT curves more eastward than the CTH (your memory is correct on this).
The third plot compares the Inmarsat route to my CTH Route. Again, they are virtually identical down to 22:41 where the CTH route curves eastward whereas Inmarsat assumed it stayed at 180 degrees (because they had no FMS navigation model). They just fiddled the speed of the last major leg so that they could fit the 00:11 BTO with a straight south path.
Still, the very close agreement of the CTH, CMT, and the Inmarsat routes from 18:41 to 22:41 is actually quite striking. All in all, I think Inmarsat did an admirable job at the time, except for the last leg where they were unsure what the bearing should do.
@sk999,
You said: “What, exactly, does “Mean BFO error” in Table 5.1 refer to? Mean of what relative to what? Are the on-tarmac residuals relative to a bias determined by the on-tarmac values themselves, and the in-flight residuals relative to a slightly tinted bias? Any insight would be welcome.“
I can only guess what DSTG did. I suspect they picked a BFO Bias value for each flight so that the in-flight mean error for each flight was very close to zero. Therefore, the mean BFO error for the ensemble of flights (shown in Table 5.1) was also very close to zero. Because the best-fit bias values were somewhat different from each other, DSTG correctly concluded that the mean BFO error over a long time period would not stay at zero because of drift (i.e., “the mean varies with time”). I don’t recall DSTG discussing how many automatic calibration events occurred over the span of the 20 flights. We do know one occurred for MH370 at 00:16:27 (-16 Hz).
Adding in the Tarmac values shifted the mean BFO errors for each flight as well as the ensemble of flights only very slightly away from zero, as expected.
You also said: “On a related note, the DSTG had no example of a cold restart of a SATCOM while in flight. Will the BFO bias come back to its original value? It is worth noting that the BFO bias offset for MH371 was 25 hz bigger than that for MH370 (pre-IGARI).”
Who knows? That is one of the reasons why I directly requested Dr. Holland and ATSB to arrange for additional SDU thermal tests when cooled to in-flight temperatures. I believe Dr. Holland explored the feasibility of such testing by the manufacturer, but I have not received a clear answer as to whether or not those tests have occurred or will occur. At this late date, I suspect they aren’t likely to happen.
I don’t seem to have any BTO/BFO data for MH371. Where is it available? I’d like to run some examples using my BTO/BFO model.
If we had access to the bias values determined by DSTG for each of the 20 flights as well as the self-calibration adjustments, we could plot the long-term drift over a period of weeks. That would be helpful in estimating the possible drift from flight-to-flight as well as the drift during a single flight. Unfortunately, DSTG did not list those values in their report. I’ll ask Dr. Holland for them.
Bobby: Re: “I don’t seem to have any BTO/BFO data for MH371. Where is it available? I’d like to run some examples using my BTO/BFO model.”
Check your email.
@Niels: I emailed you the results for the 16 constant Mach and 16 LRC cases.
@Brock McEwen:
1) I think a fit to 6 arcs is better than 3.
2) I’m not sure what you are referring to as best fit. If you mean the great circle to the South Pole, the coordinates at 19:41 are (2.6,93.7).
3) I have not and will not compile a complete list of everybody I’ve interacted with since March 8, 2014. If you have a specific question, ask it, and if I am free to answer it, I will.
4) As we all know, the likelihood of this data being suspect grows with each passing day, and is something the “discovery” of deep sea “wreckage” is unlikely to quell.
The only thing I know is that the assumptions that went into the DSTG Bayesian analysis were incorrect. Please don’t ascribe your opinions as something “we all know”. And if the wreckage is found, only fringe elements will believe the evidence was fabricated.
5) I have no special knowledge about the information from Meteo. As for the RMP report, I have stated many times that the report was leaked to the French media, and subsequently Florence de Changy shared large portions with members of the IG.
6) I have seen comments regarding the recent paper in Nature discussing AGWs and MH370, including comments from Alec Duncan. It appears that experts in the field doubt the methodology and conclusions from that paper. I claim no expertise in this domain.
7) Has Florence de Changy backed up her claim that the simulator data “has been dismissed as a clumsy fabrication based on several simulator routes flown by Shah, not one”?
@DrB: In addition to what @ALSM is emailing you regarding the satellite data from MH371, there were two posts and many associated comments from contributors that discussed these data at length:
The Unredacted Inmarsat Data for MH370
Some Insights from the Unredacted Satellite Logs
@All
Reading @DrB’s analytics and others on possible flightpaths and FMT’s it comes up to me again the FMT probably did not took place between ~18:25 and ~18:40 or after with holding patterns, race tracks or triangle emergency legs.
All much too complicated and thought out to fill the void till 19:41.
Much less complicated and logical imo is the plane flew straight on after ~18:25 (possibly with a descent and off-set) till ~8N/~92E and made a major left turn there flying back till the 2d arc and made a second smaller right turn before or after till it’s final destination.
This will put the crash area further north ~35S also which imo fits better with the forward drift analysis.
I’m not in to the specific scientific details. It just seems more logical to me.
Is a route like this possible considering the BFO/BTO’s and all other known data?
@Ge Rijn
Yes that route is very possible. That is basically the 180S CTH path I shared a while back, and that is similar to other 180S paths. DrB just made the statement that 180S paths are the best at fitting BTO/BFO. The only question is: are we looking for paths that do closely fit BFO/BTO data, or are we instead looking for paths that don’t fit the data exactly (needed if the BTO/BFO data is imperfect).
I personally favor close match to BTO/BFO at the moment. Assuming live pilot allows almost exact match to BTO/BFO on a 180S path. Yes I think that could mean MH370 went to 92S (Indonesia FIR boundary) and came back to ISBIX/BEDAX area for the real FMT.
@Victor: thank you for responding. I’m still awaiting a response fro FdC on her source.
Specific question #1: can you please tell us the name of the person who gave you the report whose inspection caused you to publicly dispute FdC’s reporting that 11 of 12 flaperon serial numbers did not match – and that the 12th was a handwritten number (?). If I recall, you were impressed by the fact that “only” 9 of 12 serial numbers were wrong.
@Brock McEwen: Don’t attribute statements to me I didn’t make. I never said I was “impressed by the fact that only 9 of 12 serial numbers were wrong”. When you distort statements, sources are less willing share information.
Here are the facts: Florence asked me to look over the evidence that she was able to obtain related to using the serial numbers from the flaperon to link it to 9M-MRO. She was doubtful that a positive ID could be made. It was also clear that she was confusing the serial numbers of the parts and the airframe.
Based on my assessment, I told her I had little doubt that the flaperon was from 9M-MRO. There were serial numbers from 4 part types: front spar, rear spar, cleat, and fittings. Of these, only the front and rear spars had recordable numbers. That made the serial numbers for the cleat and fittings useless for identification, but not “wrong”.
For the front spar, the part number and serial number were clearly legible, and these were related to flaperon serial number 405 installed on airframe 404, which was registered as 9M-MRO. The numbers on the rear spar were harder to read in the image she had, but by comparing the fuzzy numbers to what would be expected for a rear spar from this flaperon from 9M-MRO, a match was plausible. I am not aware of any “wrong” serial numbers.
@Victor
Regarding 6) I have seen comments regarding the recent paper in Nature discussing AGWs and MH370, including comments from Alec Duncan. It appears that experts in the field doubt the methodology and conclusions from that paper. I claim no expertise in this domain.
Do you have a link or correspondance your willing to share as regards to the comments from the experts about that particular paper?
Thanks in Advance
@Joseph Coleman: None that I could share without permission.
@Victor
Ok thanks anyway. I won’t bug anyone for these comments. As a layman to most things it just seemed there was slightly different results as to distances and directions of source compared to the previous HA01 study in particular for SIO. It does seem interesting if just co-incidental that the recent paper points to a source further south close to where a lot of searching was done and found nothing related to MH370. It’s sounds like an interesting study as most others we have seen but still very vague as to at least a near close to confidant place to start looking again.
@Lauren H @all
I am embarking on an exercise to look at “exact solutions” to the 180S paths. Just getting started, but tentatively looking like:
Exact Solutions to 180S Paths (Work in progress)
CTH: M0.810 from about ISBIX (final Arc5 longitude 93.15E @ 478 GS)
CTT: M0.845 from about ISBIX (final Arc5 longitude 93.70E @ 498 GS )
CMH: TBD
CMT: TBD
LRC: TBD
where: Exact solution defined based on assuming Inmarsat Arcs 3-5 BTO’s are accurate and that the aircraft autopilot settings and behavior (altitude/speed/heading) was constant during this period.
Does this make sense?
Joseph Coleman: I’ve been a party to a new discussion recently about the SIO hydroacoustic data, stimulated by Usama Kadri’s paper in Nature. The “E2 event” described therein does not appear to have any possible connection to MH370. The E1 event appears to have occurred too far NW of the 7th arc, but the HA01 bearing (301.6 degrees) to E1 raises some questions. When A. Duncan et. al. first identified this HA01 signal in 2014, it appeared to be coming from a direction too far north of the search area identified from the Isat data, and the distance was too far. Since then, we have debris analysis and Z’s sim data pointing to locations further north east, potentially consistent with the 301.6 bearing. And Kadri’s distance put’s it closer to the 7th arc, though still too far NW. This is why it is being reconsidered now.
The experts in the discussion (not me) are skeptical about this E1 observation being related to MH370, but everyone agrees that if the range estimate is wrong for some reason TBD, the bearing is potentially important. So we are looking into that possibility. It is a long shot, but we are working on it.
Table 1 SWAMS (43.0 South 75.6 East), and NEAMS (31.6 South 83.2 East) ceased operations 01-01-2014. What a shame.
Then of course, I seem to remember that there was a comment by former French President Nicolas Sarkozy, that France had some information, but he would not elaborate.
Perhaps what he was referring, to came from the OHASISBIO-5 network ?
@Andrew,
“I’m not aware of any other purpose. I’ve already given you my view on the likelihood of MH370 flying a triangular pattern; I really don’t think it has ‘legs’ (if you’ll pardon the pun).”
Thanks for your comment. Well, the FMT was born without ‘legs’. But this did not prevent the ATSB, DSTG and IG and many others from using respective assumptions in their models for more than 3 years.
Triangular patterns are interesting because they have a discrete set of possible headings, one of which is consistent with the heading into the SIO, thus offering a trivial explanation of how the plane ended up in the SIO.
@DrB,
“This route is an excellent fit to the satellite data, except that the endurance is a few minutes too long using my new fuel model. Another issue is why a pilot would set the NORM/TRUE switch to TRUE at MH370 latitudes.”
I think it is time to admit that “the best fit” is not “the most likely”.
In addition, the “best fit” depends on the metrics you introduce to quantify errors. I trust you are using RMS, correct? If you use the smallest absolute error, you will get somewhat different result. Which one would be preferred? Also, in general case you need to assign weights to the BFO, BTO and fuel errors, so that the “best fit” trajectory would be dependent on these weights.
@TBill,
Can you enter 2D/3D wind field in your simulator?
@Oleksandr,
My route fitter minimizes an objective function by simultaneously varying numerous route parameters. The key to effective route fitting is actually in selecting the form of the objective function. My objective function forces close matches, if possible, between the calculated RMS values of key error parameters and their independently-determined expected values. Currently I use 29 microseconds for the RMS BTO error, 4 Hz for the RMS BFO error, and 5.7 kts for the RMS tailwind and crosswind errors. I also require the absolute endurance error to be < 8 minutes (2-sigma). I don’t fit the temperature deviation error since the temperature error using GDAS is small (probably < 1 C).
I always start with equal weighting factors for the RMS components. Sometimes I adjust those weighting factors to improve the overall fit, taking into account the expected deviation of a RMS metric when the ensemble size is small (which it is for all the parameters fitted using a RMS figure of merit). Generally we have about 5 numbers to work with, so the estimate of the RMS error is itself "noisy" due to small-number statistics. That error in the calculated RMS statistic (based on 5 samples) is about half the calculated RMS value. So if we calculate an RMS of 30 microseconds for the BTO error, the uncertainty in that estimate is about 15 microseconds (1-sigma). Thus one should really only require the calculated RMS BTO error to be in the range of 15 to 45 microseconds in order to be consistent with the expected value of 29 microseconds (which is based on large-number statistics from 20 flights).
I am not forcing RMS errors to be zero. That is an incorrect method.
I believe my approach causes the "best fit" to be at/near a peak in the probability function. Note that I said "a peak", not "the peak". It remains to be seen exactly how many "peaks" the satellite data allow, but this number is not large. For the routes without an extended loiter (which I have not modeled in detail), I think it is 1-3.
@sk999,
After re-reading the DSTG report for the nth time, it seems they set the BFO bias value for each flight in order to make the (non-outlying) BFO errors zero using the Tarmac data, except for the log-on requests, which they ignored for this purpose. In other words, they used R1200 data but not R600 data (used for log-on requests only). However, the R1200 events used R8, R11, and R4 transmit channels, which have bias offsets with differences up to 4.6 Hz. There is no indication they corrected the BFO error data plotted in Figure 5.5 for channel-to-channel bias differences. Doing so would obviously produce a narrower probability density function.
I think the width of the Figure 5.5 PDF is caused by two effects: (1) the uncorrected channel-to-channel bias differences and (2) the frequency drift during a single flight. The problem is, we don’t have enough information to accurately separate the contributions of each effect. We do know the channel-to-channel bias differences are significant, and if those were removed, the PDF should be noticeably narrower (with a smaller standard deviation). For that reason, I think it is proper to require a somewhat smaller RMS BFO error than the DSTG calculated when one is fitting BFO data which has already been corrected for the channel bias difference, as I do.
@DrB, @sk999, @DennisW: In the DSTG report, there are disconnects regarding the BFO error that I have never been able to reconcile. On one hand, the DSTG advises that the BFO bias should be modeled as a prior mean given by the tarmac value, but with a standard deviation of 25 Hz due to bias drift. On the other hand, the standard deviation is 4.3 Hz for the 20 previous flights using in-flight values and excluding outliers, including BOTH noise and bias variation, and with the mean BFO error only 0.2 Hz. Then they say their model uses a standard deviation of 7 Hz to be conservative. Those three statements don’t appear to be consistent.
I agree regarding the inconsistent/incomplete description of BFO errors. It is also troubling they did not mention the automatic calibration procedure effects. Perhaps they ignored or corrected the Tarmac data taken before an auto-cal occurred (which I think should have occurred on some of the 20 flights and always on the ground before taxi).
Bobby: Re “Perhaps they ignored or corrected the Tarmac data taken before an auto-cal occurred (which I think should have occurred on some of the 20 flights and always on the ground before taxi).”
My understanding from ATSB is that those OCXO calibrations only occur on boot if at least 26 hrs have past since the last OCXO offset adjustment. So they do not automatically happen prior to every flight.
Victor,
The description of the use of the tarmac value as a “prior” on the in-flight BFO bias is what throws people. In Bayesian analysis, a “prior” encapsulates what knowledge you have about a parameter in the absence of new information. In practice, the BFO bias is determined the way you might imagine – make the mean of the BFO residuals zero, but other parameters are affecting the mean as well, so the prior is treated like a direct observation of the BFO bias, but with a large error, so it doesn’t skew the answer too much. Anyway, that’s how I implement them. All parameters are assigned priors, even if “diffuse”.
ALSM,
Has the self-calibration procedure been described here before? It keeps getting mentioned, but how it works, how long it takes, and what impact it would have (e.g., are communications suppressed during the process) are mysteries to me and any clarification would be appreciated.
@sk999,
I would like to extend my BTO and BFO models to include the time frame of MH371. That would allow us to compare calculations for that flight and perhaps understand the “BTO drift” you reported earlier.
What I need are lists of X/Y/Z and Xdot/Ydot/Zdot and δf(sat) + δf(AFC) at time intervals of an hour or less. Perhaps more time points are needed for the EAFC term if it is changing rapidly.
I can then post a revised model that covers both MH371 and MH370.
The inputs to my model are time, lat, lon, flight level, temp deviation, true course, ground speed, and ROC. We also need a list of those parameters for the MH371 BTO/BFO measurement times. You must already have generated this from the ACARS reports.
Perhaps others also have this information and can provide it. Thanks.
sk999: I asked ATSB about the 17 Hz jump circa 16:00 UTC. They confirmed it was a routine recalibration of the OCXO offset. Note that adjustments can only be made in increments of 4 Hz. Thus, the adjustment at 16:00 was 16 Hz (~17 Hz observed). I then asked ATSB to inquire w/ Inmarsat about the details of the calibration process. But ATSB never got an answer to my questions.
From my prior experience with similar mobile satellite systems, and the Inmarsat system in particular, I can make an educated guess that the system uses the GES (Perth) clock to calibrate the offset. As far as I know, there are no independent clocks on the aircraft better than the SDU OCXO. If that is true, then there is no way to calibrate the SDU OCXO using another independent standard on the aircraft. Of course, there is a GPS on board, but I’m not aware of any mechanism to compare the GPS clock to the SDU clock. OTOH, it would only take a simple algorithm at the Perth GES to measure the BFO bias on the ground and send a command back to the SDU to bump the local standard 4*N Hz.
@DrB: I asked Inmarsat for the EAFC + Satellite terms during MH371. Inmarsat said they would check to see if that data was available (which was a bit odd considering they needed this data to determine the BFO error for previous flights). I never heard back from them. The best we can do is approximate these terms based on the periodic data we have from March 7 – 8, 2014.
@sk999: I think of the standard deviation on the prior value of the BFO bias in the same way as the prior value and standard deviation of the speed and track at 18:02.
So, I’ll give you a specific example. For LRC speed, FL350, great circle path, and with initial conditions at 19:41 of a track angle of 168° and position of (9.0,82.9), the path crosses the arc at 26.6S latitude. With a bias of 150 Hz, the RMS error for the BFO is 7.8 Hz and the mean error is -7.3 Hz. If I increase the bias to 157.3 Hz, the RMS error is now 2.8 Hz and the mean error is 0. Is this an acceptable BFO error? (The RMS BTO error is 32 μs.)
@sk999: Here is response from the ATSB regarding the SDU frequency calibration:
There is an automatic SDU calibration process to correct log-term OCXO drift. Analysis of the GES logs from 9M-MRO from 04/03/14 to 08/03/14 shows three such probable calibration events at: 04/03/14 11:43:32 (-15Hz), 06/03/14 00:35:25 (+16Hz) and 07/03/14 16:00:28 (-17Hz). The actual adjustments will have been +/-16Hz, and these three calibrations appear to show a system adjusting around nominal as seen in SDU logs from other aircraft. This calibration is performed after logging-on and, if necessary an adjustment is made. For an adjustment to be made, one hour must have elapsed since power on, and 26 hours of on-time must have elapsed since the last adjustment. It is not possible to know from the GES logs, when and for how long, the SDU on board 9M-MRO had been powered on prior to flight MH370.
@Oleksandr
“Can you enter 2D/3D wind field in your simulator?”
As it pertains to MH370, all I know how to do is adjust wind manually. I can set different winds in different levels of atmosphere. You can also set weather at weather stations, but all I got is COCOS.
Bobby Ulich,
You say, “I would like to extend my BTO and BFO models to include the time frame of MH371. That would allow us to compare calculations for that flight and perhaps understand the ‘BTO drift’ you reported earlier.”
Yes. I’m all ears!
But then you request, “What I need are lists of X/Y/Z and Xdot/Ydot/Zdot and δf(sat) + δf(AFC) at time intervals of an hour or less. Perhaps more time points are needed for the EAFC term if it is changing rapidly.”
And further, “The inputs to my model are time, lat, lon, flight level, temp deviation, true course, ground speed, and ROC. We also need a list of those parameters for the MH371 BTO/BFO measurement times. You must already have generated this from the ACARS reports.”
First of all, more than half of the data that you request do not exist in the form that you need – I would have to generate them (e.g., satellite parameters.) That introduces a hazard. Second, most of the rest of those data (e.g, ground speed and true course) are not fundamental but are derived from primary sources. Yes, I have computed them. But what if my derivation was faulty? I would be more than happy to provide and/or generate any numbers needed for a cross-check. I am less than happy to generate numbers simply to be used as “fundamental” input.
As usual, for reference, my index of reports is here:
https://docs.google.com/document/d/14hleZyx1pUPL44yaeHKt6jnSQ3DbgRq2zibbKkFLq2c/edit?pref=2&pli=1
I wrote multiple reports r.e MH371 back in June and July (2017), including one on the AFC+SAT correction. That was a squirrely effect to figure out. For MH371, there is not such thing as “δf(sat) + δf(AFC)” as Inmarsat provided for MH370 – I had to use a different method.
Finally, all of my calculations and results are based 100% on publicly available data.
ALSM & Victor,
Thanks for your input, but it is still rather unclear what is used as the calibration reference. Yes, one can use a clock to calibrate a frequency, but one would need to have a coherent source and count cycles. (I’ve done it with pulsars.) I highly doubt that the OCXO allows one to do that. Alternatively, the SDU might simply monitor the Psmc frequency (a la Rockwell Collins), which is known, As long as you are on the ground and the satellite orbit is known, most other extraneous effects are removed. Or something else.
Sk999: Every GES has a freqency standard (aka a clock) good to 10^-15 or so. Usually it is a cesium or rubidium oscillator. The down conversion chain and all the CUs are phase locked to the station standard. So the CUs can measure the incomming carrier frequency to a fraction of a Hz, ignoring the pll noise. That is how it can and has been done in some systems. The SDU does not need to trim the ocxo frequency. It simply uses the NCO divider chain to add an offset.
@Victor
re: BFO bias:
>In the DSTG report, there are disconnects regarding the BFO error that
>I have never been able to reconcile. On one hand, the DSTG advises that
>the BFO bias should be modeled as a prior mean given by the tarmac value,
>but with a standard deviation of 25 Hz due to bias drift. On the other
>hand, the standard deviation is 4.3 >Hz for the 20 previous flights
>using in flight values and excluding outliers, including BOTH noise and
>bias variation, and with the mean BFO error only 0.2 Hz. Then they say
>their model uses a standard deviation of 7 Hz to be conservative. Those
>three statements don’t appear to be consistent.
My reading of the situation is as follows:
i) The BFO offset (delta f bias) is modelled as a slowly varying function of time, with a prior mean of the tarmac value and a prior standard deviation of 25Hz. Each flight’s BFO data is then analysed (“its distribution conditioned on the other states can be estimated with a Kalman filter”), adjusting the BFO offset distribution, to minimise the mean of the BFO residual noise (omega k BFO) for that flight. The BFO residual noise is then as far as possible the random noise at each measurement.
ii) Fig 5.1 shows the values of the BFO residual noise, but _excludes_ the BFO offset noise. The last paragraph of p30 (of the published book) is clear on that.
iii) The paper does not give the output values of BFO offset distribution analysis for each flight. It states that since the BFO measurements on the accident flight are far apart in time, the noise from the bias variation is uncorrelated, so can be added to the residual (random) noise. The adjustment from 4.3Hz to 7Hz would suggest that the bias noise is evaluated to have a standard deviation of ~5.5Hz.
@Richard Cole: Again, for the flight I generated above, would you say that the BFO error falls within acceptable bounds?
@Victor
Assuming that you are fitting 5 data points (BFOs at 5 arcs) and for the first case only the starting point (so not the on-tarmac bias), then the first case is not excluded at the 90% level (using the chi-squared test – my experience). The second case looks like an overfit, reduced chi-squared is much less than one.
@Richard Cole: These are not two cases. They are both the same path in which a great circle path at FL350 is found (after imposing the starting track angle) starting at 19:41 which minimizes the RMS BTO error at 19:41, 20:41, 21:41, 22:41, and 00:11, and the BFO errors are examined only after the path is generated. Using a constant bias of 150 Hz results in an RMS error of 7.8 Hz and the mean error is -7.3 Hz. By incorporating the mean error into the bias, the mean error is eliminated and the RMS error is reduced to 2.8 Hz. Again, using your interpretation of the BFO error statistics, would you say this is an acceptable path? By what logic?
@Victor
The basic point, made before, is that the noise in the data must be preserved in the fit. So the BFO noise of 7Hz, or something like it, must remain. An RMS error of 2.8Hz on a set of five datapoints, when the dataset has a noise of 7Hz, will happen in less than 5% of cases. It’s not excluded at very high significance, but the data suggests it’s unlikely and that the extra parameter (changing the bias) is not justified, or indeed required as the first set of parameters is not excluded.
The 7Hz BFO noise is a big number and makes it hard to exclude a lot of tracks.
@Richard Cole: I apologize for repeating the question, but I wanted to be sure that we fully understood your interpretation. For MH370, if we use a BFO bias of 150 Hz (the tarmac mean), and if we had many samples during the flight, we would expect the BFO error to have a standard deviation of 7 Hz, of which 4.3 Hz is due to the (short term) BFO noise and 5.5 Hz is due to (long term) bias drift, and the variances add since the uncertainties are not correlated.
@Victor
That’s my interpretation. Formally, the figure of a standard deviation of 7Hz only applies to datapoints that are well separated in time (which applies to the accident flight), with separations greater that the minutes timescale of the drift. It is probably not the standard deviation of the whole set of BFOs, including short term noise and long term drift, since the latter errors are correlated.
We haven’t been given the distribution of the long-term bias drift so we have to take their word that it can be represented as a normal distribution (for well separated samples) and can be added to the short-term noise and the sum remain normal.
@Victor
erratum
…probably not the standard deviation *of the errors* on the whole set of BFOs including short term noise and long term drift…
@Victor
I was wondering…
The BFO bias of 150 Hz was after the 16:00:27 recalibration sequence.
Can we have confidence that the 16Hz adjustment was saved to nvram and reapplied after the power-on reboot at 18:25 or did the BFO bias revert to the pre 16:00 value?
Is there any way to tease out the answer from the post 18:25 data?
@George Tilton: As the calibration is meant to compensate for long-term drift, I would be surprised if calibration value was not retained. A more general question is whether the BFO bias changes after a shutdown of an hour.
@Victor
Would any bias change be the same for all channels (incl. the sat phone channel)? Inmarsat did not seem too concerned about drift it when putting their JoN path together.
sk999, Victor, Don, George…
Re: method of OCXO ground calibration
Don and I had a chat this morning about the OCXO calibration method. Don took a look at the SU packets sent to the AES immediately preceding the -16 Hz adjustment at 16:00, but found no evidence of that any of those SUs looked like a “OCXO calibration command”. I am now more inclined to believe the calibration procedure uses the P channel carrier frequency as the reference, as suggested by sk999.
Although the P channel carrier frequency was an obvious technical possibility from the start, I was reluctant to go there for several reasons. First, I thought the use of the P channel as a reference would be covered under the Rockwell patent, thus not permitted. Second, the P channel has some uncompensated C band uplink Doppler due to the Miteq firmware bug. Third, the L band downlink has uncompensated s/c motion induced Doppler. However, after further review of the patent, I don’t think the use of the P channel for OCXO calibration purposes would be covered, since the patent is all about Doppler compensation, not OCXO drift compensation. Perhaps the residual C band uplink Doppler and uncompensated L band downlink Doppler (with the plane on the ground) account for the non zero BFO Bias observed (~+150 Hz). This would also explain why the Bias changes a little from one cal to the next (depending on s/c and a/c state?).
Re: “Can we have confidence that the 16Hz adjustment was saved to nvram and reapplied after the power-on reboot at 18:25…?”, I think that is a safe assumption. Once calibrated, the calibration should not change until the next calibration occurs, which requires at least 26 hrs of operating time to pass. Obviously, the AES power could be interrupted several times during that 26 hr period, so the design would need to account for that.
TBill:
Re: “Would any bias change be the same for all channels (incl. the sat phone channel)?”
The BFO bias is approximately, but not exactly the same for all channels. Although it is always expressed as a frequency offset *term*, it is actually a *factor*, not a term. Since the bandwidth (~40 MHz) is small compared to the carrier frequency (~1600 MHz), applying a correction factor to a carrier at, say, 1630 MHz gives approximately the same offset in Hz as applying the same factor to 1640 MHz.
@ALSM
Thanks…
I suspected that the recalibration is internally triggered by the SDU power-on time when I did not see any SU command from the GES.
In my BFO model the 18:27 and 18:28 BFO values are 19Hz higher than predicted.
Obviously your OCXO warm-up transient would account for much of that even ~2 minutes after power was restored. The manufacturer of my bench frequency counter recommends ~10 mins warm-up to meet spec.
George: Yes, it takes several minutes for equilibrium to be reached. The last few hZ of settling can take much longer than the first 100 Hz.
The devil is in the detail. It is important to understand the detail wrt the settling at 18:25-18:30. Once the thermal control loop settles in at the setpoint temp, the precise physical point at which the temperature is measured is held within a few milli-Kelvins of the setpoint temperature, but 3D thermal gradients throughout the OCXO thermal envelope continue to settle. Those gradients continue to settle for several more minutes depending on the thermal mass distribution properties, which act like a low pass filter to the heater input.
The residual temperature coefficient for an OCXO exists mainly due to the finite gradients inside the envelope. As the external ambient temperature changes, the setpoint temperature stays constant, but the difference between the wall temperature and the point of measurement changes due to imperfect insulation. Thus, the gradients change. This is also why a double wall OCXO has much better temperature stability than a single wall.
Richard Cole,
I was waiting for DennisW to say “balderdash”, but if he won’t, I will.
The DSTG BFO residuals plot shows a standard deviation of 4.0 Hz without even correcting for channel-to-channel bias differences. Those are up to 4 Hz, That means that the standard deviation is actually noticeably smaller than 4 Hz after these corrections are made, and probably near 3 Hz.
The calculations of residual errors illustrated by DSTG is exactly the same as what we do when we find a BFO bias value that gives zero mean BFO error on the Tarmac at zero speed. Their published distribution is what is left if one analyzes the rest of a flight using that one value for BFO bias.
Your notion that the BFO error has 7 Hz standard deviation after Tarmac bias calibration is obviously incorrect. You will also recall that Inmarsat used a PEAK error limit of 7 Hz, which for small ensembles is consistent with ~3 Hz standard deviation.
@Victor: Thanks for the reply. So is it fair to say, then, that FdC has looked at the same evidence you have, but come to an opposite conclusion re: flaperon authenticity (your extreme confidence vs. her extreme doubt)?
Perhaps we should all have a look at this evidence, so we can judge for ourselves.
@Brock McEwen: Exactly where has she expressed “extreme doubt” that the flaperon is from 9M-MRO, other than her questioning of the missing ID plate?
@Brock: You managed a comment with no scare quotes [“evidence”], no demand of names and only one insinuation that our host is an agent of disinformation… You’re slipping!
@DrB,
“My route fitter minimizes an objective function by simultaneously varying numerous route parameters.”
As you know I am also using similar approach. My point is that a resulting trajectory depends on the exact formulation of your objective function. Why would minimizing RMS error be better compared to, say, max abs?
Also, take a look at DSTG Fig. 5.4. To me it is obvious that we miss some term/formulation. Gysbreght noticed that period of ‘structured’ oscillations resembles Schuler’s oscillations, but amplitudes would be smaller as per paper found by Dennis. We don’t account for the cause of the ‘structured’ variation (aka “geographic dependence”), so what are the real BFO errors in our simulations? Can be as high as 25 Hz by the end of flight.
Another issue. When I added fuel into my minimization functional (in the form of the final mass error, which is accurately known), a new problem popped up: the amount of fuel which was consumed between 17:30 and 19:41 is not known. Of course, if one considers only straight constant level path, this problem does not exist. But any maneuvering (e.g. triangular patterns, racetracks, etc.) would result in more fuel consumed during 18:25-19:41. On the other hand, descent would save some fuel.
@TBill,
Re: “As it pertains to MH370, all I know how to do is adjust wind manually. I can set different winds in different levels of atmosphere. You can also set weather at weather stations, but all I got is COCOS.”
If I understood you correctly, you cannot feed a 2D/3D field (GDAS was in my mind) into your simulator, because this would require enormous effort, correct?
@DrB,
@TBill,
P.S. Btw, deviation of 23:14 BFOs from the “trend line” could also be caused by the same unknown effect as seen in DSTG Fig. 5.4. This is another explanation.
@Oleksandr, @TBill: There are commercial packages that will generate a file with the high altitude wind and temperature fields for the entire earth, and those can be imported in FSX and FS9. Some of those packages also offer the capability to load historical data, and not just the present conditions. I haven’t taken the time to do this because I don’t use FSX for path reconstructions. I have other tools much better suited for this purpose (MATLAB and EXCEL programs).
@DrB
> Their published distribution is what is left if one analyzes the rest of a
>flight using that one value for BFO bias.
That’s not what the report says. Selected phrases from section 5.3:
– The bias term δ f bias k (xk , sk) is time varying. In the BTO case the variations in bias were slow enough to be ignored within a single flight and we were able to assume that T channel was constant for each flight. This is not the case for the BFO bias term. The mean bias is different between flights and even within a single flight there is evidence of structured variation.
-The variations in [BFO] bias shown in Fig. 5.4 happen over a timescale of minutes rather than hours.
– However, the drift of the BFO bias means that it is not sufficient to assume that δ f bias k (xk , sk) will be the same in flight as on the tarmac before takeoff.
– The mean BFO error [in table 5.1] was close to zero in all cases, indicating appropriate δ f bias k (xk , sk) values were chosen for each flight.
Fig 5.4 shows the BFO errors for the 2-Mar-2014 to Kuala Lumpur. There are dozens of datapoints with errors between 8 and 20Hz. If the data plotted in fig 5.5 is the total BFO error (rather than just the residual measurement noise after removal of the time varying bias) where are those datapoints with large values in the figure?
>Your notion that the BFO error has 7 Hz standard deviation after Tarmac bias calibration is obviously incorrect.
I know you want the BFO error to be small, but the report does not sustain that position.
ALSM, Victor –
It would seem that monitoring the P-channel frequency is the likely calibration mechanism. Are adjustments limited to +/- 16 hz in any single adjustment? I agree with ALSM that there is residual uncompensated Doppler in the frequency that is received, and it can be sizeable, particularly if Inmarsat does not compensate the uplink C-channel Doppler shift. [I doubt that the Miteq pilot receiver is involved here, not that it matters.] Otherwise huge jumps are possible, which would explain why the few steady-state BFOs in the Holland paper are so widely spread.
Bobby Ulich,
I, too, apply channel-dependent bias corrections to the MH370 data. However, I couldn’t get them to work for the MH371 data. At that point I gave up.
@Victor,
Re: “I have other tools much better suited for this purpose (MATLAB and EXCEL programs).”
Yes, indeed.
Air/Ground signal in Boeing 777-200 turned out to be a rather sophisticated product of various sensors (WOW (weight on wheels), TILT-UNTILT, airspeed, ground speed, Mach number, altitude and pitch) analyzed by dedicated hardware in the EE-Bay:
http://www.google.com/patents/US5826833
So, what is supplied to the SDU/AES: Air/Ground or WOW?
And the most interesting question: what does it do to the SDU/AES?
@Oleksandr,
You posed some good questions. You said: “Why would minimizing RMS error be better compared to, say, max abs?“
We know from DSTG that the probability distribution functions are approximately gaussian. When this is the case, the RMS statistic is much more reliable than a peak metric. The reason for this is simply the fact that the RMS statistic uses all the data, whereas the peak metric only uses one data point. If the distribution were uniform, then a peak statistic would be preferred.
You also said: “. . . what are the real BFO errors in our simulations? Can be as high as 25 Hz by the end of flight.”
No. The DSTG probability density function for PDF includes ALL sources of error occurring after setting the bias so the mean Tarmac error is zero. That plot includes noise, quantization error, structured variation (≈± 1 Hz and which is contributed to by the use of low-accuracy trig functions in the frequency compensation algorithm), drift DURING the flight, and channel-to-channel bias offsets. The ONLY effect not included is the drift from the time of the Tarmac start-up for one flight to the time of the Tarmac start-up for another flight, which DSTG removed by fitting (for each flight) the BFO bias term to zero the mean errors on the Tarmac. The fact that, using this method, the distribution of residuals measured over 20 flights also has very-near-zero mean proves that the MEAN in-flight drift is actually quite small. Otherwise the mean error would be clearly non-zero. In other words, the drift over a period of days/weeks is not monotonic in the DSTG data set. That said, on any given flight, in-flight drift can occur, and it can be monotonic, but the magnitude of that drift cannot be very large (I would guess a few Hz) because the overall error distribution is not that wide. Errors are large as 25 Hz are not possible based on the DSTG method (which I also use) and their analyses. Another indicator of the expected drift over days/weeks is the automatic self-calibration step, which typically is 16 Hz. Drift of that magnitude is not expected to occur in 24 hours or less, since the auto-cal does not apply another correction unless a time interval of at least 26 hours has passed.
Using the 4.3 HZ “in-flight only” standard deviation of BFO error from DSTG, and (roughly) removing the effect of the channel-to channel bias offsets (which itself is 3 Hz 1σ), we are left with 3.1 Hz as an approximate standard deviation of the in-flight BFO errors with the channel bias corrections removed. That is my best estimate based on the data available today, and that is what I am now using to assess “Calibrated” BFO residuals (which have the channel offset differences removed in the CBFO values).
You also said: “When I added fuel into my minimization functional (in the form of the final mass error, which is accurately known), a new problem popped up: the amount of fuel which was consumed between 17:30 and 19:41 is not known.”
Exactly. It is not known, but it is predictable given assumptions. That is why my Endurance Model actually begins at 17:07. Knowing the fuel then, and the flight conditions shortly afterward, I can compute the fuel remaining at 17:22. The Endurance Model I posted has a default starting time of 17:22, but the fuel then is found using the same model from 17:07 to 17:22. Using my Endurance Model you can find the fuel available at any point from 17:22 through fuel exhaustion, but of course you have to assume the speed mode, altitude, and temperature deviation between at least 18:29 and 19:41.
You also said: “Of course, if one considers only straight constant level path, this problem does not exist. But any maneuvering (e.g. triangular patterns, racetracks, etc.) would result in more fuel consumed during 18:25-19:41. On the other hand, descent would save some fuel.”
I suspect the effect of the triangular turns on fuel consumption would be similar to that for the racetrack turns, which is a 5% penalty. You should be able to model the triangular pattern fuel consumption well using the racetrack numbers. That option is built into my Endurance Model. There is a flag to set to include the fuel penalty during Holding turns. It is called “Switch to set for racetrack pattern fuel flows” which is applied only in HOLDING or INOPHOLDING. As I demonstrated previously, the savings for a descent to a Hold, followed by a climb back to the stratosphere, produces a net fuel savings, but it is rather small.
You also said: “P.S. Btw, deviation of 23:14 BFOs from the “trend line” could also be caused by the same unknown effect as seen in DSTG Fig. 5.4. This is another explanation.“
That “unknown effect” might be possible. In my opinion, the one effect we do KNOW must occur is the difference in channel bias, and I think that is the most likely cause.
@Richard Cole,
DSTG’s report is confusingly written, but I think Figure 5.5 is straightforward to understand. It directly shows the residuals from 20 flights when ONLY ONE BFO “pre-bias” value was used for each flight (and that value was determined using the Tarmac data). In other words, the drift in bias value DURING each flight was (necessarily) uncompensated, because there are no means to do so. DSTG acknowledges this contribution (i.e., in-flight time-varying bias) to the BFO residuals, but it cannot be compensated with the sparse BFO data available. It is “included” in the Figure 5.5 residuals because it is uncompensated.
DSTG later decided, arbitrarily, to ASSUME a 7 Hz standard deviation in their modeling, but this is not substantiated by their empirical data (Table 5.1 and Figure 5.5, which includes Figure 5.4).
To quote DSTG: “The statistics show that even when outliers are discarded a standard deviation of about 4.3 Hz is applicable.” Also: “Figure 5.5 shows a histogram of the 3392 in-flight BFO errors. On-tarmac BFO errors were excluded due to the pre-biasing described above.” The emphasis is mine. This “pre-biasing” is just a fancy way of saying they found the bias value using the pre-flight (i.e., Tarmac) BFOs, and they used those bias values to determine the residuals for the in-flight data. DSTG didn’t include the Tarmac residuals in Figure 5.5 because they had already forced the mean of those to be zero by finding the appropriate bias value for that pre-flight, and they didn’t want that inclusion to mask a possible non-zero mean result for the in-flight data. They used that same “pre-bias” value for the in-flight data. That is quite a reasonable approach, and probably the best one can do in this case. If there was monotonic drift of the bias during the flight(s), the density function of the in-flight data would have non-zero mean. For the 20 flights, it did not have a non-zero mean, so the mean in-flight drift (change in bias) is essentially zero. That means the expected value of the in-flight bias drift, averaged over many flights, is zero. It is likely, however, to have a noticeable variance, and therefore it contributes to the width of Figure 5.5.
You said: “If the data plotted in fig 5.5 is the total BFO error (rather than just the residual measurement noise after removal of the time varying bias) where are those datapoints with large values in the figure?”
The short answer is, they are on the left end of Figure 5.5. Here’s the long answer. In general, there are no data or other means for determining and removing the time-varying bias drift during a flight. That is the whole point behind the method they did use, which did not attempt to do that. I suspect the one example given in Figure 5.4 with large errors was a fluke, possibly caused by a computational error or by small uncompensated altitude changes. Perhaps that possibility is one reason why DSTG analyzed the residuals with and without the outliers. Whatever their cause, the larger negative errors in Figure 5.4 appear to be the negative outliers (at -10 to -20 Hz) shown in Figure 5.5. Obviously, this (Figure 5.4) was an unusual case because there aren’t that many outliers altogether in Figure 5.5.
You also said: “Your notion that the BFO error has 7 Hz standard deviation after Tarmac bias calibration is obviously incorrect.” I know you want the BFO error to be small, but the report does not sustain that position.”
It is not what I want that counts. It is what Table 5.1 and Figure 5.5 show. Including the one Mumbai flight, which dominates the outliers, the RMS is 5.5 Hz. Without the outliers, the standard deviation is 4.3 Hz (including uncompensated channel-to-channel offsets). It is even smaller (~3 Hz) when the channel offsets are compensated.
The 7 Hz BFO standard deviation is NOT A CALCULATION. It is NOT BASED ON DATA. It is a “conservative” ASSUMPTION that DSTG made early on when BFOs were a new concept. I remind you also that Inmarsat used a 7 Hz peak error criterion, which is consistent with BFO errors being much smaller than the 7 Hz standard deviation assumed by DSTG in their Bayesian analysis, and which you incorrectly portray as a real statistic.
Sk999: A Miteq eafc is used to pre compensate for the C band uplink Doppler. It has the same software bug that the corrupts the inbound link.
@sk999,
You said: “I, too, apply channel-dependent bias corrections to the MH370 data. However, I couldn’t get them to work for the MH371 data. At that point I gave up.”
Unless someone can give me a table/equations of POR/IOR satellite XYZ and Xdot/Ydot/Zdot for the time period of MH371, I don’t plan on pursuing those BTO/BFO data either. It’s quite a bit of work, especially the BFO prediction, with no certain benefit. The BTO predictions are much simpler since you only need aircraft time/lat/lon/FL.
Bobby: Why not use Richard’s sat data I sent to you?
ALSM,
You say, “A Miteq eafc is used to pre compensate for the C band uplink Doppler. It has the same software bug that the corrupts the inbound link.”
Doh! Is there a Miteq Technical Note that describes how this bug … I mean compensation … works?
ALSM –
Addendum – in the uplink direction. I have all the technical notes for the downlink direction.
Bobby Ulich,
FYI, My analysis of channel offsets for MH371 was all based off the raw Inmarsat data, for which Victor has now provided links to more than once. My analysis of offsets for MH370 was also largely based on the raw data as well – just can’t remember. (C channel is the exception). Regrading MH370, the analysis basically mirrored what the IG had already done, so I take no credit.
However, I have abandoned any idea that channel-dependent offsets can somehow reduce the BFO errors.
sk999,
You said: “However, I have abandoned any idea that channel-dependent offsets can somehow reduce the BFO errors.”
I have not and they do.
@ALSM,
Thanks. I will have a look at the stuff you sent me after I do a few other things first.
sk999: There is no Tech Note for the firmware bug I was referring to. I was referring to the residual (uncompensated) C band Up-link Doppler (caused by the inverted Perth Latitude). That error “leaks” to the L band P channel downlink frequency. That will cause a small error in the OCXO calibration, if in fact, that is how the OCXO is calibrated.
@DrB @Oleksandr
When Oleksandr and I are talking 23:14 deviation from the trend line, I think we are both talking about the scatter in the raw readings, before correction:
216 217 216 216 216 216 216 216 216 216 216 216 217 216 216 216 216 (Steady trend) all of a sudden now we get next:
220 218 222 220 220 218 218 217 219 219 217 219
As far as Sat Call Channel Bias correction you are making (+4 hz), you’ve convinced me the BFO’s from the Sat Call Channel are not calibrated the same as the hourly BTO/BFO’s of the ping rings. But because I think pilot maneuvers could be happening at both 18:40 and 23:14, I am not comfortable assigning a +4 correction which basically assumes level steady flight at those times.
@Brock
If you are interested in the positive identification of the flaperon, this has been discussed here with the post of the photographs. (http://jeffwise.net/2017/10/03/mh370-mission-accomplished/comment-page-3/#comments).
The chance of the debris being from Mh370 is definitely more than 0%. However, the residual weaknesses in the “positive” identification argument are:
* the only number linking the part to 9M-MRO is handwritten and I am not sure if the handwritten number has been associated positively to the person in charge at that time.
* even though it is traced to 9M-MRO, i may have missed that but as far as i know, it was not positively identified by Malaysian Airlines to be on the actual flight MH370. There were actually reports in the press by the NYT and by FdG that modifications made did not appear on the recovered flaperon but i am not sure if this issue was further clarified with Malaysian Airlines. The full set of maintenance records for this part is not publically available and I personnally think that only Malaysia Airlines is in a position to positively identify the debris, linking it to 9M-MRO is only 90% of the argument. This would be usefull to convince the unconvinced.
@HB: thanks. I’m well aware FdC isn’t the only person who has publicly cast doubt on the flaperon’s authenticity. It’s what makes publication of this “evidence” (@lkr) so important. It is interesting to me that no one who refers to it can actually produce it…
@Victor: when an author, giving an MH370 book tour, calls attention to 11 of 12 identification marks not matching, with the 12th – the only match – being handwritten, I take this as an expression of extreme doubt re: flaperon authenticity. Do you disagree? Do you dispute that this is how FdC characterized the report? I’m honestly confused.
But hey: I don’t want to be a ping pong ball in this bizarre dispute among folks who’ve seen a report the rest of us haven’t. Let’s all just review it together, and draw our own conclusions. I ask you please to publish it.
@Brock
The link to the report is posted in the link i gave you.
This is for the front spar. Other parts are not mentioned.
@Don Thompson, Victor. As earlier, search rate IMO could well be dominant in looking into Victor’s query as to OI search options, if these are constrained by season. This aims to contribute towards that.
Don, about your, “I expect that the six Hugin AUVs should cover 600km² per day, taking recovery cycles into consideration”, under your 1600m individual AUV search width assumption, a 1.5 knots average speed-of-advance would be required, as you imply.
Supposing battery replacement per AUV every couple of days, that taking 3 hrs from off-task to back on-task, and also around the clock searching, AUV search speed would need to be lifted 0.1 knots to realise that advance.
Presumably ‘simultaneous’ battery replacements after a 6 fold AUV joint off-task would be impractical and anyway would extend the turnaround. Assuming that just 6 AUVs are active (any others being just spares), that would leave serial withdrawal for battery replacement by pairs as the approach most likely adopted.
AUVs serially rejoining would trail 4.8nm behind where otherwise they would have been, that is pending others joining them in turn on that line and that cycle repeating. The 4.8 nm would increase maximum telemetry distance only a little and presumably the stagger would not affect performance otherwise.
The search distance loss by not supplementing those 6 AUVs would be 2.4nm/day or 6.3%.
The 3hrs would depend on the overall closing rate from depth. Allowing 1¼ hrs for both up and down, to achieve that from 6000m would require a vector component of 1.6 knots in the ship’s direction. A vertical vector of 2.7 knots would be added. Overall more than 3.2 knots water speed would be required to meet these alone. Hence an AUV speed increase would be needed to meet recovery plus redeployment time.
A second horizontal component perpendicular to the ship’s track would be required also, that becoming larger as AUV stationing distance out increases.
From 5000m in 1¼ hrs would require 2.8 knots closing speed towards the track. The resultant overall average water speed needed for recovery and redeployment for the outermost pair would be 4.2 knots, entailing higher battery consumption during that total of 2½ hrs; that is if timing and the stagger cycle between pairs are to be preserved. In other words the inner pairs would have higher reserve battery capacity when withdrawn, all pairs having the same on-task time.
This basic model might be useful depending on any changes to its underlying assumptions and also on search speed being central to OI search options.
@Oleksandr,
From the abstract of the patent you reference, “provide a signal to a flight control system of the aircraft to indicate whether the aircraft is in the air or on the ground, particularly during transition from air to ground or from ground to air.”
Note the qualification, “particularly during transition“. The requirement of the PFCS to sense conditions throughout air-ground/ground-air transitions is significantly more complex than a simple WOW, binary, discrete.
Weight on wheels, WOW, is primarily detected by load sensors on the Main Landing Gear beans, the sensor outputs are processed by electronics ‘cards’ which then forward discrete signals by means of relays in ELMS and datawords on the L & R Systems buses.
ARINC 741 Part 1 (SATCOM, Aircraft Installation Provisions) states that a single bit WOW status is included in the A429 SDU-HPA command word. The same document states that ‘standard interwiring’ provides two discretes to the SDU. Multiple references describes that a ‘simple’ discrete binary WOW signal is presented to the SDU for use within the AES (at least SDU & HPAs).
What remains explicitly undefined by the ARINC 741 specifications, or the Thales SDU System Description, is how WOW is exploited in the operation of the the AES. However, the observations stand that 9M-MRO was powered, on the ground, with the ADIRU not aligned, while a SATCOM Log On was maintained from 12:50:19 until 15:56:36 using the LGA. That the LGA was specifically selected to be the preferred antenna is denoted by the Class Of AES field in the Log On Requests (ie 00b: Class 1, LGA, packet data only) for the Log On sessions 12:50:19 thru to 15:56:36. It’s entirely consistent that the LGA is employed while the SDU receives ‘IRS’ datawords containing NCD ‘IRS’ attitude data AND while on the ground.
@Oleksandr,
I’m sure you’ll note that I omitted to reference condition of ‘IRS’ position data during the period 12:50:19 thru 15:56:36. After power up and before alignment the ADIRU has position available, “the last stored position comes from the nonvolatile memory of the ADIRU”.
@David
Kudos for your curiosity and tenacity in estimating the performance of the Hugin AUV fleet! While OI appears to continue its open ocean trials at this time, I would be surprised if some more detail is not released to further describe its deep ocean search coverage performance. However, I’m content with ‘about 6x’ at this stage.
The AUV speed is variable through the mission, dive/ascent to and from the survey depth is likely to be at higher speed than when on task, scanning. The ASVs provide the command & tracking telemetry relay between the host ship and the AUVs. The mission may be modified on while at depth.
I’m particularly interested to know if there are any other developments in sonar/backscatter processing, using available sensor techologies, that will improve the search performance. The key factor in performance is speed! It’s reported that OI has invested in Kraken’s SAS technology for deployment on AUVs, my understanding is that improvements in AUV navigation accuracy has contributed to adoption of SAS on deep ocean AUVs (however, the useful range remains less than dual freq SSS). What else? is an open question.
@Brock McEwen: when an author, giving an MH370 book tour, calls attention to 11 of 12 identification marks not matching, with the 12th – the only match – being handwritten, I take this as an expression of extreme doubt re: flaperon authenticity. Do you disagree? Do you dispute that this is how FdC characterized the report? I’m honestly confused.
Please produce what exactly what she said and not what you recall. Then I will say whether or not I dispute it, and the reasons why.
@Richard Cole, @sk999, @DrB: I have closely read your comments regarding BFO error, and re-read (many times) what was said in the DSTG report. Although I do believe it is confusing, in my opinion, the interpretation of Richard is correct. The standard deviations and means tabulated in Table 5.1, and shown graphically in Fig 5.5 for the population of in-flight BFO errors, reflect the residual error after the time-varying bias is applied, which was estimated using a Kalman filter and using the tarmac-derived value as the prior for the filter. The fact that the mean values in Table 5.1 are close to zero is an indication that the calculated time-varying bias for each flight was appropriately estimated, and not that that the drift in bias was close to zero. The calculated time-varying bias was not reported, but we do know that after incorporating the time-varying bias, the residual BFO error due to noise is 4.3 Hz, and we also know that the DSTG estimates the standard deviation due to both BFO noise and drift to be around 7 Hz, which would imply that the drift contributes about 5.5 Hz, as Richard has said. It would have been helpful if the DSTG chose to show the actual time-varying bias for some flights, but they did not.
@Don Thompson. Thank you.
@Victor: please present the report so we all can see it. Thanks in advance for your transparency.
@Brock McEwen: Please present the public statements you claim that FdC has made so I can state whether or not I agree with them rather than reacting to your characterization of the statements. You have a history of distorting statements made by me and others. Here is a recent example.
As for the report on identification of the flaperon, as @HB has said, some of the source materials were previously made available elsewhere.
Here is the message I wrote to Florence in March 2016 regarding the identification of the flaperon. I do not know how she chose to interpret these statements:
I reviewed the flaperon report. In summary, I see no mistakes and nothing wrong with the conclusions that the serial numbers show that the part is from 9M-MRO. Here is why I make this claim:
1. The photographs show identification numbers from 4 part types: The front spar, the rear spar, a cleat, and fittings.
2. Only the front spar and rear spar have recordable serial numbers. I think it is reasonable that cleats and fittings are not uniquely recorded.
3. On the front spar, the Part No. 113W6142-2 and Serial No. 3FZG81 can clearly be read.
4. On Product Sheet No. 2, the front spar part number and the (hand-written) serial number are shown to be from Order No. 38G175.
5. On Product Sheet No. 1, Order No. 38G175 is linked to the flaperon Serial No. 405.
6. On the Master Schedule of Flaperon, it shows that flaperon Serial No. 405 was installed on airframe Line No. 404.
7. This Line No. 404 was registered at 9M-MRO. See for example: https://www.planespotters.net/airframe/Boeing/777/28420/9M-MRO-Malaysia-Airlines
8. The numbers on the rear spar are recordable but difficult to read.
9. Based on Product Sheet No. 2, for the rear spar, one would expect Part No. 113W6144-2 and Serial No. 3FZQ16.
10. As you can see in the figure below, the numbers on the rear spar may indeed be these numbers.
In my mind, there is little doubt that the recovered flaperon is from 9M-MRO.
@Victor: have a listen to minutes ~14-17 for FdC’s research into the flaperon:
http://www.radionz.co.nz/audio/player?audio_id=201793735
Victor, FdC was your source for this report; are you saying you did not know until now what she concluded from its analysis, and said about it publicly?
@Brock McEwen: I don’t claim to know everything that she or anybody else says about MH370. I disagree with a lot of what she says. I disagree with a lot of what most authors on MH370 say.
The particular interview you cite was recorded on March 18, 2016, which was before I supplied my analysis to her on March 31. If you want to pursue discrepancies between what she has said publicly and what I have told her, you are free to do so. I don’t try to correct every incorrect statement that is made. If you falsely equate not being able to make a match because information has not been recorded with recorded information not matching, that’s a distortion of the truth.
@Brock McEwen
My God. Where does your paranoïa and stubborness end? Please settle down.
The flaperon is 9M-MRO. And it’s not only the flaperon you know.
Many other pieces have been found that are definitely 9M-MRO too and totally fit the context of the flaperon find.
Please stop looking for nails on shallow water and come back to reality.
The flaperon is a total non-issue in this regard and within the whole context.
Your assumptions on reverse drift studies and all that came with it are out of date a long time. You’ll find no proof for it anywhere no matter how much you ask for it to anyone in your sincerely way.
Put your obvious intelligence to current reality I suggest.
You could be a lot more helpfull that way I think.
Don’t want to offend you, just wanted to speak out.
I always respect your independent input.
@VictorI,
@Richard,
I will pose a question to Dr. Holland regarding the interpretation of Figure 5.5. Due to certain current events, he may not be able to respond for a while. Hopefully he will settle the issue regarding subtracting the Kalman filter outputs, but he may or may not be able to settle immediately the issue regarding the BFO error variance (see below).
If Richard and you are correct, and a Kalman-filtered time-varying bias was derived by DSTG using only prior BFOs, and then subtracted, we also need to know what the typical drift rates/amplitudes were for the 20 flights. If those are small, then the two interpretations converge to the same result. If they are large, then the higher variance might be appropriate (but see below) unless one does the same process for MH370 of removing the time-varying bias as the one used by DSTG (but the filter used in this process is not defined in the DSTG report).
The fact that Inmarsat used a 7 Hz peak BFO error criterion, with no removal of time-varying bias, seems totally incompatible with your/DSTG’s prediction of BFO error statistics (7 Hz standard deviation). But what does Inmarsat know? They just designed and built the system.
A back-of-the-envelope calculation can offer some insight into the expected drift rate. If the auto-cal is designed to apply +/- 16 Hz corrections not more frequently than every 26 hours, the worst-case drift rate is 16/26 = 0.62 Hz/hour. Over an 8-hour flight like MH370 the worst-case drift would be 4.9 Hz, and the typical drift should be a fraction of that, or a couple of Hz. That low drift-rate estimate is also incompatible with “. . . the drift contributing 5.5 Hz . . .” standard deviation, as you and Richard (and DSTG) claim.
An additional and telling fact is that the auto-cal corrections are not applied every day or two, but typically every week or so. This confirms my statement above that the typical drift rate (several Hz over one flight) is a fraction of the worst-case estimate.
There is also a different interpretation to consider. Suppose DSTG actually did what you claim by subtracting an estimated time-varying bias. However, if that estimator were imperfect, which it certainly must be considering the paucity of BFOs and their inherent noise, then it could increase the residuals instead of decreasing them, as you and Richard (and DSTG) have assumed in computing the 5.5 Hz (1-σ) contribution due to drift. Get my drift? Sorry, I could not resist the pun.
Basically, what the Kalman filter does is fit a slowly-varying function to all the available data up to, but not including the BFO in question. When that BFO point is close in time to lots of prior BFOs, one would expect the estimator to be relatively good with low noise. However, when the data are few and are sparse (well-separated in time), the estimator is noisy. That is because you are trying to fit at least a slope, and possible a parabola, to data which itself has noise. The noise in each BFO error is substantially magnified when a slope (or higher order term) is fit. As an example, take 3 BFO errors (with equal noise error bars) evenly spaced in time, and fit a line to the first two. Then see how well the 3rd error is predicted. The slope is noisy so that the spread of the prediction at point #3, using all lines passing within the error bounds on the first two points, is twice the noise at each point. In other words, with few and sparse data the Kalman filter can add noise in the process of attempting to remove drift.
What if Figure 5.5 is actually broader than the true BFO error distribution because DSTG applied a noisy process to remove the time-varying baseline? You (and DSTG) have made an assumption that the true BFO error PDF is broader than Figure 5.5, and therefore by applying the time-varying bias removal, the distribution was made narrower. In other words, you/DSTG have assumed:
Variance (Fig. 5.5) = Variance (BFO error) – Variance (time-varying drift estimator).
This assumption is equivalent to assuming the calculated bias drift is +100% correlated with the BFO errors.
Assuming this, naturally you found the BFO error variance using this rearranged equation:
Variance (BFO error) = Variance(Fig. 5.5) + Variance (time-varying drift estimator).
That assumption led you and DSTG to conclude that the BFO error variance was larger than the Figure 5.5 variance. I say assumption because DSTG did not present any data to determine the validity of the equations above.
I don’t think this assumption (that the drift estimator is completely correlated with the BFO errors) is correct for the BFO data. More likely, I think they are mostly uncorrelated with a small correlation coefficient (i.e., closer to zero than to one). In that case, the true BFO error PDF would be narrower than Figure 5.5. This scenario is equivalent to this assumption:
Variance (Fig. 5.5) = Variance (BFO error) + Variance (time-varying drift estimator).
Note the sign change (compared to the first equation above) from plus to minus. In other words, maybe we are both partly right and partly wrong (and what DSTG did actually made it worse not better)?
In the scenario I just described, the time-varying bias estimate is removed from the BFO data. On that point Richard and you would be correct. The Kalman-filtered bias estimator is noisy because there is very little data to work with (the data are few and sparse). DSTG’s bias removal process adds the process variance (due to noise in the Kalman filter estimate of time-varying bias) to the true BFO error PDF. It does not subtract variance. In this case Figure 5.5 is wider than the true BFO PDF. In calculating the true BFO error PDF, perhaps you and DSTG have made the same error in assuming the process will reduce the variance instead of increasing it (by the process of subtracting a noisy estimator for the time-varying bias instead of a low-noise, 100% correlated estimator, which you assume and which I don’t think is even possible for these data).
We don’t have any data to determine the variance of the drifting-bias estimator. Apparently DSTG made a conservative guess that the standard deviation would be increased from ~4.3 Hz to 7 Hz. It’s too bad DSTG did not (later on) produce a PDF similar to Figure 5.5 without the time-varying bias removal (if that indeed is what they did). If my theory is correct, we know the variance of the BFO errors will be less than shown in Figure 5.5, but we can’t calculate exactly how much less.
In summary, I am suggesting that the assumption that the time-varying bias estimator is completely correlated with the BFO errors is possibly incorrect, and that an assumption that it is closer to uncorrelated is perhaps more appropriate. (the “truth” may be in between the two cases). By the way, if we had the exact formula for the Kalman Filter DSTG used, we could run it over the MH370 BFO data and see if removing the time-varying bias using the DSTG method increases or decreases the BFO residual variance for a number of good-fit routes. That would be interesting to do. In other words, we could measure the correlation coefficient between the bias drift estimator and the BFO errors. If it is +1, the BFO error variance is larger than shown in Figure 5.5. If the correlation coefficient is much smaller than 1, then the BFO error variance is less than shown in Figure 5.5.
The apparent “disconnect” between the expected bias drift rates (based on the auto-cal) and your derived bias-subtraction variance can be resolved by assuming a low correlation coefficient between the BFO errors and the estimator. This also removes the obvious “disconnect” between the Inmarsat 7 Hz peak error bound and the DSTG prediction of 7 Hz standard deviation.
@Victor: thanks for responding. Did FdC, to your knowledge, reverse her position after speaking with you, or with anyone else? I believe her book puts forth the same position indicated in the interview (I do appreciate that its publication likewise pre-dates your email to her).
Also: can we please see all the images you reviewed? I think we’d all appreciate the chance to judge for ourselves. Thanks in advance for your transparency.
@Ge Rijn: thanks much for your contribution. Wonderful to hear that you don’t want to offend me.
I will continue to work hard to ensure that only verifiable evidence shapes my views on MH370’s fate. I am trying my best, at present, to verify the endoscopic evidence; two of the only people on the planet who claim to have actually seen it have expressed to me radically different views. I have adopted neither extreme position, but rather asked – in my sincerely way – that you and I – and the NoK, and everyone else – get a good look at these images, so we can all judge for ourselves.
My last paragraph was inadvertently left off my previous post:
Please don’t think I am criticizing what DSTG did. I am not. This was new stuff when they started, and they were pretty rigorous in their methodology. Looking back with the benefit of several additional years of study, one can say some of their assumptions might be different if one had the chance to do it over again. All in all, they did a good job using the tools they had to produce some useful predictions.
@DrB: First, the methodology is DSTG’s, not mine. I am simply trying to understand what they did based on what is written in the report together with comments from you, Richard, and sk999.
If you are trying to persuade me that a bad Kalman filter can create noise, no persuasion is required. However, I have to believe that the DSTG is experienced enough to know whether the variance reported in Table 5.1 is greater or less than the total variance of the BFO error.
I believe that the Kalman filter essentially separates the low frequency error (due to drift) from the high frequency error (due to noise). You can see this in Fig 5.4, where there are clusters of values occurring over a short time (aligning almost vertically in the plot), and the clusters are irregularly spaced from each other over time. The mean value of each cluster would represent the drift.
You can also see in Fig 5.4 that the drift is not monotonic, but appears to have some periodicity, albeit with an offset. My guess is that the data before 22:00 is representative of most flights, and the data after 22:00 shows abnormally high drift due to the “geographic dependency”. None of this drift would need to be corrected by the auto-cal feature because it is not cumulative, so I don’t think you can use arguments about the resolution and timing of the auto-cal to invalidate the 5.5 Hz standard deviation of the drift.
@Brock McEwen: FdC can speak for herself. I have no idea what her current position is. Last I heard, she believed the plane crashed in the South China Sea, and Inmarsat, the US, the UK, and Australia were complicit in a cover up. If she still thinks this is true, I would be in serious disagreement with her.
You keep asking me for the materials I used to make my assessment about the provenance of the flaperon. When somebody provides me with materials in confidence, I only disclose that material with permission. I don’t have that permission from Florence. I told you the source. You can get that material directly from Florence if she wishes to disclose it to you. Stop asking me.
@Don,
Thanks for your comment.
The patent link to which I provided, appears to be somewhat inconsistent with AMM, chapter “AIR/GROUND SYSTEM – INTERFACES”. For example, WOW Card Inputs. Citation from AMM, 32-09-00 (pdf p. 4398):
“The WOW cards get inputs from:
– AIMS (time and date, flight phase/leg, airplane registration number, ICAO code)
– Bus power control unit (external power available)
– ELMS (air/ground relay status)
– Ground test enable switch
– Load sensors
– Radio altimeter (3).”
Nothing is mentioned about air/ground speed, mentioned in the patent.
On the other hand, the SDU does not seem to be listed in the users systems, to which output from WoW cards is sent.
Re: “It’s entirely consistent that the LGA is employed while the SDU receives ‘IRS’ datawords containing NCD ‘IRS’ attitude data AND while on the ground.”
Yes, consistent. However, remember that ADIRU’s internal logic prevents its from switching off when ground speed exceeds 30 kts. Respectively, the SDU does not need WoW to judge whether the plane is on the ground or not, as the absence of the data from the ADIRU is already indicative of the plane on the ground. Of course, except ‘exotic’ cases.
RE: “After power up and before alignment the ADIRU has position available, “the last stored position comes from the nonvolatile memory of the ADIRU”.”
This is interesting. So, in theory the SDU may transmit in the air without updated data from the ADIRU, unless WoW bit prevents it from doing so.
@DrB,
Re: “Errors are large as 25 Hz are not possible based on the DSTG method (which I also use) and their analyses. ”
I disagree with this. Take a look at DSTG Fig 5.4. To me it clearly indicates a superposition of a structured error and random error. The random component generally has a relatively small sigma, somewhat around 5 Hz by naked eye (I don’t have data to derive accurate numbers; DSTG does have). The structured ‘drift’ could reach 20Hz amplitude in 4 hours on that particular flight. It appears the amplitude of this structured deviation growths exponentially starting from zero. Without understanding a reason and accounting for this effect, how can you state that the BFO errors can not be as high as 25 Hz in more than 4 hours of flight?
@TBill,
“…all of a sudden now we get next…”
In the reality the plane could be affected by gust wind, and it would take some while for the plane to adjust to new conditions (stabilize yaw). This could result in temporal oscillations of the heading, which could consequently result is the sequence of BFOs: 216-216-…-216-202-218-222-220-…
The spatial resolution of wind data I am using is 1 deg, so modeled transition occurs smoothly.
@Brock,
Perhaps you could switch to somewhat closer to your profession? There are plenty of things within your domain (BTO and BFO statistics, expected number of fragments of 9M-MRO / MH370 objects; size distribution of washed ashore debris, etc.). But you are wasting your energy doubting that the flaperon is genuine. I don’t quite understand your motivation.
Oleksandr,
You wrote “The patent link to which I provided, appears to be somewhat inconsistent with AMM”
Why would you even expect a generalised patent to be in any way consistent with the specific description of a B777 system?
Be careful not to conflate “absence of data“, no data words passed over a bus, with data words beinh passed but communicating no computed data (NCD).
“in theory the SDU may transmit in the air without updated data from the ADIRU” if one chooses to ignore, contort, or misrepresent the preceding statement, i.e. “after power up, and before alignment of the ADIRU… the last stored position comes from the non-volatile memory of the ADIRU”.
Thanks for the expert discussion on BFO stats that has been illuminating.
Now, a related question on the size of BTO errors that we would expect to see from the “correct” path. If it’s the case that:-
– 1 sigma BTO bias estimate is 29 microsecs
– RMS true wind error vs GDAS model is about 6 knots crosswind and 6 knots tailwind (*is that correct or is it 6kt on wind strength rather than 6 knots zonal, 6 knots meridional?)
– heading accuracy of the autopilot is +/- 0.1 degree or so
– and we are implicitly assuming that our satellite orbit model is perfect
then…
How big would we expect RMS BTO residuals to be on any given path (before baking in the wind and heading uncertainties)? The reason that I ask is that I’d expect it to be bigger than the 20-30 microsecs shown in Victor’s charts above. The 6 kts crosswind error alone can shift you 10kms in longitude over one hour, equating to a BTO error of ~70 microsecs? 0.1 degree heading error over an hour is another 5km lateral. So when we have all of these various error noise going on in real life (observed), what do we really expect the BTO error RMS to be for a flight path model generated using an imperfect wind model and “perfect” heading accuracy (predicted)?
Could someone with stats in their blood please put me out of my misery?
@Don,
“if one chooses to ignore, contort, or misrepresent the preceding statement, i.e. “after power up, and before alignment of the ADIRU… the last stored position comes from the non-volatile memory of the ADIRU”.”
The ADIRU alignment can be started in the air. But it cannot be successfully completed. There is time in between.
@Oleksandr wrote “The ADIRU alignment can be started in the air.”
You tried that one previously.
I will add “if the airplane moves during the alignment, the align reset mode occurs until there is no movement.“, how can that be construed as starting alignment?
Further, consider that normal ADIRU shutdown is an orderly process, not the same as removing all power (which requires six cct breakers, located on three power panels in the MEC, to be opened).
@Paul Smithson,
The GDAS wind errors are given (using the only published value I could find) as 5.7 kts per horizontal axis (out of two possible horizontal axes). So long as the axes are perpendicular, you can use any axes you want. I find it convenient to use tailwind and left crosswind.
The prediction of the BTO only depends on the satellite and aircraft positions in ECEF coordinates.
The BTO measurement errors do not depend on the wind or on the heading or track (or on their errors), just lat/lon/altitude at a given time.
The BTO errors can be 29 or 43 or 62 microseconds 1-sigma depending on the channel/message type. Most of the BTO data have 29 microseconds 1-sigma.
The satellite location error is mostly removed by selecting a BTO bias value that matched the KLIA gate location. The Inmarsat/ATSB value works just fine in my model.
I normalize all my residual fitting errors to the expected 1-sigma value for that particular data point. That way I don’t have to compute some weighted standard deviation of points with various standard deviations for each point. So my expectation for a good fit is a RMS residual of 1.0 sigma. When the number of data points is not large, there is an expected standard deviation of the calculated RMS value, and it is approximately equal to the RMS divided by the square root of the number of data points – 1. So if you have 10 data points, the sigma of the calculated RMS is approximately RMS/3. So one should “accept” fits (at the 1 sigma level)which have RMS values of 1.0 sigma +/- 0.3 sigma, or from 0.7-1.3 sigma.
Pual Smithson,
As an initial matter, the BTO errors in the measurements are what they are and do not care about the wind. What I think you are asking about is errors in the prediction (i.e., a constant heading path).
Wind errors seem to be uniformly quoted on a “per-axis” basis – thus, 5.7 knot rms from Bayesian Methods is 1-d. One thing that BM makes obscure is the spatial correlation of the wind errors. BM treats correlations as a decay in time with the time constant of 16 minutes (roughly 2 degrees of arc at typical aircraft speeds), but that is incomplete. From a study I did ages ago, the rms seems to be independent of direction, but the correlation length is roughly twice as great in the longitude direction as in the latitude direction. Since the flight path of MH370 was along a predominantly N-S line, it is the latter that matters most. Over 1 hour, the mean error in wind speed is less that the instantaneous 5.7 knots rms, since some averaging of errors will occur. However, another factor is at work that goes in the opposite direction. Most of the flights analyzed by the DSTG were in areas well-trafficed by aircraft, and aircraft-derived wind data are incorporated into these global models. MH370 went South into a region that is poorly sampled (since very few commercial jets pass through that region), so the models may have errors in those regions that are worse than where the DSTG made its comparisons.
In my constant heading models, I allow for independent N/S and E/W wind error parameters, one per hour, and I impose a prior of 0 knots with an error usually of 4 knots rms, but sometimes bigger.
Back to your question – the best approach is to recast the wind errors into components parallel to an arc and those perpendicular. Thanks to Pythagoras, the rms errors in each direction are the same 5.7 knots. Only errors in the direction perpendicular to the arc affect the BTO. Further, these errors tell you directly how much the plane is shoved in that direction, independent of the heading or speed of the aircraft. Thus, a 5.7 knot wind will shove the plane 5.7 nm, and contribute an error to the BTO prediction by whatever the conversion factor from nm to BTO microsec is at that point.
Now, this calculation is only good for the 1st arc. Distance errors are cumulative, so at the next arc, the BTO error due to wind at that arc is correlated with the BTO error at the 1st arc. Ain’t statistics wonderful?
Oleksandr,
You said: “It appears the amplitude of this structured deviation growths exponentially starting from zero. Without understanding a reason and accounting for this effect, how can you state that the BFO errors can not be as high as 25 Hz in more than 4 hours of flight?”
DSTG had no explanation for that odd behavior shown in the one flight in Figure 5.4. They don’t specifically characterize that one flight as being extreme or typical. My conclusion was, and still is, that it was an extreme event. I concluded this based on the fact that it contributes almost all of the residuals in Figure 5.5 from -10 Hz to -20 Hz. Most or all of the other data sets must have had much smaller amplitudes. The dip might be a satellite eclipse event. The amplitude is about right (the same 10 Hz as the eclipse at 20:00 UTC on 7 March 2014), but I am not sure about the sign convention. The duration of the Figure 5.4 event is consistent with the data provided by ATSB for the 7 March eclipse, which shows only that the event was completed from start to finish in less than two hours and was ~10 Hz at maximum effect. I don’t see the “exponential growth” you described in Figure 5.4.
The reasons I think the BFO errors on a typical flight, or on MH370, cannot be as high as 25 Hz are as follows:
1. I think the Figure 5.5 distribution is contaminated by uncompensated and misunderstood effects such as computation errors and possible eclipse events. DSTG acknowledged their existence, but nonetheless included them without understanding their cause(s).
2. I think the time-varying bias subtraction process added noise to Figure 5.4. (This is straightforward to test. All DSTG had to do was show the same plot as Figure 5.5 without the bias subtraction.)
3. There is nothing in the MH370 data up to 17:07 indicating errors outside +/- 7 Hz. In addition, it is possible to fit auto-pilot routes with 3 Hz RMS BFO errors. This is consistent with, but not proof of, small BFO errors.
4. Inmarsat made a sincere (and I think a reasonably accurate) effort to predict a route using the BFO data. They applied a +/- 7 Hz peak criterion. Clearly, Inmarsat doesn’t believe the BFO error could be anywhere near 25 Hz.
Unfortunately, DSTG did not provide the detailed data used in their BFO analyses. If we had that data, we could resolve most of the current issues.
@VictorI,
Thank for commenting on the BFO time-varying bias process. It’s too bad DSTG did not show diagrams similar to Figure 5.5 for (a) the uncorrected BFO errors, and (b) the bias corrections. That would have provided a lot of information and still avoided the difficulty of providing thousands of data points. Unfortunately, they chose to show only one diagram which is a mixture of two parameters (BFO errors and time-varying bias), and we have no means of separating them.
Regarding the size of BFO errors, my money is on Inmarsat.
Ask yourself why the “reconstructed” flights using BFO and BTO were not accurate when there was a turn involved. The larger the turn was, the larger the track error. I suspect that is a result of the Kalman BFO filter not being able to follow accurately the BFO steps when turns occurred. That will cause errors in the BFOs after the time-varying bias is subtracted (because no Kalman filter can follow a step accurately with sparse data). That introduced BFO error leads to track errors in the reconstructed path, and the reconstructed track error will grow as the size of turn (= size of BFO step) grows.
This effect could also contribute to the width of Figure 5.5. Perhaps the Kalman filter worked well for straight paths but poorly at and immediately after turns (I don’t see how it could do otherwise). I don’t think DSTG segregated the data in Figure 5.5 between turns and no-turns (although they did remove climbs and descents).
@Victor
Here is a link to a comprehensive review of the MH370 Floating Debris finds. The results compare well to your present post regarding “Possible MH370 Paths Along Great Circles”:
https://www.dropbox.com/s/ma9pt8zf3b0whc7/MH370%20Drift%20Analysis%20-%20Calibration%2C%20Results%20and%20Conclusion.pdf?dl=0
@Dr B – you misunderstood my question (and I must have framed it poorly). sk999 is a bit closer to what I was getting at. Thanks to both for initial response, but let me try again.
I do understand that the BTO error stats are just that. Noise arising mainly from jitter and quantisation creates some uncertainty in the derivation of the bias from a given position (or, conversely, uncertainty in a position from a given BTO) as long as our satellite orbital model is perfect. If that was all, then a “perfect” path model ought to have BTO residual RMS somewhere in the mid 20s. But that’s not primarily what I’m asking about.
Path models predict position and associated BTO using an underlying model wind and also presume 100% accuracy in aircraft speed and heading with respect to modes. In practice, the winds encountered by MH370 did not perfectly match the wind model and whatever the mode, the aircraft heading and speed would have varied according to the tolerance of the autopilot.
Let’s say we happen upon the actual path flown by MH370 (start time & position, altitude, speed & heading modes) and now reproduce it with our path modelling tool. In addition to the BTO noise attributable to its underlying statistical characteristics, we will also have additional error (BTO predicted vs observed) attributable to errors on wind x,y aircraft heading accuracy and aircraft speed accuracy. So our “correct” path should have bigger BTO residuals RMS than would be the case if we had perfect wind/speed/heading. And a “typical” wind error alone can contribute error of at least 10km in lateral position, or +/- about 70 microseconds over the course of an hour.
So I ask again, how big would we expect our BTO residual (predicted vs observed) RMS to be acknowledging not only the error stats associated with BTO per se, but also errors in wind, speed and heading?
@sk999. Thanks also for the explanation on the correlated nature of wind errors. I do appreciate that this is more likely to give us a “one sided” or cumulative error rather than random “noise” from hour to hour.
I did once go to the trouble of comparing the predicted wind along a candidate MH370 path using current (ie on the day I did the calculation, not historic model of 7.Mar.2014) wind models GFS and ECMWF and found RMS difference between the two of about 7kts and peak difference of >15kts.
@DrB: I don’t know the details of the Kalman filter, so I won’t predict whether or not it was properly implemented, but for prior flights, if we know the state, we know the BFO error, whether or not in a turn. Of course, imperfect knowledge of the state could increase the error in the extracted bias drift. I would think that a Kalman filter that simply sets limits on the drift rate would do fine in extracting the bias drift from the BFO noise, assuming the state is known at each BFO time. As I said, the mean error of any BFO burst is essentially the bias drift.
As for betting on Inmarsat versus the DSTG, I don’t have to bet, so I won’t. I’m simply trying to objectively understand what the expectations should be for BFO error, a matter which should have been settled a long time ago. There is an obviously strong disagreement among the modelers here. I do observe, however, that much knowledge has been gained since Inmarsat published the JON paper in September 2014, including understanding effects of vertical speed and power up transients. Much of that knowledge was advanced with efforts led by Ian Holland of the DSTG, not Inmarsat, although Inmarsat probably had input. I’m also not sure how comprehensively the BFO error for prior flights was studied and understood in September 2014. We’ve all learned a lot since then.
@DrB: A couple of points from your recent posts:
“I think the time-varying bias subtraction process added noise to Figure 5.4.”
Figure 5.4 shows the data before the subtraction process – bias error and statistical noise have not been separated. I assume you are referring to your idea that the Kalman filter added noise to the data between figure 5.4 and 5.5.
“Ask yourself why the “reconstructed” flights using BFO and BTO were not accurate when there was a turn involved. The larger the turn was, the larger the track error. I suspect that is a result of the Kalman BFO filter not being able to follow accurately the BFO steps when turns occurred.”
The discussion around page 30 of the DSTG book is about the attempt to separate and analyse the bias drift from the historic flight BFO data and a Kalman filter is used in that process. In the end, that analysis was unsuccessful and unseparated BFO data, with the larger 7Hz overall error, had to be used for subsequent BFO analysis. In the flight reconstruction a very small sample of BTO and BFO data was used for each flight to match what was available on the accident flight. There can be no measurement of time varying bias in that exercise, so no use of that particular filter.
As Victor has said, I cannot verify the DSTG analysis is correct since their data is not published (nor could I replicate it even if the data was available!). I am just trying to understand what the report states.
If we did an unconstrained model (allowing pilot input) but holding as closely as possible to the BTO/BFO data, my assertion is that probably gives “x marks the spot” search area. And it is probably fairly close to the Inmarsat JoN hot spot.
In any case, please give me that location first, and then I can accept that the BFO might be off, which indicates other search areas.
We keep saying the BTO/BFO data does not tell us where the aircraft is, but it probably does indeed give an answer. To me, what we are really saying is that we do not believe the data should be used directly, so we are not even going to calculate it. This is my criticism of the search process to date.
In my view the drift-data are as important as the other data now.
@Richard’s latest paper again suggests a crash area around 30S but anyway north of 36S.
Others point between 33S and 28S. The ones that predict areas between ~15S and 40S don’t predict anything at all imo and are useless.
Imo it’s remarkable still no other debris finds are reported. Imo still indicating a small debris field.
Still the 177 historical drifters that passed the previous priority area over 20 years are a fairly realistic indication of what the debris field looked like shortly after impact imo. It fairly acurate shows the current finds to date.
31 reached African shores and islands within 22 months and 13 reached WA shores.
But the 13 drifters to WA shores only passed south of 36S, none north this latitude.
With annual and seasonal fluctuations you would expect at least one of those drifters north of 36S would have beached on WA.
But none did in those 20 years.
33S to 28S is imo the best estimate regarding possible drift and arriving times of all found pieces within the window of reasonable opportunity.
This window started with the flaperon and closed with the RR-piece imo.
Everthing (or at least most) found later arrived earlier than RR I think.
TBill. See victor’s article above. If I understand him correctly it shows that the aircraft could be pretty much anywhere between 20S and 40S in one or other autopilot mode from 1941 onwards and obtain excellent BTO fit and reasonable BFO fit. If you believe that BFO error must be 7Hz or less then you can still pick any spot between 25S and 38S. And that’s even before you start allowing additional pilot inputs after 1941. In other words, there isn’t any X to mark the spot unless our starting point on the 1941 arc is quite tightly constrained in one way or another.
Personally I was surprised that there is such a wide spectrum of ISAT-compatible routes and I’m a bit staggered that the BTO residual RMS is as low as this over such a wide range of paths.
@Paul Smithson,
You said: “So I ask again, how big would we expect our BTO residual (predicted vs observed) RMS to be acknowledging not only the error stats associated with BTO per se, but also errors in wind, speed and heading?”
There is no single answer to your question because different routes intersect the arcs at different angles. That means that wind errors, and navigation errors, and speed control errors all produce varying BTO errors. Crosswind errors are a bit more complicated, because, in this case, the BTO error also depends on the navigation mode (more particularly, whether it is a constant heading or a constant track).
In constant heading modes, the impact of wind errors and navigation errors will be larger than for constant track modes because there is no reference except the “now” readings. What I mean is that the path errors will accumulate over a leg and from leg to leg. There is no way to know exactly what the cumulative effect is at a given point in time. For constant track and LNAV routes, the errors do not accumulate because the aircraft is following a calculated path. It wanders left and right of that path as it flies along it, but the errors do not accumulate (it always has a current reference position it is trying to maintain), and so its end position is much more accurately predicted and achieved than the constant heading mode. For constant heading modes, the effect of varying crosswinds is much larger than the aircraft’s ability to know a constant heading (i.e., the navigation error). In other words, the aircraft is blown laterally by varying winds, and we don’t know exactly what the winds were. We do know roughly what their mean value was (from GDAS, etc.).
For constant heading modes, the “navigation error” (a small fraction of a degree) is swamped by the “crosswind error” (on the order of 1 degree), so I just fit the crosswind error alone, understanding it also contains a small contribution from navigation errors.
The “tailwind error” is much larger than the speed control errors in its effect on ground speed, for all flight modes. So, I ignore the speed control errors, understanding they make a very small contribution to my fitted tailwind errors (I fit 1 per leg).
For navigation errors in constant track modes, we are only affected by the mean navigation error over one leg. The common-mode portion of the navigation error (i.e., common to all legs) is compensated in fitting the track bearing, so it does not need to be included separately. One can allow possibly ± 0.1 degree errors in the track angle from leg to leg, and I have done that as well.
For LNAV (waypoint) navigation, the crosswinds are accommodated without significant errors in predicted/achieved aircraft location in the cross-track direction. Tailwinds and tailwind errors directly affect the ground speed and therefore the predicted aircraft location along the great circle path. Therefore, in this case, tailwind errors must be allowed for, either as a separately fitted leg-average tailwind, or by increasing the allowable BTO errors in the fit. The two methods are essentially identical in result. I fit the tailwind errors so that I can see them separately from the BTO errors. I found it is very convenient to express all errors in units of standard deviation (sigma) for that particular data point. So, I just take the ratio of the error to its expected standard deviation. That way it does not matter how many data points have particular values of standard deviation. It is self-normalizing for all data sets.
You also said: “In other words, there isn’t any X to mark the spot unless our starting point on the 1941 arc is quite tightly constrained in one way or another. Personally I was surprised that there is such a wide spectrum of ISAT-compatible routes and I’m a bit staggered that the BTO residual RMS is as low as this over such a wide range of paths.”
Actually, this is only true for “straight” paths such as waypoint navigation to Antarctica. It is not true for “curved” paths such as CTH, CMT, and especially CMH. I have yet to find any CMH paths matching the satellite data, and I don’t think they exist. I did find one CTH route and one possible CMT route. For those solutions the range of acceptable bearings is small (< 1 degree).
Apparently, the non-concentricity of the BTO arcs has less of a deleterious effect on straight paths than it does on curved paths. It is fortunate the satellite moved during the southern route. Otherwise no autopiloted route would have a single solution. They all would be redundant in bearing (i.e., they would be rotationally symmetric about the sub-satellite point). For LNAV routes from 19:41 to MEFE, the only way to obtain an “X” spot location is to make an assumption about the target waypoint.
@Richard Cole,
Yes, your assumption was right. I meant to say Figure 5.5 instead of 5.4 in that instance.
@Richard Cole,
You said: “The discussion around page 30 of the DSTG book is about the attempt to separate and analyse the bias drift from the historic flight BFO data and a Kalman filter is used in that process. In the end, that analysis was unsuccessful and unseparated BFO data, with the larger 7Hz overall error, had to be used for subsequent BFO analysis.”
I think you are saying the BFO bias Kalman filter was not used in creating the probability distributions shown along the 7th Arc for MH370. If that is what you meant, then why does “Section 8.2 Algorithm” on page 71/128 list step 3 as “Initialize the BFO bias Kalman filter” and step 4c as “Use the sampled trajectory to update the BFO bias Kalman filter”? It appears to me that the Kalman filter was used in the algorithm that created the probability density functions near the 7th Arc.
If that is not what you meant, then please define what you meant by “subsequent BFO analysis”. Thanks.
@Paul S
I would say Victor’s article above shows what I am saying, that the SPOLE direction is where the BFO/BTO data best point to. Victor assumed no pilot input, so the BFO fit is not as obvious. I believe there is an “exact” solution in there, if we open up the (eg; Bayesian) model to very low BFO error and allow pilot input to South Pole (or 180S variant). Instead we told Bayesian model to assume BFO error was relatively large, and the pilot was not taking any control. I am thinking 180S is the only place the fits the data closely. Yes the data could be wrong, I get it. But I don’t like the idea of not even showing the solution.
@DrB (others)
The DSTG fumbled the BFO interpretation badly. I called them on it, and they (Holland) pretty much admitted that issue, but stood by their approach.
BFO error has two components – a component due to measurement and hardware implementations such as the NCO used to generate the Doppler compensation in the AES. A second source of error has to do with oscillator drift. The first component is a candidate for a “normal” distribution with the usual application of mean and variance. The second component is not. It truly is analogous (not identical) to a random walk. You do not model a random walk with a Kalman filter. That would be ridiculous – future states have no relationship to past states.
The oscillator drift (like a random walk) will have a zero ensemble mean and a variance that grows with time. Any single sample of a random walk would not be expected to exhibit a zero mean (hence, non-ergodic). The fact that the variance grows with time means that the sample statistics are also not stationary. The oscillator drift is not a candidate for Gaussian statistics which is why Dave Allan (and others at NIST) developed the Allan Variance approach which is now an industry standard. You never see oscillator specifications in terms of a standard interpretation of mean and variance.
What the DSTG has done is to compile ensemble statistics using the previous flights. These statistics are essentially meaningless for predicting what might happen on any given flight.
DennisW: Within the context of one flight (or a time period of 1 day), I agree with your BFO statement above. (Shocking, isn’t it?) Of course, there is also a long term aging term which is not a random walk. It is typically more like (but not exactly) a constant monotonic drift towards higher frequency. But this LT drift is negligible over a day. Here’s a short tutorial https://goo.gl/iSv3xK
@TBill – S Pole / 180S path may well be close to minimum RMS on BTO and BFO (basically 33S-35S). That would make it the peak of a very wide distribution in which there is very little difference in probability across a very wide range of latitude end points. Thus we cannot say with much confidence that this “peak” is much better than neighbouring latitudes across quite a large swathe. And, as previously stated, we seem to have “acceptable” BTO/BFO residuals all the way from ~25S to ~38S. @VI – please correct me if I am interpreting your article above wrongly.
@ALSM
Hugo is a great guy. He was president of Efratom (Rubidium supplier) when the company I was working for at the time, Datum, bought Efratom. I got to know both him and his wife quite well. Hugo was very much into physics, and pretty much coined the opinion that “microprocessors would never replace physics”. He liked to annoy me with that position since I was more of a math/computer guy. Like my concert violinist neighbor at the beach house enjoys referring to me as a “propeller head”.
Nice to see you are back from hibernation @Dennis.
Now, if I may poke you a little. We have heard (again) your refrain on BFO error, the mistaken approach of DSTG et cetera. Its clear from the explanation of experts that this oscillator drift aspect should be anticipated, that we don’t know which direction it was moving, that it has not been properly characterised for 9M-MRO’s SDU, and that the DSTG’s characterisation of BFO errors wrongly lumped this in with other errors with gaussian or quasi-normal distribution.
Fine. But having repeated this over and over again, do you have a notion of how large this oscillator drift might be? Do we effectively throw BFO out altogether as a discriminatory data sources and say the error could easily be 20+ Hz?
Dr B above has made clear his own understanding of the error characteristics and his reasons for inferring a magnitude/rate of oscillator drift error. Would you, as an oscillator “fundi” [Kiswahili], care to hazard your own estimate of drift magnitude over the period of a single flight?
@Paul
Yes, I know I have been a bit of a broken record on BFO issues. Certainly BFO tells us the plane went South and came down rapidly at the end. Beyond that it is dicey to use BFO other than as a broad path qualifier.
I do agree with DrB that figure 5.4 of the DSTG book probably represents the worst case of all the logged 9M-MRO flights. That is why it became Figure 5.4. I do claim, however, that other flights exhibit similar behavior, simply not as extreme. What the behavior was on the “accident” flight is anyone’s guess.
@Victor. Could I trouble you to post path characteristics and BTO errors for each of the ping rings for one example where you have BTO residual RMS of low 20s? I’m still having trouble understanding how you can find path solutions with so little error unless you have “absorbed” some of the prima facie residuals by assigning a chunk of them to wind error or navigation track error.
@Path Modelers,
I have briefly revamped my old CMT (constant magnetic track) model, and here are some preliminary results (so far I looked at SPD MACH only):
https://www.dropbox.com/s/3ib90mxp1l7ffya/stats_cmh.pdf?dl=0
I used my fuel flow model, Rev.2 (discussed earlier this year at Victor’s blog, it seems in April or so). In brief – it appears fuel is sufficient at FL above 9 km altitude (approximately). Found Mach are in the range 0.70-0.73, which explain why the DSTG did not have these paths in their study. Headings and positions at 19:41 are generally consistent with a wrong exit from a triangular pattern. Interestingly, the terminuses are between 27S and 28.5S – ‘hotspot’ of my drift study.
@Victor, @sk999, I recall you did some CMH/CMT fitting attempts; could you pls. remind your conclusions?
@Victor. For your “best BTO path fit”across all arcs 2-6, can you please tell us what was the BTO error at 1941 for a) LRC b) constant M?
@Don,
Re: “You tried that one previously.”
Yes.
Re: “I will add “if the airplane moves during the alignment, the align reset mode occurs until there is no movement.“, how can that be construed as starting alignment?”
How alignment cannot be completed if it is never started? Perhaps you differentiate between the align mode and alignment?
Re: “Further, consider that normal ADIRU shutdown is an orderly process, not the same as removing all power (which requires six cct breakers, located on three power panels in the MEC, to be opened).”
Let’s do not mix up things. How the ADIRU could be shut down is a different issue. Right now my question is whether LGA could be engaged at 18:25:34, and what is the role of WoW bit in SATCOM system.
@Dennis,
Re: “I do agree with DrB that figure 5.4 of the DSTG book probably represents the worst case of all the logged 9M-MRO flights. That is why it became Figure 5.4. I do claim, however, that other flights exhibit similar behavior, simply not as extreme. ”
I guess that depends on what the DSTG implied under the “geographic dependence”. If flights on the same/similar routes using the same aircraft exhibit similar ‘structured’ components of the BFO error, then it has nothing to do with the oscillator, but with the navigation system. Otherwise, why would the DSTG use the term ‘geographic’, but not, say, ‘time’ dependence?
@Oleksandr
1. Your sheet heading is CMH. Which is it, CMH or CMT?
2. Have you discriminated wind models at the various altitudes posited? If not, which pressure altitude winds are you using?
3, Likewise ISAT delta. Are you using the (forecast) delta at one pressure altitude and then interpolating temperature at another with lapse rate?
4. Which magnetic variation table epoch are you using?
5. (Most importantly) I’m also struggling to understand how any of the magnetic hdg/trk options can be such a good fit. Can you please provide one path example (speed/altitude, magnetic heading/track) that produces such small BTO errors?
Oleksandr,
I have never looked serious at CMT routes that are initialized on the 2nd arc. In the past I have always assumed (as did the DSTG) that the plane flew straight line segments, and in particular excluded the possibility of a hold. Your starting latitudes of 5+ degrees at 19:41 are considerably North of the straight-line routes, which generally reached the vicinity of ISBIX (0.4 deg N latitude) at that time. My final latitudes tended to be in the range -32 to -34 deg. The speeds were in your range however. The BTO fits were never very good (60 microsec rms) although the BFO fits were often improved over routes that went further South.
Note that even if the DSTG had included speeds down to Mach 0.70, it would not have found your routes, on account of the straight-line constraint going back to the penultimate radar point.
@Oleksandr
I guess that depends on what the DSTG implied under the “geographic dependence”.
I don’t know what the DSTG implied by “geographic dependence” or how they arrived at that possibility. They do say that other flights exhibited “structured variation” in the mean bias.
@Oleksandr
OK thank you. I give you extra credit for breaking 23:14 sat call into two points. But what are the base BFO’s you are assuming to calc the error?
Interesting how the sat call happens right on the L894 flight path by POLUM. In one of my paths that I might revisit, I use McNurdo path and then exit on L894.
Finally, some word out of Malaysia about the August 2017 Madagascar debris
https://goo.gl/AZ7AvH
Any apparent “geographic dependence” is purely coincidental. It did not happen.
@ALSM
I am curious as to why figure 5.4 was even included in the book. It does not add anything to the conclusion or other analytics.
@ASLM: The ‘crime’, I presume, that prevents handing over to the Malaysian, refers to the murder of Zahid Raza, and not the downing of MH370. Hard to see what evidentiary value the pieces would be to their investigation. But also hard to see how much value they’d have for MH370. But an echo of the flaperon and the tendency for Napolenonic-trained investigators to hold onto their trophies and just about all the information they prise from them.
lkr: The vortex generator debris is potentially very important to the new search. The Madagascar mafia may have a financial stake in stopping the debris from leaving Madagascar. Watch this space.
Dennis: Fig 5.4 is important not because it helps to quantify the BFO noise, but becauze it helps to quantify the limits to using BFO data to ID the POI.
ALSM. The Malaysians have the photos, the inference being those are insufficient.
@Oleksandr,
You asked, ““Right now my question is whether LGA could be engaged at 18:25:34””
The LGA could be engaged at any time. However, the expanded GES Log (published at this site) shows that, in its Log On Request at 18:25:27, the AES defined itself as HGA equipped and the Log On proceeded accordingly.
I draw your attention to the ‘SU Contents’, associated with that Log On Request:
18:25:27.421 1F D0 10 75 00 8F C5 D0 FC 05 82 09 00 00 00 00 00 B4 06
Now, consider octet #11 where the content is ‘0x82’. The most significant two bits of this octet are defined as a data field to communicate the ‘Class of AES’. A Class 1 AES (LGA, packet-mode only) is indicated by ’00b’, A Class 3 AES (HGA, packet & circuit-mode operation) is indicated by ’10b’.
Further, consider octet #12 where the content is ‘0x09’. This octet is defined as communicating the Data Bit Rate Capability for the Log On. The lsb (bit 1/8) implies P-ch capability for 1,200bps and bit4/8 implies P-ch capability for 10,500bps.
The 18:25:27, and 00:19:29, Log On Requests both indicate the AES requesting capabilities for Class 3 AES operation, via HGA, and to be allocated a 10,500bps P-channel. These two Log Ons were completed as requested.
I’ll maybe return WoW later.
@ALSM
“Madagascar mafia”
Does the use of the word ‘mafia’ merely imply gangsterism, i.e. the use of intimidation, violence, in pursuit of criminal ends. Or is a broader, widely federated, coalition of criminal enterprises inferred?
@ALSM
It’s disappointing the vortex-generator piece won’t be available for detailed examination by Malaysia any time soon probably.
It could really hold some important clues about impact forces/speed and attitude of the plane on impact imo.
On the other hand it could be a possitive the Madagaskar authorities are going to investigate the piece in detail first and to see if there is any faul play linked with the MH370 investigation.
They probably have some good reason to suspect something like this otherwise they would have had no problem with handing the piece over to Malaysia.
France also still refuses to hand the flaperon over ( and it’s information). There might be good reasons for acting like this.
Not necessarily ‘maffioso-practise’.
Don: I think it is the latter. We will eventially know more about the connection between the debris and the murder.
@VictorI
Something I wonder about.
All your flight paths in your graphic above (your topic) seem to start from the second arc around ~7N/93E. I know you consider a loiter, descent and/or some kind of holding pattern somewhere between 18:28 an 19:41 (if I understood you well enough).
I wonder, did you also consider the plane flew past the second arc position and turned around later like @TBill suggested also?
Maybe till ~8N/92E or even further north/west? Then the turned flight producing the second arc on it’s way back and made another smaller turn to the right into the SIO?
In my imagination no loiter or other complicating manouvres would be needed in such a case.
I probably miss something essential here but I cann’t see what and why yet.
@Ge Rijn
One element I have not looked closely at is fuel consumption. The reason I do not look too closely at fuel (yet), is because I can think of ways to save fuel, having to do with an active pilot. The air packs can be turned off, I can easily envision a slow down/descent or even a hold after Arc5, tentatively looks to me like a CTH or CMH heading, that works with the winds, may save fuel over a CTT or CMT or waypoint setting that fights the winds (specifically in the MH370 path scenario where we have winds from East and then winds from West). So I am not too worried (yet) about fuel. I am instead worried about close match to BTO/BFO. At some point there is a day of accounting for fuel, to help decide on real life paths.
Victor I think is assuming inactive pilot after Arc5, so he needs to take his fuel savings via a hold before Arc2, to over-simplify.
@sk999
@Paul Smithson
@VictorI
@TBill
@Oleksandr
I have been trying in vain to find a candidate constant Mach great circle path into the SIO, one that used known waypoints, and I’ve come to the following conclusion; I don’t think the aircraft used any of the known waypoints to navigate from N571 into the SIO. I think the pilot flew basically same way that he flew his simulator on 2nd March 2014. For MH370 I believe he chose in advance, a specific set of coordinates that suited the purpose (Not an airfield in Antartica, BTW) that was beyond the fuel range of the aircraft, and used these to set up a manual waypoint he could designate the FMC to fly toward just prior to reaching a pre-determined waypoint on N571. On the MH370 flight, this waypoint was IGOGU. The purpose was to make absolutely sure his flight-path could never be reconstructed.
DrB’s range v. endurance table has proven particularly useful. In my opinion, a constant Mach 0.82 at FL380 has probably the most promising combination of range and endurance if one wants to avoid loiter, fly as far as possible into the remotest part of the SIO and arrive at the terminus in daylight.
I find that if the pilot timed the FMT to begin 20NM before reaching IGOGU, and then flew toward a manual waypoint located beyond S37.62, E89.08 – at this point, temporarily suspend your disbelief – it would comply hopefully with the BTO, comply with the total range from DrB’s start point at N7.18, E95.68 (adjusted accordingly for the no offset case) and comply with the endurance.
FMT of 12NM radius beginning 20.3NM before IGOGU is initiated at 18:36:30, completed 18:39;00, at N07.25, E94.528, bearing 186.1364.
Range from the 18:29 point onwards works out as follows : estimated 70NM from 18:29 point to the FMT, plus 2,655.5NM up to the 6th arc crossing, plus a further 47.5NM to MEFE = 2,773NM (fuel model 2,774). Fuel model MEFE time is 00:16.
The great circle distance between FMT and the 6th arc is 2,655.5Nm, and the journey time is 5.5542hrs (5hrs, 33.25mins) taking the FMT mid-point time as 18:37:45. When an average 2.2Kts headwind is factored in, the airspeed works out at M0.8184: 478.1Kts +2.2Kts headwind =480.31/587* = M0.8184. (taking 587Kts as average value of Mach 1 between FMT and the 6th arc, at average temp 42.5C). As you can see, the calculated airspeed is slightly less than an exact M0.82. It is possible the aircraft cruised south at slightly above FL380. After the 5th arc, altitude could have slowly risen to FL400. My estimated headwind for the leg could be a slight overestimate.
FMT to 2nd arc: 512Nm, 485Kts average groundspeed, 1.8Kts average tailwind = Mach 0.822 (Mach 1=588.4Kts, Temp -41C) 2nd arc tangent point S1.00, E93.65.
2nd arc to 3rd arc: 479.51Nm, 479.51Kts average groundspeed, 1.6Kts average tailwind = Mach 0.812.(Mach 1=588.4Kts, Temp -41C) 3rd arc crossing S9.00, E92.799
3rd arc to 4th arc: 489.43Nm, 486.42Kts average groundspeed, 4.6Kts average tailwind = Mach 0.819.(Mach 1=588.4Kts, Temp -41C) 4th arc crossing S17.12, E91.89.
4th arc to 5th arc: 480.82Nm, 480.41Kts average groundspeed, Zero average head/tailwind = Mach 0.816.(Mach 1=588.4Kts, Temp -42C) 5th arc crossing S25.113, E90.916.
5th arc to 6th arc: 693.68Nm, 462.3Kts average groundspeed, 13.5Kts average headwind = Mach 0.816.(Mach 1=583.0Kts ave. Temp -46C ave.) 6th arc crossing point S36.60, E89.25.
6th arc to 7th arc: 61.5Nm, 434Kts average groundspeed, 33Kts average headwind = Mach 0.81.(Mach1=577.46Kts, Temp -50C)
@VictorI
Re my post 2 hours ago. Please could you tell me why it’s taking you so long to moderate?
@Rob: I was on a plane. Patience, please.
@VictorI
Phew, that’s a relief!
@Rob
Well any point on the map can be a manual waypoint. Your path projects closely to whole number waypoint 3889S…but with a little more complexity the pilot can also add minutes and seconds, to fine tune it. I find I use the whole number waypoints quite a lot when working with MH370 flight paths.
@Paul Smithson:
1. Your sheet heading is CMH. Which is it, CMH or CMT?
CMH – constant magnetic heading.
2. Have you discriminated wind models at the various altitudes posited? If not, which pressure altitude winds are you using?
Yes. I am using 3D GDAS. In the model I assumed that a constant pressure altitude corresponds to constant altitude (the difference varied within approximately 50 m along the path).
3, Likewise ISAT delta. Are you using the (forecast) delta at one pressure altitude and then interpolating temperature at another with lapse rate?
No. My script directly interpolates GDAS data at a location, altitude and time.
4. Which magnetic variation table epoch are you using?
A good question. According to my records, I generated 2D magnetic declination from one of the following links:
http://www.ngdc.noaa.gov/geomag-web/#igrfgrid
http://www.ngdc.noaa.gov/geomag/WMM/calculators.shtml
But it was in the mid of July 2014, before we learnt about magvar tables. I believe I generated magnetic tables for the actual date of the disappearance (2014-03-08).
5. (Most importantly) I’m also struggling to understand how any of the magnetic hdg/trk options can be such a good fit. Can you please provide one path example (speed/altitude, magnetic heading/track) that produces such small BTO errors?
Perhaps it flew in that way?
3.5 years ago I did some simulations of CMH (it was posted at Duncan’s site), and the fit was rather good. Then someone claimed that magnetic hdg/trk is used for display only, and I abandoned CMH/CMT class of simulations. It seems nobody seriously modeled magnetic routes: I am aware only of @sk999 work, and, if I am not mistaken, one Victor’s route. The DSTG imposed a-priory limit of 0.73M on the speed, while all the CMH are slightly slower.
Here is a link to the plot of the flight path at 9,000 m:
https://www.dropbox.com/s/g5usvhgwjxn0p3d/mh370_cmh_alt9000_rev2017_11_09.jpg?dl=0
I could not resist to include my earlier estimation of the intersection of the 7th arc with “Curtin boom” bearing (HA01+RCS).
@Rob
I like the idea of a manually entered final waypoint “at the fuel limit or beyond fuel range” lat/lon to head for, since the sim point 45s104E suggests that. I also like the idea of 45S as his preferred goal lat to reach, for reasons previously stated.
So, as a suggestion, why not run a whole series of paths from your FMT to 45S, for each longitude from 104E back to say 84E, ie, 104, 103, 102, 101, 100, 99 etc, and see where you get the best BTO/BFO fits ?
@TBill,
Re: “But what are the base BFO’s you are assuming to calc the error?”
19:41:02.906 111Hz 2nd handshake
20:41:04.904 141Hz 3rd handshake
21:41:26.905 168Hz 4th handshake
22:41:21.906 204Hz 5th handshake
23:13:58.407 216Hz 2nd satcom call start
23:15:02.032 219Hz 2nd satcom call end
00:10:59.928 252Hz 6th handshake
The difference is defined as a sampled BFO minus modeled BFO.
@sk999,
Thanks for your comment.
RE: “In the past I have always assumed (as did the DSTG) that the plane flew straight line segments, and in particular excluded the possibility of a hold. Your starting latitudes of 5+ degrees at 19:41 are considerably North of the straight-line routes, which generally reached the vicinity of ISBIX (0.4 deg N latitude) at that time.”
Yes. If you assume the final phase starting at 18:40 or earlier, then 5N+ is not possible. In this regard triangular patterns are the most intriguing: I already see that it will likely be possible to connect at least one of them to the post-19:41 CMH path. However, I am somewhat reluctant to do this bearing in mind recent Andrew’s comments. I don’t know about racetrack pattern.
Re: “Note that even if the DSTG had included speeds down to Mach 0.70, it would not have found your routes, on account of the straight-line constraint going back to the penultimate radar point.”
That is true.
@Oleksandr
Re: “…what is the role of WoW bit in SATCOM system.”
The only information I have come across relates to PAST (Person-Activated Self-Test). PAST is inhibited when the aircraft is airborne, except when initiated via the CMT (Commissioning & Maintenance Terminal). WOW is one of the criteria used by the SDU to determine the airborne/on-ground status.
Re: ‘The patent link to which I provided, appears to be somewhat inconsistent with AMM, chapter “AIR/GROUND SYSTEM – INTERFACES” For example, WOW Card Inputs. Citation from AMM, 32-09-00 (pdf p. 4398):
“The WOW cards get inputs from:
– AIMS (time and date, flight phase/leg, airplane registration number, ICAO code)
– Bus power control unit (external power available)
– ELMS (air/ground relay status)
– Ground test enable switch
– Load sensors
– Radio altimeter (3).”
Nothing is mentioned about air/ground speed, mentioned in the patent.’
I don’t believe the patent information is inconsistent with the AMM. The patent relates to the air/ground sensing for the flight control system, which uses a variety of data inputs to determine the air/ground status, including WOW, TILT-UNTILT, airspeed, groundspeed, Mach number, altitude and pitch. Some aircraft systems only use the WOW data to determine the air/ground status, while others use a combination of data such as WOW, airspeed, altitude, etc. The reference you cited only describes the interfaces to the WOW cards, which do not require airspeed, groundspeed, etc to determine the WOW status.
@Don,
Re: “I draw your attention to the ‘SU Contents’, associated with that Log On Request:
18:25:27.421 1F D0 10 75 00 8F C5 D0 FC 05 82 09 00 00 00 00 00 B4 06
”
Thanks for your detailed explanation. Now I admit it looks like the ADIRU failure can really be ruled out because the Inmarsat data indicate transmission via HGA, and not via LGA.
Btw, do you have a link to complete Inmarsat logs? Somehow I missed it: in the “Update 2014” SU content was still cut out as not important. Do all other records indicate the use of HGA after 18:25? It could also be interesting to take a look at RX-power fields.
Re: “I’ll maybe return WoW later.”
I am looking forward for your comment with regard to WoW.
@Andrew,
Thanks for your comment.
Re: “WOW is one of the criteria used by the SDU to determine the airborne/on-ground status. ”
Why is it so essential for the SDU to know whether the plane is on the ground or in the air? Why is the ADIRU insufficient?
Re: “I don’t believe the patent information is inconsistent with the AMM.”
I don’t know. The patent states a lot of input information is used to define the status. AMM does not say anything how TILT-UNTILT, airspeed, groundspeed, Mach number, altitude and pitch information reach the WoW cards; only 4 WoW sensors are mentioned. Am I missing something?
@Dennis,
Re: “I don’t know what the DSTG implied by “geographic dependence” or how they arrived at that possibility. They do say that other flights exhibited “structured variation” in the mean bias.”
I also don’t know. Why “geographic dependence”, why not “time dependence”? The latter seem to be more logical, unless they did really observe some kind of geographic dependence of the structured deviation.
@Ge Rijn. “It’s disappointing the vortex-generator piece won’t be available for detailed examination by Malaysia any time soon probably”.
As reported, the equanimity of Minister Liow’s acceptance of the indefinite delay, already coming up 3 months, hardly accords with the Malaysian task of identifying the cause of the crash. We could have expected at least a work-around initiative by now or signs of one. Purportedly a search renewal is being investigated though with no sign of the urgency needed to meet the forthcoming search season.
Why could the Malaysians not ask to examine the item under Malagasy supervision? Interview the finders? As a minimum ask for more photographs if needs be and use those as the ATSB did those of the flaperon obtained from the French. Then they could at least come to a tentative finding on whether the main item is of 777 vortex generator origin based on the photographs, the Blaine Gibson description and Boeing’s opinion.
What to me increases interest in the origin of that item is that it has features needing explanation. That might also be feasible now even if its fracture mechanics need to wait.
It is in the interest of the tripartite countries and search refinement that they glean what they can. The appearance however is that the Malaysians, at least, are sanguine about the delay. That joins the tenor of Liow’s remark quoted on the 1st November, “If we are convinced, with credible evidence, only then will we continue the search mission..”
The only legitimate reason I see for downplaying the need for a report on this item, and for a new search, would be that finding the wreckage is now less important than it was, implying that there is a likelihood of finding the crash cause from other sources.
To the French view that the flaperon is evidence of malfeasance now add Madagascar’s reason for withholding these two items. Add Blaine Gibson’s withdrawal ostensibly under threat and I am left wondering why the media are not into all this.
@Oleksandr
“23:13:58.407 216Hz 2nd satcom call start
23:15:02.032 219Hz 2nd satcom call end”
OK I agree with those 23:14 BFO values, some are adding offsets to those. Apparently we need to think of those as having higher error bar.
Like Paul I am surprised at how good the fit is. I will try to see if I can match it in FS9 when I get time.
@Oleksandr
Re: “Why is it so essential for the SDU to know whether the plane is on the ground or in the air? Why is the ADIRU insufficient?”
As I said previously, PAST is inhibited when the aircraft is airborne, except when initiated from the CMT. As I understand it, one of the following criteria must be met to satisfy the ‘on-ground’ status:
– Both WOW discretes indicate ‘on-ground’; or
– IRS data indicates a ground speed of less than 40 knots; or
– IRS data is invalid.
Re: “The patent states a lot of input information is used to define the status. AMM does not say anything how TILT-UNTILT, airspeed, groundspeed, Mach number, altitude and pitch information reach the WoW cards; only 4 WoW sensors are mentioned. Am I missing something?”
Yes, you are missing something. TILT-UNTILT, airspeed, groundspeed, Mach number, altitude and pitch data is not used by the WOW cards. It is used by the flight control system in conjunction with the WOW data to determine the air/ground status for flight control system purposes only.
@Andrew,
Re: “TILT-UNTILT, airspeed, groundspeed, Mach number, altitude and pitch data is not used by the WOW cards. It is used by the flight control system in conjunction with the WOW data to determine the air/ground status for flight control system purposes only”.
Thanks for clarifying this.
Re: “As I said previously, PAST is inhibited when the aircraft is airborne, except when initiated from the CMT. As I understand it, one of the following criteria must be met to satisfy the ‘on-ground’ status:
– Both WOW discretes indicate ‘on-ground’; or
– IRS data indicates a ground speed of less than 40 knots; or
– IRS data is invalid.
”
Why would WoW be required to activate self-test or by PAST?
@Oleksandr
“3.5 years ago I did some simulations of CMH (it was posted at Duncan’s site), and the fit was rather good. Then someone claimed that magnetic hdg/trk is used for display only, and I abandoned CMH/CMT class of simulations. It seems nobody seriously modeled magnetic routes…”
That is a key point, I am thinking it was maybe only 6 months ago @Matt over on JW started to change “our” collective thinking that Magnetic Heading (not True Heading) is the default A/P mode (after waypoint discontinuity).
It is still quite controversial to me that the ATSB 38S hot spot was basically a straight (True) path pretty much based on assuming a hypoxic-style (unintentional ghost) flight. That is a illogical as it would be a Magnetic Heading in that case.
Anyways that means CMH paths are more important now, and at least @Rob still embraces an intentional True straight path flight to 38S.
@ventus45: In a previous comment, I mentioned that I found the great circle path that satisfies the satellite data that also passes the point 45S, 104E, which are the final simulator coordinates. The position at 19:41 is 8.0N, 93.1E, and the path crosses the 7th arc near 28.3S latitude. For an LRC speed profile, the RMS BTO error is 33 μs and the RMS BFO error is 6.6 Hz. I believe this is a candidate hot spot.
Can anyone explain jitter in the course reported by FlightAware FlightAware ADS-B for Frankfurt and Mumbai flights of 9M-MRO, typically reaching 3 deg by the end of flights (beginnings appear to be much more stable)?
https://www.dropbox.com/s/18rrb60ecygnc4k/tracklog-mas006-frankfurt-20140307.pdf?dl=0
https://www.dropbox.com/s/k913zw0m07cik17/tracklog-mas195-mumbai-20140302.pdf?dl=0
@Ge Rijn said: All your flight paths in your graphic above (your topic) seem to start from the second arc around ~7N/93E.
It might look like that in the figure, but in fact the position at 19:41 rotates around the 2nd arc for various paths as the position at 00:19 also rotates around the 7th arc.
Since several people have asked for it, I’ll add a table to the post that summarizes the great circle results, including position at 19:41, position at 00:19, and BTO/BFO errors.
@TBill: No pilot input after 19:41 does not require non-response due to hypoxia from an accident. There could have been deliberate actions to guide the plane to the SIO that required no pilot input.
@TBill,
Re: “I am thinking it was maybe only 6 months ago @Matt over on JW started to change “our” collective thinking that Magnetic Heading…”
If I understand it correctly, Andrew says the same.
As you know I was banned at JW site when I opposed JW’s idea that NOK and Blaine planted debris, so I did not read his blog since then.
Re: “It is still quite controversial to me that the ATSB 38S hot spot was basically a straight (True) path pretty much based on assuming a hypoxic-style (unintentional ghost) flight. That is a illogical as it would be a Magnetic Heading in that case. ”
It is a mystery to me why the ATSB and DSTG avoid discussions of magnetic routes, especially keeping in mind all the uncertainties in the BTO and BFO data.
Re: “Anyways that means CMH paths are more important now, and at least @Rob still embraces an intentional True straight path flight to 38S.”
It is not possible to reconcile 38S with the drift studies, including measured data. I don’t know why @Rob cannot understand this.
@Olekksandr
It is not possible to reconcile 38S with the drift studies, including measured data. I don’t know why @Rob cannot understand this.
@Rob is a whacko.
@DennisW
“It is not possible to reconcile 38S with the drift studies, including measured data. I don’t know why @Rob cannot understand this.”
Really ?
Mike Chillit’s latest chart and tabulated data say otherwise.
https://pbs.twimg.com/media/DOO0o-BU8AAd0pF.jpg
https://pbs.twimg.com/media/DOO0pAoVoAAAzk8.jpg
The bottom 6 red dots for Arc Latitudes 34South to 39South inclusive are very interesting, MOST PARTICULARLY for Latitudes 36, 37, 38 and 39 South, which account 55 buoys, (out of 141 for the WHOLE arc) and of them, ONLY 31 went west, and a significant number, 24 buoys went EAST.
Near enough to a 60 / 40 split.
Where did those 24 buoys go ?
In fact for the bottom 3 red dots for Lats 37, 38, and 39 south, for 44 buoys, 26 west, 18 east, it is a 60 / 40 split.
Moreover, those east going buoys are too far south to make landfall anywhere on Australia, except perhaps Tasmania, so obviously they didn’t, and similarly for any wreckage debris.
When 40 percent of those buoys could go east and never beach anywhere, it is false logic to say they didn’t because we never found any. If it was 95% to 5% I might swallow it, but at 60 / 40 – no way. Absence of evidence is not evidence of absence.
The drift studies have all (in my opinion) not been extended far enough south to give a true picture. Even Mike stopped at 39 South. I think the drift studies should be extended both sout (to 45S) and west (to 80E) at a minimum.
@Ventus
The lack of debris found in WA speaks volumes relative to terminal location at 38S and beyond. Why are you beating on a dead horse?
@Dennis: Yes, you’re right, a lack of debris in WA, where there was a search. Can’t say the same for ANY area not visited by BG on the western shores!
@Ventus45 @Mike Chillit
I wonder on what data @Mike Chillit’s numbers are based. Global Drifter?
I referre again to @MPat’s study based on Global Drifter data spanning 20 years of drifters that past the previous priority area between 32S and and 39S.
177 past this area in those 20 years. 39 of those are listed to have beached. 31 on East African shores, 7 on WA shores and one on Sumatra.
Those 7 that landed on WA shores all passed the area south of 36S.
North of 36S none of those 177 drifters reached WA in those 20 years.
This reflects the situation we have now; no debris finds in WA and around 30 finds in Africa and it’s islands.
And this study indicates north of 36S debris is not expected to wash ashore in WA (which I deduced from @MPat’s study back then mentioned in the follow-up article).
Have a read again please:
http://jeffwise.net/2016/07/07/guest-post-where-mh370-search-area-debris-has-historically-gone/
http://jeffwise.net/2016/07/15/how-we-know-where-mh370-went/
(with thanks to Jeff Wise for borrowing his articles again)
@TBill
On your comment;
‘One element I have not looked closely at is fuel consumption. The reason I do not look too closely at fuel (yet), is because I can think of ways to save fuel, having to do with an active pilot.’
I don’t quite understand why you would want to look into saving fuel if the FMT shifts north-west past the second arc toward 10N/90.
Wouldn’t the range at a specific altitude (conform @DrB’ tables) stay the same? Would not only shift the final reachable latitude to the north compared to a ~18:40 FMT?
@TBill
to add another question:
Wouldn’t an active pilot make shure he could reach a specific latitude (if this was intended) without complicating things by saving fuel by complicated means?
He could pick his FMT/route at will with the available fuel to make shure he could reach his latitude/destination without complicating matters I think.
@DennisW
“It is not possible to reconcile 38S with the drift studies, including measured data. I don’t know why @Rob cannot understand this. @Rob is a whacko.”
@DennisW
“It is not possible to reconcile 38S with the drift studies, including measured data. I don’t know why @Rob cannot understand this. @Rob is a whacko.”
DennisW. I am sorry you see it this way. I am not offended, btw. I will wear my whacko badge with pride. As I told you before, many times, the drift studies simply cannot be considered reliable. Be honest, you are not rejecting S38 because of the drift studies. You rejected S38
@Rob
It’s not only the forward drift studies that are decicive.
As @DrB has calculated ~38S is only reachable with the available fuel from the earliest possible FMT at ~18:25.
I think no one thinks the FMT was at ~18:25. Do you?
@DennisW
Continued: You rejected S38 a long time ago because it had no place in your “thwarted negotiation” theory. The pilot of MH370 was no expert on the ocean currents of the Indian Ocean. He simply figured that the further south he flew, the less likely any debris would come ashore. That’s why he flew south at optimum altitude between 38,000 and 40,000ft, to get as as far as possible on the fuel, then when CV the fuel was exhausted, glide as far as possible on the same heading. The final BFO’s don’t rule out a glide from 40,000ft, imo.
@GeRijn
“It’s not only the forward drift studies that are decicive.
As @DrB has calculated ~38S is only reachable with the available fuel from the earliest possible FMT at ~18:25.
I think no one thinks the FMT was at ~18:25. Do you?”
Ge Rijn, please check your figures. DrB’s assumed earliest FMT was taken to be 18:29, NOT 18:25. And his FMT was also deemed to have begun on an offset flight path. The offset at around 18:25 is still very much a moot point. For myself, I can see no evidence to support it. What I am seeing is a slowdown from M0.84 to M0.80, possibly accompanied by a descent, between 18:22 and 18;29, the aircraft remaining on N571. After 18:29, I think the aircraft began to climb to FL380 in readiness for the flight south.
@TBill
“Well any point on the map can be a manual waypoint. Your path projects closely to whole number waypoint 3889S…but with a little more complexity the pilot can also add minutes and seconds, to fine tune it. I find I use the whole number waypoints quite a lot when working with MH370 flight paths.””
TBill, thank you for keeping an open mind on the subject. I gives me encouragement. Yes, I agree than any point on the map can be a manual waypoint. What our particular pilot was looking for was a waypoint that ensured his plane flew in darkness until the last half hour or so. The recovered debris is telling me that the pilot was in control until the final moments. He was preoccupied with the need to minimise the amount of debris while at the same time, sinking the plane as efficiently and quickly as possible.
I think he miscalculated slightly iro synchronising with sunrise. Not the easiest thing to do in advance, when you also want to keep to a straight flight path to maximise distance covered into the SIO, and you are not sure exactly at what point the fuel is going to run out. I think he would have preferred the Sun no more than 2 degrees above the horizon. What he ended up with was approx 6 degrees.
@Rob
Yes, 18:29.. But it’s about the earliest possible FMT and the maximum range I was talking about. Conclusion is the same.
Update on November 10, 2017:
Here is a CSV file with data for the great circle paths, including the position and track at 19:41, position at 00:19, and speed mode. Included are the data for four paths that align with waypoints past the 7th arc. The four waypoints are the South Pole (NZSP), Wilkins Runway (YWKS), Pegasus Field-McMurdo (NZPG), and the fuel exhaustion position from the simulator data (45S, 104E).
@Victor. Many thanks – will have a look at these with interest.
@Oleksandr. Thanks for posting the depiction of your magnetic route. For a path that finishes around 25S I don’t have too much of a problem, particularly if it is mag track rather than heading. By this point your maximum magnetic declination is only about 6 degrees. But by 30S 100E it is 9 degrees and by 35S its 15 degrees. So M paths with more southerly end points have a lot of bend towards the end – and I think its difficult to reconcile these with the BTO unless this is accompanied by much slower speed for the last ~2hrs.
@Ge Rijn
Re: Fuel
Assuming a 180S heading, the only obvious target I can see is trying to get over Broken Ridge at 31S and 93-94E. And it looks like MH370 made that with fuel to spare, and went even further south.
Correcting my 180S CTH path for outside temp: Now M0.81 (180S CTH) fairly slow
I see many “events” after Arc5 that may have required pilot input/descent: >Twilight
>Sat Call
>Sunrise
>very high wind from the West
>Cloud cover
>Stretching the fuel (Ge Rijn gives me another list item)
Using Flight Sim, I am not inactive when these things are happening out the window. Rather I envision descending to closer to the cloud level, possibly a heading adjustment to keep going southerly in the wind, possibly other maneuvers if there was a specific flight end plan.
This is a long winded way of saying, I do not see descent to stretch fuel as a complex action, I was already descending to reduce the aircraft visual profile in the Sun.
@TBill
I agree and I can imagine a long gradual descent between 22:41 and 00:11 could meet the objectives you name and save a lot of fuel too as a circumstantial result of a long gradual descent (maybe only flying on idle a long time..)
The time laps between arc 5 and 6 is also 30 minutes longer as the previous. Maybe this shows the gradual drop in speed and altitude while descending till 00:11?
@Ge Rijn
I like a slow 300 ft/min descent starting at twilight at 22:50 and this makes the 23:14 BFO fit (which may not be as important factor as I orig thought), by the time the Sun comes out the altitude is much lower but above the clouds. But the only people can see me are anyone flying low altitude above the clouds like me.
@Victor,
The information you posted on your great circle routes is interesting but insufficient for anyone to duplicate and to verify your results.
I suggest that you post, for the 4 particular routes you have proposed, the following numbers for each Arc (beginning at 19:41 and ending either at 00:11 or at 00:19):
Time
Latitude
Longitude
Flight Level
Temperature Deviation
True Course
Ground Speed
Rate of Climb
Please also list your predicted BTO and BFO and Mach air speed at each Arc location.
The first list is the minimum information needed to independently compute BTO and BFO. The second list (predicted BTO/BFO) allows us to compare BTO and BFO models to look for possible discrepancies. Knowing the Mach you used will permit checking the speed model.
Thanks, Victor.
@DrB: Actually, for the constant Mach number flights, starting with the position at 19:41, the flight level (FL350), the Mach number, and the track angle, you should be able to duplicate the results, as the path is uniquely determined for given meteorological conditions. (Vertical speed was assumed to be zero except at 00:19.) As for ground speed, it varies continuously along the path, so I’m not sure whether it is useful to report results only at times we have BTO or BFO data.
Let me think about whether or not it is useful to compile more detailed results.
@ventus45,
Re: “The drift studies have all (in my opinion) not been extended far enough south to give a true picture. Even Mike stopped at 39 South. I think the drift studies should be extended both sout (to 45S) and west (to 80E) at a minimum.”
There several things to consider.
Firstly, you need to differentiate between 9M-MRO fragments and MH370 debris. Absence of 9M-MRO fragments in Australia does not mean absence of MH370 debris. The MAS unopened towelette could be from MH370, for example.
Secondly, you need to consider spatial distribution of found debris. W/E of the 7nd arc or absence in Australia are too coarse ‘binary’ indicators, so your appeal to these factors look at least childish in comparison with a dozen of drift studies.
Thirdly, the areas corresponding to origins in 38S-40S were well-covered during AMSA aerial search March 18 – March 27. Nothing.
Fourthy, the flaperon barnacles could not experience the temperatures derived from ‘forensic’ analysis by Prof. De Deckker if the origin was south of 36S based on NASA’s measured SST data.
Fifthly, you need to consider actual currents, winds and leeway factors of debris. N-year buoy data are useful only for understanding of general flow patterns, perhaps seasonal features.
In summary, if you look at various criterion, none is met for the origins south of 38S.
I hope this will help you to understand why your suggestion above makes no sense.
@Oleksandr
In your post to Venture. You said: “Fourthy, the flaperon barnacles could not experience the temperatures derived from ‘forensic’ analysis by Prof. De Deckker if the origin was south of 36S based on NASA’s measured SST data”.
This is not the case. The barnacles could well have colonised the flaperon after it had drifted north into warmer waters. The flaperon could have started its journey from S38.
This is a bit off the topic, but I would really appreciate if someone can provide an answer. It is related to SDU power off and re-logon.
In Holland’s paper it is explained how 7 previous SDU re-logons (p7, p8 and table 3) were recorded and further used for the BFO analysis. Particularly, Holland states that:
“The periods of SATCOM outages followed by log-on events were identied from Inmarsat-provided ground-station logs by identifying sequences of three or more unsuccessful log-on interrogations to 9M-MRO (suggesting the SDU was likely powered off) followed by a log-on to the satellite system initiated from 9M-MRO at some later time.”
Yet, there is a common opinion that isolating (intentionally) the left AC bus was the reason for the SDU power outage and reconnection brought the SDU back on followed by the re-logon.
However, data in table 3 suggests that the SDU in 9M-MRO was occasionally staying without a power before the Flight 370. If so, is it more probable that there was a occasional technical issue with the SDU in this particular airplane?
@Marijan: First, welcome to the discussion.
The previous power downs were most likely related to shutdown of the APU and/or disconnect of ground power after both engines were shutdown, which would be normal if there was an extended period between flights. Those power downs would be considered normal, and not due to a problem with the SATCOM. If something was abnormal in the signaling logs, it would have been flagged long ago.
@Rob,
“The barnacles could well have colonised the flaperon after it had drifted north into warmer waters.”
No. The temperature would not drop back to 18C, or time would be insufficient to reach La Reunion. Compatible area is between 26S to 36S, subject to the flotation characteristics of the flaperon (French or Australian). French data result in the peak probability at approximately 28S; CSIRO’s – 30.5S. Whatever you like more among these two, but not 38 and even not 36.
Re: “The flaperon could have started its journey from S38.”
No, it could not. That is what barnacles, NASA and at least two drift studies tell.
@Victor,
@sk999,
Do you have actual magnetic declination table used in 9M-MRO?
@Oleksandr: I don’t. Others do.
@Victor,
Thanks. I recall you modelled magnetic+FPA path, if my memory is correct. What was your source of magnetic declination data?
@Oleksandr: I looked at 180°M paths (heading and track) with a constant rate descent and constant FPA, with a M0.84/310 KIAS speed setting. This produced the right ground speed profile, which in general needs to decrease with time to match the BTO data. I used the actual magnetic declination on Mar 8, 2014, and not the magnetic declination table that was likely loaded.
@Victor,
Thanks; so did I with regards to the magnetic declination.
I think you are in a good standing to easily replicate my latest CMH experiments starting 19:41 as you have all the same forcing. It would be interesting to see if you can obtain similar results.
Oleksandr,
I doubt anyone has the precise table used by 9M-MRO. Some time ago I downloaded a source code program geomag70.c and two data files, IGRF12.COF and WMM2010.COF and computed magnetic deviations from those for several years (1980, 1995, 2005, 2014). My choice at the moment, based on advice from ALSM, is 2005. I store the information in the form of coefficients to polynomial equations, not in tabular form. These were all included in a code dump that I posted several months ago.
@sk999,
Thanks. I have also seen this script, but I simply generated 2D field 0.25×0.25 deg resolution using online calculator from the same website (link is above)
The magnetic declination tables for Jan 1, 2005 and March 7, 2014 are here:
https://goo.gl/ugF2GL
Covers:
0 to -50S
80 to 110E
0 to 10 km
9M-MRO had 2005 tables installed, according to an ATSB source in late 2015. I choose Jan 1, 2005 is a reasonable assumption. The largest change over the 9 years was 2 degrees, so it is not very sensitive.
Were the magnetic tables of 9M-MRO corresponding to Jan 1, 2005, or some kind of averaged, say, over the interval 2005-2010 (or 2005-2015)?
The table in 9M-MRO was not an average. It was as of a date, which I assume was jan 1, 2005. The average for all of 2005 is virtually the same.
BTW…The NOAA software used to generate the tables also output a rate of change value to estimate future values. I asked ATSB to check with Boeing, and they reported back that the B777 software does not use the rate of change information to compute a current value. Thus, I left the rate of change values off in the tables.
ALSM,
R.E. rate change not being used – thanks for checking. It was a nagging issue, although after reading much literature, I kind of figured out it had to be that way. It would seem that, rather than make any value be as accurate as possible, it is preferable to make the error in the value be as accurate as possible. The latter is easier to accomplish if the values are fixed.
ALSM,
Nice sequence of posts. Thank you.
@ALSM,
Thanks for this info.
I will ‘update’ magnetic declinations to Jan 1, 2005 in my CMH model (currently March 8, 2014). I don’t expect much difference, but let’s see.
@Victor: thank you for replying. I understand completely. I will not ask again for this imagery. The audit will reflect that you refused to share evidence you thought offered strong corroboration of the claim the ISAT data is authentic – but it will duly add that you claimed to have a perfectly good reason for refusing. Thanks anyway.
New topic: did the IG – as a group, or as individuals – ever publicly express or imply support for the absurd official claim that one or more of the acoustic “pings” detected at the Wallaby Plateau stood a material (i.e. >30%) chance of having been emitted by MH370’s black boxes? This once-official claim is now widely recognized as, at best, a time-wasting blunder; if any IG members ever supported the absurd decision to go underwater at 23s for April and May (à la R. Quest, e.g.), I’d like to develop a crystal clear understanding as to why, so that we all might learn from this honest mistake. (I don’t recall anyone in your learned group ever having made so basic an error – but if so, i’m still keen to document this explicit and immediate opposition, for posterity).
Second topic: same request, but re: absurd decision to halt the surface debris search, what with the debris having “mostly waterlogged and sunk”.
Third topic: same request, but re: absurd official claim that surface debris had “drifted West”, with first landfall expected on Sumatran shores.
Fourth topic: same request, but re: absurd official claim that the flaperon vindicated the s38-centred search zone (when it demonstrably and emphatically did not).
Profuse thanks for your time and consideration.
@Brock McEwen said: The audit will reflect that you refused to share evidence you thought offered strong corroboration of the claim the ISAT data is authentic – but it will duly add that you claimed to have a perfectly good reason for refusing.
A more honest statement would be that I gave you the source of information that was confidentially shared with me regarding the provenance of the flaperon, and I encouraged you to ask the source for the information directly. I also provided you with the exact language that I provided the person that asked me to analyze the information.
Based on the many times that you have misrepresented information, I am done communicating with you.
@Brock
Fourth topic: same request, but re: absurd official claim that the flaperon vindicated the s38-centred search zone (when it demonstrably and emphatically did not).
That is a bit harsh, IMO. The differentiator being what is probable versus what is possible.
@Victor
Thank you for the clarification. I didn’t realize that all of them were recorded on tarmac.
@VictorI
Maybe a silly question but are all those flight paths till the 7th arc within fuel range (according @DrB’s endurance/range tables)?
And if not which fall short?
@TBill
What I like is you are one of the few seriously looking into an all active piloted flight.
I mentioned several times before this is the most sensibel and logical thing to assume.
There is no proof at all even no clear indication the flight went into a ‘ghost flight’ anywhere along it’s route.
The chance of something like that to happen must be one in several millions of flights.
Therefore it’s kind of strange so many took the road of an ‘unpiloted flight’ somewhere after IGARI.
They rather take the one in a million chance than the obvious statistical normal without any proof to do so.
It might be more convenient to take this approach for else it becomes a lot more complicated.
But this should be no reason to reject normal reality.
Imo out of millions of flights this one was actively piloted from beginning till end also.
There’s no sensible reason, no proof and no clear indication to think otherwise.
@Ge Rijn said: There is no proof at all even no clear indication the flight went into a ‘ghost flight’ anywhere along it’s route.
We know there are reconstructed flight paths for MH370 that match the satellite data without pilot input after 19:41. That fact alone means we have to consider this possibility.
I don’t know for sure whether or not there was pilot input after 19:41. However, if there was a decision to fly south to the SIO, I would prefer to soon after die of hypoxia (turn off the air packs and open the outflow valves) rather than die in a plane crash after flying for 5 hours into oblivion, or worse, survive the crash and die of starvation, injuries, drowning, hypothermia, shark bites, or other terrible ways.
..to add. For this reason I think there could have been no NORM magnetic heading after FMT. It must have been either a track towards a specific waypoint or a true heading with the NORM/TRUE switch set to TRUE after FMT.
@VictorI
Yes, I would preferre hypoxia any time too when I had no other goal in mind and was forced to fly into the SIO by something or someone.
There’s no indication (yet) the pilot/plane was forced to fly into the SIO.
All indications and circumstantial evidence point to a deliberate choice of actions. All manouvres, sim-data. Nothing similar against those facts.
The point I make is the chance of a flight turning into a ‘ghost flight’ is one in a million. This chance is not a chance to build a case on when there is no actual proof or clear indication for it.
Most long haul flights go without pilot input between getting on altitude and starting the descent. This is not a legitimed criterium I think.
I agree about considering the one in a million possibility.
But why not put more attention to the most obvious?
In my latest paper on the MH370 Drift Analysis, I show how the South Equatorial Current at around 18°S 80°E can be reached from 30°S on the 7th Arc. Reaching the South Equatorial Current is essential, if MH370 Floating Debris is going to reach all 27 locations within the timeframe, where finds have been made.
I also show, by how many months in advance or behind the nominal time of April 2015, the location of all 27 MH370 debris finds can be reached, from Rodrigues to Mozambique, or from Tanzania to South Africa, by only varying the start month from 18°S 80°E from the nominal start month of April 2015 +/- 5 months.
https://www.dropbox.com/s/ma9pt8zf3b0whc7/MH370%20Drift%20Analysis%20-%20Calibration%2C%20Results%20and%20Conclusion.pdf?dl=0
..to correct; ‘when I had another goal in mind..’
@Ge Rijn asked: Maybe a silly question but are all those flight paths till the 7th arc within fuel range (according @DrB’s endurance/range tables)?
First, be careful using the value for the maximum southern latitude after a hold as the assumption is the flight to the south begins at the 18:29 position. In fact, the plane could have flown south before 19:29.
Bobby’s model predicts that there is sufficient fuel endurance for a descent to a one-hour hold at FL210 followed by LRC flight at cruise altitude. This is consistent with the great circle paths reaching 34S and further north, especially if the LRC flight occurred with air packs off, which I estimate results in a fuel flow reduction of 2.5%. As end points further south have already been searched, I’d estimate that any potential impact point along the 7th arc and north of the previous search area would not be excluded based on fuel endurance.
@Ge Rijn
I am thankful we have Victor and Richard offering flight path scenarios closer to my thinking. The avoidance of pilot input scenarios is (1) partially reluctance to “go there” but also (2) gives the models problems as there is no easy way to model that scenario. The lack of finding MH370 at 38S implies that a more complex flight path with pilot inputs is possible, which Victor and Richard pointed out a long time ago in their critique of the ATSB Bayesian model’s assumptions.
Ge Rijn: The probability of a ghost flight may be 1 in a million as you say, but the probability of a suicide flight is far lower. There are approximately 100,000 scheduled commercial flights per day now. There have been 6 cases of a suicide flight on a commercial flight in the last 35 years. That works out to be ~1 in 100 million.
@ALSM
But, we have a solid Bayesian prior with respect to MH370 – the flight went missing. 🙂
In the 35 year period approximately 3000 (85 per year average) commercial flights experienced an accident (not all fatal crashes). So the suicide probability is approximately 6 in 3000 or about 1 in 500.
@Richard: Thank you for sharing your most recent work with us.
If I understand you correctly, you believe there is much more variability in the timing to travel between the 7th arc and the South Equatorial Current (represented by the position 18S, 80E) than there is variability in the path after reaching the current at a particular time.
Your results suggest an impact point along the 7th arc between 27S and 31S latitudes, which is significantly further north than the small search area recommended by Griffin of around 35.6S latitude. I think the main reasons for the discrepancy are:
1) You put more weight on the timing of the discovery of “Roy” in Mossel Bay, South Africa, in December 2015, which moves the impact point well north of 35.6S.
2) Griffin assigns a higher level of confidence to the efficiency of the surface search for latitudes north of 33S.
I’d say that neither the timing of the discovery of the flaperon on Reunion Island nor the lack of debris on Western Australia can discriminate between 35.6S latitude and impact points further north along the 7th arc.
Another observation is that even if we accept CSIRO’s calculations of probability of detection of debris during the surface search (which some do not), there are significant holes in coverage at latitudes north of 33S, especially if the impact was to the northwest of the 7th arc.
Based on this, Ocean Infinity is wise that it is planning to search beyond the 25,000 sq km search area that was prioritized by CSIRO.
@TBill
Yes, also @Victor’s latest tables point to an area between ~29S and ~34S with the smallest (BFO/BTO) errors.
Endurance and range beyond ~34S I read as not very probable from any point at 19:41 according his flight paths.
@Richard has always interesting papers.
@Ge Rijn: Paths with smallest BFO/BTO errors are not necessarily the most likely. Depending on what we expect the BFO error to be, acceptable paths can extend significantly further north than 34S.
I don’t know the exact cut-off latitude for what impact points are not allowed by fuel considerations, as it depends on how the plane was flown before 19:41 and whether or not air packs were on after 19:41. However, I do estimate that latitudes further north than 34S are allowed.
DennisW: Re: Yes, you could say that ~1 in 500 crashes involved a suicide. Either way you crunch the numbers, there is no purely statistical basis to suggest that a suicide was likely involved in MH370. Based on these statistics, the probability is somewhere between 1 in 100 to 1 in 500…either way, very unlikely. That does not rule it out. We certainly know more than historical stat’s.
My point is that the statement:
“…the chance of a flight turning into a ‘ghost flight’ is one in a million.”
… is totally wrong. Given that MH370 did in fact disappear, the odds of a ghost flight or a suicide flight are roughly equal at this point, and together, that covers >90% of the possibilities.
@ALSM
So a straight suicide flight can be excluded I agree.
9/11 were no straight suicide flights also. They had a well thought out purpose and destination.
This was also the case with MH370 I believe.
Or the PIC was interupted in achieving his end goal, or his end goal was a deep trench in the SIO just under Broken Ridge.
Update on November 11, 2017:
In Figure 4 above, I have plotted the paths to the four waypoints (NZSP, YWKS, NZPG, 45S) on the same plot that was generated by CSIRO to show the cumulative probability of detection of low-windage debris by the surface search for various impact points along the arc. The calculated probabilities include the drift that might have occurred between the time and location of the impact and the time and location of the search. It can be seen that there are impact points along the 7th arc and north of 33S where the probability of detection is significantly less than 100%, especially if the impact was to the northwest of the arc.
@ALSM
To add. We only have the Helios flight out of those million flights as an accident without suicidal intentions.
That’s not enough to build any ‘ghost flight’ assumptions on regarding MH370 imo.
Victor- Fig 4 is very good.
If we say the area of most interest is 20-40S, we could calculate the % of Arc7 adequately searched so far. This could help push back on the bogus argument that Arc7 has already been totally searched.
Trying to think if there is some way we could superimpose a drift study fuzzy area from 28-35S to have all 3 indicators (Sat data/Surface debris/drift data) all on one plot.
Ge Rijn: At least 5 ghost flights, not just one…
https://goo.gl/6K7R2E
Victor:
Based on your chart added this morning, the 180 route to NZSP looks like the most likely route, if there was any route selected and the cumulative search data are accurate. It is also very close to the area suggested by CSIRO. Perhaps the first area to be searched should be expanded slightly to cover both areas.
@ALSM: Yes, of the four great circle paths I selected, the NZSP route has the highest probability of non-detection of surface debris. As shown in Figure 3 above, that impact point is part of the 25,000 sq km that will be searched first by Ocean Infinity. However, there are also indicators that points further north are possible. The path crossing the 7th arc at 28.3S latitude and ending at 45S, 104E, for instance, better fits the timing of the discovery of “Roy”, as Richard has shown. Also, as Figure 4 shows, the surface search had a reasonable probability of missing the debris for a 28S crossing if the plane turned and circled back, impacting to the northwest of the arc.
@VictorI,
You said: “As for ground speed, it varies continuously along the path, so I’m not sure whether it is useful to report results only at times we have BTO or BFO data.”
I believe it is not only useful, it is also sufficient to validate all proposed routes with acceptable accuracy. As you well know, it is very much easier to evaluate a route than to generate one.
The “usefulness” of the ground speed is two-fold: (1) it a necessary parameter to compute the BFO at the arcs, and (2) it is necessary to know it along the track to generate (but not necessarily to evaluate) latitude and longitude points along a path. To minimize the amount of data I suggested be provided for any proposed route, including yours, I only asked for values of ground speed at the arcs. Primarily, that allows one to duplicate the BFO calculation as a means of comparison to confirm those results.
I only requested the minimum amount of information that would allow reasonably and sufficiently accurate verification of a proposed route. Anything less than that defeats the purpose of verification. Anything more than creates a lot of work that is generally unnecessary. What I mean is that one can take the ground speeds at the arcs plus the temperature deviations and the altitudes/lats/lons at the arcs, and from them generate a very good estimate of the instantaneous Mach at the arcs and also of the average Mach and average ground speed along a leg. This will be of sufficient accuracy to determine consistency with the satellite data.
You really only need 3 things for verification: a calculator, a weather database for the arc locations and times (wind and temp from NOAA GDAS online, for instance), and a distance calculator (SkyVector, etc.). Since the wind data are of limited accuracy (~6 kts RMS in two directions), small computational air speed and course errors are unimportant since they will be absorbed as a wind error anyway. For this reason, for many parameters, one can use the average of the arc values at the leg ends as an estimate for the (integrated) leg average value, without introducing significant errors.
I was thinking about modifying my posted BTO/BFO calculator to add the calculations of the following parameters:
Both at the arcs and average values for each leg:
Ground speed
Mach
True course
Magnetic course
True heading
Magnetic heading
At the arcs only:
Predicted BTO
Measured BTO
BTO error
Mean BTO error (all arcs)
RMS BTO error (all arcs)
Predicted BFO
Measured BFO
BFO error
Mean BFO error (all arcs)
RMS BFO error (all arcs)
For the leg averages only:
Average database tailwind (for each leg)
Average route tailwind (for each leg)
Tailwind error (for each leg)
RMS tailwind error (all legs)
Average predicted crosswind (for each leg)
Average route crosswind
Crosswind error (for each leg)
RMS crosswind error (all legs)
Initially, one would have to manually enter temperature, wind speed, and wind direction at each arc location from the online database, although eventually I might automate this using the GDAS weather tables. Similarly, perhaps eventually I could integrate my fuel model so that endurance may be simultaneously determined.
Such a tool would allow a larger number of people to evaluate (and perhaps even to generate) routes, both published and unpublished, and provide a standard method for this process. If you provide the data requested, I will create the tool for everybody to use.
@Ge Rijn,
I am surprised by the series of your recent posts. You have kicked yourself into the “whacko” category.
Re: “There is no proof at all even no clear indication the flight went into a ‘ghost flight’ anywhere along it’s route.”
There is strong indication: BTO and BFO data post 19:41 are consistent with the simple modes of the autopilot. Chances of such a coincidence assuming a piloted flight are minimal.
Re: “They rather take the one in a million chance than the obvious statistical normal without any proof to do so.”
Exactly the opposite is true: chances of an actively piloted flight past 19:41 are one in a million: that is because of the “trend line” in the BTO and BFO data.
Re: “Imo out of millions of flights this one was actively piloted from beginning till end also.”
How did you arrive to this nonsense?
Re: “For this reason I think there could have been no NORM magnetic heading after FMT. It must have been either a track towards a specific waypoint or a true heading with the NORM/TRUE switch set to TRUE after FMT.”
Why would NORM be less likely than TRUE? It was in the shadow for long time because there was confusion with regard to whether NORM is used for display or navigation. In addition, the DSTG a priory implicitly eliminated magnetic modes, without conducting a proper fuel analysis. I actually suspect the ATSB knows about the existence of the magnetic mode routes, but they are reluctant to publicly admit this.
So… be realistic.
@DrB: I don’t think that it is prudent to simply average the meteorological conditions at the start and end of the legs to represent the average conditions during the leg. I calculate all parameters at a time resolution of 1 minute (except near ping times where the time step is chosen to match the ping time to the nearest second) and I don’t average.
Here are some more detailed results for the great circle path ending at 45S, 104E. You should be able to replicate these results.
@Ge Rijn
““For this reason I think there could have been no NORM magnetic heading after FMT”
Although I have found a 180S True Heading case I like, that implies there could be 180S Magnetic case I like too. Since I am taking the liberty to pilot the aircraft, I can certainly can and do watch the POS longitude tick off along the way and I can double-click and switch over to True or say 185 when the winds start pushing me East past 94E.
@Victor,
Your Fig. 4 should be treated with great caution as it may give false impression.
CSIRO’s result in background correspond to low-windage objects (1.2%) only. In comparison, the DGA has experimentally found the leeway factors of the flaperon of 2.76% and 3.29% corresponding to the two stable configurations. The latter is close to my theoretical estimates of 3.33% for a thin flat-floating object. I was also involved in some drogue studies, and we estimated the leeway coefficients of 5-6%. So this CSIRO’s particular plot is unlikely representative.
@Oleksandr: I agree with your caution in using Fig 4. However, this is what CSIRO has used to justify that debris should have been detected for an impact along the 7th arc that was further north than 33S latitude. Using their own results, there are significant holes in the coverage, especially for an impact to the northwest of the arc.
@Brock,
I don’t know what you are trying to achieve with your endless requests, but you seem to be off on a tangent, a wild goose chase, with no prospect of ever reaching an end-point.
Just for the record, I am not aware of any IG support for the “acoustic pings”. In fact I dismissed the claims as rubbish [as I think others did too], because the technical evidence could never support such a claim.
You seem to be labouring under the misapprehension that the IG had some direct influence over the official investigation and the decisions made by the ATSB and other official parties directing aspects of the search. Emphatically, the IG had no such influence.
Papers published collectively, and individually, by the IG were all based on publicly available information at the time, and expressed the views of the IG at that time. The papers were produced, always, to provide interpretation and comment in the public domain. Official organisations may have chosen to make use of this work, just as they may have taken into account work done by a number of other commentators and contributors both private and in the public domain.
What “audit”? Your “audit”? No one is interested. Please stop asking dumb questions.
@Victor
I have zero confidence in the CSIRO surface search probability graphic. The S3/S4 search zones (the area of interest for the NZPG path was not even started until 28 March 2014. Furthermore, I have never seen a surface search probability graphic published anywhere else. Where are they getting this stuff? What is the basis for the graphic? Frankly, I think they just made it up.
@DennisW: I think questioning of the probabilities is justified. But even assuming they are correct, there are a lot of holes.
Indonesia.
Some pretty strange things can happen completely unnoticed down there…
http://www.bbc.co.uk/news/world-asia-37997640
@Dennis,
Re: “I have zero confidence in the CSIRO surface search probability graphic.”
I have obtained similar results, so I am confident this CSIRO’s plot is correct. However, I noted ‘dramatic’ dependence of the debris coverage on the leeway factor. At higher leeway factor our models show some discrepancies: I think this is because I used different wind data for forcing.
Re: “Where are they getting this stuff? What is the basis for the graphic?”
Based on coverages. Probabilities assumed to be proportional to the coverages of the modelled ensembles. AMSA provided daily surveyed areas.
Of course, there is a factor of ‘detectability’. I don’t know how AMSA detected debris besides using ‘brutal’ manpower, but say we used Fugro’s LiDAR bathymetric surveys of 0.2 m resolution in 10×10 km areas – I trust floating debris could also be detected using LiDAR or similar technology.
You may also read Garcia et al. “A dynamical systems approach to the surface search for debris associated with the disappearance of flight MH370”, Nonlin. Processes Geophys., 22, pp. 701-712, 2015.
Oleksandr,
Nice find of the Garcia et al article. From the abstract: “Perhaps the most relevant aspect of this mystery is that not a single piece of debris from the aircraft was found during the intensive surface search carried out for roughly 2 months following the crash.” The article was published on July 27, 2015, which happened to be 2 days before Johnny Begue discovered the flaperon on Reunion Island.
@Oleksandr
Interesting reference. Thanks for that.
Of course, there is a factor of ‘detectability’.
That was the basis for my skepticism of the CSIRO probability map. That and the amount of time that passed between the incident and when the areas were searched. No matter. I don’t get the sense that the aerial search is a big factor in future search decision making.
@all
Generally no one likes to look stupid, but I done so many stupid things over the course of my life that are part of the public record that I no longer have any fear of it (although I did refrain from making this post for some time now).
The subject is integrated Doppler. Integrated Doppler is path independent. It is only a function of the end points of the path. A path difference of -1km with a transmit wavelength of 1 meter will produce will produce an integrated Doppler of 1000 cycles. If the time of the path transit is 1000 seconds, the average Doppler will be +1Hz.
So looking at the measured Doppler residuals, that is the difference between the actual aircraft Doppler and the Doppler compensation necessary to produce the measured BFO, one gets an average Doppler residual between IGARI and 00:11 of around 11Hz. If one computes where the integrated Doppler residual is 11Hz based on positions on the 6th ring relative to IGARI, one finds a latitude of about 30S. Of course, all the uncertainties about AES oscillator drift apply.
I will write this up in some detail, but I just wanted to toss it out there for comments.
The geometric algebra solution also homes in on 30S, but I have no explanation for that which is why I took down the link to it. I am still fiddling around with that, but have no clarity as yet. As near as I can tell Gibbs should work just fine. No one on this blog dove into that, and I don’t blame them. The learning curve is steep. (Steeper with the age of the reader.)
The annimated graphics in the supplement to the report are very interesting.
https://www.nonlin-processes-geophys.net/22/701/2015/npg-22-701-2015-supplement.zip
Obtainable on the right – in very small print under the PDF download button for the main report.
https://www.nonlin-processes-geophys.net/22/701/2015/npg-22-701-2015.html
@Ventus45
Interesting article and animations indeed.
Particulary interesting I find the 6 drifters in the 32S ‘above Broken Ridge’ animations are not moving to the east towards Australia.
Actualy the two closest to the 7th arc move to the west and north-west. The others stay more or less stationary during the period.
None show tendency to drift towards Australia.
It’s a pity there is no animation of the area between ~36S and 32S.
This would possibly show CSIRO/Griffin’s narrow drift-flow to the west and east around 35S where they based his latest priority area on.
Then finaly in their conclusions they suggest also other areas should have been search and some could have been avoided without naming specific areas. That’s a piy too imo.
..a pity too..
@DennisW @all
Straw man to develop realistic/approximate expectations for future OI bottom search.
Prelim. Assumptions/Guesstimates:
95% Chance MH370 is between 20-40S +- 200 nm of Arc7
90% Chance MH370 is between 20-40S +- 60 nm of Arc7
80% Chance MH370 is between 20-40S +- 30 nm of Arc7
15% Chance MH370 is Unfindable due to Undersea Mountains/Trenches/etc.
Results derived from the above assumptions:
20% of Arc7 searched to date between 20-40S +-30 nm of Arc7
68% Chance of finding MH370 between 20-40S +- 30 nm of Arc7
77% Chance of finding MH370 between 20-40S +- 60 nm of Arc7
5% Chance finding MH370 outside of 20-40S
10% Chance finding MH370 between 20-40S but further away than +-60 nm
Less than 68% chance finding MH370 in CSIRO next 25000 km search area
@Oleksandr: I briefly looked at your CMH results at various altitudes. Are you sure you are properly calculating BTO errors? I looked at a couple of points and my calculated errors were about twice yours.
@All: I will repeat my question. After the first 25,000 sq km is searched, where should OI search next? Please provide the logic that supports your answer.
Have we come full circle back to Inmarsat’s original prediction?
http://www.bbc.co.uk/news/science-environment-27870467
@Victor
For OI
> In general, cover Arc7 +- approx 30 km2 between 20-40S
> Priority to 180S paths which extends East to 32S very difficult area, but please try. I feel ATSB says below 32.5S just to avoid the BR area. Some feel MH370 may have turned east at the end, and some feel BR was the target, so that could possibly be a 180S flight path outcome.
> Priority to McMurdo option
Correction above +-30 nm of Arc7
@Victor,
Possible sources of discrepancy:
1. Do you compute round-trip error, or single-way error (i.e. distance error divided by the speed of light)? My table depicted the latter.
2. ECEF coordinates of the satellite. We are likely using different interpolations. I will post what I am using if not #1 or #3.
3. Geographis system: I am using WGS’84 geocentric lon, lat and geodetic altitude.
@VictorI
All proof and indications are the flight was actively and well planned piloted at least till 18:28. There is no proof, no clear indication and no reason why the plane wasn’t anymore without active pilot control somewhere after this point.
Therefore we have to assume the most logical; the plane was actively piloted till the end. Which would imply a specific end-destination in the SIO imo. The SIM-data also clearly suggest a flight and end-of-flight scenario was rehearsed with fuel exhaustion.
There are no specific features between ~26S and 40S that could serve as a specific end-destination with a specific purpose but only Broken Ridge and its deep trenches just under ~32S to hide the plane and evidence as best as possible.
The debris shows it could not have been a vertical or near vertical high speed nose-down impact. It must have been a nose-up impact with relatively low horizontal and vertical speed.
A phugoïd, a A447 impact, or a controlled glide.
Considering all I still opt for the area between ~33.5S and 32S in the trenches west and east of the 7th arc between ~95S and ~96S.
correction; between ~95E and ~97E..
@Oleksandr: I report my results using WGS84 geodetic latitudes. To be consistent with others here, you should, too. But that is not the main source of the discrepancy, as I suspected.
The BTO is the round trip latency adjusted by a constant offset. As such, BTO errors are twice the aircraft-to-satellite latency (range) error, and the reported BTO error statistics (such as the 29 μs standard deviation for R1200 signals) have been calculated on that basis. Your BTO errors are actually twice what you show in the tables, and your magnetic heading paths exhibit unacceptably high BTO errors.
@ulric,
You said: “Have we come full circle back to Inmarsat’s original prediction?”
My answer is: “Sort of.” I make the following points:
1. Inmarsat’s JoN article presented the first technical solution to match the BTOs/BFOs. I admire what they did back then with the little data and knowledge they had at hand, and I think they mostly got it right.
2. Their proposed route had two major shortcomings which hampered its acceptance by others: (a) there was no connection to causality (still a concern today), and (b) the small turns needed to match the satellite data did not match expectations for either actively piloted flight or for auto-piloted flight.
3. A minor criticism is that it basically ignored endurance (but, to be fair, no one at Inmarsat was expert in the FMC navigation modes nor in B777 fuel modeling).
4. A number of contributors to this blog have continued to search for acceptable routes for the past 3+ years.
5. Some of the proposed solutions are quite different from Inmarsat’s solution (for instance, Victor’s great circles to Antarctica).
6. A very few routes are quite similar to Inmarsat’s. HERE . is a comparison of the Inmarsat route with the CTH/CMT route I proposed last January.
7. The major problem I have with Inmarsat’s route is the arbitrariness of the course and speed changes. It includes 7 degrees of course changes and a 4% step increase in speed after 19:41.
8. The seemingly random changes in course are odd. Why would a pilot make changes in course of only several degrees? How could an auto-pilot fly such a route (without adding numerous waypoints, and how in that case could they possibly be coincident with the Arc locations?)?
9. An auto-piloted, non-LNAV route matching the satellite data is possible, as I have shown, but it curves more eastward late in the flight and hits the 7th Arc farther north than Inmarsat’s prediction.
@Ge Rijn: I think what you are proposing is that we accept the validity of the 7th arc, we don’t try to reconstruct paths since you believe the plane was actively piloted, and just assume the pilot was trying to reach Broken Ridge, so search there.
@VictorI
No, I did not and do not think that way at all. You asked again; where should OI search next. I again repeat my view considering all I can, that’s all.
@DrB: I must have missed something. The CTH route you proposed in January is based on overflying a waypoint after a route discontinuity. However, we now know that this would result in a CMH route. A CTH route would require pilot input, which should equally permit any other navigational mode and setting.
Do you have any suggestions on where to search if the initial 25,000 sq km does not find the plane?
@Ge Rijn: Yes, thank you for answering the question.
@Victor,
Re: “The BTO is the round trip latency adjusted by a constant offset. As such, BTO errors are twice the aircraft-to-satellite latency (range) error, and the reported BTO error statistics (such as the 29 μs standard deviation for R1200 signals) have been calculated on that basis. Your BTO errors are actually twice what you show in the tables, and your magnetic heading paths exhibit unacceptably high BTO errors.”
I agree with the first part. Yes, BTOs represent round trip, so the shown BTO errors should actually be doubled. I’ve just switched to the commonly used time metrics instead of distance-equivalent, so thanks for catching up this issue.
However, I disagree with your assessment that BTO errors are unacceptably large.
Firstly, 29 μs standard deviation is not the the limit of acceptance. Do you remember ATSB’s analysis:
http://www.atsb.gov.au/media/5187038/mh370_burst_timing_offset_dec2014.pdf
Secondly, lower paths are characterised by notably smaller errors, presumably due to wind. They are inconsistent with fuel range, but you need to keep in mind the sensitivity of BTO to radial wind component and possible errors in wind data.
Thirdly, this was only “CMH feasibility screening”. Other weighting coefficients, magnetic declination corresponding to 2005, other speed mode, may somewhat alter this result. So I think your conclusion with regard to this sort of CMH is premature.
@Ge Rijn,
What is your consideration if it were known only that the debris part, found at St André on the coast of La Réunion, was simply a buoyant part of 9M-MRO? Or indeed, that any debris fragment is regarded as simply a buoyant fragment of 9M-MRO.
Just trying to simplify the problem.
@All: I will repeat my question. After the first 25,000 sq km is searched, where should OI search next? Please provide the logic that supports your answer.
My first choice would be where the 45S 104E path crosses the 7th arc (~terminus 28.3S 99.6E). I would not start with the CSIRO 25,000 sq km area.
1> terminus agrees with known simulator data
2> terminus fits Richard’s debris study
3> terminus is compatible with a loiter and late FMT (~6N at 19:41)
4> terminus is compatible with fuel range
5> ISAT data fit is acceptable
@Oleksandr: I evaluated your paths based on the BTO errors, and they are not acceptable as the RMS errors are much higher than the standard deviation of the population. If you want to alter your magnetic paths by including uncertainty in the winds or by using different declination tables, that’s fine. When you are ready to propose new paths, please let us know.
@DennisW: Thank you for your answer.
@TBill: Thank you for your suggestion.
@VictorI,
I don’t think you missed anything. I should have been more explicit.
There are three current possibilities for auto-piloted flight into the SIO that have been shown to be fairly close to matching the satellite data (I won’t quibble right now over how close that match has to be, but your range of acceptability is larger than mine with respect to BFO errors):
1. LNAV to far south waypoints (possibly 3, as you and Richard have proposed),
2. A CTH route (possibly after a route discontinuity), which requires the NORM/TRUE switch to be set to TRUE (my 9 January 2017 CTH route in “Possible MH370 Route”), and
3. A CMT route at, which I demonstrated in “Update on MH370 Route Fitting Results” on 2 January 2017. This route has 33 microsec BTO errors, 4 Hz RMS BFO errors, and 4 kts RMS tailwind errors.
A number of us identified early on some high-speed straight paths ending far south in the area already searched. I think those may now be put aside. As far as I know, there are no other acceptable solutions to date, besides the 3 listed above.
I am working toward refining my 7th Arc prediction(s). I have gotten some very interesting results in a new and more refined analysis of the 18:25-18:28 BFOs after removing the OCXO transient errors from this entire data set, instead of only using the 18:28 BFOs for route fitting and ignoring the 18:25-18:27 BFOs, as we have done so far. I expect to post this work on possible 18:22-18:41 paths in the next few days. Then I’ll address the 18:41 to 00:11 route fitting again.
@Victor
Many thanks for the plot of LNAV Flight Paths vs the AMSA Aerial Search coverage.
The aerial search flight paths were initially 0.25° of latitude apart, which is 27.8 km in the case of the RNZAF sorties starting at 32.5°S 98°E on 28th March 2014.
In my view, it is not possible to deem an area 100% searched, when you are flying at 230 knots and 600 feet above the ocean and have to look 13.9 km either side of the aircraft.
For this reason, the aerial search flight paths were narrowed to 0.125° of latitude, later in the search.
In any case, the crew of the RNZAF sorties believe they saw debris fields.
Even if we accept, that certain areas were searched 100%, were all these areas empty of MH370 Floating Debris?
Here is one example of a debris field:
https://www.dropbox.com/s/iaeigij8bv69d21/2014-03-31_045309_U_14-005860%20Debris%20Field.jpg?dl=0
Then there was the so called “Flaperon”:
https://www.dropbox.com/s/4fhsydpeq60sv4h/2014-03-28_040738_U_14-005809%20Flaperon.jpg?dl=0
and as picked up on the RNZAF operations screen:
https://www.dropbox.com/s/g87m82gqexfi402/RNZAF%20Object%20Screen%20Shot%2028032014%20041324%20Tony%20Cheng.jpg?dl=0
Was this a suitcase?
https://www.dropbox.com/s/3jdlt3qh1ndq79s/2014-03-29_075242_U_14-005833%20Suitcase.jpg?dl=0
Was this a cargo tray?
https://www.dropbox.com/s/r9a9c2x4nokwo80/2014-03-29_092033_U_14-005854%20White%20Box.jpg?dl=0
Was this some aircraft part with wiring hanging off?
https://www.dropbox.com/s/gvug15m775n1g16/2014-03-29_085848_U_14-005848%20Part%20with%20Wiring.jpg?dl=0
Maybe, MH370 floating debris was seen, but incorrectly discounted as fishing debris or something else thrown overboard from a passing ship.
Victor:
Have you attempted to work backwards with any scenarios? For example, selecting start locations on the 7th Arc and flying back to KLIA? Or to the Banda Aceh area where many feel the plane turned south?
I’ve experimented with drift that way. For example, to find out how much of it hits Australia at various locations along the 7th Arc. In one degree of latitude increments. Suggests there is a point beyond which we would have had lots of debris on Australia.
I’m working with a pilot group that suspects the flaps were partially extended at or near Penang, and left extended for the duration. They believe that would have put the plane down somewhere between Batavia and Wharton Basin. Fuel exhausted just as in zombie scenarios.
Mike
@DrB said: 1. LNAV to far south waypoints (possibly 3, as you and Richard have proposed)
First, we are up to 4 paths that align with a distant waypoint, as I think the path to 45S,104E is an important one to consider. In some ways, it is more likely than the paths to Antarctic runways.
But even if we only allow integral latitude/longitude coordinates as possible waypoints past the 7th arc, the number of paths becomes much larger.
Plus, a large range of true track paths is possible. For tracks in the range of 162° to 180°, there are 19 possible tracks that a pilot could have selected.
Since we know that Ocean Infinity plans to begin the search with the 25,000 sq km that was recommended by CSIRO, it is important to identify possible paths that cross the 7th arc north of 32.6S. Do you have any to share?
@Richard: Yes, I think it is very fair to question the search probabilities that CSIRO has calculated.
@Mike Chillit asked: Have you attempted to work backwards with any scenarios?
The calculations are deterministic. It doesn’t matter which direction the simulations run. Choosing to go forward in time is only a matter of convention and convenience.
I’m working with a pilot group that suspects the flaps were partially extended at or near Penang, and left extended for the duration.
If they are B777 pilots, they would know that
1) flaps can’t be extended at altitudes higher than 20,000 ft
2) the placard speed for flaps-1 is 255 KIAS for the 777-200ER
3) there would be a large reduction in fuel endurance
There is little chance the flaps were extended at Penang and remained extended. The speed, altitude, and endurance would not allow it.
@Mike Chillit
A ground speed near 500kts is required to reconcile the timing of the cell phone registration with the 18:25 range ring. That would not be possible with the flaps extended. It is a non-starter, IMO.
Victor,
You ask, “After the first 25,000 sq km is searched, where should OI search next?”
I have never recommended where anyone should search. However, for the first time, I am going to recommend where anyone should NOT search, and that is the first 25,000 sq km.
Why? Because. up to now, none of the flight path analyses from the JIT/ATSB/whatever (including the DSTG “book”) have ever been subject to a proper external peer review, and such review is now way overdue. It is more than clear now that blunders have been made in the past, and the problem is not that blunders are made (this stuff is hard!) but that there is no clear process to find and correct them (that’s where peer review comes in), and in fact, it is as if there were a deliberate attempt to hide them.
Case in point. My current focus is on Figures 2 and 3 from the Nov 2014 “Flight Path Analysis Update”, where MRC flight paths and endurance limits are shown under a range of assumptions. Perfect place to test a fuel model. However, we encounter the following:
“The MRC (maximum range cruise) performance was calculated for a turn shortly after the last radar contact near the 1st arc (1828) and at the time of the 1st telephone call (1840). These scenarios were used to estimate the MRC boundary as they represented an early turn and a late turn.”
What coordinates were used at the times of the turns? E.G., IGOGU for the 18:40 turn? This lack of specificity has permeated the ATSB and other reports since the beginning of this event, and makes any reliable independent reconstruction of what was calculated impossible.
It is easy to throw darts at a map of the SIO, and that seems to be what most respondees to your question are doing. By chance, one of them is bound to land on the wreckage of MH370. How to figure out which one it is?
@Richard – you said @ November 12, 2017 at 6:13 pm
“Many thanks for the plot of LNAV Flight Paths vs the AMSA Aerial Search coverage. The aerial search flight paths were initially 0.25° of latitude apart, which is 27.8 km in the case of the RNZAF sorties starting at 32.5°S 98°E on 28th March 2014. In my view, it is not possible to deem an area 100% searched, when you are flying at 230 knots and 600 feet above the ocean and have to look 13.9 km either side of the aircraft. For this reason, the aerial search flight paths were narrowed to 0.125° of latitude, later in the search. In any case, the crew of the RNZAF sorties believe they saw debris fields. Even if we accept, that certain areas were searched 100%, were all these areas empty of MH370 Floating Debris ?”
We may have to totally re-evaluate the effectiveness of the air search, downwards.
Having just consulted the tables at pages 287 and 288 of the AMSA SAR MANUAL – in hindsight, I think it would have been a miracle to spot small debris at 230 knots and 600 feet much more than a kilometre from the aircraft. The search track spacing must have been determined on the basis of expecting to find large pieces of debris, or life rafts, which had spead out in the days between 8th March and the air search. It was a SAR mission at that stage. They were probably driven by finding rafts to rescue people (hopefully), and were not looking for small pieces of composite materials, as such.
@ventus45
Re: “We may have to totally re-evaluate the effectiveness of the air search, downwards.
Having just consulted the tables at pages 287 and 288 of the AMSA SAR MANUAL – in hindsight, I think it would have been a miracle to spot small debris at 230 knots and 600 feet much more than a kilometre from the aircraft.”
Bear in mind that the tables in the AMSA manual relate to visual searches over water. Military aircraft such as the P-3 Orion and P-8 Poseidon that were used in the MH370 surface search have a variety of sensors that are capable of detecting objects in the water at a much greater range than is possible with the human eye. I would assume the search pattern width was based on the capabilities of those systems.
@Richard,
There are a number of RNZAF photos of interesting flotsam [debris], in areas that may now be much more significant. Unfortunately none was ever recovered.
For example, there are a number of photographs of scattered fragments like this . .
https://www.dropbox.com/s/b58n9yvroqcfnok/2014-03-29_U_14-005832.jpg?dl=0
And this piece is interesting, and very different from other examples of “fishing debris” . . .
https://www.dropbox.com/s/907vq2gql2a17vi/2014-03-29_U_14-005849.jpg?dl=0
@Don Thompson
On your comment;
‘What is your consideration if it were known only that the debris part, found at St André on the coast of La Réunion, was simply a buoyant part of 9M-MRO? Or indeed, that any debris fragment is regarded as simply a buoyant fragment of 9M-MRO. Just trying to simplify the problem.’
The question contains a contradictio in terminis and is so far besides reality that it’s not relavant to consider imo.
If all pieces were identified/known as 9M-MRO but not identifiable as specific parts from the plane (which is the contradictio) the problem would be even more complex. It would be a completely different situation in many aspects I choose not to bother with.
Maybe I don’t understand your question well enough and you could be more specific?
@Richard @Brian Anderson
Do you have the lat/long coördinates on each specific debris-picture you showed?
It would be helpfull to put them in context that way.
@Ventus45. Interesting find thank you.
About the CSIRO report part 4, I note that they could not come to a conclusion as to probability of detection except by estimating debris field spread, this increasing the prospects of a find, visually or by radar. The outcome was that the prospects of “at least one” being spotted were “very high”.
Even so, at the end they say that more work “may be worth doing”, including, “field measurements of the radar detection ranges of example pieces of debris….”
That the CSIRO mentions a need for this suggests search widths were set by the assets available and the need for speed. Though the SAR phase had concluded on 25th March there would be a toss-up between debris search thoroughness and the increasing uncertainties arising from drift and dispersion. The need for establishing the capabilities of the various radars in detecting low and flat-in-the-water debris amongst waves/wavelets, much of it without much metal, might have been too delaying and of course there was no knowledge then of debris size.
However the outcome of that now could have a major effect on the quantity of radar reflective or visibility debris the CSIRO has assumed in its probability assessment. Until there is some sort of quantitative assessment the value of the search results and the CSIRO’s part 4 remain in question.
@ventus45, @Andrew
The AMSA National SAR Manual is a useful resource. It has been confirmed to me that radar wasn’t an effective tool in the surface search.
@Ge Rijn.
1) Location for images: exiftool is your friend.
2) “Maybe I don’t understand your question well enough and you could be more specific?”
Try to put aside the confusing and misleading speculation concerning the state of the high lift control system.
@Richard,
@Brian,
Do you have coordinates of these debris and a more or less formal reference to the source? AMSA has mentioned debris in their reports, but I’ve not found a properly documented photographs with locations.
The location of the rectangular object I am aware of (I think posted by Brian long time ago) is consistent with my drift study, origins approximately between 29S and 30S, but for low-windage objects (not the flaperon). I am interested in comparing with the locations of other photographed objects.
@Don Thompson
‘Try to put aside the confusing and misleading speculation concerning the state of the high lift control system.’
This is impossible to do. You ask me to put aside one of the most striking facts about the found debris.
The fast majority of it is directly or indirectly related to the high lift control system and the engines which are in a way also high lift control systems. Two of those pieces were relatively speaking undamaged.
Imagening your suggestion ofcourse would be more indicative of a high speed nose down impact. Reality of the found debris shows a different picture. This is the reality we have to deal with.
Not a hypothetical one like you suggest.
It might be confusing to speculate about but I object it is misleading to do so. To follow your suggestion would be denial imo. And that never brings a solution to anything.
I don’t insist on a ditch-like impact to explain the debris. I only think it’s still the most logical explanation considering all the available evidence/indications on them.
If it gets proven one of the high lift pieces (particularry the flaperon and outboard flap section) seperated by flutter or other excesive (aerodynamic) loads before impact that would be fine with me the same.
I would welcome such proof.
But this evidence is not there yet or not made public.
As long this is not available, speculation and interpretation is on others (like us). And this is important. Confusing or not.
The whole case is still confusing. No reason to deny things though.
@DennisW said: I will write this [thoughts about the integrated Doppler residual] up in some detail, but I just wanted to toss it out there for comments.
I agree that the integrated Doppler shift between two points in time and space is independent of the path. The Doppler shift represents the rate of change of range, so the integrated Doppler shift is simply the change in range.
The Doppler residual is a bit different. It is the difference between the actual Doppler shift and the Doppler shift to the nominal satellite, which is geostationary. If you integrate each term separately over a path, one term represents the change in range and the other term represents the change in range to the nominal satellite.
If we start our integration at a known position in time, we know the range and the nominal range. Now using the BTO, we know what the change in range is, and we can determine the range and nominal range at the end point. We now have two ranges from two satellite positions (actual and nominal), and the aircraft position is where both ranges are satisfied. There are two solutions (one to the east and one to the west of the subsatellite position), and we reject one (the one to the west) based on the requirement of continuity of position from the known starting position.
This technique was first proposed by Henrik years ago, and I believe @Niels uses a version of this.
However, in order to use this technique, we need to know the residual Doppler from the start point to the end point. The BFO data is sparse, so assumptions must be made between data points. On top of this, even when there is data, there is sufficient uncertainty in the actual Doppler residual due to noise and drift that a range of solutions are possible.
In summary, I don’t see how you can use this technique to uniquely determine the end point, but I am willing to be persuaded otherwise.
@Victor
If you integrate each term separately over a path, one term represents the change in range and the other term represents the change in range to the nominal satellite.
That is fundamentally what I have been trying. The sensitivity to noise (AES drift) is very high (on the order of several degrees in latitude per Hz). You have to assume virtually perfect frequency stability which is simply not realistic. At this moment I do not think it is going to work out.
@DennisW: One other point. You said: So looking at the measured Doppler residuals, that is the difference between the actual aircraft Doppler and the Doppler compensation necessary to produce the measured BFO, one gets an average Doppler residual between IGARI and 00:11 of around 11Hz.
The mean value of the residual can’t be determined from only the start and end values, as it is path dependent. However, for a given start and end position, the mean value of the residual is independent of the path.
@sk999
“It is easy to throw darts at a map of the SIO, and that seems to be what most respondees to your question are doing.”
Fair point, but in previous posts I have voiced my preference for less constrained Bayesian models (less “garbage-in” assumptions telling the model what somebody thinks happened). Both Victor and I have speculated that an unconstrained model would probably just say the crash is somewhere on Arc7, but of course it would be better to model it, and not speculate.
In the lack of official model results, I am in support of ATSB 25000-km2 (I would expand to 32S Broken Ridge area) because within my own limited capabilities, I do think 180S paths fit the data well, and also I can envision a target (getting over Broken Ridge) and also I can fly that route in MS Flight Sim – it is easy to look at lat/long position to make sure you are going down around 93-94E. McMurdo is my 2nd fav path. Basically I said they should just do Arc7, but if they want to hop around to “hot spots” I am open to that.
@Brian Anderson
As regards to your Flotsam comment (last link) earlier. Not sure if you got the email I asked to be forwarded to you back in May as regards to this https://www.dropbox.com/s/nhx38k3liit3tse/Photo%2013-11-2017%2C%2014%2056%2036.png?dl=0
I know this is probably nothing interesting or of use and is as vague of finding an explanation for other images shown, but I’d thought I’d share with you anyway, as you mentioned about this particular flotsam piece earlier today.
@Oleksandr
You asked the same question as I on coördinates of the debris pictures.
Exiftools don’t show them on my computer. Does yours?
You also put me in the ‘whacko’ category considering CMH routes.
Please read more carefull before you leap on this.
You don’t consider @DrB a ‘whacko’ too I guess?
@Oleksandr
By the way.. the term ‘whacko’ is undeniable resevered to @DennisW who introduced it by means of disagreement and projection of inflated ego responses back then imo.
I take those terms with a smile now.
@Victor
The mean value of the residual can’t be determined from only the start and end values, as it is path dependent. However, for a given start and end position, the mean value of the residual is independent of the path.
I was struggling with your comment until I realized that the 00:11 residual and 17:07 residual differ by the close to the amount I mentioned. That is a pure coincidence. What I actually did was a block fit to the chain of residual values and manually integrated it. I did not merely subtract the starting and ending values of residual.
@DennisW: In order to do that integration of the Doppler residual, you had to assume a particular path between 18:25 and 19:41. Neglecting BFO uncertainty, the path you chose will determine the position at 00:11. Essentially, assuming a perfect continuous fit of the BTO and BFO data between 19:41 and 00:11, and no uncertainty assigned to either, the latitude at 19:41 determines the latitude at 00:11. But we don’t know the latitude at 19:41, and the BTO and BFO measurements have errors.
@VictorI,
Your criteriaon for acceptability of BFO errors is much larger than mine. Your fit to 45S 104E has a mean BFO error of -6.2 Hz and a RMS of 6.6 Hz. Using the Inmarsat criterion of +/- 7 Hz, as I do, this route is not acceptable. Many/most of the other routes you suggested are in the same category. I think the only one of those that perhaps has BFO errors meeting the Inmarsat BFO criterion is the one at 180 degrees, which may not necessarily have used NZSP in LNAV. That is essentially the Inmarsat route from September 2014.
Ocean Infinity will decide where to search, and I expect their strategy will be priority-based, even within the new ATSB-recommended search area. That prioritization process will also be ongoing, and it could change even after the search has begun (if indeed it does begin). It now seems that Malaysia wants to complete their negotiation with Ocean Infinity, but most likely not sign a contract, before meeting with China and Australia.
I will make a recommendation to Ocean Infinity and to ATSB when I have completed the process I began last spring of creating and using accurate models for all the processes need to generate and to assess the full range of auto-piloted routes. Using the more stringent BFO error criterion, I think there will only be about three solutions.
@Victor
I just weighted my eight computed residual values at 17:07, 18:25, 19:41, 20:40, 21:40, 22:40, 23:15, 00:11.
I agree with your comments regarding measurement errors, and more importantly AES oscillator drift. I was merely looking for another way to estimate 00:11 latitude.
For what it is worth, the weighted integration came to ~11 Hz.
The table of values associated with sampled endpoints on the 00:11 arc relative to IGARI is listed below.
18S – 8.04Hz
22S – 9.04Hz
26S – 10.0Hz
30S – 10.92Hz
34S – 11.79Hz
38S – 12.78Hz
4 degrees of variation per Hz!!
Hence, my conclusion that 30S was the closest fit to a wildly simplistic (and most likely meaningless) analysis. I told you I was not afraid of being embarrassed. To my credit I did not use this information in my list of reasons for picking the 45S 104E path. Likewise, I did not use any geometric algebra arguments (which I still don’t understand completely) which also seem to provide weak support for 30S (and a 19:41 latitude of 6N).
I am fishing, obviously. But as I am fond of saying “even a blind squirrel finds an acorn once in awhile”. Unless you explore the edges you won’t know what you will find there. So far, I have found nothing of additional value.
@Oleksandr @Ge Rijn
Brian obtained 183 Photos under a FOI from the RNZAF in New Zealand.
Unfortunately only 121 pictures contained latitude and longitude, so only one picture we showed here has position data attached. But all pictures have date and time data.
Picture data for the area of interest with Date and Time as well as Position where given:
https://www.dropbox.com/s/4kuqn4ctavc137p/RNZAF%20Image%20Catalogue.xlsx?dl=0
List of all pictures with Position where given:
https://www.dropbox.com/s/e48hk462ihdpe2u/RNZAF%20Image%20Catalogue%20Position%20Data.xlsx?dl=0
The coordinates for the two images I posted are:
…….5832 28.3927S, 97.775E
…….5849 28.8866S, 96.0844E
Note also that both images were photographed on 29 March 2014.
@ Joseph, Yes, I remember the email, but I couldn’t reconcile the satellite image with the piece of debris in the water. I have little faith in the validity of any of the satellite images that I have seen.
@DrB: I commend you for your hard work, but your criteria for BFO error and no pilot input starting with a time before 18:40 is unlikely to produce paths that terminate outside of the priority search area of 25,000 sq km. That will certainly be the first area searched. (I base this on discussions I’ve had with knowledgeable people, not the nonsense I read in the press.) Figure 3 above is my best estimate of where within the priority search area the plane might be found, and that’s based on a route (BEDAX-SouthPole [180°S]) that I proposed in July 2014. Either the plane will be found in that area or it will not. If it is not, OI will need to plan where to search next. I think there is a significant probability it will not be found in the priority search area. My observations about paths ending north of 32.6S latitude are made in that light.
@Brian Anderson
Thanks for co-ordinates. The blurry depiction on the image in the link I provided wasn’t from any satellite image it was simply rotated and cropped from the top shape in the image showing the flotsam shown here; [link removed due to malware] which I presume is the same flotsam as shown for image snapped on the 29th March 2014 (could be wrong). I’m not asking for explanation to be drawn from this because there is none. Just thought I’d share with you. Apologies for time wasting.
I suppose it’s true not to have much faith in satellite images, there’s no concrete proof of what they show.
@Joseph Coleman: That link has re-direction malware. I removed the link.
Liow: there is no particular hurry.
Apparently not. Basic questions unanswered; “What kind of wreckage to find? If there’s a fee, how much is it asking for?”
https://www.thestar.com.my/news/nation/2017/11/13/liow-ministry-will-have-to-negotiate-with-us-firm-first-on-mh370-search/
@David: I ignore most of the statements coming out of Putrajaya as the statements are usually wrong and often self-contradicting. For instance, first we heard that Malaysia could not move forward with OI without consent from Australia and China. Now we hear that talks can’t begin with Australia and China until Malaysia finalizes an agreement with OI. But don’t worry because there is a lot of time between now and January, as if preparations for a subsea search require zero time and a ship can instantaneously be transported to the SIO from offshore the east coast of the US. Public statements are meant for public consumption and often bear little resemblance to reality. All that I know behind the scenes suggest that negotiations will soon be finalized. Of course, the PM could simply cancel the whole thing, so there is that unknown.
My pilot group flies a range of Boeing a/c, including 777.
The central issue for me is that most of the analyses I’ve seen put the plane south of Broken Ridge. Is it generally accepted on this forum that it could not possibly have gone down anywhere else on the 7th Arc?
@Mike Chillit said: My pilot group flies a range of Boeing a/c, including 777
Then you should ask your pilot group how flaps can be lowered at FL340, M0.84, and 498 KTAS, which we believe were the approximate conditions near Penang. I already told you the placard speed at flaps-1 and the maximum altitude of 20,000 ft for deploying flaps.
In this blog, we deal with facts, not fantasy. If they have facts which refute what we believe to be true, please present it.
The central issue for me is that most of the analyses I’ve seen put the plane south of Broken Ridge.
Did you read my post above? I accept the possibility of an impact as far north as 26.9S latitude.
@Richard,
@Brian,
Thanks for this info. Would you be able to share a complete set images, which have coordinates?
Previously I had only coordinates of the rectangular object shared by Barry Carlson (32°31’S 097°57’E) at JW site. Its location on 20140328 matches my modeled ensemble originated from 30S, but for low-windage objects.
The image of small scattered objects may correspond to my screened origin at 28.8S.
The suitcase image looks to me like a barrel, btw.
@Ge Rijn,
Re: “By the way.. the term ‘whacko’ is undeniable resevered to @DennisW ”
I hope he does not mind if I apply this term to those, who suggest something apparently wrong without any justification. I mean you statement that the plane was actively piloted to the end. It does not have any basis, right?
@Brian Anderson
Screen shots From removed “redirection malware link”
https://www.dropbox.com/sh/8123pwd80jtedtg/AAC8JugB5IlzHjgb0Ru59n9Fa?dl=0
@Victor,
You wrote to @Mike Chillit:
“Then you should ask your pilot group how flaps can be lowered at FL340, M0.84, and 498 KTAS, which we believe were the approximate conditions near Penang.”
I don’t want to be involved into your arguing about flaps, but I should note that the IG is famous for mixing up assumptions and facts. For example, where did you get it that the plane was at FL340 near Penang? On contrary, the cellphone connection and gaps in the radar data suggests that the plane was at a significantly lower altitude.
@sk999,
Re: “It is easy to throw darts at a map of the SIO, and that seems to be what most respondees to your question are doing.”
Well said. We are yet to see a path, which would be well justified logic-wise and data-wise. For now it really looks like throwing darts at a map of the SIO.
But I also agree with Dennis. If I were up to give a formal recommendation at this stage, I would certainly recommend NOT to start from CSIRO’s 25,000 sq km area; 28.3 is a lot more promising area, though for other reasons, not listed by @Dennis.
@Oleksandr: The cell phone connection could occur at FL340. We’ve (really Mike Exner) shown this based on a link margin analysis.
But let’s suppose we don’t know the altitude. The military radar data (which doesn’t have gaps near Penang if you read the RMP report) says the ground speeds are in excess of 500 kn. Let’s ignore the light winds and take the true air speed to be 500 kn. To lower the flaps, the plane has to be at 20,000 ft or less. Let’s assume it’s at 20,000 ft. The indicated air speed at 20,000 ft, 500 KTAS, and ISA+13K is 370 kn (!). Besides being way above Vmo = 330 KIAS, the flaps won’t lower due to “load relief”, which protects the integrity of the flaps. If they did lower somehow due to a malfunction, they would be surely torn off at this air speed.
The only way the flaps could have lowered would be if we reject the speed derived from the radar data. However, considering the cell phone connection at Penang confirms the radar data, that is very unlikely.
I’d like to hear what the pilot group says in their own words.
@Victor. “All that I know behind the scenes suggest that negotiations will soon be finalized”. Good. The apparent false trails (eg tripartite involvement at this stage; and aiming to reduce from 25,000 sq km to 5000) do not help much with confidence.
Then there is the other side. I imagine OI will have a good idea of where the marginal return of reward prospects’ line crosses marginal search costs/sq km. As I understand it they are looking for where that point might come in extensions beyond 25,000 since they seem to be seeking search ideas still. As to costs they will need to be clear on expected search rate to allow conversion of $/day to $/sq km.
Then there will be seasonal limitations. Interesting times.
@Victor,
Firstly, I concur with your earlier post that the flaps could not remain extended till the end of flight due to the reasons you listed. In this context it does not matter if the flaps were extended or not near Penang.
Secondly, I only object your statement that the plane was at FL340, M0.84, and 498 KTAS near Penang. What side of Penang? Formally, there are only a few ‘blips’ near Penang, recorded by unknown radar. Do you really believe that the Butterworth radar would not detect a large aircraft flying at a cruise altitude at a cruise speed 60 nm (or so) away? And that it would not be able to derive its altitude at such a distance?
Thirdly, this is in my understanding that the cellphone connection at FL340 is a very unlikely event.
Fourthly, the DSTG has suggested slowdown before and after Penang based on their own analysis (Fig. 4.2).
Fifthly, Vmo = 330 KIAS can be exceeded during descent. Of course, subject to a pilot’s ‘wish’ to ignore OVERSPEED message.
And finally, there were initial reports suggesting altitude drops, which were later discarded as unreliable.
In summary, I believe descent near Penang is a lot more likely than the constant altitude assumption.
@Oleksandr
The fact remains that in order to travel from the location of the cell phone registration to the 18:25 ring requires a ground speed of 500kts +/-. I do not believe this is possible with the flaps extended.
@Oleksandr said:
Formally, there are only a few ‘blips’ near Penang, recorded by unknown radar.
Did you bother to read the RMP report regarding radar captures near Penang? There were more than a few blips. Perhaps you are confusing the civil radar data that was presented in the FI, which had more intermittency after the turn back at IGARI. There was nothing in that military radar data to suggest the plane ever flew lower than FL200 near Penang. The captures were continuous until Pulau Perak.
this is in my understanding that the cellphone connection at FL340 is a very unlikely event.
I don’t know what is the basis of your understanding. The facts are the ability for a cell phone to register on a tower is determined by signal-to-noise ratio (SNR), Doppler shift, and transport latency. Mike’s link signal analysis showed that the SNR was sufficient, and we know that the transport latency is acceptable for distances up to 32 km. We also know that the plane was traveling tangential to the tower at the time of the registration, so Doppler would be low. There is no reason that a brief registration could not have occurred at FL340.
the DSTG has suggested slowdown before and after Penang based on their own analysis (Fig. 4.2).
The ground speed near Penang shown in that figure is between 524 kn at 17:52 and 495 kn at 17:54. This in no way that suggests an altitude of FL200 or lower. There might have been some changes in altitude near Penang, but certainly not a descent to FL200.
Vmo = 330 KIAS can be exceeded during descent. Of course, subject to a pilot’s ‘wish’ to ignore OVERSPEED message.
Vmo can be exceed even during level flight. But that doesn’t mean flaps can extend at these speeds.
And finally, there were initial reports suggesting altitude drops, which were later discarded as unreliable.
I am aware of a report of a plane at low altitude near Kota Bharu, not Penang. Nonetheless, there have been many reports that are unreliable and offer proof of nothing.
Victor:
Why are you so combative? Rude?
I asked a couple of straight-forward questions. Didn’t push any buttons.
Do you read anyone’s analysis that if you drop 24 pieces of debris in the water south of Broken Ridge, at least one-quarter of them will hit WA? You can confirm that easily. NOAA and Geomar already have. That’s what they do for a living.
I don’t understand your determination to block everything out until someone else finds it.
No need to respond.
Mike
@all
P-C3 Orion anecdotes.
Moffett Field in the Bay Area had a ton of the things. I was involved in several aspects of the sonobuoys – both sensors on the device as well as analytical software on the aircraft and the ground.
Moffett was the main West Coast anti-sub naval air station, and drills were often conducted using US submarines as target vessels. It was largely hopeless. More often than not the aircraft had to request that the submarine surface and shoot off a flare to get them started. Within minutes the US sub would literally disappear. Sub skippers are smart, and the platform is very quiet. Basically it was a hopeless mismatch that I watched tangentially many times.
I have almost zero confidence in the ability of an air search to spot anything smaller than a fishing boat on a reliable basis.
@Mike Chillit
I will respond anyway. This group is tough, and most of the main contributors are very bright and very well credentialed. You won’t get far here with speculation. Put it in black and white with good analytics or with good links, and the world is a happy place.
Mike Chillit said: I asked a couple of straight-forward questions. Didn’t push any buttons.
You have been pushing buttons on Twitter for years now. You have made a series of absolutely false and disgusting lies about me and other members of the IG. Years ago, I came to the conclusion that it is better to just ignore you rather than try to reason with you. You also have a long history of creating theories based on incorrect math and physics, from your spectral analysis of debris using satellite images, to your insistence that the 7th arc is incorrectly calculated by the IG, Inmarsat, the ATSB, and any other serious investigator, all based on your “GPS calibration”. A recent example is your false claim that a Chinese satellite tracking ship was scanning the seabed looking for MH370.
If your pilot group has some new insights to present, we’d be interested in seeing them. However, the statements have to be based on facts, math, and science. I haven’t seen any yet, and I won’t tolerate here the pseudo-science that is found on Twitter.
As for drift models, there is an obvious difference in opinion among the experts about which impact site best explains the location and timing of debris discoveries. The paths of the tracked buoys tell only part of the story. That’s why organizations like CSIRO and UWA have invested so much time and money in developing large models that run on supercomputers that incorporate day-to-day currents and winds, and also include models to characterize the behavior of different kinds of debris.
@Oleksandr,
The total file of RNZAF photographs is large, about 1.1GB.
There are many photos which show little or nothing of interest, and a number which show debris which is clearly “fishing debris”.
My dropbox is limited to a few 10s of MB, and in any case uploading a file that size would take forever at the ridiculously low speeds that my ISP provides.
I have previously linked some of the photos that may be of genuine interest and within interesting areas of the search.
@Ge Rijn. Your 12th Nov, 12:59. “There is no proof…….he plane wasn’t…without active pilot control…..Therefore we have to assume the most logical; the plane was actively piloted till the end”.
Do you have an explanation for why the active pilot would plunge the aircraft, or fly it so that it would plunge, not at MEFE or at A/P disengagement but almost 2 mins after that? Beyond me.
Even if he did plunge it then, it is unlikely he had recovery in mind, so him being there would matter not.
Without an explanation there is strong circumstantial evidence there was effectively no pilot: not proof but getting close.
So I believe the burden of proof is now on one who asserts that there was an active pilot and who would have increased search width.
The more I think about it, it seems to me, that realistically, the air search was really only a “hit and miss” affair, and unfortunatley, there were no hits.
If another aircraft is ever lost at sea, in similar circumstances to AF447 and MH370, ie, where we are forced to seach a huge area for small pieces, that a totally different approach needs to be devised and used to locate that debris quickly.
We have to redefine the requirement(s) for this post SAR phase.
If we assume that the biggest thing we are likely to find is something like a flaperon, then we are looking at an item of about one metre square at best, and with a zero to very low projection height out of the water.
With those “target” parameters in mind, it is obvious that :-
(a) The human Mk-1 eyeball, even with gyro stabilised binoculars, are as good as useless, at anything more than about 2,000 feet slant range, which, for an aircraft platform flying at 2,000 feet means virtually overhead. Even at 500 feet, that still limits effective scan width to 1,936 feet, but now with a viewing grazing angle of only 14.5 degrees. Any grazing angle less than that, would make small objects virtually impossible to see within the waves anyway. Thus searching a huge area becomes utterly impractical, even with half an airforce available, let alone half a dozen aircraft on task.
(b) Opto-electronic sensors are really no better than (a) although they can see a bit further, but the same covearge restrictions of (a) apply. They can however record data for post processing and analysis back at base.
(c) Radar, even Synthetic Appeture Radar, is less than useless at low grazing angles to the surface if there is nothing projecting above the wave surface, even intermittently, so really, they are still no more useful against our targets than either (a) or (b).
The only potential solution I see, is the use of the best professional aerial digital electronic survey and mapping cameras systems. Unfortunately, these systems, although suitable technically, are generally installed in light to medium aircraft of limited range and endurance, which are not capable of operating at long range as required in cases like AF447 and MH370.
So, a proposal.
Someone should configure one, or a handful of these systems, on palletised platforms, so that they can be mounted in a cargo aircraft, (anything like a C-17 or C-130 would be suitable), complete with all the recording gear and a couple of opperator workstations as well, with the lens part able to be extended and hung out the back over the cargo ramp when opened at low altitude. This would allow the aircraft to be pressurised for the long range high speed high altitude transits to and from the search areas. These systems would be able to be used at 2,000 feet, perhaps even higher, and at the full low level maximum speed of the host aircraft platform. Multiple cameras (say 5) mounted at angles such that 2 were looking left, one down, and 2 right, with a slight overlap in their fields of view, would, depending on the operating height, signicantly increase the scan swarth width and maintain a very high probability of detection, both in real time on-board, but particularly by post processing back at base. A few of these systems could be built, stored somewhere, and could be deployed anywhere in the world, with their operators and maintainers, in a matter of days, should the need arise, for task flying in locally available aircraft.
@Ventus45. An up to date tracking and locating system would be better I suggest plus long lived and powerful pingers.
@David
Agree, on the tracking, but that will take many years to happen, too many road blocks in the way to negotiate any time soon.
As for the pingers, no, they are not viable really.
It would be better if they could be programmed to ping say for only an hour per day to conserve the battery. That would give a longer time to marshal resources, and even have a dormant version, that only started pinging when interrogated. Besides, they may be destroyed, as in AF447, or too deep to find easily.
The bottom line is, some debris will float, so find that, quickly.
That localises your pinger search much more quickly, and if not, gives a better datum for an area bathy / sonar search.
The system I proposed could be designed, built, trialed, and commissioned in a few weeks, if someone with some clout decided to do it. Have it ready in case there is a next time.
Oleksandr wrote “Do you really believe that the Butterworth radar would not detect a large aircraft flying at a cruise altitude at a cruise speed 60 nm (or so) away? And that it would not be able to derive its altitude at such a distance?”
The ‘Butterworth radar’ is a Selex ATCR-33 system. It is a primary surveillance radar, it is not capable of discriminating and reporting the altitude of an aircraft. This particular radar is located on the airfield and operated by RMAF air traffic control staff to provide terminal area surveillance of traffic using both Penang International and RMAF Butterworth.
If a model of the detection envelope was available for this radar, it would be possible to derive an approximate aircraft altitude from the DCA’s radar plots (Factual Information Fig 1.1E & F) which show a short track segment as the aircraft intercepted the top of the envelope. While it is an ATCR-33 deployed at both Butterworth & Kota Bharu, the two installations are stated to be of dissimilar configurations so simple comparisons of the DCA’s tracks to infer altitude are not reliable.
@Victor. I have alerted David Griffin to this discussion on your site, including my Nov 13th, 4.19AM post.
His comment.
“I’ve just had a quick skim …..I see it like this: some sections of the arc (drifted forward) were surface-searched as best as could be done with available resources. Other sections were not searched at all. Similarly, some sections of the seafloor have been searched very thoroughly, but others not at all. Surely it makes sense to resume the search with a focus on areas that have not been searched by either technique. But what about the holes in the surface search? Unfortunately, we don’t know where the little ones are. So let’s start by searching in the big holes (whose location is known), especially those that are pointed at by other lines of evidence.”
@David, Ventus45
@ventus45: what swath width do you expect the deployable imaging system to cover?
MH370 is among the blackest of black swan events: the loss of all routine surveillance was followed by approx 6hrs of continued flight.
Consider surveillance: the EU and FAA mandates for ADS-B equippage are progressing to completion, Aireon’s space based ADS-B surveillance is very close to full operation. The outcome is worldwide surveillance coverage for all ADS-B equipped aircraft. Routine surveillance & reporting processes have been the key to the timely location of debris associated with many over water accidents from Air India 182, through UA811’s cargo door, MS992 off New England, Air Asia QZ8501, MS804 over the Med, and AF447 (FMS progress reporting).
Consider surface debris detection: even in the case of AF447, floating debris was identified and recovered within days using Mk.1 Eyeball (BEA’s reports noted that Brazil’s airborne maritime surveillance radar assets successfully detected debris). Mk.1 Eyeball remains the most successful asset. Records for contemporaneous weather and oceanographic data is critical. ELTs contribution is poor as automatic triggering is reactive, rather than proactive. The search area must be manageable, 10 minute location updates dictates a 17,500km/sq, less is good. Deployable recorders, maybe/maybe not?
Consider deep water debris field detection: there does not appear to be any motivation to replace ULBs, >90 day battery life is a necessity. Deployment of deep water search assets can be effected rapidly. Confidence for the accurate tasking of a deep sea search is paramount (however, if 600km/sq can be searched per day, even the entire 17,500km/sq area defined for AF447 could be cleared in 30 days).
Consider flight intent monitoring: given wide area, even global, air transport surveillance together with the knowledge (flight plans) of the route expected to be flown by each aircraft it’s possible to detect exceptions from planned flight intent. This technique was demonstrated in the case of Germanwings 4U9525: when the PF set an exceptional target altitude on the A320’s Flight Control Panel it was immediately apparent to air traffic control.
Finally, ICAO’s GADSS recommendation aims to close gaps in the preceding, exploiting existent routine activity, with minimal impact to aircraft configuration. The final phase of GADSS is for a new generation of ELTs, capable of remote initiation, to be fitted to aircraft. Flight intent monitoring provides the source for remote initiation. The new generation ELT will remain an autonomous, non-dependent, device onboard the aircraft.
@David: Thank you for David Griffin’s response. He’s justifying the priority search area of 25,000 sq km. Some of us are thinking about where to search next. I suppose he (and others) are not ready to do that. The wreckage might be found in the first area. I’m not sure it will be.
@DennisW, VictorI
Regarding the integration of Doppler residual D(t):
Sorry for jumping in late; I have been travelling for a while. Indeed it is interesting to have a closer look at Henrik Rydberg’s document “MH370: finding the path”, see:
http://bitmath.org/mh370/mh370-path.pdf
Henrik uses the concept of “stationary” and “dynamic” ping rings to find the path solution and the difference between the two is determined by L(t) which is an integral of D(t).
In a similar way (the “differential” version of this procedure) I use D(t) and dr(t) / dt to determine a velocity vector based on a “known” location at each time t. Integration of the velocity vector starting from an initial location (for example Igari) will give you a unique path solution.
Indeed, as Victor pointed out, we don’t have enough information to determine the D(t) function especially between 18:22 and 19:41. Because of this gap I now tend to start the path calculation from 19:41 onwards (or even later) and can find unique paths under an additional assumption (for example minimal path curvature). Still then we are left with the much debated BFO -> D(t) errors, which then IMO lead to at least +- 5 degrees uncertainty in end-latitude.
@David
On your comment/question;
‘Do you have an explanation for why the active pilot would plunge the aircraft, or fly it so that it would plunge, not at MEFE or at A/P disengagement but almost 2 mins after that? Beyond me.’
I base my opinion mainly on two issues;
1. A piloted flight turning into a ‘ghost-flight’ is an extremely rare occasion. As far as I know we only have the Helios flight in history (as a commercial airliner). A one chance in many, many millions of flights.
There’s no proof or clear indication the flight went into a ‘ghost-flight’ anywhere along the route. It went dark and did not communicate anymore that’s all (besides the pings).
On the contrary the flight has many indications and proof of a deliberate, planned disappearance into the SIO.
To ignore the most obvious; a actively piloted flight from beginning till end with a destination is not logical imo.
2. The debris shows clearly some conflicting data. Most of it indicates a ditch-like impact imo. But other data doesn’t I agree. Pieces like the flaperon and outboard flap section either seperated during a high speed dive or seperated during a relatively low speed, nose-up, ditch-like impact. One of the two.
This problem is not conclusively solved yet by evidence.
Further;
If the plane was actively piloted till the end the fuel exhaust would be anticipated and controlled to reach a certain destination without fuel left for a reason (I think to minimalize risk of explosion and fuel tracks).
To wait for the steep descent two minutes after MEFE could have several reasons. At least the plane did not dive right after MEFE. This could be an indication of a piloted end flight too.
If the IFE-switch was switched of during the flight (which would be logical in the whole context imo) we have no way of knowing what happened after 00:19:37.
It could have recovered after the steep descent within ~1500ft of altitude and glided towards a destination.
The PIC could also have chosen to plunge the plane with high speed into the ocean near the 7th arc. But the debris contradicts this till now and the plane is not found near the 7th arc where it was expected.
I think good reasons to seriously consider an all actively piloted flight. Well planned and executed.
The fact that it’s not found yet is an understatement of the above imo.
Hi Niels,
In principle the integrated Doppler approach should work well for locating the aircraft. The Doppler residuals are independent of aircraft position and depend only time (the motion of the satellite). The reality is that the harvested BFO data is sparse (as you and Victor both pointed out), and the sensitivity to frequency errors is severe. If we had more BFO data and cesium clocks we would be good to go. We don’t so that is that.
@Victor
“The wreckage might be found in the first area. I’m not sure it will be.”
Even with the best technology there is still a bit of luck involved…
When Bob Ballard went looking for the Titanic in 1985 he had the French research ship Le Suroit “mow the lawn” for a week with the best side-scan sonar available at the time. After a week he went to Plan- B and used the Argo to search for the debris field. When the Titanic was found they discovered that Le Suroit had passed within several hundred yards of the wreck on it’s first pass.
DennisW,
The BFO has two contributions. The first is the Doppler compensation error and the second is the motion of the satellite.
At 19:41, when the satellite is close to its furthest North and is virtually stationary, then what you said is correct – the BFO is insensitive to position and maximally sensitive to the direction and speed of travel. At the opposite extreme, when the satellite is directly over the equator, the Doppler compensation calculation is correct (i.e. error is zero) but now you are sensitive to position, since the plane sees a Doppler due to the satellite motion. At the end of the flight, MH370 was closer to the second extreme than the first. It is unclear if, even with abundant BFO data and hydrogen masers (much better than cesium for the purpose – it’s what my precision timing experiments would use back in the day), you could reconstruct an arbitrary path.
@sk999
What I define as the “Doppler residual” depends on satellite motion relative to the GES, the GES frequency corrections, and the measured BFO. You can construct a table of values without any regard to the aircraft. This table is static for any conceivable path.
The problem for path modelers then becomes to find an aircraft position and velocity that produces the required Doppler residuals given the difference between actual Doppler to the satellite (a function of aircraft and satellite positions and velocities), and the Doppler compensation. Of course the satellite position and velocity is known (I use your orbit equations for that. Thank you very much.)
As far as path reconstruction is concerned it is a slam dunk. Back in the day I was actively engaged with people who tracked Soviet launch vehicles using the known launch point and the Doppler shift of the telemetry data. It worked extremely well.
We used cesiums, BTW. In those days a hydrogen maser was the size of a refrigerator.
Update on November 14, 2017
IG Member Brian Anderson has reminded us that There are a number of RNZAF photos of interesting flotsam (debris), in areas that may now be much more significant. Unfortunately none was ever recovered.
In the updated article above, I compare where the debris was found on March 29, 2014, with where the debris is modeled to drift for an impact near 28.3S latitude, which is where the path to 45S,104E crosses the 7th arc. It seems possible that the debris was from an impact near 28.3S latitude, which makes this site even more interesting.
Ge Rijn et al:
Yes, my drift studies are based on NOAA’s satellite tracked buoy program with data available from its ENVIDS server. I generally use data pulled from the equator to -60S and from 20E to 120E or in that general area, which includes most of the South Indian Ocean. I use both Metadata and Interpolated data, depending on my focus.
So far, I’ve not seen other studies use quite the same method to identify selected drifters. For example, most use “boxes” centered somewhere near the original search area. Those boxes cover a lot of territory: several degrees of longitude and latitude.
I decided early on that the box method has problems. For example, it requires all drifters selected to enter the study south of -30S. From my POV, that biases the study by ignoring drifters that enter from much farther north. NOAA deploys drifters in many many locations across the Indian Ocean. Most with contracting vessels that drop them in an agreed location during the normal course of operations.
So, my solution was to require a drifter to physically cross the Seventh Arc at a known day and location before it was included. Moreover, I also require that selected drifter be selected only after they have reached a point where they will never again cross the Seventh Arc. That is important because many of them drift northeast and zigzag back and forth across the Arc. Selecting drifters before they’ve crossed the Arc the final time would also introduce bias.
In all, it’s a lengthy analysis process, but this is why I trust my selection method to provide the kind of information we need to determine how those current and wind vectors play out on those buoys.
I encourage the moderator to publish my entire response.
Best, Mike
@Victor, @Brian, and @Joseph C,
The item depicted in fig.5 appears to be a flexible sheet or mat. It’s the focus of four RNZAF images, the edge closest to the camera is flexing with the passing waves.
The RNZAF image set does contain images of recognisable objects which are useful for reference: five images show SLMDBs (5831, 5832-35), another eight show a floating device that is believed to be a fish net marking beacon (5814-5821).
@VictorI,
Your Figure 5 above looks to me like a square tarp floating on the surface with one corner blown over the top by the wind.
Your Figure 6 appears to show a lot of small items. However, I am skeptical they are from an aircraft crash for several reasons. First, the size distribution does not seem to include any larger,resolved objects, nor do any of them have irregular outlines. Second,in spite of excellent illumination, they all appear to be uniform in reflectance and color (white).
The “clipping” of the white pixels of the small objects, if that is what happened in this image, might be caused by overexposure in the image. Because the sea is so dark (about 2% equivalent Lambertian reflectance), it’s easy to saturate the filled pixels of even low-reflectance objects in the same ocean scene. This will always occur when using an automatic exposure mode in the camera. It takes a knowledgeable photographer to manually reduce the exposure time so that the brightest pixels are not saturated. In this regard, film cameras are decidedly superior, because the film sensitivity has a much larger dynamic range (being more or less logarithmic) than a CCD (which has a linear response until well saturation occurs, at which point blooming begins to occur).
@ventus45,
The best electro-optical method for detecting objects floating in the ocean is an active, airborne imaging lidar using a blue-green pulsed laser. I built many of those for the U.S. Navy to detect floating and drifting sea mines. The image contrast is high for opaque objects. You set the range gate so the laser light backscattered from subsurface seawater is imaged, and this backscatter is blocked (twice) by any opaque object in the field of view. I can tell you from about 200 sorties of testing I did, some going back 30 years, that this method works very well, and it is virtually impossible to countermeasure. It would take a large laser with high average power to get 10-15 km range on each side of the aircraft, and the aircraft would need to be flown at an altitude much higher than 600 feet. The technology is there today to do this, but I think a better solution is real-time tracking of the aircraft implemented so that it cannot be disabled on board. That would allow a low-altitude visual search for debris, which is the fastest deployed aircraft-based method, to go directly to the last known position and search outward from there.
@Don Thompson: Thank you, Don. I agree that the unknown object could be a mat or flexible plastic covering of some kind.
Details about the Self-locating Marker Buoy Drifters (SLMDBs) might be helpful to calibrate the object sizes and the drift patterns. The images may in the end amount to nothing, but we have to investigate what little we have. I suspect the photos were largely ignored after the search moved further south.
@DrB: Skepticism is good. Considering the only other images we have of potential debris near the 7th arc are the satellite images that are even less likely to be from MH370, the debris is worth investigating before dismissing.
As for the unknown object, we know it is a thin sheet that is flexible and buoyant. From that alone, I don’t think we know whether or not it is from an aircraft.
It is not surprising that the parts from the debris field are mostly the same size, as differential drift after 21 days should tend to group objects of similar size, construction, and material.
@Don Thompson @Brian Anderson
You may be right Don. As seen 005849 image, on the larger triangular shaped piece you can see part of it is either showing transparency or has water over it showing its flexibility.
@Ge Rijn “I think good reasons to seriously consider an all actively piloted flight. Well planned and executed.
The fact that it’s not found yet is an understatement of the above imo.”
Well said. There is no direct evidence of any sort that sheds doubt on the proposition that it was meticulously planned and meticulously executed from start to finish.
MC: Re: “So, my solution was to require a drifter to physically cross the Seventh Arc at a known day and location before it was included. Moreover, I also require that selected drifter be selected only after they have reached a point where they will never again cross the Seventh Arc. That is important because many of them drift northeast and zigzag back and forth across the Arc. Selecting drifters before they’ve crossed the Arc the final time would also introduce bias.”
…I believe the exact opposite is true. Selecting only those paths that do not re-cross the 7th arc is what would bias the resulting distribution. Allowing for all naturally occurring paths, including those that cross the 7th arc many more times (common) provides the most representative statistics.
@Victor
The “new” 45S flight path you are showing has much more of a trajectory towards the Dordrecht Hole and Diamantina Deep areas, than your/Richard’s 26.9S McMurdo path. That makes it more interesting for me as I can see a possible target and strategy.
@Victor,
I shall post an update if my enquiry solicits a result.
@Don
Ami was looking over my shoulder at your post, and was impressed that a techie correctly used “I shall…” instead of “I will…” with the first person pronoun. I explained to her that you are not from the US. She shook her head knowingly.
@DennisW
I try. Interesting to read your earlier comment about NAS Moffet Field. I visited a research facility on the NASA Ames complex in the mid 80s, the arrival and departure of P-3Cs certainly did seem incessant.
@Don
Things are certainly different in the real world. I was pretty active in coastal fishing for some time, and had a drive shaft failure about 50 miles out. I was in the process of giving a Coast Guard cutter my Loran lines (this was before GPS was common) when the Coast Guardsman (that is how they prefer to be addressed, and are annoyed at being called “coasties”) interrupted me, and said to just key the mic for 20 seconds. The coast guard greatly prefers to use their directional antenna to find people. It is simple, and they don’t have to worry about being misled intentionally or unintentionally. I am told that is how they still do it. Technology is great. Simple is better.
@DrB
I have never disagreed with the need for real time tracking, but I think we have to be realistic and realise that it will take some time (years +) to get those systems in place across the entire world airline fleet, and there is still the issue of it possibly being disabled in a “deliberate” scenario, in which case, the search problem would remain the same as it currently is, so a new, better, Search Plan B is required.
I hear where you are coming from with the ALMDS, and I agree it would be much better than the camera system. Back in the 1990’s, I had a little bit to do with (on the logistics side) the RAN’s LADS. and even managed to go on one mission as an observer out of Cairns in the old F-27, which was retired, and replaced by a DHC-8 in 2009, now operated by Fugro.
The problem is, neither a Seahawk nor a DHC-8 have anywhere near the range or endurance to do the job at hand, which was, and remains, my initial point, and why whatever system is put together, it has to be palletised as described.
@Brian:
Re: “There are many photos which show little or nothing of interest, and a number which show debris which is clearly “fishing debris”.”
I am more interested in the statistics. My earlier analysis has shown that the rectangular object is consistent with 30S origin. A few other objects are consistent with more northern origins, but there was the abundance of eddies. It looks like these objects do not add any new value to my drift-based conclusion that the origin must have been between 26 and 31S.
Re: “My dropbox is limited to a few 10s of MB, and in any case uploading a file that size would take forever at the ridiculously low speeds that my ISP provides.”
I thought these speeds and volumes are in the past. It usually takes me around 10-20 minutes to upload 1 Gb file to my dropbox. Anyway, thanks.
@Ventus
still the issue of it possibly being disabled in a “deliberate” scenario, in which case, the search problem would remain the same as it currently is…
Yes, disabled or jammed. It is not as trivial a problem as many people believe it to be given the seemingly advanced technology we have to throw at the problem. Google and Tesla (Bay Area companies, of course) might save the day with their efforts in driverless cars. Pilotless planes would eliminate the issue completely. Or the planes could be controlled from the ground as drones are today. If there are no controls on the aircraft, it cannot be diverted by someone on the plane in the air.
Of course, I am not a romanticist with tales of Sully in my brain. I tell friends who go to Rome or Machu Picchu to soak in the history, that if you want to see a bunch of stuff falling apart it is cheaper to drive to Detroit.
@Don,
Re: “The ‘Butterworth radar’ is a Selex ATCR-33 system. It is a primary surveillance radar, it is not capable of discriminating and reporting the altitude of an aircraft. This particular radar is located on the airfield and operated by RMAF air traffic control staff to provide terminal area surveillance of traffic using both Penang International and RMAF Butterworth.”
I am afraid that you assessment of the Buttwerworth capabilities is somewhat naïve. Common sense. Any information about equipment, capabilities and operations of a military radar would be classified. Especially at a military airbase. Detection of altitude is among the most important priorities of any military radar installation.
@Dennis,
“The fact remains that in order to travel from the location of the cell phone registration to the 18:25 ring requires a ground speed of 500kts +/-. I do not believe this is possible with the flaps extended.”
But my arguing is not about flaps, but about altitude near Penang: was it FL340-FL350, at the cruise M.84 or some ‘vertical’ maneuver took place?
In general, what is more unreliable: assumptions or poor quality data/observations?
@Oleksandr
Maybe so, but the distance and time from the cell phone connection to the 18:25 ring (both uniquely attributable to MH370) require ~500 kts ground speed. That won’t happen with the flaps extended. I have always maintained that the radar information adds virtually nothing to our understanding of the incident.
@Ge Rijn. As to an active pilot being there, not or not known depends on weighting of the evidence.
You say that an unpiloted end in a transport aircraft had just the one precedent. I make the comparison to you that a transport aircraft being diverted to the SIO has no precedent at all.
So, therefore is it unlikely to have happened?
“Pieces like the flaperon and outboard flap section either separated during a high speed dive or separated during a relatively low speed, nose-up, ditch-like impact. One of the two. This problem is not conclusively solved yet by evidence.” I agree. It does not lead either way. Therefore it too carries no evidentiary weight.
“At least the plane did not dive right after MEFE. This could be an indication of a piloted end flight too.” Simulations indicate that if it had dived right after MEFE, there was a pilot. Lack of a dive then does not lead either way, so again no evidentiary weight.
You say, “To wait for the steep descent two minutes after MEFE could have several reasons”. But do not advance any.
A piloted glide for around 2 minutes followed then by a sudden nose down followed then by a recovery and glide remains highly unlikely IMO: a roadblock to a glide possibility.
As a possibility I conjure up an impaired pilot recovering his senses during the dive and pulling out of it. That beg questions as to how that came to be and its likelihood, so just shifts the roadblock.
@Oleksandr
But my arguing is not about flaps, but about altitude near Penang: was it FL340-FL350, at the cruise M.84 or some ‘vertical’ maneuver took place?
Your initial response was to a flaps extended question, but no matter. Likewise it does not matter what the altitude was at Penang or after Penang. Who cares, and why? Perhaps the implications relative to fuel range?
@Victor,
Re: “Did you bother to read the RMP report regarding radar captures near Penang? There were more than a few blips.”
Yes, I read. Perhaps more than a few blips, but not enough to derive sounding conclusion about constant FL340 and M0.84.
Re: “I don’t know what is the basis of your understanding.”
RMP.
Re: “The ground speed near Penang shown in that figure is between 524 kn at 17:52 and 495 kn at 17:54.”
I recall our digitizing of, especially lower curve (mean minus 3 sigma), showed different result.
Re: “This in no way that suggests an altitude of FL200 or lower.”
I am not suggesting lower altitude than FL200. I am not suggesting altitude at all. I am only arguing that your assumption of a constant FL340 (or FL350) at Penang is likely wrong.
Re: “There might have been some changes in altitude near Penang”
Finally we agreed on this.
Re: “Vmo can be exceed even during level flight. But that doesn’t mean flaps can extend at these speeds”
Agree.
Re: “I am aware of a report of a plane at low altitude near Kota Bharu, not Penang. Nonetheless, there have been many reports that are unreliable and offer proof of nothing.”
Yes, but there is no smog without fire.
@Dennis,
“Who cares, and why? Perhaps the implications relative to fuel range?”
Yes, first issue is fuel implications. Perhaps one maneuver is not decisive, but several such maneuvers (e.g. ascent at IGARI, VAMPI-MEKAR gap, presumable descent after 18:25) may have some notable implications compared to the constant FL.
Secondly, such a maneuver at Penang would logically be counter-indicating of a planned suicide in the SIO or achieving the max-possible range hypotheses.
@TBill,
@sk999,
@Victor,
I am doing some experiments with CMH, and results are quite interesting. Firstly I ‘updated’ magnetic declinations to 2005, and results did not change much, as expected.
Secondly, when I artificially forced wind at 9,000 m altitude to be the same as at 4,400 m altitude, I am getting a rather good agreement with the measured BTO and BFO. RMS BTO error is 21.9 μs (round trip), and BFO RMS error is 2.95 Hz assuming 150 Hz bias (DSTG), and 4.03 Hz assuming 152.5 Hz bias (ATSB, 2014). Terminus is at 27S. Wind patterns at 4,400 m and 9,000 m turned out to be significantly different. This rises an interesting question about GDAS errors in wind data in the open ocean at 5-10 km altitude, where almost no data are available for calibration/validation.
@Oleksandr,
The reality is that no one cares. The people writing checks are tired of spreadsheets, which is a correct and belated conclusion. Your stuff is no better than what was presented by the DSTG, IG, and many others months ago. It is a tired theme, and totally inappropriate to current thinking.
As I said long ago, the analytics relative to the MH370 event are the worst in the history of the world (with the possible exception of ABS).
@Oleksandr: Or perhaps the plane was in CMH mode at 15,000 ft instead of higher than 30,000 ft.
@David
In a way you reflect my opinion well. There is no conclusive evidentiary weight for any case I mentioned.
‘So, therefore is it unlikely to have happened?’
In case of a piloted flight turning into a ‘ghost-flight’; yes.
Statistically speaking this chance is one in many millions of flights.
Could it have happened? Yes. Murphy’s law tells us so.
No reason though to ignore the more obvious possibility of an all pilot controlled flight.
‘You say, “To wait for the steep descent two minutes after MEFE could have several reasons”. But do not advance any.’
This would be all speculation that’s why I did not advance on it.
To name one; the pilot could have waited for the APU to kick in. Knowing the APU won’t last very long could have made him decide to descent very fast initially and recover later. Pure speculation.
There might be no logical reason to dive first and then recover to a glide. But it’s not impossible too.
We can not know what happened after 00:19:37.
@Ge Rijn. There needs to be a good reason to clear that roadblock IMO.
It is unlikely that the pilot would be aware that the APU would autostart after MEFE: the availability of residual fuel has been established post-crash. Likewise he would have no rationale for trying a manual APU start.
When it did auto start he would not have any way of knowing for how long it would run, for the same reason.
We still do not have that good reason. That needs attention still.
@David
I don’t see a roadblock in a sence that justifies blocking the road to serious investigation of an all pilot controlled flight.
I wanted to make clear there are good reasons to pay serious attention to this possibility too.
I assume any commercial airline pilot would know the APU autostarts after both engines stop working. But I’m no pilot so I’m not shure.
I was just speculating.
More things could have happened if the flight was an all pilot controlled one.
Once more, I think it’s important to look at this possibilities too.
@Oleksandr,
No, not naive, simply taken time & made effort to ensure that my information about the radar installations is correct.
I suggest that you are unclear about the identity and location of the long range, air defence surveillance, sites and the ATC sites. The radar located at Butterworth AB is a Selex ATCR-33 while the long range, air defence surveillance radar is located near the peak of Western Hill on Penang Island. The latter is also a Selex product, a RAT-31/DL (although keeping track of the ‘brand’ is as much a challenge, AMS, Selex, Leonardo…). The capabilities of both are well understood.
After looking at the photograph of the so-called “flaperon”, I am convinced it cannot be the actual MH370 flaperon, which has its trailing edge torn off in an uneven, somewhat jagged fashion. The object in the photograph appears to have all four edges intact and straight, with no visible roughness/jaggedness.
MH370 – China’s9-11.
In the year 2014, many Chinese businessman bought large amounts of properties in Johor as well as across malaysia. This caused an unusual surge in house prices to the extend of national security. Many muslim malay saw this as a threat to the nation.
As a predominantly muslim and malay country that dislikes chinese and non muslim the answer was obvious. An attack on china. But how? Enter mh370. Mh370 was a flight with 95% china chinese passengers. It was the perfect flight for a terror attack.
If u lived in malaysia long enough u will know that the muslim malay government is very anti chinese. They share similar traits as their indonesian counterparts who massacre their chinese population when things go wrong.
U can see how uninterested the malaysian authorities are in finding mh370. They rather close the case ASAP. The muslims who lost their lives on the plane has been told to keep quiet and accept it as a form of Jihad. So take note, MH370 is China’s 9-11.
@Ge Rijn. I agree that no explanation being found for this does not mean there is none but finding one looks highly unlikely. That means to me that it was highly likely there was no pilot induced gliding after the final BFO.
The context of course is the discussion about priorities should the portended 25000 sq km search be unsuccessful.
I will be happy to leave it there if you are.
@David
Yes, it was meant to me also in this context.
I think we’ve made our points clear so I’m fine with leaving it here too.
Thanks for coöperating in this matter.
@Truth is here said: If u lived in malaysia long enough u will know that the muslim malay government is very anti chinese.
The Malaysian government has strong ties with China, which could be their financial savior. I can’t imagine Malaysia would deliberately cause a crisis with China.
@Truth is here
I would like to read; ‘Proof is here’
@DennisW
Off topic just for some lightness..
Wij Nederlanders hebben het geluk dat Engels ons al vroeg wordt aangeleerd op school. Wij weten dan ook al eeuwen, dat wij ons moeten aanpassen aan onze buren qua taal en, dat wij dat niet andersom kunnen verwachten.
Desalniettemin is het niet eenvoudig ons subtiel uit te drukken in de Engelse taal. Het heeft op zijn minst zoveel nuances als onze taal maar vaak nét even anders qua betekenis en zinsbouw.
Dit leidt natuurlijk regelmatig tot misverstanden tussen Engelstaligen en Nederlanders.
Niettemin doen de meeste Nederlanders altijd erg hun best om zich zo goed mogelijk uit te drukken in het Engels.
Maar geloof me; het niveau en jargon wat op een blog als deze gebruikt wordt, is echt een uitdaging.
Dus wat compassie met wat een Nederlander hier schrijft qua Engelse taal-correctheid is wel op zijn plaats naar mijn mening.
Good luck with translating.. 😉
@DrB @Richard @Brian Anderson
The flaperon-like object was discussed in lenght on JW’s blog back then.
It was surely not the found flaperon considering the details you also mention.
With manipulating contrast, color and even pixels it was tried (by me also) to find out what it could be. Dimensions and shape seemed to fit but it was concluded it was probably some kind of pallet.
It’s a shame though it was not recovered to make shure.
Most of the relavant objects that were posted by @Richard and @Brian Anderson were spotted in the ~32S/96/97E region.
If only one of them was MH370 this would be most telling.
The flaperon-like piece could have been high-windage traveling farther north.
It’s a shame none of those objects were ever recovered.
@Oleksandr: I surveyed the family of paths using CMH navigation and lower altitudes, and there are some paths with surprisingly good fits to the BTO data due to the wind fields at the lower altitudes. However, the indicated air speeds at the lower altitudes are in general too high for the required endurance. The way around this is to apply lower altitude wind fields at higher altitudes, as you have done. However, I know of no justification for doing this.
@Ge Rijn
I did the translation. Your English is just fine. I would be proud to be able to contribute to any blog that was not in my native tongue. I have a hard enough time contributing in English.
I too am disappointed by the level of forensics published relative to the recovered debris. Perhaps I am wrong relative to what is possible. Certainly one would expect that inflight versus impact separation would be an achievable conclusion. Likewise flutter damage to the flaperon trailing edge versus water impact damage.
@Oleksandr
Can you show us a short data table of winds at the ping rings over the path, low vs. high alt? I always like to see the winds others use sometimes I use that.
@VictorI,
In your lead article above, “Possible MH370 Paths Along Great Circles”, you said:
“Another procedure would be to use TRK SEL mode, with a value of 180° and the NORM/TRUE switch set to TRUE. Although this would produce similar results as the method using LNAV, it is possible that the aircraft could at times deviate from the required track, and the path could deviate from a great circle. For instance, a wind gust or turbulence could momentarily cause the track to deviate. Although the autopilot would correct for the deviation and bring the track back to the target value of 180°T, the error in path that accumulated during the track deviation would not be corrected. By contrast, in LNAV mode, deviations from the great circle path are continuously corrected so path errors don’t accumulate.”
This is an interesting question. I am unsure about the reality of this effect when using the TRK SEL mode. It depends on how the FMC is programmed. If the FMC is simply trying the maintain the current direction of travel, using only ADIRU data, what you say above is correct, and cross-track errors due to disturbances will accumulate over time. On the other hand, if the FMC computed a rhumb line path from the initial position when TRK SEL was executed, then the FMC could follow that path without accumulating cross-track errors. In that case, the navigation would be as accurate as LNAV following geodesics between waypoints.
Do you have any documentation on what TRK SEL actually does, or are you making an educated guess?
@Andrew,
Do you know what the FMC actually does in TRK SEL mode?
@DrB: Educated guess. For LNAV, the great circle path between waypoints is shown in the navigational display, and the deviation is displayed and corrected on a continuous basis. There is nothing like that for TRK SEL, nor do I think it makes sense to have something like that.
@DrB
The AFDS only uses ADIRU data for TRK SEL mode; it does not use the FMC. TRK SEL mode is available even if both FMCs fail.
@Victor,
Re: “Or perhaps the plane was in CMH mode at 15,000 ft instead of higher than 30,000 ft.”
Fuel was insufficient, unless some cargo/passengers were dropped/unloaded from the plane during 18:25-19:41 interval. Does this make sense? Also need to look carefully at IAS.
Re: “I surveyed the family of paths using CMH navigation and lower altitudes, and there are some paths with surprisingly good fits to the BTO data due to the wind fields at the lower altitudes.”
Exactly. Surprisingly good. BFO fit is also excellent. And the terminal location is generally between 27 and 29S, being in a good agreement with drift studies.
Re: “However, the indicated air speeds at the lower altitudes are in general too high for the required endurance.”
Yes.
Re: “The way around this is to apply lower altitude wind fields at higher altitudes, as you have done. However, I know of no justification for doing this.”
I was rather testing whether wind is a reason for a good fit. The answer is yes. The best wind field to fit BTO/BFO in CMH mode is at around 4,400 m (I screened at 200 m vertical resolution).
@TBill,
Re: “Can you show us a short data table of winds at the ping rings over the path, low vs. high alt? I always like to see the winds others use sometimes I use that.”
I have extracted wind components at the altitudes of 9,000 m and 4,400 m (the best fit) along the CMH path, where wind at 4,400 m was used as input forcing for the flight at 9,000 m:
https://www.dropbox.com/s/kjem3q0poebp9kb/wind_u_along_traj.png?dl=0
https://www.dropbox.com/s/mnf1s51pzgnhl2m/wind_v_along_traj.png?dl=0
The first observation is that wind would greatly affect BTO due to radial displacement. The second observation is that tailwind/headwind has very minor effect.
@DennisW – and other maths experts
I stumbled across this. Bachmann groups Any use ? Way over my head.
@all,
HERE is a new paper which addresses the MH370 route from 18:22 – 18:41.
I did two analyses. First, I refined my analysis of the OCXO transient errors at 18:25-18:28 and corrected the raw BFOs by removing the transient errors. Second, I built a new model for fitting multiple maneuvers and applied it to the 18:22-18:40 radar and satellite data.
I found that only the lateral offset maneuver at 18:24 can fit all the corrected data, including the 18:25 corrected BFOs.
After that, there are two possibilities (as before): a FMT south before 18:40 and an ongoing descent at 18:40. The FMT case before 18:40 must be accompanied by a significant reduction in speed from M0.84 in order to match the 18:40 BFOs. It is also likely that, if the aircraft descended at 18:40 at > 2,000 fpm ROD, it also slowed then. So, we have a slowdown at about 18:40 no matter whether you think the aircraft was southbound or was descending then.
@VictorI,
@Andrew,
Thanks for responding to my question on TRK SEL. It is clear that, if it only uses ADIRU inputs ,cross-track errors will accumulate over time.
@Oleksandr
Very nice…violates my rule of thumb for 180S paths that the East/West components tend to cancel out by the time you get to the end. Integrating under the curve, your CMH track @ 9000m gets much more East to West wind, I presume the more easterly trajectory of your heading keeps MH370 out of the stiff wind from West to East below 22S.
@Ventus
I never heard of Bachmann.
Some more drift animations:
https://www.dropbox.com/s/2r41trjm2l1zp79/Ensemble_85.72E_39.17S.mp4?dl=0
https://www.dropbox.com/s/r6eo9su7u0v86ap/Ensemble_99.09E_28.84S.mp4?dl=0
https://www.dropbox.com/s/dzaxvkdnrqpdqyp/Ensemble_105.75E_16.94S.mp4?dl=0
@Ge Rijn,
A long while ago you asked how debris from the southern locations along the 7th arc could reach Sri Lanka. Now you may watch how. The absence of debris in Sri Lanka is also indicative of 25-30S, btw.
@DrB
Very nice paper. I have to read more thoroughly, but Section 3 you say the change in strategy after 18:22 may be due to on-board events. But also UAE343 is coming up fairly closely from behind MH370, potentially accounting for some of pilot actions at 18:22.
@DrB
Do you have a reference for the channel bias differences you state in section 5.1 and use in Table 1. Thanks in advance.
@DennisW,
The references to the BFO bias corrections are given on the right side of the second worksheet in my BTO/BFO model (called “BTO & BFO Data”) HERE.
One of them goes back to December 2014 (Geoff Hyman and Barry Martin), and Mike Exner worked on it, too. I followed their lead and re-did all the calculations. In some cases, my results were very slightly different. It is important because you have to interpolate between the 22:41 and the 00:11 BFOs to determine the offset of the (second) phone call channel at 23:15. Then you can use that same correction at 18:40 for the first phone call. Without that second call, the uncertainty in the first call BFO at 18:40 would be much larger.
@DrB
Sorry, I could not find the “BTO an BFO Data” sheet.
@DrB
Take a look at the un-redacted logs. There is a spike in the BFO at 12:50:20 when MH370 logged onto POR. I overlayed it over the 18:25 warm-up transient and they appear to be essentially identical.
@DennisW: Here is the paper by Barry Martin and Geoff Hyman on the BFO bias for each channel.
@Victor
Thanks, I am familiar with that paper and actually raised several questions about it at the time. The most troubling questions had to do with what possible physical explanation could be given for these channel offsets when the channels were all driven by the same reference oscillator using the same BFO compensation algorithm? Never got any answers. I was hoping DrB had another source for that data.
Thee publication by the ATSB linked below implies that BFO biases were equivalent across different channels (page 21).
https://www.atsb.gov.au/media/5733650/AE-2014-054_MH370-Definition%20of%20Underwater%20Search%20Areas_3Dec2015.pdf
@DennisW,
If you look at the file in Google sheets, you will see at the bottom left three tabs for three worksheets. Pick the middle one. Ditto for EXCEL.
@George Tilton,
They are very similar, of course, as they must be. The only difference is the first BFO for the Log-on Request. The only time it is not very high is at 18:25 UTC, which is the only log-on after an extended unpowered time in flight.
That power-up at 12:50 UTC on 7 March 2014 is Log-On #6 in Table III in Ian Holland’s paper “The Use of Burst Frequency Offsets in the Search for MH370”.
@DennisW,
I can’t provide any info as to the physical cause of the frequency differences among channels, but I recall ALSM saying once they were actually a multiplicative effect, not an additive effect. Maybe he can answer your question.
On the “equivalent” statement by ATSB, I take that to mean the differences were small. In three cases the correction is nearly zero. In five cases it is about 4 Hz. Looks like 2 groups to me. I have no doubt about the reality of measurable differences – the 4 Hz ones, anyway. The small ones could be measurement noise.
@TBill,
You said: “But also UAE343 is coming up fairly closely from behind MH370, potentially accounting for some of pilot actions at 18:22.”
That is an interesting thought, but since 9M-MRO was flying at M0.84, it was probably flying faster than all other commercial traffic. I have not kept up with UA343’s route, but I don’t think it would gain on MH370. Where was UAE343 with respect to MH370 near 18:22?
@George Tilton,
You can also see the 12:50 UTC Log-On (Event #6) plotted in Figure 3 of my paper on the OCXO transient effect from last March, which you can get HERE.
@Drb
@Tbill
Bobby, I’ve sent you an email as regards predicted UAE343 flight path in that part of the SOM for that date.
@DrB
Congratulations on another very thorough paper. I want to reread it before posing a few questions for you but in the interim a quick clarification please. On p.2 you refer to “… the ATSB conclusion that N571 was followed from MEKAR to NILAM …“. What is your reference for that please? I can’t recall reading that the ATSB have ever said that they thought that the airplane tracked along N571 between MEKAR and NILAM.
@Oleksandr
Interesting animations again. Suprising indeed your 39.17S animation shows particals landing on Sri Lanka and even the Indonesian Islands and Thailand in late 2015.
But it’s clear the fast majority of particals drift towards Australia and many land there before the end of 2014.
So I think also according your model we can effectively rule out this latitude as an origin of the found debris.
Your 16.94S animation shows many particals landing on Sumatra and Thailand after two months and arrive in great numbers on the African coast by august 2014 which is much too soon imo. And they pass Reunion and the other islands far north.
So I think we can effectively rule out this latitude too according your model.
That leaves your 28.84S latitude. Main problem here is imo particals start to arrive on Reunion and the other islands as soon as may 2014 and start to arrive on Madagaskar in great numbers as soon as july 2014 covering the coast of Madagaskar by the thousands at the end of 2014.
This is way too soon imo. I think 28.84S is too far north for this reason.
Do you have an explanation for this related to the timing of the found pieces especially the Flaperon?
@DrB
OK. Thanks again. I don’t think any of the values are large enough to impact your conclusions in any case. I was just trying to determine if there was a BFO reference I missed along the way.
@Oleksandr
Another question. Maybe you mentioned it before but I cann’t recall.
How many particals you put in your model to start with?
@DrB: Very nice work, as always. I have two quick comments:
1) I don’t understand the basis for concluding that it is most likely that MH370 followed N571 after MEKAR. The radar data says otherwise. I understand that the radar data may be unreliable at maximum range, but what evidence is there that MH370 continued on N571? A route discontinuity at MEKAR seems more likely.
2) I don’t understand your reasoning for rejecting 4C, i.e., a slowdown and turn to the right after passing MEKAR, and an ongoing descent at 18:40. Depending on the exact timing of the deceleration and turn, I find acceptable solutions for 225 KIAS and 308° towards VOCX. The route discontinuity in route at MEKAR is easily explained by the discontinuity added when the [runway] for VOCX is selected.
@Victor
Re: “The route discontinuity in route at MEKAR is easily explained by the discontinuity added when the STAR for VOCX is selected.”
There’s a STAR for VOCX?!
@Mick Gilbert: You are correct. There is neither a STAR or approach for VOCX. I was referring to the process in which VOCX is selected as the arrival airport and a runway is selected, which would produce a route discontinuity.
@VictorI
Am I still right in thinking a route discontinuity after FMT will produce a CMH route?
@Joseph Coleman @DrB
“Bobby, I’ve sent you an email as regards predicted UAE343 flight path in that part of the SOM for that date.”
I am thinking that there are two flight path versions for UAE343 floating around:
(1) estimated “raw” FlightAware flight path (which interestingly shows a path offset from N571 a little like we are thinking for MH370); and
(2) adjusted-to-N571 FlightAware flight path (whereas the ATSB/JIT team apparently adjusted Flight Aware data to N571- suggesting to me the teams knew the estimated flight path was wrong and it really went on N571.
In both cases UAE343 is approx. 6 minutes behind MH370, after MH370 finally catches up to path N571 at VAMPI. The SLOP offset would take about 3 minutes, so now they are neck-and-neck, so to speak.
From the recent ATSB report, sounds like JIT studied UAE343 closely and decided it was really on N571, at least thru around MEKAR. Presumably JIT contacted Emirates to get the route details of their UAE343 flight. This would be good info to have…
…if there is any truth to the FlightAware “estimated” path which is offset from N571 (that we got from Joseph a few weeks ago) then UAE343 would be inadvertently chasing MH370 up thru the Andamans and VOCX.
@DrB:
Thank you for taking the BFO warm-up transient analysis a step further. Since I first proposed this concept (swag concept first shared online circa 11-2-2016; https://goo.gl/91Pj9J) and discussed it with you, there has been both support and skepticism in the blogosphere. Then Holland published his paper on 2-16-2016, providing additional OCXO warmup data that was consistent with the transient theory (although Holland did not recognize at that time what caused the pattern he published). At my request, ATSB organized a conference call with Holland to discuss the warm-up transients. Victor and I were all set to dial in when DSTG upper management cancelled the call without any explanation. Oh well…Then you published your first paper on 2-27-2017, which provided a much stronger and more detailed explanation for the transient. Then the unredacted log was leaked by NOK, and we got additional confirming data. Your latest BFO calibration refinement and path analysis leaves no doubt that the warm-up transient caused the anomalous values circa 1825, and your estimated corrections are well founded. Now, we not only know what caused the anomalies, we can actually use all the corrected values (with caution) for path reconstruction.
Three additional notes:
1. Your preferred route (5a) is remarkably close to what we concluded in December 2014 https://goo.gl/cez6yq
2. Re. Kate’s observation, the estimated route was only 2nm from her position, but the timing was off by nearly 30 minutes https://goo.gl/dvHfPu If she did see MH370, one of the other (delayed; slower) routes must have occurred.
3. While I agree with your excellent re-analysis, if there is a hidden assumption here, it is that the response was a classic text book 2nd order “overshoot”. I’m sure it was close to that, but in the real world, the true response will be slightly more complicated due to the interaction of the thermal and mechanical properties of the oven enclosure. Thus, the error bars might need to be slightly greater, but the basic 2nd order response is an excellent assumption.
@DrB
P.S.- in my mind there are at least 2 air traffic aircraft that could have influenced/interfered with MH370’s flight plans:
(1) UAE343
(2) Singapore AWACS-type radar plane in the area
Am I still right in thinking a route discontinuity after FMT will produce a CMH route?
The work of @Andrew on a Level D simulator suggests that a CMH path is followed when A/P is engaged, LNAV is selected, and a route discontinuity is reached.
Victor: Re “…a CMH path is followed when A/P is engaged…”, doesn’t that depend on the mode selected (Normal vs. True, and Heading vs. Track)? I suspect that is only true if the mode was Normal. It could have been Normal-Heading or Normal-Track before, and CMH after the final waypoint, but I think all that would change if True had been selected instead of Normal.
@ALSM asked: doesn’t that depend on the mode selected (Normal vs. True, and Heading vs. Track)?
I don’t think so. If the A/P mode automatically transitioned to TRK/HDG HOLD after the discontinuity, I would agree. But that’s not what happens. The mode remains in LNAV and an FMC message is generated alerting to the discontinuity. The positions of the NORM/TRUE or TRK/HDG switches do not influence the behavior in LNAV mode, I believe even after a discontinuity.
@Andrew of course would be better to answer this than me.
Victor: But why would LNAV default to a magnetic track or heading? Internally, the math is in the true reference frame, right? If the code doesn’t read the True/Normal switch, why default to magnetic?
@DrB
While I agree that an early FMT is more likely, I wonder why you suggest a 180 degree course. How do you propose to comply with the 19:41 “ping ring”?
@ALSM: Yes, I agree that the “simplest” logic would be a constant true heading path, as no adjustments to the heading would be made for wind or magnetic declination.
The reason to default to the magnetic heading after a discontinuity may be related to what would be expected in an aerodrome under ATC instructions. If the discontinuity is part of an approach, for instance, ATC might be expecting the aircraft to maintain a magnetic heading until further instructions are given.
@ALSM
From prior discussions, my understanding is that the raw “math” is all in ideal sphere coordinates, and what we see (CMT, CTH, etc) is a calculation off that basis. So I am thinking there is not no-calc base base.
@Victor
PSS777 at least my installation works the way you are describing (CMH), whereas I know you have said PMDG seems to be wrong about that.
I already said a few days ago how important this relatviely new understanding is, I feel.
@Tbill
So where do you believe the route discontinuity (reaching the last waypoint) occurred?
@Ge Rijn,
Re: “That leaves your 28.84S latitude.”
I have screened 40 locations, but prepared animations only for a few of them.Generally there is gradual transition in terms of the distribution of beached debris.
Re: “Do you have an explanation for this related to the timing of the found pieces especially the Flaperon?”
1. You need to keep in mind that this is a probabilistic model, not deterministic. There is no way to know how many floating pieces were generated by the crash, and were their floatation characteristics. Each particle is subjected to deterministic and stochastic forcing, so that only the average is meaningful.
2. In connection with #1, only significant is the arrival of a subset of particles to the same location, not just a single particle. The number particles in this subset must be proportional to the number of objects generated by the impact (which is unknown).
3. My ensembles are comprised of particles of different leeway factors. High-windage items (>5%) travel notably faster.
4. We don’t know actual arrival time of the flaperon. A half of it was covered by sand, indicating that it was on the beach for a while before discovery. Do you have any idea when fragments found by Blaine arrived to Madagascar? I don’t.
5. My model does not differentiate between 9M-MRO fragments and MH370 objects. Who would pay attention to a plastic bottle, remaining of a bag etc. in 2014?
6. I am sure, most of villagers in Madagascar have never heard about MH370. Awareness is one of the key factors.
Re: “How many particals you put in your model to start with?”
50,000. Same as UWA. In comparison: Jensen used 5,000; GEOMAR – 2,000,000.
@Dennis,
Re: “The most troubling questions had to do with what possible physical explanation could be given for these channel offsets when the channels were all driven by the same reference oscillator using the same BFO compensation algorithm? Never got any answers. I was hoping DrB had another source for that data.”
Relax. I have also asked this question many times. Also never got any answers. My impression is that this ‘invention’ was proposed only to justify inability to fit SATCOM calls’ BFOs within the frames of the same models and assumptions.
@ALSM
In “notes on Kate Tee observation” there seems to be a UTC +7 hours assumption for the time base in the excel file with GPS readings which was shared. Could you confirm and explain that?
@DennisW
“So where do you believe the route discontinuity (reaching the last waypoint) occurred?”
Not sure what you mean, but I feel the flight was probably intentional and one possibility the pilot intentionally keyed in 180S True Heading somewhere around ISBIX. ISBIX is almost 180S of BEDAX, so Victor has already staked out the 180S True Track from BEDAX or SPOLE option.
But even McMurdo option, yes if you keyed in say POLUM the discontinuity would probably follow a similar CMH trajectory as NZPG.
@TBill
My thought was that the transition from LNAV to CMH was what you were referring to in your comment about the importance of understanding that magnetic heading is used at that time. If Shah simply entered the 45S simulator waypoint there would never have been such a transition before fuel exhaustion.
Cocos is another reasonable possibility with even more time for an Eastward drift when transitioned to CMH.
@Olex: (4) Presence of fresh Lepas barnacles on the flaperon should establish that it had reached that position on the beach within a week or two of discovery. If there was any pattern to the beach clean-up patrol, the time may be restricted further. Of course it could have reached Reunion and washed around a bit before casting up on shore.
The Rob piece [first observation at Mossel Bay, with Lepas] also gives a tight window for its arrival. Most or all of the remaining pieces could have lain on the beach for weeks, months, or years before retrieval.
6) “Awareness” — very apt, but not limited to villagers in Madagascar. As far as I can tell, only the Australians actually looked for debris. Being affluent and reading newspapers or watching cable news doesn’t mean that someone on the west shores will connect fragments [unless, perhaps, an obvious airfoil like the flap or flaperon] with an airplane, and let alone MH370. Each of the pieces found in South Africa and Mozambique by parties not named Blaine Gibson have a story of being looked at more than once, or taken home as a souvenir against parental judgment, etc, etc. South Africa, like Australia, does large scale beach cleans. Unlike Australia, there was never an MH370 alert. And none of the recoveries came via the clean up.
Also, Olexander, I was interested early on in how you found Sri Lanka to be a “tell” for different sources along the 7th arc. Again, one would think that absence is not an artifact — there’s a large urban complex along the sw coast with many prosperous residences along the coast highway. Also many resorts along the se, s, and east coasts. But I’m not persuaded that anyone in that population would have paid attention to smallish fragments of aircraft composite. any more than the first 100 or so RSA folks did for the ‘Roy’
If the Madagascan pieces lay on the beach for a long time, it might still be worthwhile for someone to buy Blaine tickets to a few of the SL resorts?
Responses to all inquiries are segregated below:
@Mick,
You said: “On p.2 you refer to “… the ATSB conclusion that N571 was followed from MEKAR to NILAM …“. What is your reference for that please?”
ATSB Report on 26 June 2014: Page 38 says “Primary radar data showed that the aircraft tracked along the Malacca Strait. During this time the aircraft passed close to waypoints VAMPI, MEKAR, NILAM and possibly IGOGU along a section of airway N571.”
@DennisW,
You said: “I don’t think any of the values are large enough to impact your conclusions in any case.”
That is correct. Even a 4 Hz change in channel frequency bias is swamped by the best-fit 27 Hz difference from 18:25 to 18:27.
@VictorI,
You said: “1) I don’t understand the basis for concluding that it is most likely that MH370 followed N571 after MEKAR. The radar data says otherwise. I understand that the radar data may be unreliable at maximum range, but what evidence is there that MH370 continued on N571? A route discontinuity at MEKAR seems more likely.”
First, I will address the question on following N571. The last two radar points are both to the left of the MEKAR/NILAM track on N571. That is the reason I initially thought the aircraft continued without turning at MEKAR. However, NEARLY ALL the radar positions are to the left of N571 (by a small distance) between VAMPI and MEKAR. It appears there is a slight bias in the radar locations toward longer range in this map. This small bias can explain the two last points both being to the left of the MEKAR/NILAM track. I tried fitting from both assumed 18:22:12 positions. Starting at the last radar contact position, the fits are not very different from what I presented, and none of the conclusions are altered, as I said in the paper. Just look at the route map at the top of Figure 8 in my paper. See how close the last radar contact and the N571 locations are to each other compared to the size of the SLOP. It doesn’t matter which one you start from.
Second, I will address the possibility of a route discontinuity at MEKAR. The complete set of satellite data, now including the 18:25 CBFOs, is inconsistent with a discontinuity at MEKAR, which would essentially extend the VAMPI/MEKAR track at 286 degrees true. The satellite data require a double turn to the right/left (or a SLOP) beginning at 18:24 (which is before reaching NILAM if you are following N571). Delaying that first turn until after NILAM is reached (or to ≈ 18:25) does not produce an acceptable fit. My logic is simple. You have to have a double turn or a SLOP starting at 18:24, and by 18:25 you have to be traveling essentially northward. The SLOP would be used if one wanted to move off the currently followed Airway. A double turn could look like a SLOP, but only if there is a nearby waypoint corresponding to the “apex” of the turns. That is, you would need a waypoint in between the right and the left turns. There are none, since NILAM is far too close, and there are no others in the right place. So, my thinking is that it could not have been a right turn to a nearby waypoint followed shortly by a left turn to a course which is parallel to N571. Therefore, it must be a SLOP. Remember also that the post-SLOP course is determined by the satellite data to be 296 +/- 8 degrees (which matches being parallel to N571.) The only solution I can see is a SLOP to the right of N571. Single turns, no matter when executed, cannot fit ALL the data.
VictorI also said: “2) I don’t understand your reasoning for rejecting 4C, i.e., a slowdown and turn to the right after passing MEKAR, and an ongoing descent at 18:40. Depending on the exact timing of the deceleration and turn, I find acceptable solutions for 225 KIAS and 308° towards VOCX. The route discontinuity in route at MEKAR is easily explained by the discontinuity added when the [runway] for VOCX is selected.”
HERE are the plots of the best fit for Route 4c. Look at the BFO errors. You cannot fit the 18:25/18:27/18:28 groups with a single course.
The difference in your result and mine is probably that you have not used the 18:25 BFO data at all, and, if you used the 18:27 BFOs, you may not have corrected the 18:27 BFOs for the transient errors (which are large, at 32 Hz). When you use the corrected 18:25 and 18:27 BFOs, as I have done, the route you described (my case 4c) is found not to fit.
@ALSM,
You said: “Re. Kate’s observation, the estimated route was only 2nm from her position, but the timing was off by nearly 30 minutes . . . .”
Kate Tee was in a position to have seen the aircraft anywhere from 18:45 to 19:10. Her recollection, several days later, was that it was just before the jibe at 19:15. Possibly her recollection of what she saw was good, but the time interval before the jibe was a bit misjudged. She did not have a clock to look at then, and she did not make contemporaneous notes. I am quite sure she made every effort to be accurate and precise, but I am thinking the unusual image of what she saw is more likely to be faithfully remembered than the exact time when that occurred (of which she was not aware at the time). At what time did you have lunch 3 days ago? Remember she was on a northerly course for quite a while before the jibe., and I think she could have made the sighting at any time from 18:30 to 19:10. Isn’t is striking that there is such a close match in location and time? The difficulty is that, if 9M-MRO were the aircraft she saw, how could it have flown at that low altitude until MEFE (if it actually did)?
ALSM also said: “While I agree with your excellent re-analysis, if there is a hidden assumption here, it is that the response was a classic text book 2nd order “overshoot”. I’m sure it was close to that, but in the real world, the true response will be slightly more complicated due to the interaction of the thermal and mechanical properties of the oven enclosure. Thus, the error bars might need to be slightly greater, but the basic 2nd order response is an excellent assumption.”
Yes, the second order equation assumption is just that. There are far too few BFOs to determine any minor deviations from that response curve. That assumed servo step response is the simplest form that is consistent with all the log-on data sets we have.
@Niels,
You said: “While I agree that an early FMT is more likely, I wonder why you suggest a 180 degree course. How do you propose to comply with the 19:41 “ping ring”?”
I have already done so with a both CTH route and a CMT route (both posted previously several times), which begin at or very near the IGOGU/ANOKO/NOPEK line at the end of the FMT and comply with all the later arcs, including the one at 19:41. The CTH case is, in fact, the example I used in my BTO & BFO Model spreadsheet. It has a constant heading value slightly larger than 180 degrees that would have been the case with the slight westerly wind there if on a 180 degree true course when the CTH was begun.
@VictorI and ALSM and Andrew,
My recollection is that Andrew’s simulator tests conclusively proved that a CMH route was followed (if the NORM/TRUE switch was set to NORM) after a route discontinuity or an End of Route error occurred, depending on the position of the NORM/TRUE switch. If the switch were set to TRUE, the route would be CTH. Andrew will correct me if my memory is faulty.
Niels: Yes, there is an offset between the excel file times and the raw GPS times in UTC. The excel times are UTC-7, so add 7 to the excel times to get UTC. I have forgotten the exact reason, but I recall it had something to do with the way MapSource interprets .gpx files (raw data file). The data is in UTC (Z at the end of the times), but MapSource/Windows thinks it is helping by converting to local time (not), depending on what time your computer is set to. In this case, MST, which is UTC-7. It took some time and help from someone to figure out what was happening. But it is easily confirmed by comparing the excel data at 12:15 and the .gpx raw data at 19:15.
Three examples pulled from the .gpx file at the Jibe Time follow.
Longitude: 94.437735
Latitude: 6.628159
Altitude: 52.493 ft
Speed: 2.0 mph
Heading: 257.9
Time: 2014-03-07T19:15:45Z
Longitude: 94.439441
Latitude: 6.627305
Altitude: 49.344 ft
Speed: 1.6 mph
Heading: 116.7
Time: 2014-03-07T19:20:45Z
Longitude: 94.441389
Latitude: 6.627375
Altitude: 49.344 ft
Speed: 1.6 mph
Heading: 87.9
Time: 2014-03-07T19:25:45Z
@DennisW
” the importance of understanding that magnetic heading is used at that time.”
Let me be clear on the point, because I feel we often make innuendos here, but I never know how somebody else’s innuendo ends (you have to spell it out for me).
The ATSB path to 38S was basically a straight path assuming a hypoxic, unintentiomal “Payne Stewart” look-alike flight. But that flight path would be curved, not straight (not sure about Lear jets as my 777 pilot friend tells me Lear Jets are peculiar).
So the Bayesian answer (38S straight path) never matched the assumptions the ATSB started out with. Until approx. 12 months ago, this was not a logic issue because we all assumed it was True Heading after discontinuity. So the implication to me is 38S search was a “wild goose chase”.
I know some wee it differently. But I think Ge Rijn is trying to say, and perhaps correctly, all of the path models and Bayesian models really say that there is no way to model this flight as a curved, unintentional flight. By default the models are saying intentional path. The “unintentional flight” proponents might be better off accepting an intentional loiter, which might at least yield a few possible curved paths (eg; Oleksandr is on the right track…but…I end with another innuendo).
” some see it differently” apologies
@Ikr,
Re: “Presence of fresh Lepas barnacles on the flaperon should establish that it had reached that position on the beach within a week or two of discovery.”
Why could not they grow on the side, which was still in the water, taking into account tides? I have analysed winds and tides at La Reunion, but no obvious reason to be washed ashore during the last week but not a month before.
Re: the Mossel Bay piece…
According to the description it was waterlogged. A storm was a day or two earlier with winds blowing from the east or north-east, coinciding with high tide. I think it is reasonable to assume this piece arrived a day or two before it was found.
Re: Sri-Lanka.
I think it was Ge Rijn, who proposed that tourists in Sri Lanka would eventually found fragments if they were washed ashore there. Keeping in mind that tourism in Sri Lanka is really blooming, I would concur.
Re: fragments in Madagascar.
CSIROs model shows the same. Just nobody is looking there. One of the problem would be logistic: no roads, swamps, etc. But the authorities could certainly organize the search if they were willing to.
@ALSM,
Mike, thanks for posting the links. I updated my paper to include references to the two papers on the OCXO compensation and the FMT timing, and I also made an explicit reference to the assumed 2nd order OCXO response. This kind of feedback is very helpful. The new Rev 1 is at the same link. So far, I did not make any other substantive changes, but I will if the need arises.
@DrB
Thank you for that reference. I don’t think that saying that “… the aircraft passed close to waypoints VAMPI, MEKAR, NILAM and possibly IGOGU along a section of airway N571” is the same as concluding “… that N571 was followed from MEKAR to NILAM“, particularly when three years after that initial statement was made there’s no radar data placing the airplane within 20 nm of NILAM, leave alone IGOGU.
I’m with Victor (mark the date, Victor) on the airplane most likely having initially maintained its previous heading post-MEKAR.
@ALSM
@Victor
@DrB
My work in the simulator showed that, outside the polar region, the autopilot maintains a CMH following a route discontinuity, with the HDG REF switch selected to NORM. At the time it wasn’t clear if the autopilot would maintain a constant heading or a constant track after the discontinuity, because there is conflicting information in the Boeing/Honeywell manuals. The test was only designed to settle that conflict and unfortunately there wasn’t sufficient simulator time available to repeat the experiment with the HDG REF switch selected to TRUE.
The HDG/TRK switch shouldn’t affect the result, but I believe HDG REF switch will cause the autopilot to maintain a CTH after a discontinuity if the switch is selected to TRUE. I asked one of our engineering specialists that question some time ago and he said my understanding was correct.
I have been on the road the last several days, and keeping up with all that is happening is difficult.
DennisW, you said, “In those days a hydrogen maser was the size of a refrigerator.” In those days, a tape drive was the size of the refigerator, and we had several. Additionally, there were rows of relay racks crammed with equipment. I cannot recall if I ever saw the maser. Even though it was far better than cesium or rhubidium, it was hardly perfect. The data analysis included various “clock terms” to account for the imperfections – kind of like how we have a Fixed Frequence Bias and, at one time, a rate to account for the Anti-Perth effect.
While flying home today (pilot said the plane was just a month old, accounting for the “new plane smell”), I was working on routes defined by the simulator data files and found it notable that one could very nearly connect together the N10 and S45 points with a CMT route starting from N10 with a heading 180S, and (depending on what winds, if any, were used in the simulation) exactly connect them with a CMH route of the same heading. These routes are in addition to the McMurdo route already reported. Has anyone else noted that previously? [Perhaps TBill?]
If one wants to throw darts at the SIO based on the simulator data, there are still multiple places for the darts to land. One could probably add in CTT and CTH routes as well.
The complete set of satellite data, now including the 18:25 CBFOs, is inconsistent with a discontinuity at MEKAR, which would essentially extend the VAMPI/MEKAR track at 286 degrees true.
Bobby, I was referring to a decel and turn AFTER the discontinuity, not a continuation along this heading for any length of time. I recognized long ago that two manoeuvers are required to match the BTO–two turns, or a decel and turn.
The difference in your result and mine is probably that you have not used the 18:25 BFO data at all, and, if you used the 18:27 BFOs, you may not have corrected the 18:27 BFOs for the transient errors (which are large, at 32 Hz).
The only BFO values I trust are the two at 18:28, which show evidence of having reached the final value. I don’t believe you can fit the others with sufficient accuracy, especially considering the slope of the curve, to extract any useful information. The path of 308°, 225 KIAS, and FL340 (with the turn commencing between 18:21 and 18:22) fits the BTO values and BFO values (at 18:28) nicely. You obviously disagree. That’s fine.
@Andrew
@Victor
@DrB
Thanks for confirming mode selected for the tests Andrew.
@sk999 said: While flying home today (pilot said the plane was just a month old, accounting for the “new plane smell”), I was working on routes defined by the simulator data files and found it notable that one could very nearly connect together the N10 and S45 points with a CMT route starting from N10 with a heading 180S, and (depending on what winds, if any, were used in the simulation) exactly connect them with a CMH route of the same heading. These routes are in addition to the McMurdo route already reported. Has anyone else noted that previously?
Back in June 2016, I investigated CMT and CMH paths and I found two that end near 45S,104E. (At the time, the simulator data was not yet public.) Here are two paths that pass through BEDAX with heading and track selections of 180°. In order to match the BTOs, I had to impose a (decreasing ground) speed profile of 310 KIAS and a constant descent of 100 fpm. The problem with this path is it will burn too much fuel as the air speed is high, so I haven’t done much with it.
I’m not sure you have followed, but I have recently proposed another possibility for a sim data-based route. Accepting 45S,104E as the final waypoint, the great circle path that satisfies the satellite data starts just to the east of Car Nicobar and crosses the 7th arc near 28.3S latitude. This path is referenced in Figures 1 and 2 above. An impact at this latitude would also produce debris that would drift to where some unidentified debris was photographed by the aerial search on March 29, 2014 (see Figures 5-7).
I should add that Brian is working to find the exact coordinates of other debris that was photographed on that same day.
@Ole.: I would respectfully disagree that western tourists would be more likely to recognize and report the first SL debris. Perhaps more likely an independent cleaner like the Reunion guy. Absent some clue that debris might be present, most of the smaller shreds of composite would be completely overlooked.
In the spirit of VIs suggestion that we should be helping OI, I’d suggest that it would probably pay OI to recruit a crew, have them trained in by Blaine [if he were willing, if not, by one of his Madagascan contacts], and make intensive surveys in Sri Lanka and any other coast that differentiates latitude of origin along the 7th arc.
Best prospect would be to select sandy reaches with low populations. I’d think that a small crew, perhaps 3-4 persons on ATVs could sweep 10-20km of beach in a couple of days, perhaps 3 reaches in a week. So, Olexander,accrding to your models any suggestion of 3-4 such stretches of shore that would best differentiate 7th arc origins?
@Victor
To clarify my statement above (which is only significant re: PSS777 simulator)
PSS777 at least my installation works the way you are describing (CMH), and it is CMH also even if the TRUE switch is on, after a discontinuity.
I do gather PSS may have made corrections to that behavior over the course of software upgrades, so I am thinking the final updated PSS version behaves like you said.
@TBill: The problem with both the PSS777 and PMDG777 models is they use the FCOM as a reference for how systems operate. If something is poorly documented or missing in the FCOM, it’s difficult to know whether it will be properly modeled.
@lkr suggested to make intensive surveys in Sri Lanka and any other coast that differentiates latitude of origin along the 7th arc.
At this point, any new debris would have little value in helping to estimate the impact point along the 7th arc.
@sk999
You are showing your age. Yes, the big reel to reel machines (Honeywell and Bell & Howell) were the way data was collected before disk farms. And yes, they were the size of a refrigerator. My second startup was a company called Bancomm. Our mission was to offer bandwidth compression technology (which I was heavily involved with back in the early sat recon days) for a number of applications including voice and video. Along comes the CIA, and asks me (along with a big check) to develop a timebase corrector for the reel to reel machines. So we did, and sold a ton of them. Never did do any bandwidth compression. Sold Bancomm to Datum back in the late 70’s, and bought a big place in Morgan Hill. Got bored after awhile, and went back to work.
Our timebase corrector was called the Tymcor 1400. Maybe you used one along the way. They worked really great. Found one on line. 🙂
https://www.surplustraders.net/tymcor-model-1400-digital-time-base-corrector.html
Victor,
Victor,
My work today was not based on MH370 satellite data – it was strictly based on the sim data alone. N10 to S45 via CMT or CMH, very nearly 180S heading/track at N10. Have you examined such routes?
I came across this document (https://www.aea.net/AvionicsNews/ANArchives/SatComDec03.pdf) explaining the Satcom system in lament terms.
I have a few questions that i am sure some of you will have the answers:
1) It was mentioned in this blog that the SDU relogon may be due to restablishement of power after a power failure. Q: Based on this document, any power on will trigger a self-test. i presume this is done before any log on transmission takes place. Does anyone know how long this self test last? would the plane moving influence the result from this test? and in case of negative test, will the SDU freeze, restart or continue with the fault on in degraded condition?
2) The technology uses a Beam Steering Unit for the antena(s). I wonder whether a jaming of this unit while the plane was manoevering could explain the loss of signal (beam misalignment) and the subsequent relongon (beam coincidenly pointing to the IOR satelite)?
Can cabin depressurisation freezes that mechanism?
3) Compensation algorithm. Is this implemented on an EPROM solid state logic on the SDU or else? ie is it configurable or set at manufacture?
@sk999 asked: Have you examined such routes?
Not really. The sim data shows evidence that the plane was manually advanced along the route. While it is possible to do this along a great circle between waypoints as the path would be shown in the MAP view, I don’t see how this could be done for CMT or CMH paths.
@sk999
Yes I have also mentioned 180S 2005 Magvar from 1090E with 25-knot wind from West (“Fair Weather” setting in FS9) is close.
Mick was first to suggest that.
Here is some data where 180S w/ 25 knot wind from 1090E hits 45S:
Case-1: 45S @ 105.3E (FS9 default Magvar – circa 1995)
Case-2: 45S @ 104.3E (FS9 magvar updated to 2005) only 7 nm from 45S1
Case-3: 45S @ 103.2E (FS9 magvar updated to 2017)
But later work I feel the N10 turn points directly to DOTEN (not 1090E) so I am thinking that going exactly thru N10 may pull Case-2 a little further east.
The magnetic epochs change results about 42 nm further west each 10 years forward.
DennisW,
All the precision timing experiments I worked on were pre-GPS. For the record, at one time I also worked on primary radar data which has a range of 24 million nm. Somewhat greater than the range of a RAT-31DL.
@sk999
Seems to me a curve going thru 10N *exactly* ends *exactly* on the DOTEN to NZPG great circle when the turn is completed. This possibly proves the path is DOTEN to NZPG (but I have not tried the same experiment with 180S).
It raises the question if Z somehow knew or had a way to fix to FS9 such that the 10N turn is started at the exact correct timing. This is where I am up to.
@VictorI,
You said: “Bobby, I was referring to a decel and turn AFTER the discontinuity, not a continuation along this heading for any length of time. I recognized long ago that two manoeuvers are required to match the BTO–two turns, or a decel and turn.”
Yes, Victor, I know what you meant. That is what my case 4c does, just from a starting point about 2 NM away from a brief extension through MEKAR, which is immaterial to the results. The bottom line is that neither a simple extension, nor a turn only, nor a turn and a slowdown, can match the corrected 18:25-18:28 BFOs. If you don’t include all the data in the fit, then you are less constrained and simpler maneuvers can appear to fit.
@Victor. Search priorities after the 25,000 sq km. You look still for suggestions with logic. Below I flesh out the logic behind my proposal of a couple of days ago.
Assume 600 sq km/day to be the OI search rate. The duration of searching will be constrained either by search season, the contract, OI funding, or whether the search vessel and/or expertise would have been spoken for elsewhere. With no clue as to the others, as a constraint I choose search season, arbitrarily of 85 days. This is just for illustrative purposes, as before.
From the ensuing search area total, after completing the ATSB 25,000 sq km there will be 26,000 left and 43 days supplementary searching remaining.
We can be confident that the wreckage will be close to the 7th arc, probability reducing with width from it.
What we cannot be confident about is where along the arc it is. Blurring of probabilities there stems from FMT assumptions, imprecisions with BFOs/ BTOs, uncertainties in fuel consumption, historical weather and other data accuracy and navigation mode selection. Then there are broader imponderables like what a pilot might have done if active until close to fuel exhaustion. Added to all this are questions as to the realism of some models and simulations, particularly some drift models. Overarching the lot are other arguables of judgement and interpretation.
As to supporting indicators, if the search of the ATSB area has drawn a blank this not just affects confidence in the interpretation of the French satellite images but also some specifics of the CSIRO drift assessment; even though that still would support other prospects farther to the NE. Regarding surface searches, these had to cover such large areas for the aircraft available that as indicators they have little value.
Thus while the ATSB area has hot spots there is none with like empirical and analytical support outside that.
Of the remaining prospects I argue that the lode close to the 7th arc offers high detection probability while the above uncertainties obscure variations in probabilities along it, so these should be treated as even. Therefore the width of a search along the arc should be even.
Based on some figuring you did earlier, supplementary search capacity would allow one sweep along the arc from the area already searched (32.6˚S) to 28˚S, and return, each of 10 km width (5.4 nm). Widening of the search at the two warm spots on the way (29.75˚S, 28.3˚S) would detract from reaching the end and I doubt that the probability at the increased width via supplementary runs there would be higher than that right alongside the arc farther up.
Likewise for a transit up to the third warm spot at 26.95˚S, if 28˚S were the aim point otherwise, to elect that transit would mean a shortfall of a day’s searching overall and the aim point would not be reached.
That transit time includes that elapsed during AUV/USV recovery and redeployment and also the time making up the lost distance while stopped. The total comes to close on 7 hours by my estimation to which of course should be added the actual transit time. Seabed Constructor’s service speed is 12½ knots.
More generally, electing to take advantage of service speed in a transit would be warranted if searching between the departure and arrival points were superfluous and the distance more than around 25 miles, transit at service speed thereafter reducing the total time to a more distant destination. The penalties of transits in lost search time though would need to be addressed if ATSB hot spot searches were to be separated as an first priority.
Also about the 25,000 search I take it that that amount at least (supposing no wreckage find during it) would be contracted, that is disregarding a Malaysian remark that the tripartite preferred 5,000. Otherwise the question would arise as to whether completing that in width, or indeed more than just the hot spots’ search, would be more or less prospective than swapping it for an extension of the supplementary NE search; though I would expect the full ATSB search would retain its priority even so.
The figures above are indicative only (for example I suspect the search rate would exceed 600 sqkm/day) as is of course the assumption of an 85 day season. Extending that broad brush though, were the OI budget to be limited to half that required for the 26,000 supplement, just one run straddling the arc would be possible. On the other hand an increased search rate, extended season or second season might allow the NE search width to be extended, or the 25,000’s width for that matter, the latter depending on priorities at the time.
@VI: My suggestion that OI do their own shore survey in such places as Sri Lanka and Sumatra was only semi-serious. But the idea that Western guests at fly-in resorts would have found any debris [which I’ve debated with Olex and others off and on] is risible. To my knowledge not one piece has been found by a tourist who didn’t have a boat or caravan to haul souvenirs back home..
Knowing the qualitative spread of debris should be as useful as the surface search has been in restricting the area to be searched. And unlike the surface search, shore search may offer a do-over.
@David: Thank you for your thoughts. I am fairly certain that OI will first search the full 25,000 sq km, and then if required, continue in other areas.
@Victor
MY says they have plenty of time to decide on OI, but it is already getting too late to hit the ground running on 1-Jan when the weather is favorable.
@TBill: Ignore what Malaysian politicians say.
@TBill
MY says they have plenty of time to decide on OI, but it is already getting too late to hit the ground running on 1-Jan when the weather is favorable.
As a practical matter, what value is there in finding the wreckage in 2018? The FDR will show that it was flown to where it was found. The CVR will be blank. The only element of urgency has to do with the useful life of the FDR data, and that should be relatively long at the temperatures where the FDR is likely to be located.
People here continue to generate spreadsheets. We have been watching this movie for three plus years now. It has yet to have a happy ending. Spreadsheets are not now nor have they ever been of any significant value. The ISAT data tells us three things, and only three things:
1> The plane went South
2> The plane came down rapidly at the end
3> The plane is located near the 7th arc
Beyond that, there is nothing the data can reliably tell us. Assumptions relative to the flight dynamics are just that. Likewise which switch was in which position is “feel good” exercise that is purely speculative.
Payne Stewart’s tragic flight (hypoxia) appears to have a curved path here:
https://en.wikipedia.org/wiki/1999_South_Dakota_Learjet_crash
@DennisW
Agreed except important closure for the family. I am not expecting to learn more about what happened. At least if we know the terminus we can do better flight path approximations.
@Victor,
Re: “At this point, any new debris would have little value in helping to estimate the impact point along the 7th arc.”
No, I strongly disagree with this statement for at least the following reasons:
1. More debris would allow for more accurate distribution maps, hence narrowing down location of the origin with lesser uncertainty.
2. There could be unique debris in terms of their floatation characteristics or locations.
3. Some debris may arrive with barnacles, which could be subjected to biochemical analysis, including temperature.
These items can help in refining the crash site location.
@TBill,
“MY says they have plenty of time to decide on OI, but it is already getting too late to hit the ground running on 1-Jan when the weather is favorable.”
I agree with MY and @Dennis: they have plenty of time. There is no substantial difference between the situation 3.5 year ago and now. There are only two new points:
1. The plane was not found where it was predicted to be;
2. About 30 fragments were recovered.
Unfortunately no lesson was learnt from #1. And unfortunately, drift of recovered fragments was not analysed in details. Instead, there are many questions, which could be answered by hardware and software developers, or tested experimentally. But this does not seem to happen. So OI is in not much better position than Fugro 3 years ago. Throwing darts into the SIO.
@Ge Rijn,
Just a thought. You were worrying about early arrival. Do remember the unopened MAS towelette? It was found on July 2, 2014, being in a good agreement with model for certain locations. Imagine now similar items, but without MAS logo, in SA, Mozambique, Madagascar or Reunion. Who would pay attention to this sort of objects back in 2014?
@DennisW
“People here continue to generate spreadsheets. We have been watching this movie for three plus years now. It has yet to have a happy ending. Spreadsheets are not now nor have they ever been of any significant value. The ISAT data tells us three things, and only three things
1> The plane went South
2> The plane came down rapidly at the end
3> The plane is located near the 7th arc”
Dennis, spreadsheets can be very useful. Dr Bobby’s fuel model should not be underestimated as a useful tool for finding where MH370 ended up. Yes, the plane went south. No, the plane did not necessarily come down rapidly at the end. If it had, it would have been found by now. A piloted glide from 40,000ft allows room for a steep descent (8sec snapshot, remember) at some stage, and has enough energy remaining, theoretically, for a glide beyond the search area. No, the plane is not located near the 7th arc! The ATSB thought that, if you recall.
I read Dr Bobby’s latest paper with interest. A loiter scenario look much less likely now, and so does a terminus north of S36.
I must break off for now.
@ALSM
Thank you for clarifying the timing of Kate Tee positions. Good to know it is based on the .gpx file. Possibly the extraction to excel was done in Thailand hence this local time base. Anyway the .gpx fields leave little doubt.
I agree with Bobby that perhaps the timing of her observations with respect to the jibe could have a considerable uncertainty.
@Andrew, @Mick. Let’s imagine that you decide you want to try an approach to WITT. You want to intercept R010 towards your initial approach fix ANSAX for the ANSAX 2C STAR. Is there a “procedure turn” that you might do to intercept this radial? Or is there a rationale for a right/left manoeuvre to buy some time because you are past T/D? Either scenario could result in a right-then-left turn that provides an alternative to SLOP to explain BTOs 1825-1828.
If you’d like path illustration and associated predicted BTO/BFO I could work that up. But thought it would be useful first to consider “what might a pilot do” and then produce a path example accordingly.
DennisW wrote “The CVR will be blank.”
The CVR records two hours of audio including a channel supplied by the cockpit area microphone. The CVR is supplied with power from the 115V Transfer Bus that is not interruptable by any control within the cockpit.
If the CVR is eventually found & its recording is ‘silent’. That, in itself, is useful information. The flight deck should not be a silent environment over the period of two hours.
@Victor @Andrew
How do you feel about the Kate Tee observations? The only way I can think if an orange color is in the setting Sun, for that I have pictures to document, that also that makes the contrails black like smoke (see my 180S proposal).
Now then we did have a setting half Moon that 8-March night, setting around 1241 at KLIA and a little later at Great Nicobar, but I don’t know if that could account for orange lighting (Andrew?), but timing I do not think would be consistent with MH370.
@Don
Yes.
We would then have two possibilities to consider:
a> Everyone was hypoxic and the plane was a ghost flight to fuel exhaustion.
b> The pilot silently and deliberately flew the plane into the sea.
@TBill,
We have discussed Kate’s observation in great detail at Duncan’s blog. She was there as well.
According to her original testimony, the plane was at 3,000 m altitude. And it was much later after the moonset. The humidity at FL100 was high. My belief is that internal and external light together with reflection from the wet surfaces could be responsible for the effects she observed. You may look through Duncan’s blog if these discussions are still available.
One of the triangular patterns (radar alerting maneuver) I proposed earlier match her description, including altitude, time and even minor change in heading. However, fuel is insufficient to continue at FL100 to reach the 7th arc. Also HGA does not work if the ADIRU fails (a logical justification for the triangular pattern).
The other possibility is that Kate saw other aircraft.
@Oleksandr
Thank you. Yes we have the Singapore surveillance aircraft. I am thinking straight on the sides for reflections.
I am thinking Duncan’s blog is gone. As far as I know there is no place to get the ping rings for Google Earth except to recalc by yourself.
@DennisW.
Well, yes, but the CVR can only possibly indicate conditions during the last two hours.
Much could have been initiated before the FMT.
@TBill,
Arcs, aka, ‘ping rings’.
No, I’m quite sure what you need is available at aqqa.org.
Assuming you know how to translate lat, long, alt triplets into a KML path.
Oleksandr, TBill, Niels
Re Kate T: I had several extended SKYPE video calls and a number of emails with Kate and Mark. Mark supplied the GPS file, which I converted to an excel file. Don joined in on some of those calls. I also exchanged telcons and email with Stewart Stoddart. Stewart and I had a 2 hour lunch too. Also corresponded with Lizzie about her artist’s rendition of the plane Kate described. Victor, Richard, Don and I have corresponded numerous times about Kate’s story. Richard and Victor have looked many possible paths consistent with Kate’s reported time and place. After all that, I can’t say for sure what Kate saw.
If MH370 turned south circa 18:35-18:40, then it would have passed close to her position around 18:46, which is 30 minutes before the Jibe at ~19:15. If she did see MH370 and she saw it at 19:15 during the jibe, then MH370 must have spent approximately 30 additional minutes north of her position before turning south. If MH370 continued WNW for sometime after 1828, descended at 1840, then turned south later, Kate could not have seen MH370. If MH370 was circling ITVO IGOGU between 18:30 and 19:10, then headed south, she could have seen MH370 at 19:15 when she says she saw a plane headed south.
TBill: All the arc data is here:
https://goo.gl/XqUngW
@ALSM,
@TBill,
I meant something like this (triangular pattern with two exit mistakes):
https://www.dropbox.com/s/1d5emi36jvadh7u/trajectory-v3.png?dl=0
Compare with this early image at Kate’s blog:
https://saucysailoress.files.wordpress.com/2014/07/ad-passing.jpg
Btw, I’ve just noticed that the final altitude is close to the one, where the wind pattern is optimal to fit post 19:41 BTO and BFO in CMH mode. Interesting.
Oleksandr,
What might have inhibited the PF from turning back towards Penang and performing that manoeuvre near the best choice of diversion airport? Or even executing that manoeuvre in the vicinity of Penang Island as the aircraft passed at around 17:55? Or using one of the three VHF radios, two HF radios or SATCOM, to communicate the dilemma that might then faced the aircraft after 18:25, when it’s hypothesised that the manoeuvre occurred?
@TBill asked: @Victor @Andrew: How do you feel about the Kate Tee observations?
I think she means well. I don’t see how we can use her observation as evidence to support or refute any particular path, so I stopped considering it long ago. People seem to use her observation, sometimes with modified timing, when convenient.
@Paul Smithson
Over to Andrew for those approach set-up questions, Paul.
@Victor
Relative to Katherine Tee, I did exchange a couple of emails with her. My sense is that she is sincere, and has no intentions other than trying to be helpful. Like you, I find it very difficult to place much weight on eyewitness reports. I spent many years as a member of the Bay Area Skeptics (investigating strange and paranormal events, and even met the Great Randi).
I don’t even know why the moon looks bigger on the horizon.
@ALSB @Victor @Oleksandr
Thank you for Kate Tee summary. I don’t think I ever see much regular commercial air traffic going south that way at all, especially at late night. Nobody seemed to ask her about the Singapore surveillance plane (I think the engines are in the rear).
@ALSM @Don
Thank you for the Arc’s. I will check my arcs with it. I do fly thru the arcs using FS9 tracking in Google Earth.
@Oleksandr
Very nice flight path graphics.
@Oleksandr
With UAE343 6 min behind MH370, the first triangle pattern could conceivably put the two aircraft too close or also looks like a maneuver to let UAE343 go ahead.
Tbill: Don and I discussed several possible surveillance aircraft with Kate. Don did most of the digging and came up with some possibilities but none fit Kate’s observations.
@TBill
Re: ‘How do you feel about the Kate Tee observations?’
I can’t add much more to the comments that have already been made. I doubt that reflections or moonlight would explain the orange glow she reported and it was far too late at night for the sun to be a factor. I also think it would be extremely difficult (if not impossible) to see a black contrail against the night sky, especially at a distance.
@Paul Smithson
Re: ‘Is there a “procedure turn” that you might do to intercept this radial? Or is there a rationale for a right/left manoeuvre to buy some time because you are past T/D?’
As I recall, the initial track you suggested in a previous post was 292°, so a continuous turn to track 190° inbound to ANSAX requires a turn through 102°. The FMC is perfectly capable of flying such an intercept without a procedure turn. However, if the pilot did decide to intercept the inbound track via a procedure turn, he would probably overfly the intersection of the two tracks and then fly a ‘base turn’ or ‘racetrack’ procedure that would require a series of right hand turns.
I suppose there might be some rationale for a right/left manoeuvre if extra track miles were required for descent.
@Oleksandr
On your comment;
‘Do remember the unopened MAS towelette? It was found on July 2, 2014, being in a good agreement with model for certain locations. Imagine now similar items, but without MAS logo, in SA, Mozambique, Madagascar or Reunion. Who would pay attention to this sort of objects back in 2014?
Yes, I remember the towelette well. 5 years ago I also flew from KL to Perth with MAS. I, like many others, also have the habit of putting those unused items in my handlugage. I’ve even been on the beach where it was found. Maybe I lost one there?
A bit kidding but the chance the towelette ended up that beach that way is far greater than coming from MH370. MAS flyes once a week to Perth.
If a towelette like this was found on one of the east African coasts it would have been a bit different story.
Anyway there is/was no proof possible it came from MH370 and therefore it’s still useless.
I agree back then no one would have payed attention at all to items like this without a MAS logo. Which is logical ofcourse. No one ever will for it has no use at all to collect and investigate the thousends of bottles, bags, shoes etc. that wash up those shores every day.
You know as well as I do only identifiable likely, highly likely or confirmed MH370 pieces matter.
@Ge Rijn,
The MAS towelette is an equation with two unknowns: if it was from MH370, it’s location and arrival time are consistent with locations around 28S; on the other hand if the crash was around 28S, there is a great chance that the towelette came from MH370 rather than it was lost by a tourist.
But my comment was on somewhat different issue. You wrote:
“If a towelette like this was found on one of the east African coasts it would have been a bit different story.”
It would not be noticed at all. This is because MH370 debris were expected in WA, and not expected in Africa. Who would care about a towelette with MAS logo in Mozambique or Tanzania in late 2014 or early 2015? Not talking about other objects, without any apparent relation to the aircraft, MAS, passengers or cargo?
You wrote: “You know as well as I do only identifiable likely, highly likely or confirmed MH370 pieces matter.”
Yes. The first identifiable debris was a fragment of 9M-MRO, the flaperon. Who knows how many unidentifiable debris were washed ashore before August 2015, where and when. So modelled earlier arrival times are not inconsistent with the time of the discovery of the first confirmed fragment.
@Ikr
I think it would have been usefull (and probably still is) if a simple paper with example debris pictures was/is send to as many coastal villages and towns as possible promising a ~100 dollar reward for every verifiable and identifiable piece brought in.
I’m sure many thousands of people in those countries are going on the look out for those pieces.
Knowing probably not more than an additional ~100 pieces like this will ever be found the costs would only be the organizing and sending and spreading of the papers and the rewards.
Which would be peanuts-costs compared to what has been spend already so far.
@Oleksandr
Your comment:
‘It would not be noticed at all. This is because MH370 debris were expected in WA, and not expected in Africa. Who would care about a towelette with MAS logo in Mozambique or Tanzania in late 2014 or early 2015?’
I don’t think so. A MAS towelette or any piece with a MAS-logo on it found on a beach in Mozambique, Tanzania, South Africa, Reunion or Madagaskar would be a lot more remarkable for MAS hasn’t any destination in Africa and it’s islands. Also many people in Africa knew about the dissaperance of MH370. They watch the news also like anywhere on the planet these days.
I’m sure if people there found a MAS towelette or something else with a MAS-logo they would have wondered even more and someone would have made the link.
@Oleksandr
‘if it was from MH370, it’s location and arrival time are consistent with locations around 28S’
The problem with it is imo that if it was MH370 and consistent with 28S more debris should have been found in Australia quite soon or later.
Nothing likely or confirmed still.
This rather is a clear indication 28S is not consistent with debris arriving on Australian shores.
Your model predicts it but reality shows something different.
So what will be wrong someway; your model or reality?
@Ge Rijn,
“So what will be wrong someway; your model or reality?”
Neither. Your understanding of drift modelling is fundamentally wrong.
@Oleksandr
I compare all drift-modeling with the reality of the actualy found, likely, highly likely or confirmed debris and their timeframes.
If the modeling clearly doesn’t fit this I rather doubt the modeling than this reality.
Don’t take this as critisism please. I fully recoqnise the value of the work you are doing.
@Ge Rijn,
My drift model for 28S shows an excellent agreement with the reality. It shows that a number of objects expected to be found in Australia by the end of 2016 is approximately 5-6 times lower than in SA and Mozambique. True or not?
Your statement that there would be more debris in Australia for 28S indicates more debris in Mozambique and SA. If you expect 5 objects in Australia, there would be 25 and 30 objects in SA and Mozambique respectively. Where are those 50 objects?
Dennis, Victor and I already tried to explain to you that there is no way a drift model can predict the number of originally generated debris and exact locations where they would be washed ashore. If you take 50M particles you would have 10x more particles washed ashore everywhere.
Also, your assessment that villagers in Mozambique, Madagascar etc. would be aware of MH370 and alerted in by objects bearing MAS logotype such as towelette in 2014 is wrong. Ask your neighbours what they know about MH370.
@DennisW
“So where do you believe the route discontinuity (reaching the last waypoint) occurred?”
My guess would be BEDAX.
@Oleksandr
I copied your whole content for almost all issues ask for reply.
‘@Ge Rijn,
My drift model for 28S shows an excellent agreement with the reality. It shows that a number of objects expected to be found in Australia by the end of 2016 is approximately 5-6 times lower than in SA and Mozambique. True or not?
Your statement that there would be more debris in Australia for 28S indicates more debris in Mozambique and SA. If you expect 5 objects in Australia, there would be 25 and 30 objects in SA and Mozambique respectively. Where are those 50 objects?
Dennis, Victor and I already tried to explain to you that there is no way a drift model can predict the number of originally generated debris and exact locations where they would be washed ashore. If you take 50M particles you would have 10x more particles washed ashore everywhere.
Also, your assessment that villagers in Mozambique, Madagascar etc. would be aware of MH370 and alerted in by objects bearing MAS logotype such as towelette in 2014 is wrong. Ask your neighbours what they know about MH370.
First; Nothing likely has been found in Australia. So your 5 to 6 times more debris in Mozambique or SA doesn’t hold water. ~30 pieces have been found in regions there which comply to your equation if nothing was found in Australia. Which has been the case till now.
Second; if a drift analysis of 50k particals cannot predict a probability of beaching debris in a timeframe it would be useless. Statistically this is not true imo. You could stop working on your models if this was the case.
I already suggested to put in a more reasonable amount of particles into the models. Try a thousand I suggest to start with.
Third; You underestimate the awareness of ordinairy people around the world imo.
@ulric
My guess would be BEDAX.
That is an interesting choice. Do you think everyone on board was hypoxic at that point? I could make it resonate with a negotiation gone bad scenario – dial in BEDAX from a point further North and say goodbye to the world.
The three broad categories of what could have happened are (for me):
1> A complex sequence of equipment failures – not at all likely.
2> A diversion to commit suicide – behavioral history does not seem to support it, and I have looked pretty hard (no formal training however).
3> A diversion with a preferred outcome that did not work out.
@Andrew. Many thanks for your response. Passing over the radial at nearly right-angles and then turning back towards it will not fit either BFO or BTO.
Turning right then back left to come in and join the radial at a shallow angle could do so. But it is not an elegant solution since Dr B’s “calibrated BFO” appears to show steady heading rather than turn underway between 1827 and 1828.
Certainly if no slowdown had occurred by 1822 and the intention was to approach WITT via ANSAX 2C then he would have been 8+ minutes past T/D so would need to do “something” in order to buy extra space/time for descent. I’m not sure what the default “something” would be – a racetrack with slow-down and descent, or a sigmoid off-set (like a slop, but ending with a left turn instead of continuation WNW) to begin the approach from a little further out.
@DennisW
I’m in the mood so I ‘d opt for category 3.
But then with a possible preferred plan A which turned out in a preferred (and planned) plan B outcome.
I for myself rather consider the PIC had only one specific outcome (plan B) in mind. Which was vanishing in the SIO with leaving as less possible evidence as possible to who was responsible.
If this has been the case he succeeded very well I would say.
@Paul Smithson said: Certainly if no slowdown had occurred by 1822 and the intention was to approach WITT via ANSAX 2C then he would have been 8+ minutes past T/D so would need to do “something” in order to buy extra space/time for descent. I’m not sure what the default “something” would be
If the descent was started late, employing speedbrakes could reduce the descent time from around 20 minutes to around 12 minutes or less while staying on the route. In an emergency, I think this is what would be done. That said, in my opinion, no prior actions by the pilot are consistent with an emergency.
@Ge Rijn,
Re: “First; Nothing likely has been found in Australia. So your 5 to 6 times more debris in Mozambique or SA doesn’t hold water. ~30 pieces have been found in regions there which comply to your equation if nothing was found in Australia. Which has been the case till now.”
You are totally confused. My response was to what you wrote before:
“The problem with it is imo that if it was MH370 and consistent with 28S more debris should have been found in Australia quite soon or later.
Nothing likely or confirmed still.
This rather is a clear indication 28S is not consistent with debris arriving on Australian shores.”
My model predicts 1 object in Australia by the end of 2016 if the origin is at 28S – 5-6 times less than in SA. Where do you get it that more debris would be expected for 28S origin? This 1 object could well be the towelette. Note this is expected number objects to be found; there could be no objects at all.
Re: “I already suggested to put in a more reasonable amount of particles into the models. Try a thousand I suggest to start with.”
Your suggestion makes no sense as we explained to you many times. It only demonstrates that you still do not understand what a drift model does.
Re: “You underestimate the awareness of ordinairy people around the world imo.”
I don’t know any other person except you, who is so confident in the awareness of everyone about MH370.
@DennisW From my perspective you have been very sensible and consistent in your analysis of the data and have a realistic view of the limitations of the sat data and the debris. However, I continue to struggle to imagine a ‘negotiation scenario’ that could have resulted in a ‘win’ for Shah. Whatever the subject of the negotiation, whatever agreement reached while airborne – how could he possibly guarantee his safety or fulfillment of the agreement once he landed? Perhaps he regarded his own safety of secondary? I remember some time back you suggested some irreversible transfer of funds. Perhaps. It seems a long shot.
@Don,
“What might have inhibited the PF from turning back towards Penang and performing that manoeuvre near the best choice of diversion airport? Or even executing that manoeuvre in the vicinity of Penang Island as the aircraft passed at around 17:55? Or using one of the three VHF radios, two HF radios or SATCOM, to communicate the dilemma that might then faced the aircraft after 18:25, when it’s hypothesised that the manoeuvre occurred?”
I was not there, so I don’t know and can only speculate. What I know is:
1. Triangular patterns explain heading or track of approximately 172 deg as a result of a trivial counting mistake or failure to complete a triangle.
2. There are several triangular patterns that can fit BTO and BFO (combined with descent). Of of them is fairly consistent with Kate’s observation.
3. 172 deg heading or track 19:41 has a good chance to be consistent with CMH mode or constant gyroscopic heading, all terminating in 25-30S zone. But there is inconsistency with endurance at low altitudes.
Indeed, underlying hypothesis is that the crew were unable to communicate via VHF, HF and SATCOM for some reason.
Compared to a single FMT, or a right lateral offset followed by a single FMT to the left, triangular patterns are more meaningful in my opinion.
@Shadynuk
Diving into Shah’s background as best as can be done from the Internet shows him to be a patriot. He wanted Malaysia to be a better place, and was willing to sacrifice his own future for his country.
Your question relative to what could be negotiated, and then easily rescinded once the plane landed safely is a key question. Obviously political demands of any sort do not fall into that category. What does fall into that category is a money transfer of a substantial amount of the funds Najib and Jho Low diverted from the 1MDB coffers. There is a ton of info on this subject (the 1MDB scandal) on the Internet, including a lot of actions taken by the US DOJ in this matter.
I have done a lot of research on money transfers, and not just WEB browsing. I have actually talked to people in several institutions familiar with the process. I can say without any doubt that a funds transfer is absolutely irreversible without both parties going to a lot work to accomplish it. The simplest way is for the receiving party to simply transfer it back. If the receiving party does not do that, it will take a very long and drawn out legal process to accomplish, even in the case of an obvious “ransom” which the MH370 event would certainly be portrayed as. Going to court is not something Najib and his helpers would want to do. At the moment Jho Low appears to have gone missing.
@Dennis said: Your question relative to what could be negotiated, and then easily rescinded once the plane landed safely is a key question. Obviously political demands of any sort do not fall into that category.
It depends on the kind of political demand. For instance, the safe passage of a political prisoner to a country where he or she could declare political refugee status is a demand that if met could not be easily rescinded.
I see two weaknesses of the negotiation theory:
1) After all this time, we have no knowledge of any negotiation. (I am discounting the claims of @TimR, who refuses to release any details that could verify his story, which includes a political negotiation.)
2) The decision to end the negotiation and fly south would have occurred about an hour after leaving Malaysian radar space. This seems too short a period of time to take a drastic action.
But as I have said many times, every scenario I have seen has weaknesses.
@Victor
The prisoner transfer would take too much time. The money transfer could be done and verified in minutes (especially by a very sophisticated finance guru like Jho Low).
Contact by the “ground team” would be made with Jho Low who probably has a direct personal line to Najib.
All speculation, of course, but in principle only Najib and Jho Low would need to be involved. I agree that TimR’s comments need substantial validation checking to be given weight in this discussion.
@Victor,
@Dennis,
Re: “I see two weaknesses of the negotiation theory”.
There are more weaknesses, including
3) Why not negotiating when in the SCS? Why would risk flying back over the land?
4) Any political demands are usually made with attraction of as much media as possible, which was not the case.
@Victor As you rightly say I am not prepared to disclose my source without his express approval which will not be given due to the risks.
However, it gave me the basis for putting forward a possible route with a lot of confidence.
To recap, by the middle of 2014 Duncan Steel had finalised the ping rings.
These were plotted and being a pilot myself I thought about Shah’s approach to flying.
He was a professional pilot with, in my opinion, no reason to commit suicide and certainly no reason to kill a whole lot of passengers.
He would have used waypoints while flying and would have been determined to land.
A flight path round below Sumatra turning up at the Cocos Islands past Christmas Island to a landing in Indonesia was possible.
The extension of the Cocos Islands to Christmas Island flight path intersected the 7th arc at about 10°S 108°E
Given a position of 10°S 108°E it was not too difficult to work backwards.
Using the waypoints below Sumatra I drew a straight flight path between two prominent waypoints that crossed two consecutive ping rings subsequent to 19:41
ISBIX to Cocos Islands gave 370nm between 20:41 and 21:41 which became the ground speed for the flight.
To fit it to 19:41 the plane had to be slowing; around 410 to 420kts.
Turning up to Christmas Island at 370kts it fitted well crossing 22:41 and carrying on up past CI to a position actually closer to 9°S 108°E on the 7th arc while fitting the ping rings.
There was a possibility of disruption on the flight deck before Cocos Islands.
This could have meant there was no turn at Cocos Islands leading to overflight and continuing to a ditching further South at around 22°S near the 7th arc while still fitting the ping rings.
In summary, from 19:41 onwards the BTO’s fit and MH370 could have ditched in the vicinity of the 7th arc at either around 9°S or 22°S.
What I found disturbing was that as a long time member of pprune.org I posted this during the time I was discussing MH370 with Victor in the middle of 2014.
“…….. around Banda Aceh to the South a flightpath down to Cocos Island through Christmas Island to the 7th arc to a ditching at about 10S 108E”.
The message was taken done within the hour and I was banned from posting anything further on the MH370 blog on pprune.org.
My computer was hacked. For a period whenever I switched on my computer I could not get into it, I was locked out of my own computer.
@TimR: I am not asking you to disclose your source. I am asking for more information so we can consider the story in light of other evidence. If your source made those revelations with the expectation that others would accept the story, he or she failed. How can we accept this story on blind faith from an anonymous source? Do you realize how many MH370 stories have been proposed?
As far as what transpired after takeoff, you have said that you have no knowledge. Your theory about a crash between 9°S and 22°S is not consistent with the timing and location of the recovered parts based on the drift models. That alone makes it difficult to accept.
Don’t get me wrong. A number of us are willing to consider your story if there was more to consider.
@Victor
I do not see how we can accept anything that Malaysia says (or has said) on blind faith either.
Malaysia has, from day one, been less than forthcoming on everything regarding MH370.
The latest Malaysian “game”, being the protracted, so called negotiations, with Ocean Infinity, with an apparent series of patently rediculous conditions like:-
(a) find it in 90 days, or you don’y get paid, and
(b) only look in “this” 25,000 sq km “”area”, or you don’t get paid, and
(c) we really only think you should look in some 5,000 sq km “patch” within (b), etc
is to my mind, less than credible.
We have to ask a fundamental question, does Malaysia want MH370 found or not, yes or no ?
Given the history, I think the answer is heavily weighted to the not, hence, there must be a significant reason. TimR may have a reason, and there may be others.
Do you remember exactly when Malaysia said they will publish the promised final report ?
@TimR
Are you are a commercial pilot over there? Maybe you could help us understand how the airspace and waypoints are used. Lots of military flights? I don’t think I ever see much FlightRadar24 activity around Kate Tee in the 1900 hours.
22S is pretty much where flight path L894 to Perth hits Arc7, which I would agree is a possible outcome.
ventus45 said: I do not see how we can accept anything that Malaysia says (or has said) on blind faith either.
I don’t, including statements made about the new search effort. However, I do believe what OI has told me.
TimR may have a reason, and there may be others.
Yes, that’s why I continue to be interested in what @TimR is saying, and why I have been encouraging him to provide more information.
@DennisW Thanks for the extended response. In any case, a negotiation likely implies at least one accomplice of the ground. Perhaps we can hope for a death bed confession.
With regards to reconstructing a flight path into the SIO, I believe that a pilot trying to ‘hide’ an airplane after an extended flight would not fly between published waypoints. Perhaps more likely he would set arbitrary waypoints as that adds a degree of difficulty for anyone attempting to fit a path using the few known points and distances.
@Victor
You said;
“…in my opinion, no prior actions by the pilot are consistent with an emergency.”
Therefore are you suggesting that even though they diverted initially to the nearest airport (Kota Bharu) and flew to MIMOS (the start of the ILS RWY 10), that this is not consistent with an emergency?
And even though the aircraft continued via the standard arrival route into Penang via PUKAR (Bidmo 1A arrival or RNAV RNP Z RWY 04), you consider this as not consistent with an emergency?
And are you also suggesting that the First Officer turning on his phone following loss of communications is not consistent with an emergency?
In my opinion, the flight path, non-avoidance of Primary Radar and the way the transponder failed IS consistent with an emergency following an oxygen bottle rupture.
Now look at the big picture. The one that was responsible for the servicing that bottle is also the one withholding information and has muddied the waters with false information.
Search the accident site (40-100 nautical miles past the Bayesian hotspot) and all will be revealed. The NOK are still waiting.
@Paul Onions: The pilot flew right past Penang with neither a descent, nor a hold, nor any communications. No coherent, competent pilot would do this in an emergency. Flying near a waypoint that is associated with a particular approach does not equate to trying to land. If you claim he was acting erratic due to hypoxia, then that hypoxia would have lasted for over an hour, including a final turn to the south after 18:28. The evidence in my opinion not consistent with an emergency.
Neither the BFO-derived descent rates, nor fuel consumption constraints, nor the timing and location of debris are consistent with an impact site past 40-100 NM past 38S. I don’t expect that location to be searched.
Paul Onions is right.
A rupture of the crew oxygen bottle is the ‘smoking gun’ in this mystery.
A rupture would cause massive damage to the left side of the avionics bay- multiple electrical failures mainly associated with the left bus. Possibly left hydraulic fail due nose gear bay damage. Pitot fed air modules affecting the autopilot/autothrottle and a decompression that leaves the pilots hypoxic in 40 seconds.
How the aircraft flew after this sudden event is what we need to understand. But it is likely to be a meandering ghost flight with the autopilot/autothrottle off, perhaps even in direct mode. Although I admit it’s difficult to explain a turn passing Penang, I’m not persuaded that ever happened and the Malaysian military radar might just be picking up the flight of EK343.
Correction– that’s the centre hydraulics in the nose wheel bay
@DennisW
BEDAX is my favorite but NIXUL is a close second. NIXUL appeals because of the strange adherence of some of the known flight path to FIR boundaries – presumably to create uncertainty about which ATC might be in control at any time.
My own view is that it was a ghost flight from some point before either BEDAX or NIXUL were reached. A CMH heading from either would converge on a small area of the final arc and so the choice between them might be to do with timing or loiter around the FMT.
Tim: I don’t rule out some kind of catastrophic accident…one we don’t yet understand… but “…decompression that leaves the pilots hypoxic in 40 seconds.” is inconsistent with the plane continuing to fly past IGARI. Hypoxia in 40 seconds = explosive decompression. If hypoxia was a factor in the case of MH370, it took at least several minutes for the cabin altitude to reach 35000 feet….long enough to find a mask.
@Victor/TimR/others
I have not been able to find a way that understanding the diversion scenario, whatever it may be, can help to find the aircraft.
ALSM: Crew oxygen bottle rupture would cause an explosive decompression. Possibly a 2m2 hole rather like the damage on QF30 9years ago, not unnecessarily big enough to tear the plane apart.The pilots would put on their O2 masks not knowing they were not working.
The first turn after IGARI was possibly the last input the pilots made before being incapacitated.
@Tim
So how was the FMT executed? The turn near Penang?
@Tim
@Paul Onions
The O2 bottle rupture makes no sense in this case, other than an attempt to deny the obvious likelihood of an intentional diversion.
The Qantas flight O2 bottle accident (the aircraft landed safely with no loss of radios etc) was a defective metal gas cylinder, and other defective metal cylinders were found in manufacturing. The MH370 O2 tank was a newer, composite (eg; TEFLON) gas cylinder for which I have never heard a single safety issue. So your whole theory is based on a Qantas-accident parallel, for which there is no aparallel.
With so much evidence that this accident was an intentional diversion, why do we have such a loud vocal minority in denial? I figure four reasons:
Denial of MH370 cause as Human Intervention (reasons for):
(1) Defending something (such as pilot profession, Boeing, or MY etc), or
(2) Defending other theories (like Russia involvement), or
(3) what I call “logical purists” requiring 100% proof such as video showing the cockpit actions (good luck on that), and
(4) professional/ethical refusal to consider pilot involvement (sort of like USA doctor profession refusing to assist in design of lethal injection procedure for death penalty).
Anyways I got you guys (or gals) figured for No. 1 above.
I don’t mind considering unlikely secondary explanations as long as the person acknowledges deliberate intervention is most likely cause right now. Failure to acknowledge that, and I immediately know the theory being voiced is yet another unfounded denial theory being put forward for some hidden agenda.
Tim said: Although I admit it’s difficult to explain a turn passing Penang, I’m not persuaded that ever happened and the Malaysian military radar might just be picking up the flight of EK343.
The turn passing Penang with no hold or descent AND the turn towards the SIO is persuasive evidence that there was no emergency. On the other hand, EK343 and the radar captures were different in path and timing. There could be no mistaking the two. Meanwhile, the cell phone registration near Penang links the radar captures to MH370 with near certainty.
You can’t just throw out evidence when it contradicts your theory.
@Tim
Victor may be right that the two cannot be mistaken in timing and paths, up until Vampi.
Even from Vampi it is predicted EK343 was behind MH370, perhaps an offset manœuvre included sometime after 02:2212 by MH370 for avoidance purposes.
The release of the original full radar information and methods used for the detection of this particular radar hit or even series of hits may or may or not be helpful.
I have seen ideas before online that there may have been only one major turn after IGARI as you suggest, but they totally contradict the SOM track (after Penang), and sat data. Unless proven otherwise they are just Ideas.
@TBill
Re: “The Qantas flight O2 bottle accident (the aircraft landed safely with no loss of radios etc) was a defective metal gas cylinder, and other defective metal cylinders were found in manufacturing.”
I don’t think that is an accurate summary of the ATSB’s findings, Bill. What the ATSB said was,
“The ATSB undertook a close and detailed study of the cylinder type, including a review of all possible failure scenarios and an engineering evaluation of other cylinders from the same production batch and
of the type in general. It was evident that the cylinder had failed by bursting through, or around the base – allowing the release of pressurised contents to project it vertically upwards. While it was
hypothesised that the cylinder may have contained a defect or flaw, or been damaged in a way that promoted failure, there was no evidence found to support such a finding. Nor was there any evidence found to suggest the cylinders from the subject production batch, or the type in general, were in any way predisposed to premature failure.” (My bolding.)
The oxygen bottle is not mounted on the fuselage wall like Qantas QF30, it is mounted on the left side of the nose gear wheel well next to the left electronic brain (Left AIMS Cabinet) in the Main Equipment Center.
A rupture of the oxygen bottle could result in a gradual decompression which goes unnoticed by the pilots since the Left AIMS Cabinet is also damaged.
A ruptured oxygen bottle also denies the pilots of an emergency supply of oxygen. The oxygen masks in the cockpit would be useless.
The Left AIMS Cabinet supplies Mode S air data to the Left Transponder.
The Left AIMS Cabinet supplies the flight ID to the SDU for satellite communications (Satcom).
Without 4 of the 6 display units, the automatic pop up of pressurisation indications is disabled.
Radio communications are not possible if the single Audio Management Unit is inoperative.
Although crippled with many problems, the aircraft can still fly because the Right AIMS Cabinet is still serviceable.
After the diversion to Penang has been programmed, the aircraft will not descend or hold by itself if the flight crew have passed out whilst enroute to Penang.
The diversion to Banda Aceh via Nilam and Sanob was either programmed by a hypoxic flight crew before passing out, or by a passenger on portable oxygen, or by a flight attendant on portable oxygen, similar to Helios 522.
There was a flight attendant on board MH370 who had a flight simulator at home.
Eventually all onboard will pass out due to hypoxia if the aircraft remains at 35,000 feet.
The aircraft will continue on autopilot flying the programmed diversion route to Banda Aceh.
The Satcom logged back on when the serviceable right High Gain Antenna was finally exposed to the satellite at the start of the left turn at Nilam. The log on had no flight ID.
Around 1828 the aircraft turned left at Sanob.
Around 1837 it overflew Banda Aceh and continued south to the southern Indian Ocean at ECON cruise until it ran out of fuel.
Indonesian Primary Radar would have detected MH370 as it overflew Banda Aceh.
The First Officer’s phone may have also connected to Banda Aceh.
If someone had turned on the APU before passing out, then the aircraft is an extra 40-100 nautical miles past the Bayesian hotspot.
@Mick
Thank you for reminding of the details. Based upon my experience, I have “hypothesised that the cylinder may have contained a defect or flaw,or been damaged in a way that promoted failure,” but we do not know for sure (whereas the gas cylinder was lost at sea). But if I recall, there apparently were examples of defects in some production batches, agree not the batch in question.
Anyways not the same type of cylinder on MH370, per FI.
@Mr Onions
You include the remark, above, that “the Right AIMS Cabinet is still serviceable.
That AIMS continues to function negates most of the avionics outcomes you attribute to the oxygen cylinder rupture. AIMS functions, except for ACMF, are replicated in both cabinets.
@TBill
Bill, I don’t think that I’d be ruling a line through the possibility of an oxygen bottle rupture because MH370 had kevlar/composite bottles and QF30 used steel bottles. The principal benefit of Kevlar Composite Fiber Wrapped Aluminum Lined bottles over traditional steel bottles for aviation applications is the weight saving; they are about half the weight of an equivalent capacity steel bottle. However, composite bottles are not without their shortcomings; according to Lekshmy, Renjith and Kottalil in their paper Design of Composite Gas Bottle with Elastomeric Layer (International Journal of Civil Engineering and Technology, Volume 5, Issue 10, October (2014), pp. 96-103), because of the strain incompatibility between the metal liner and the composite jacket debonding is a common problem which can result in failure of the container. In terms of durability and longevity, it’s worth noting that the composite bottles have a fixed 15 year service life (with 5 yearly hydrostatic testing) whereas steel bottles have an unlimited service life (with 4 yearly hydrostatic testing).
That aside, there’s an interesting array of equipment in the “line of fire”, so to speak, of the crew oxygen system bottles down in the Main Equipment Centre; the Left Generator Controller Unit, the Left and Centre VHF transceivers, the Left Transponder and the Audio Management Unit all sit on the E1 racks directly aft of the cylinders. It is not difficult to conceive of a situation where the failure of a bottle could damage sufficient equipment to cause the specific systems failures that are in evidence and cause the incapacitation of the crew. Now, I’m not saying that it happened that way (I’m not a proponent of this hypothesis) but I think it is unwise to just dismiss the possibility.
@Paul Onions: In addition to what @Don Thompson has said about redundant functionality of the left and right AIMS, which has been already stated in reference to some of your past comments, you again refer to a separate right high gain antenna (HGA). There is only one HGA, and it incorporates right and left arrays. The failure of the left AIMS (or any other failure induced by a hypothetical oxygen bottle rupture) would not make one array inoperable and leave the other functioning.
@Mick
“…dismiss the possibility.”
Yes I am dismissing totally because it is a “red herring” which is something that misleads or distracts from a relevant or important issue. When I say dismissing totally, we do not know the cause the accident, but the preponderance of the evidence is intentional diversion. I concede some number of 1-in-10000 chance extraordinarily rare event that would turn off transponder at IGARI and fly the aircraft in what appeared to be a get-away path.
Focus on this does not save the the next unsuspecting flight from rouge pilot.
By the way, yes KEVLAR thank you. Anyways you are making Paul Onions case for him. He/she has been stating this theory about every 3 months for the last 2 years, and every time I hit him with my argument, and he/she does not respond. Somehow he/she has the need to repeatedly drop this theory on us, with no updates or back-up or defense of the theory.
Perhaps upon study there is merit (not sure) to take the O2 bottle out of the EE Bay. But I suggest Boeing would be more wise to first disallow turning off of Transponders/ACARS in flight.
@Victor
@DrB
@All
I have found that pilot started his FMT at a point 20NM before reaching ANOKO, by entering a manual waypoint with coordinates S40.50, E88.00. This was done to make it more difficult for us to reconstruct his flight path. He had tried out this procedure in his simulator. He crossed the 7th arc at S37.88, E88.52, which is almost in the centre of the DSTG’s hotspot! So much for drift studies.
Evidently, a glide started from 39,000ft (he could have been at 40,000ft by the end of the flight) allows for a steep descent at some point, at 00:19 it seems, and still has enough energy to finish beyond the search area. Either that, or possibly the wreckage was missed by the towfish.
Time line from 18:24:
18:24 Pilot reconnects LH Main AC bus (re-energizing AES) and initiates 12NM right offset manoeuver to distance himself from N571, possibly done to confuse if military radar had tracked him flying along N571.
18:29 (N07.18, E95.68) Pilot replaces IGOGU with ANOKO and cancels N571 offset, aircraft flies directly toward ANOKO on bearing 268deg. maintaining FL350.
18:35.67, 20NM before reaching ANOKO, pilot replaces ANOKO with manual waypoint coordinates S40.50, E88.00 (S40:30:00, E88:00:00) Aircraft begins FMT toward manual waypoint calculated to be at least 170NM beyond fuel exhaustion. FMT radius taken as 7.5NM, turns through 81.2deg at 1deg/sec.
18:36 Pilot begins speed reduction from M0.84 to M0.68 (taking a nominal 2mins to complete) Maintains FL350. The 23 minute period at reduced speed M0.68 may possibly have been intended to give impression pilot was considering landing at Banda Aceh, in the unlikely event he was being followed on primary radar, or (less likely) may have been done to extend fuel range prior to beginning M0.82 cruise at FL390.
18:37 FMT completed, at position N07.0236, E94.6022 (N07 01 25, E94 36 08), bearing 186.8071 (186 48 25.66)
19:01 Pilot ends 23 min reduced speed phase, increases speed to M0.82 and at same time begins climb from FL350 to FL390. M0.82 at FL390 is then maintained until fuel exhaustion.
19:41 Aircraft makes grazing contact with 2nd arc: distance covered between 18:29 and 19:41 is 552.3NM , being 55.50NM from 18:29 to start of FMT, plus 12NM for FMT , plus 484.82NM from FMT until 2nd arc crossing, 460.25Kts average GS, 1.8Kts average TW = Mach 0.78 (Mach 1=592) 2nd arc tangent contact S1.0333, E93.65 (S01 02 00, E93 39 00)
2nd to 3rd arc: 486.42NM, 486.42Kts average GS, 1.6Kts average TW = Mach 0.8217 (Mach 1=590Kts, ) 3rd arc crossing S09.1148, E92.6897
3rd to 4th arc: 492.83NM, 489.81Kts average GS, 4.6Kts average TW = Mach 0.822 (Mach 1=590Kts) 4th arc crossing S17.2965, E91.6713.
4th arc to 5th arc: 484.12NM, 484.93Kts average GS, Zero average wind = Mach 0.823 (Mach 1=589Kts) 5th arc crossing S25.3217, E90.579.
5th arc to 6th arc: 698.18NM, 467.37Kts average GS, 13.5Kts average HW = Mach 0.824.(Average Mach 1=583.0Kts) 6th arc crossing point S36.8681, E88.7062.
6th arc to 7th arc: 61.5Nm, 434Kts average GS, 33Kts average HW = Mach 0.81.(Mach1=577) 7th arc crossing point S37.884, E88.516.
Great circle distance from 19:41 to 00:11 is 2161.5NM, with journey time 4.5hrs = 480.34Kts. Plus 2.2Kts average HW = 482.54 = M0.821 average from 2nd arc to 6th arc, average value of Mach 1 of 587.5Kts.
MEFE estimated to occur 47.5NM beyond 6th arc, at 17:30, at S37.65, E88.56. A 16:1 piloted glide from 38,000ft would end at S39.25, E88.25, adjusted for headwinds, and assuming aircraft maintained same track. By comparison, a 13:1 glide would have ended just outside the southern boundary of the search area.
Total distance covered between 18:29 and MEFE at 00:17:30 works out at 2761NM. Doctor Bobby’s fuel model predicts range and endurance for M0.82 at FL390, starting from 18:29 to be 2788NM, with MEFE at 00:18. The 27NM shortfall in range is due the less efficient speed profile flown between 18:29 and 19:10 (approx.) at the lower FL350.
What is going around here in circles is not MH370 but set beliefs that are entranched in circles. It’s about time OI is going to be able to search.
I think that many keep stating their views over the years without considering the evolving evidence and indications.
Many confirmation-biased (in my view) theories still refuse to look at the known facts. They all like to prove their right only. This can be misleading in keeping an open view. We have to look at the data, indications and evidence only.
We simply have the available radar-data. No direct communication besides the FO connection, no (emergency) descent. A re-log on at 18.25. Not any indication/proof something went wrong at IGARI mechanically or later.
We have the fuel constraints and range depending on FMT lat/long. We have the Inmarsat-data. We have ~30 pieces of debris which clearly show possible different impact-scenarios and a rather clear region of origin in the SIO
We have by now multiple drift-analysis that show the found debris came from the ~35S/~30S region.
A lot has been accomplished in this regard imo by all.
It’s now up to OI and the Tri-party to decide where to search.
There’s not much left to be added to them imo.
Maybe the fact that no debris reports have been made for almost a year now.
This would indicate a window of a ~one and half year debris arrival after the accident.
Much in line with what some drift-analizes predict when there was a small debris-field.
This is what hase been found till now.
OI will surely make their decisions on all that is known and suggested here also.
But I hope they stay to the known facts only.
@TBill
Bill, over a year ago someone raised the possibility of a ruptured oxygen bottle on Ben Sandilands’ blog and I looked into it. I found that it was not without some merit. To the extent that reiterating what I found makes a case for it then I’d suggest that indicates that there is a case to be made. I disagree with other aspects of Paul Onions’ hypothesis (Victor and Don have pointed out some of the manifest shortcomings) but the fact remains that the arrangement of equipment in the Main Equipment Centre is such that a failure of a crew oxygen system bottle could damage sufficient equipment to cause the specific systems failures that are in evidence.
With regards to “Focus on this does not save the the next unsuspecting flight from rouge pilot. “, by corollary, the reverse is also true. And it would not be the first time in the annals of aviation that a “1-in-10000 chance extraordinarily rare” mechanical failure has been ignored in favour of blaming absent aircrew only to see more preventable fatalities down the track.
Anyway, I’m not seeking to disabuse anyone of their currently held views, I was simply sharing what I had learned when I looked into the possibility of an oxygen bottle rupture.
@Mick
failure of a crew oxygen system bottle could damage sufficient equipment to cause the specific systems failures that are in evidence.
The 18:25 reboot is orthogonal to an oxygen bottle rupture as is the subsequent FMT with no attempt to remain in the vicinity of Penang. Mechanical failure scenarios are truly in the inconceivable category.
@DennisW, RE: “Mechanical failure scenarios are truly in the inconceivable category”
The exhaust the possibility, I want to confirm whether it is possible (regardless of the cause) the the SDU reboot be explained by a loss of comm due to antenna orientation as opposed to a loss of power. A common cause (whether it is electrical or mechanical) could possibly involve a jamning of the Steering Beam Unit mechanism of the Antenna such as the antenna is pointing to the POR satellite over IGARI, as the plane turns west, the antenna is pointing to nowhere and as the plane turns south the antenna is coincidently pointing to the IOR. This process would certainly trigger an explainable reboot. I am not sure whether the antenna could still pick up the statelite signal in that case and vice versa for the satellite.
@HB
I have never been a fan of the power cycling explanation. However, it has gained pretty much universal acceptance here. Certainly high gain antenna steering issues could explain the reboot or a loss of position and velocity info needed to calculate the Doppler compensation. We will not know for sure until the FDR is recovered.
@DennisW
If anyone has come up with a rational and logically compelling explanation for the 18:25 reboot, I’ve yet to hear it. It is, as you say, orthogonal (I would say, incongruent), to all hypotheses.
@HB, @DennisW, @Mick Gilbert
The HGA on 9M-MRO was a Ball electronically steered phased array antenna system. There are no moving parts. Thus, “…jamning (sic) of the Steering Beam Unit mechanism…” is impossible.
The 1825-1828 BFO data is the best evidence that the SDU lost power for ~1 hr. If the power had been on the whole time, but the SDU could not communicate due to the loss of 429 data (for example), then the there would not have been the observed power-on frequency transient. This fact alone indicates the power was off for an extended period.
The snr data in the GES log also indicates no significant link degradation due to pointing problems at any time for the whole MH370 flight (and MH371 too).
In summary, the evidence for an SDU power interruption is fairly compelling at this point.
@AlSM
then the there would not have been the observed power-on frequency transient.
Mike, the power-on frequency transient at 18:25 is unique. We have been over this before, so I will not dwell on it. Dismissing Holland’s lack of understanding of a second order effect is a “cheap shot” IMO. His paper was obviously reviewed by the AES manufacturer.
@ALSM, thanks, good to know. Should we assume that this electronic system does not have a possible antenna steered in a stuck orientation failure mode? it looks like it is either on or off but cannot be in stuck failure mode ?
@ALSM
Re: “In summary, the evidence for an SDU power interruption is fairly compelling at this point.”
No argument from me on that point, Mike.
@DennisW: in addition to the frequency transient attributed to the OCXO warm-up process, during the 18:25 Log On the AES communicated ‘077’ (base8)for ‘Previous SAT ID’. That value occurs in a Log On following certain conditions: a) a successful prior Log Off; or, b) a power interruption. Case a) is not evident after departure from KUL.
@HB, see above. Had the AES lost the Log On session, intiated at 15:59:55, due to an error within the HGA (ie the BSU plus the two flat panel apertures), the subsequent Log On would have included the IOR ID in ‘Prev SAT ID’.
@Mick, the MAS B777 fleet was equipped with two oxygen bottles, per the airline’s MEL. Would that not reduce the likelihood for a bottle rupture to affect supply to the flight compartment? The absence of supply to the flight compartment is a key feature of the ‘ballistic’ scenario.
By way of general comment… the oxygen bottles are mounted high enough on the nose wheel compartment wall that rack E3 is below direct fore/aft ‘line of fire’ from, say, a detached regulator. The AMU is typically the subject of interest in the ‘ballistic’ scenarios: while it’s a single physical LRU, it contains three discrete sets of active electronics, each powered seperately. It is located at rack E1, shelf 4 (4th down): at the same level as E3, shelf 1 (top). If anything is in the ‘line of fire’ from a pressure vessel fragment, it is the Left System Card File. Oddly, no ‘ballistic’ scenario has considered that.
@Don Thompson
Re: “… the MAS B777 fleet was equipped with two oxygen bottles, per the airline’s MEL. Would that not reduce the likelihood for a bottle rupture to affect supply to the flight compartment?”
G’day Don, yes, 9M-MRO was fitted with two 115 scf capacity oxygen bottles (presumably P/N 4110-200-4). I have only seen a pressure schematic for a one bottle set-up so I can’t really comment other than to say that I think it would depend on the extent of the damage caused to the other bottle, the regulators and plumbing.
When QF30 lost its No 4 passenger oxygen system bottle the rupture event fractured the No 4 bottle’s pressure reducer and tee-piece, its service line and its overpressure discharge line. That damage did not affect the overall operation of the passenger oxygen system but on the B747 we’re looking at a 13 bottle set up with 3 separate flow control units feeding 450-odd masks. The departing No 4 bottle damaged electrical wiring such that the functionality of the oxygen system flow control units and the system reset solenoid would have been affected although, given the cabin altitude, normal activation and control functions of the system were not affected. The rupture event also fractured both sets of right-side aileron control cables.
Unlike the B747 passenger oxygen system the B777 flight crew oxygen system uses a single supply line to the flight deck with only one pressure regulator. As you’ve probably observed, the bottles in the B777 MEC are mounted much closer together than the bottles in the B747 forward cargo compartment. The Remote Fill Port is also located quite close to the regulator assembly of the lower bottle. The configuration does not suggest that any thought was given to the bottles acting as independent or redundant supplies, well, not to my admittedly untrained eye anyway.
When I looked into this hypothesis a year or so ago I really just focused on the equipment in the E-1 rack directly behind the bottles; VHF L and C transceivers, L Transponder, L GCU, Audio Management Unit, etc. I know that some others have woven damage to the Left AIMS and ADIRU into scenarios but that is not something I looked into. As has recently been pointed out to me, the P100 Left Power Panel is also located in the MEC adjacent to the bottles, as are the P110 Left and P310 Standby Power Management Panels. Suffice to say, a bottle rupturing would inevitably cause a lot of collateral damage to a wide variety of systems. While it’s impossible to predict with any accuracy what systems would be impacted, the loss of VHF L and C comms, the L Transponder and the L AC Bus would be on the cards.
Speaking of cards, what’s the significance of the Left System Card File?
And why the term “ballistic” to describe this scenario?
@TBill,
You’re correct that I am in category 1–I do want to defend the absent pilots. They must not be blamed until there is absolutely no other possible failure scenario. So far I would say that an oxygen bottle rupture is a failure that can explain almost everything that happened. Namely, massive electrical issues focused on the left system, sudden decompression and incapacitated pilots. With air data modules(pitot,static system) also damaged the autopilot might be in a degraded mode.
What is difficult to explain is why the aircraft would make a turn near Penang and a final turn south. But until Boeing flight test a real damaged B777 it’s difficult to second guess how it would fly.
Re, this would be the first ever failure of a composite O2 bottle. Well up until QF30 there had been no steel bottle ruptures. There is a long list of aviation incidents which are seen for the first time, the smart thing do do is to stop them ever happening again.
But, I have found another bottle explosion that happened on a Petra Airlines A320 in Tripoli(3Jul2013) during servicing, not sure if it was steel or composite.
Does anyone know if there are any other Airlines that had this unusual two O2 bottle config down in the avionics bay?
@Mick Gilbert: If anyone has come up with a rational and logically compelling explanation for the 18:25 reboot, I’ve yet to hear it. It is, as you say, orthogonal (I would say, incongruent), to all hypotheses.
It is very difficult to know all the possible reasons for taking an action. On the other hand, if somebody proposes a scenario such as a decompression scenario, we can test whether pilot actions are consistent with this.
Here are some possibilities for repowering the left bus:
1) The pilot believed he could monitor ACARS messages by powering up the SATCOM with SATCOM de-selected for ACARS transmissions. (In fact, he could not monitor ACARS messages because a transmission was required to log-on to the ACARS server after a long period of inactivity.) When the left bus is repowered, the EICAS messages “SATCOM DATALINK”, “SATCOM”, and “SATCOM VOICE LOST” are cleared, at least in the FSX simulator he installed at home.
2) The pilot wished to have the capability for a fully-redundant AUTOLAND.
3) The pilot was waiting for a satellite call at a pre-arranged time.
I am sure there are other possibilities beyond what I listed above.
@VictorI
…but why would a pilot shut the left bus down in the first place?
@HB:
Re: “Should we assume that this electronic system does not have a possible antenna steered in a stuck orientation failure mode?”
Yes, fair question, it is *theoretically* possible for an electronically steered phased array antenna system to steer the beam to the wrong az/el angles. This could happen due to a hardware failure in the patch array, where solid state devices are used to add a specific phase delay to each of the patch elements in the array. It is also *theoretically* possible for the code in the BSU uP to malfunction in a way that results in steering the beam to the wrong angle. These are just 2 theoretical examples. But these hypotheticals are extremely unlikely. There are many hardware and software cross checks (BITE) designed in to detect such failure modes. In any such case, the SDU would revert to the LGA. None of that happened here.
BTW…Engineers that design avionics boxes have to comply with “DO-178C Software Considerations in Airborne Systems and Equipment Certification”. Surviving a DO-178 certification is challenging. Severe brain damage has been reported. Been there. Done that. Trust me, there was no (undetected) antenna failure.
@Dennis:
Re: “Dismissing Holland’s lack of understanding of a second order effect is a “cheap shot” IMO. His paper was obviously reviewed by the AES manufacturer.”
Let me be clear. Holland wrote an excellent paper. It was one of the best. I agreed with 99% of it, including his main conclusions. However, Holland and Honeywell/Thales may have missed the subtle importance of considering the difference one should expect in a warm (1 minute power interruption) and cold (power off >1 hour) OCXO start-up transient response. If they did, I missed it. That difference is critical to the interpretation of the 00:19 BFO values. And they apparently did not consider the how the timing of the multiple logical inputs (last to occur) to the POST test could have resulted in a first logon transmission occurring when the frequency was coincedently close to a zero error. Holland agreed to discuss this and more back in February, but his management blocked the conversation. Hopefully, it will still happen at some point. It should be emphasized that the warm/cold startup difference is absolutely critical to defining the width of the 7th arc to be searched by OI.
…but why would a pilot shut the left bus down in the first place?
Because s/he believed that would stop the flight deck door unlocking following decompression. I make no comment on whether this view is accurate.
@ALSM
Yes, you make good points, and your thesis is pretty darn solid (most likely correct, IMO).
I am mildly bothered by four things:
1> I can’t come up with a solid reason for shutting down the left bus.
2> The 142Hz is a very good value relative to the flight path at 18:25.
3> The 18:25 login is the only login example with a lower initial value.
4> The notion of a second order transient response and overshoot is so basic (every undergrad sees it early on) that it is hard to believe Holland et. al. missed it.
@Mick Gilbert wrote:
1) “Speaking of cards, what’s the significance of the Left System Card File?”
It is located immediately forward of the upper oxygen cylinder. Functionally, it’s concerned with translating (primarily) discrete signals onto the ARINC 629 Systems Busses.
2) “And why the term “ballistic” to describe this scenario?”
A failure may involve only the escape of oxygen from the cylinder(s), or it may involve a catastrophic failure: fragments, or the entire cylinder, being propelled from its fixture – hence, ballistic, as in projectiles.
@Dennis
“I can’t come up with a solid reason for shutting down the left bus.”
Consider SATCOM, TCAS (operating to TCAS-II v7.1 standards, which would be necessary in FAA & common EU controlled airspace), the IFE-EPESC unit, some Cabin Services System units, and cabin Overhead Electronics Units (reading light control, pax information signs).
News: https://goo.gl/w8j1aS
@Don
TCAS can be turned off without shutting down bus power. Pilots routinely do so on approach. Likewise SATCOM (except for the pings). I don’t believe Shah was even aware of the possibility of being tracked by BTO/BFO data or that it even existed. The other stuff seems irrelevant to me.
@Tim
I do want to defend the absent pilots. They must not be blamed until there is absolutely no other possible failure scenario. So far I would say that an oxygen bottle rupture is a failure that can explain almost everything that happened.
Nonsense. How can it explain the data points on Shah’s simulator hard drive? That data makes mechanical failure scenarios untenable.
@DennisW
Agreed, the simulator hard drive data is hard to explain.
The trouble has been that everyone has been happy to blame Capt Shah from day one, long before this data was eventually released.
@Don Thompson
@Tim
Don, thank you for the clarifications regarding the Left System Card File (as it turns out, buyerninety had raised the potential for damage to it back on May 4, 2017 at 10:56 pm) and use of the term “ballistic”.
A correction to my earlier post on the configuration of the crew oxygen system on 9M-MRO, it’s not the Remote Fill Port that is located quite close to the regulator assembly of the lower bottle, rather it is the pressure transducer, check valve and system pressure regulator assembly that is located immediately adjacent to the regulator assembly of the lower bottle. Accordingly, if the lower bottle were to rupture the entire system would almost certainly be compromised.
Tim, the two bottle set-up is optional but EgyptAir, for one, also use that configuration on their B777s.
@Tim
everyone has been happy to blame Capt Shah from day one
Really? I actually thought Shah was given way too little early blame.
1> The IG due to some psychobabble reason refused to speculate on causality or blame. I think they thought the ISAT data was all they needed.
2> The ATSB has not been pointing fingers at him.
3> The Malays have gone pretty easy on him as well – I have read nothing relative to interviews with Shah’s wife, Tim Pardi, co-workers, or anyone else for that matter.
The reality is Shah diverted the aircraft. He was not practicing an oxygen bottle emergency in the SIO.
“The trouble has been that everyone has been happy to blame Capt Shah from day one …”
Not at all. Here is a personal note I wrote early on (less than a week after the event, but not day one):
“Which pilot? I’ll wager the copilot.”
Further, “happiness” has nothing to do with it – it was a logical deduction based on the uncanny timing of the event (precisely at the “transfer of control” point between two FIRs), estimation of the probability the loss of communications and disappearance from radar being either an accident or deliberate actions, and by analogy with other similar incidents (e.g., Egyptair 960).
If you want to characterize that analysis as constituting “trouble” or an attempt to “blame” the pilot is up to you – that is not how I viewed it at the time.
@sk999
Yes, the timing of the transponder shut down, and the turn from the normal flight path to Beijing is very relevant. Especially coupled with the sim data.
@ALSM, fair enough, i agree that a software error would be unlikely. In this case, in particular, this error would be independent to other events bringing the probability very low.
The only common mode failure i could think is erratic operation in case of low ambient temperature but if the system is powered, temperature will have little effect.
So the only possible ways remaining are loss of power and loss of comm input. The latter you rule out on the basis of observed power on frequency transient and the lack of Last Sat ID in the log leaving the power loss as the most credible cause.
This then points to human intervention as the other possible causes, cable failure, swtichgear fault, etc. cannot be recovered/repaired on board to restore power.
@Tim
“@TBill,
You’re correct that I am in category 1–I do want to defend the absent pilots. They must not be blamed until there is absolutely no other possible failure scenario.”
Tim- Thank you for talking a crack at that classification system.
To me you are equating MH370 with a legal issue – “we need proof beyond shadow of doubt to say a person is guilty”. But that is not where we are.
We have a science or mathematics logic problem: what is/are the probable causes of this accident? You cannot ask me what is 2+2, but then say 4 is a politically or legally restricted answer. I need unhindered access to the apparent truth. Legal case is whole different burden of proof.
I personally put at least some, if not most, of any blame on the industry/Malaysia for creating the temptation for the rare pilot, in a moment of mental weakness, to use the aircraft controls to “go rouge”. Post 9/11, I believe USA may have taken better steps – air marshalls etc- to minimize the potential problem.
@Mick,
Thanks, and I’ve found a picture re the double bottle arrangement in the EygptAir667 report.
@TBill
I personally put at least some, if not most, of any blame on the industry/Malaysia for creating the temptation for the rare pilot, in a moment of mental weakness, to use the aircraft controls to “go rouge”.
Only so much can be done. How do you protect people from some whack job who decides to drive a truck into a crowd? Ban trucks? I am in the camp of resisting the trend to turn shocking incidents into expensive exercises of future prevention. Events like MH370 are not epidemic. If anyone is to blame it is the media for amplifying issues – mass shootings, sexual harassment, commercial transport tragedies,… the list goes on and on. Journalists and attorneys have contributed more to our increased cost of living than all the other occupational groups combined.
@DennisW
The question is could it be easily prevented or discouraged? Not sure about trucks, but in the case of B777 I see some things, like if turning off transponder in flight generated a alarm message (could not be done “secretly”) it would help take away the temptation. If intentional depressure was part of this accident, that is quite alarming if the unsuspecting public realized that. Not sure if they have to allow going to zero pressure manually and secretly.
@TBill,
It would be easy to expand your list indefinitely. You are headed in a direction that simply does not work for me.
@DennisW
Bravo. I cannot agree more. Their (and their bosses) irresposible lack of consideration and thought create only more loss of life and fear.
But that’s how they earn their money don’t they.
Ofcourse there are also thoughtfull and responsable journalists and attorneys. Probably those are among the more poor these days..
@sk999: I assume you refer to Egyptair 990 [and pilot murder/suicide]?
to all: the English term is “going rogue”! Rouge is something a lady puts on her cheek. Don’t know if this is a spell checker revolt or confusion between these two words..
@DennisW
Yes I have a lot of improvement ideas…but I know we are not headed that way. The key point is recognition of the risks and making plans to mitigate.
@Dennis,
Re:”Nonsense. How can it explain the data points on Shah’s simulator hard drive? That data makes mechanical failure scenarios untenable.”
You need to keep in mind that the two points in the SIO are possibly (or even likely) not connected with the rest: RMP was explicit about this; B.G. was explicit about this. Bearing in mind initial rumors about FBI involvement, I lean to think they also have not found any solid proof. I know Victor disagrees. I am afraid that without having physical access to the drive, it is not possible to make any solid conclusion. Furthermore, the imaginable negotiations you propose as a explanation would never begin due to the insufficient time. Your theory has more gaps than any fine strainer in any kitchen.
Yet you still rush to hang Z. like a dark-age inquisitor. Or perhaps it is just human’s nature to sacrifice someone only to please the gods in a desperate hope to find some imaginable peace?
Oleksandr: I think it has been established at this point that the points are in fact all connected. Recent data provided by ATSB shows all the points were generated within ~1 hr. Victor has documented his research on the topic, but many don’t bother to read the details. They just throw out unsubstantiated alternative opinions. No one has provided any detailed analysis showing why Victor’s research is flawed. We just have a bunch of alternate guesses and opinions against Victor’s documented details. So, why keep perpetuating the idea that the dots are not connected? No one, including Victor, claims that the sim data proves Z did it (other than Dennis maybe). But the case for that scenario can’t be dismissed on the grounds that the dots are not connected. You can argue the case that Z was innocent, just practicing, messing around, whatever…without ignoring the facts.
@Oleksandr
You are not making sense. The diversion (turn and transponder shut down) at the FIR boundary is suspicious in the extreme. Of all places, why that particular place? It is exactly where an intentional diversion would be initiated.
The simulator type and whether or not the files are connected is completely irrelevant. As I stated on the JW blog the SIO coordinates written on a scrap of paper in Shah’s wastebasket would have exactly the same impact – why were those coordinates there at all?
You and Tim and Mick are insulting people’s intelligence with your array of off the wall mechanical issues – windshield fires, oxygen bottles going ballistic or rupturing, nose wheel explosions,… Do you have any idea how dumb that line of pursuit appears to be? Then you attack people who are being completely reasonable with your off the wall comments that have no basis i.e. I am an inquisitor, I am hanging Z in a desperate quest for peace. Where are you getting that crap? I could care less about blaming Z. He is dead. My only interest is in whether a correct interpretation of what happened can help in finding the aircraft.
Someone even accused me of causing grief for Shah’s family and Fatima Pardi. Let them come forward and have their say instead of hiding in a closet somewhere.
@ALSM,
To my knowledge neither you nor Victor are MS Windows architects. Neither of you had physical access to the hard drive in question; neither of you were involved into the forensic analysis of the disk.
I was not convinced by the stuff I seen so far on this matter. I will be explicit: I consider this ‘realease’ of new ‘information’ as a dirty attempt to find a closure of MH370 case and hang Z. Timing is very suspicious. And motive is there. Probably the IG is a victim of someone’s game.
@Dennis,
“Do you have any idea how dumb that line of pursuit appears to be?”
No. By I have idea that your line is pure imagination not supported by any fact or observation.
@ALSM
No one, including Victor, claims that the sim data proves Z did it (other than Dennis maybe).
Anyone with a brain knows Shah did it. Not coming out and saying so is simply a smoke screen to appear politically correct.
@DennisW “Anyone with a brain knows Shah did it. Not coming out and saying so is simply a smoke screen to appear politically correct.”
There were actions that point to the authorities being aware of what happened to MH370 from the get go.
Some of these are –
The authorities knew what was happening yet let everyone think all was well and allowed the world to think MH370 was on its way to its destination.
ATC did not try to continue contacting the missing aircraft.
SAR was not alerted for hours.
The RMAF chief confirmed the plane was picked up by defence radar coming back over Malaysia, was subsequently forced to retract, and some time later sacked/retired.
In addition:
The Prime Minister said the pilot took the aircraft
A MAS operations manager instructed staff to stop discussing the disappearance of MH370 due to national security.
The New Zealand wife of a passenger, a month after MH370 went missing, met with the Prime Minister’s wife who said the pilots were responsible and had tried to interfere in the government of Malaysia.
General Sutarman, the Indonesian Police Chief, stated in September 2014 “I actually know what had actually happened with MH370”.
Emirates CEO Sir Tim Clark believed someone took control of the plane and maintained control until the very end. He also dismissed pilot suicide as a possible cause of the tragedy.
INMARSAT Senior Vice President Chris McLaughlin said they are certain that missing flight MH370 went west over the Andaman Islands and then went south.
Two independent drift studies undertaken by a German-British group and a French company, both of which were free of confirmation bias at that time, gave a high probability MH370 was between 8°S and 23°S at the 7th arc.
@TimR
Yes, the initial Malay response is routinely attributed to incompetence. That assessment is reinforced by the events in the days following the incident. I think the reality is that Malaysia (at the highest levels) knew what was going on early in the diversion, and even acted in an obstructionist fashion relative to what would be a normal S&R response.
The IG has never gotten engaged in these subtleties, and as a result they have not been extensively discussed (people pay a lot of attention to what the IG thinks and says, and that is an important responsibility). Likewise the IG has a long history of not speculating or commenting on causality. Of course, they have a bunch of pins in the map at 38S. Not knocking the IG here. They have helped me in many ways. I just could never sign up for their attitude.
@DennisW
Re: “You and Tim and Mick are insulting people’s intelligence with your array of off the wall mechanical issues – windshield fires, oxygen bottles going ballistic or rupturing, nose wheel explosions,… Do you have any idea how dumb that line of pursuit appears to be?”
Steady on, Dennis. One of the attractions of Victor’s blog is that most contributors maintain collegial civility most of the time. If I’ve insulted people’s intelligence by pointing out facts such as that 9M-MRO belonged to a cohort of B777s that were statistically significantly over-represented (by two orders of magnitude) in windshield heater related incidents then so be it. I’ve never viewed the presentation of verifiable facts as an insult or research to be dumb. And I know that no hypothesis, however well formed, is ever improved by uncritical and unquestioning agreement.
People will believe what they want to believe about MH370, I’m not here to disabuse anyone of their currently held notions. What I will do, however, is present information that I think to be relevant and point out where I think the information presented by others is factually incorrect or when I think their arguments are illogically constructed (and I’d like to think that I do that in a courteous and respectful manner).
Any old how, Happy Thanksgiving, I hope that everyone in your part of the world has a safe and enjoyable holiday (down under, we’ll be watching what I’m sure is a largely unfathomable game to you, cricket – Australia are playing England in the first test match for The Ashes at the ‘Gabba).
@Mick
Likewise, best wishes to you.
Good start in the test Mick, got the poms 1 for 39 already.
ALSM noted Malaysia said the report willbe delayed by the OI negotiaations. Any further word on what is going on ?
I’ve learned that it’s very difficult to impossible to have a fact-based, rationale discussion on the internet about the simulator data because it involves speculating about the guilt of the captain. Perhaps it’s not such a bad thing that some are willing to go to great lengths to protect the public reputation of somebody that can’t defend himself. But that bias also prevents some from dispassionately examining the evidence and pursuing the most probable scenario.
lkr,
Yes, Egyptair 990.
@Victor, agreed that the evidence points to human intervention with near certainty (based on earlier posts other causes can be ruled out or require independent unlikely events to occur simultaneously) but it is not possible to say by who. Besides, the assessment of crew and passengers has been superficial so involvement of others remain a strong possibility. As i am getting familiar with the satcom data and sequence of events, it seems that the SDU repower/re-logon, in particular, is key to who did it. This is an illogical event in the sequence (please correct me if otherwise):
* apparently incompatible with pilot/trainers’s normal competences / training / procedures
* it serves no apparent purpose. What could be the purpose of the left bus repower? no critical system attached to it except TCAS which is irrelevent if the intent is to crash the plane. Same applies if he wants to have power redundancy. It does not make sense for the pilot to do so assuming he has the skills. For a case of a third party did it, there could be however a strong reason to first disconnecting the satcom to ensure a communication blackout (as passenger could have place calls via the system too) and after a while reestablish a satcom to further communicate with potential complicits not on board, have power to the fuel jettison pumps if ditching is required, etc.
Despite being an easy scapegoat target, albeit no smoking guns, the logic suggests a strong possibility of 3rd party involvement.
@HB: At a time when time might have been critical, depowering the left bus is the fastest way to prevent all SATCOM communications. This is not beyond the knowledge base of pilots, as explicit EICAS messages are generated, even on home simulators. As for reasons for the re-power, I provided reasons earlier in this thread.
@Victor
@HB
There have been plenty of reasons offered as to why the Left AC Bus might have been repowered but none of them have been rationally and logically compelling.
You’ve offered three reasons recently;
1) The pilot believed he could monitor ACARS messages …
Why would the pilot want to monitor ACARS messages?
2) The pilot wished to have the capability for a fully-redundant AUTOLAND.
Why would having AUTOLAND be a requirement?
3) The pilot was waiting for a satellite call at a pre-arranged time.
Not beyond the realms of possibility but
(a) The pilot would be aware that there would be an audit trail associated with the call, and
(b) it would suggest that there is a to date unknown or undisclosed third party linked to the disappearance.
@Victor,
Sorry, could you point at the repower thread again?
@victor, found it.
Yes, not really compelling for 1 and 2 at least for me (I also thought ACARS was disabled/ not turned back on).
On 3) the same would apply for a third party and in any case, this implies a third party.
More questions to advance the topic:
1) Is any B777 pilot aware that the Left bus isolation would isolate the Satcom?
2) Are there any MAS procedures for powering / depowering the left bus? and anyone has access to it?
3) What happens if there is a total power failure or isolation ie both left and right buses out (not sure if plane still controllable in the timeframe), for that case the left bus could be restored at the same time as right bus and the PIC would not know about the Satcom connection
4) Does a cold start of the Satcom requires manual input to establish a log-on? This can be done with ACARS disabled?
5) Is the utility bus/ heating system powered from the Left Bus? this could be a possible practical reason (environment too cold).
@Mick Gilbert: There have been plenty of reasons offered as to why the Left AC Bus might have been repowered but none of them have been rationally and logically compelling.
First of all, I believe there are still missing pieces to this puzzle. We can’t be sure why the left bus was first isolated and then re-powered. That doesn’t mean it was not due to malice. The evidence to me strongly points to an intentional diversion. You disagree. Second, you are not the final arbiter on what is rationale and logically compelling. As for your questions, AUTOLAND functionality would make it easier to land if that was contemplated. ACARS monitoring could improve situational awareness. A pre-arranged call does suggested coordinated activity. These are all possible reasons for re-powering. There are others.
I also thought ACARS was disabled/ not turned back on
We think the ACARS transmissions were disabled by de-selecting all link modes. Theoretically, this would still allow messages to be received. However, because of the long period of inactivity, a log-on to the ACARS server would have been required to receive messages. This might not have been understood by the pilot.
Is any B777 pilot aware that the Left bus isolation would isolate the Satcom?
As I stated previously, there would be EICAS messages generated that would report the inoperability of the SATCOM. These messages are also generated on home simulators. I believe it is likely the captain would understand the effect that isolating the left bus would have on the functionality of the SATCOM.
Are there any MAS procedures for powering / depowering the left bus? and anyone has access to it?
I haven’t explored under which non-normal conditions the crew would be trained to depower the left bus, except that the check list for “Smoke, Fire, or Fumes” advises that if practical, to remove power from affected component by switch or breaker in the flight deck or cabin. Others might know more details. There are also checklist procedures for powering an AC bus, which would include resetting the generator switch, starting the APU, and resetting the tie breaker.
What happens if there is a total power failure or isolation ie both left and right buses out (not sure if plane still controllable in the timeframe), for that case the left bus could be restored at the same time as right bus and the PIC would not know about the Satcom connection
I don’t understand your question. The SATCOM EICAS messages are displayed if the SATCOM is inoperable due to a power down of the left bus, regardless of the status of the right bus.
Does a cold start of the Satcom requires manual input to establish a log-on? This can be done with ACARS disabled?
If properly configured, I am not aware of any manual input required for the SATCOM to log-on. The status of the ACARS is independent of the log-on sequence to the Inmarsat network.
Is the utility bus/ heating system powered from the Left Bus? this could be a possible practical reason (environment too cold).
I’d have to investigate to find the answer, but I will note that essential heating (such as the pilot window heat) is redundantly powered. Perhaps others know or can find the answer.
And that reminds me of another reason to re-power the left bus. If a landing was contemplated, fuel jettison would require the left bus. (It is doubtful fuel jettison occurred based on the endurance that was achieved.)
@VictorI @HB
‘Is the utility bus/ heating system powered from the Left Bus? this could be a possible practical reason (environment too cold).’
If I remember well it was @Mick Gilbert who once stated the left (captains) window heating is powered by the left bus. If I’m right he should have the proof for this statement.
It could be another good reason to re-power the left bus just after out of radar range or as soon as possible anyway.
For preventing the window to crack and for visibility reasons.
@Ge Rijn
link below from a Boeing engineer:
http://www.angelfire.com/ct3/ctenning/electrical_essays/777elecpwr/777_design.html
cut/paste from the link above:
Other important services, such as fuel boost pumps, cabin temperature controls, and the pilots window heat, can be supplied from either of the three main generators or the two backup generators.
@Victor,
Re: “And that reminds me of another reason to re-power the left bus. If a landing was contemplated, fuel jettison would require the left bus.”
You always need to keep in mind that an explanation of the SDU off/on has to be within the frame of your working hypothesis. I cannot reconcile “contemplated landing” with the pre-planned turn to the SIO 15 minutes later.
Approximately a year ago I suggested an attempt to jettison fuel, which would require re-powering L main bus, to explain SDU reboot – this explanation fits into a mechanical failure scenario. Furthermore, substantial damage of the electronics at the left side of EE-Bay together with intentional depowering of the main L bus may explain silence of almost all the communication means (except VHF-R).
I am not trying to convince you in a mechanical failure scenario; I am only asking you to be consistent: if “Z. did it” is your domain, then a reason for the SDU off/on must be appropriate.
Get Rijn,
“It could be another good reason to re-power the left bus just after out of radar range or as soon as possible anyway.
For preventing the window to crack and for visibility reasons.”
Which radar? Butterworth? Phuket? Lhokseumawe? Or maybe Sabang?
Why would window be cracked after existing radar range?
Visibility? It was deep night; only stars.
@Oleksandr said: I cannot reconcile “contemplated landing” with the pre-planned turn to the SIO 15 minutes later.
If there was a descent and loiter, the turn to the south occurred about an hour after the power was restored to the left bus.
For the scenario that includes a descent and a loiter before the turn to the SIO, it requires a change in objective from “stay near an airport while minimizing the burning of fuel” to “get the plane to a remote part of the SIO”. I don’t know why the objective might have changed if this scenario occurred. Some have speculated that there was a failed negotiation. What I believe is we are missing important pieces of the puzzle.
@Oleksandr
Approximately a year ago I suggested an attempt to jettison fuel, which would require re-powering L main bus, to explain SDU reboot – this explanation fits into a mechanical failure scenario. Furthermore, substantial damage of the electronics at the left side of EE-Bay together with intentional depowering of the main L bus may explain silence of almost all the communication means (except VHF-R).
I agree that de-powering of the left bus could have been the result of dealing with a failure. I did not raise this possibility because I don’t believe a failure occurred. I base this conclusion on the timing of diversion relative to the flight path, and the coordinates found on Shah’s simulator. It is also historically true that hull losses are the result of aircraft failure in only 20% of all hull losses. So even without the diversion timing and coordinates you are proposing a low probability scenario relative to pilot involvement.
Basically the diversion timing and sim coordinates have your conclusion very unlikely.
@Oleksandr
Just after the last know radar capture from Western Hill. The pilot could have known its range. Then; ‘anyway as soon as possible’ I added.
It could have been coincidence the re-logon was just after the final known radar capture.
If a window is not heated for an amount of time at high altitudes the risk of cracking is real. This would be a serious risk he could not affort to continue longer than absolutely needed.
And no pilot likes to fly with an ice-clogged window in front of him day or night.
@DennisW
You said to Oleksandr “Basically the diversion timing and sim coordinates have your conclusion very unlikely.”
Right on! The SIM coordinates demolish all the accident theories at a stroke. Diverting toward McMurdo Station in the SIM on 2nd February was just a practice run for what happened on March 8th, diversion to S40.50, E88.00.
Hope you’re going easy on the turkey and cranberry sauce.
@Oleksande
Sorry mate but it’s time to wake up and smell the coffee.
@All
I couldn’t have done it without Dr Bobby’s fuel model and his detailed BFO at 18:25/28 and 18:39/40 analyses, and Victor’s SIM evaluation work. I owe you both a big debt of gratitude.
As my hero Isaac Newton once remarked, and I quote “I saw further than any other man because I stood on the shoulders of giants”.
@Victor
“I’ve learned that it’s very difficult to impossible to have a fact-based, rationale discussion on the internet about the simulator data because it involves speculating about the guilt of the captain. Perhaps it’s not such a bad thing that some are willing to go to great lengths to protect the public reputation of somebody that can’t defend himself. But that bias also prevents some from dispassionately examining the evidence and pursuing the most probable scenario.”
Victor- thank you for your perspectives, and thank you for your MH370 blog.
@TBill: You are welcome. We are all fortunate that we live in countries where we have the freedom to express our opinions on this and other matters.
@All: I am working on a new post that should be quite interesting and thought provoking.
Looking forward to that @Victor. Keep ’em coming!
@DennisW
Thanks for the link. On the left window heat I found some more detail;
http://www.flight.org/non-normal-failures-that-impact-multiple-systems
cut/paste;
‘You try a few resets, see if the APU fixes the problem, but in the end without the ability to restore the left electrical bus, you’ve lost … Window Heat (Left) and a Primary Hydraulic Pump (Left).’
@VictorI
The linked article above also states that no EICAS/STATUS messages show you in detail what is all lost after a left main bus failure.
@Ge Rijn
The window heat for the left forward window (ie the Capt’s windshield) is powered by the L AC XFR bus.
Re: “If a window is not heated for an amount of time at high altitudes the risk of cracking is real. This would be a serious risk he could not affort to continue longer than absolutely needed.”
There are no limitations on continued operation with the window heat inoperative. Indeed, it is permissible to dispatch under the MEL with the forward window heat inoperative on one side, provided the aircraft is not operated in known or forecast icing conditions.
@Ge Rijn: With the left AC bus depowered by opening the tie breaker and isolating the left IDG, the list of EICAS messages does not include many systems that are unavailable. What is included is: ELEC BUS L, HYD PRESS PRI C1, HYD PRESS DEM L, ELEC GEN OFF L, SATCOM DATALINK, SATCOM, SATVOICE LOST, ELEC BUS ISLN L, EQUIP COOLING OVERD. The loss of fuel jettison, for instance, is not on the list. If the left transfer bus is also depowered, additional EICAS messages are: ELEC BACKUP SYS, NO LAND 3, ALTITUDE CALLOUTS, HEAT PITOT L, and WINDOW HEAT R SIDE, where I’ve taken the liberty of relying on the PMDG777 model for the message list without checking the AMM schematics to see if the model is accurate. Notice that the left transfer bus supplies power for the right window heat.
@Victor
Thank you for your reply.
Re: First of all, I believe there are still missing pieces to this puzzle.
I couldn’t agree more and I think that we are less likely to conceive of what those missing pieces might be be slavishly pursuing only one line of thought.
We can’t be sure why the left bus was first isolated and then re-powered. That doesn’t mean it was not due to malice.
Agreed. There are two elements to this matter; depowering and repowering. The depowering of the Left AC Bus may have been an automated response to a problem or it may have been a manual intervention. If it was the latter, it may have been a legitimate response to an emergency or part of a malicious plan. The repowering was almost certainly a manual intervention but that does not mean that it was part of a malicious plan.
The idea that the repowering may have been associated with a change of intent has been touched on. If the initial depowering was part of a malicious plan I’ve also wondered whether the repowering (and subsequent actions) might have been carried out by a different actor; might flight or cabin crew have regained access to the flight deck and attempted to recover the situation? To make sense of that scenario you’d have to consider that the perpetrator had permanently disabled airplane system interfaces (the display units and keypads) and communications.
The evidence to me strongly points to an intentional diversion. You disagree.
I don’t disagree that there was an intentional diversion, what I disagree with is the contention that it must have been part of a malicious plan.
Second, you are not the final arbiter on what is rationale and logically compelling.
No, I am not nor have I laid claim to that role. What I would say is that if there was a rationally and logically compelling rationale for the repowering there would be widespread or, at the very least, general acceptance of that proposition. Unless I am missing something, that level of acceptance does not exist for any proposition.
As for your questions, AUTOLAND functionality would make it easier to land if that was contemplated. ACARS monitoring could improve situational awareness. A pre-arranged call does suggested coordinated activity. These are all possible reasons for re-powering. There are others.
Thank you for those answers, Victor. The desire to restore AUTOLAND would not be inconsistent with an attempt to recover the airplane; the possibility of a pre-arranged call suggests a conspiracy; and monitoring ACARS might be associated with either recovery or a conspiracy or with malicious action terminating in murder/suicide. The variety of underlying themes – recovery, conspiracy, malicious intent – associated with just those three reasons underlines my point about the current lack of a compelling rationale.
@Victor
When you isolated the Left Transfer Bus you should have got a WINDOW HEAT L FWD EICAS message together with WINDOW HEAT R SIDE. The WINDOW HEAT R SIDE message refers to the loss of power to the First Officer’s side (or No 2) window heater as opposed to the No 1 or forward window/windshield.
@Victor
For what it’s worth, the PMDG777 model may not be accurate in respect of the WINDOW HEAT messages. According to my manuals, the left forward window heat is powered by the L AC transfer bus and the right side window heat is powered by the L AC SEC 2 bus. I would expect the WINDOW HEAT R SIDE message to appear when power is removed from the left AC bus. A WINDOW HEAT L FWD message should appear when power is also removed from the left transfer bus. Note, there are four sets of windows – L SIDE, L FWD, R FWD and R SIDE; they all have different power supplies for the window heat.
The reason there is no FUEL JETTISON MAIN message is because the message is triggered by low output pressure from the jettison pump(s). That will only occur when the FUEL JETTISON NOZZLE valve switches are selected ON to activate the system and there is no pressure from the pump(s). In that scenario, fuel jettison is still available from the centre tank.
@Victor
@Andrew
There you go, strike what I said, replace it with what Andrew said.
@DennisW
Re: “It is also historically true that hull losses are the result of aircraft failure in only 20% of all hull losses.”
And deliberate malicious action by flight crew accounts for 0.5% of all hull losses. Just saying, you know.
@Victor, thanks for the answer.
I got it this time re EICAS relationship. Yes someone who play with a simulator can easily make the linkage between Left Bus and Satcom.
RE RE I also thought ACARS was disabled/ not turned back on
Understand the linkage, but if the intention is to use the ACARS, the failure will be revealed on demand and the PIC should have reestablished ACARS after noticing since he/she intended to use it. This seems to involve other independent concurrent events lowering the probability.
Please elaborate how you think turning back on the ACARS could improve situation awareness? also how the ACARS display looks like (as it appears to the PIC) in such a case?
RE RE Are there any MAS procedures for powering / depowering the left bus? and anyone has access to it?
It would be interesting to drill down on this.
RE RE What happens if there is a total power failure
i am probing the possibility of total power failure as the initiating cause whatever the reason (eg total power shudown initiated manually from either cockpit or EE/bay as opposed to left bus only). If that event occurred, there is an obvious reason to willing to restore power after some time to BOTH buses without bothering to know what are the electrical loads fed from each bus. Whether the plane can fly for some time in this condition i don’t know.
RE RE Jettison/ AUTOLAND
If intention is to run out of fuel in SIO those systems are indeed useless. If true other events must have happened to prevent a landing or like you mentioned a change in objective. It does not look likely.
Also why on earth a decision to go to SIO? can the plane be flown remotely or incapacitation led to auto direction to SIO? Difficult to imagine the pilot on his own making all these decisions bearing in mind there was no obvious attempt to preserve fuel (that one might have expected) while in direction to the SIO.
RE Utility bus/heating system.
Would be good to have the single line diagrams of the configuration.
Apart from the ulitiy / heating system linkages if it exists, other possibilities seem to involve more than one events occurring independently.
RE Left bus isolation. In case of fire, the logic would be to isolate the outgoing breakers feeding the affected loads but not the full bus I would have thought. Here the issue seems to be around full bus isolation. I’d like to hear from others too.
@Mick
I’m pretty much done arguing about it with you guys. It has been a frustrating three years. I am going to continue (first baby steps were looking into GA) taking it to the next level. It is obvious that humans cannot deal affectively with analytics of this type. As Malaysia CEO Bellow has stated, AI is the likely answer to finding the plane.
https://analyticsindiamag.com/artificial-intelligence-looked-upon-way-locate-mysteriously-disappeared-mh370/
Google has recently made some pretty amazing stuff available in this domain via their public domain TensorFlow releases.
https://www.tensorflow.org
@DennisW
Dennis, I was just making the point that crash statistics are not your friend in this instance.
@Mick
Yes, I got your drift. The 20% failure statistic is unaltered by any of the information we have. The 0.5% pilot malice statistic is altered substantially by two priors – the timing of the diversion initiation, and the simulator coordinates. I could site lack of communication as a third prior, but you would argue that a failure could have rendered all the coms inoperative.
@Mick Gilbert: I couldn’t agree more and I think that we are less likely to conceive of what those missing pieces might be be slavishly pursuing only one line of thought.
In the event that comment was directed at me, let me say for the record that I have studied MANY scenarios, including mechanical failure followed by single turn and cruise conditions, which predicted a termination near 37.5S latitude, BFO spoofing, which predicted northern terminations in Kazakhstan and China (but not at Baikonur), and the descent/loiter scenario, which predicted a termination over a range of latitudes north of 36S. However, the recovered debris eliminates the northern path, and the null result for the previous search eliminates the single turn/cruise speed scenario. The recovered simulation data makes captain involvement very likely, and I’ve pursued that line. If you characterize my reasoning as “slavishly pursuing only one line of thought”, you are sadly mistaken.
But perhaps you were not referring to me in your comment.
@Victor
I get a general sense from the comments of the “failure brigade people” that investigations outside that domain are somehow waging a vendetta against a defenseless captain – an affront to basic human decency in the age of political correctness. I encounter the same attitude in many situations unrelated to MH370. I attribute it to the liberal bias in academia and education (and, of course, journalism).
@DennisW: As I said in a previous comment, it might not be all bad that people jump up to speak against a scenario that can’t be proven with certainty but implicates somebody who has no prior offenses. That’s why I say it is so difficult to investigate this possibility on the internet. We have to accept this. In this case, I don’t think it is related to the political ideology of the investigators.
@VictorI @Andrew @Mick Gilbert
Thanks for clarifying the EICAS messages and window heating issue.
I referred to the article only to take notion of it. There have been several window cracks as @Mick Gilbert (? no confirmation yet, please confirm) discribed in the past by failing window heating.
I took those statements for granted and did not check them further.
So I assumed window heat failure was a serious problem.
Therefore it suprised me @Andrew stated it’s not a flight-limiting failure unless icing weather conditions are expected.
Nevertheless I think it could be a problem when watervapour from inside the cockpit/cabin freezes on the inside of the window hindering visibility. Just when your front window heating in your car does not work in winter ice would build up on the inside.
Further I agree with your (@VictorI) line of thought about the known facts to date and their implications for now.
I also think a (long) descent was involved after ~18:25.
I still doubt the loiter though. In my thinking the plane could have traveled farther noth-west towards DOTEN and made a partial return towards Indonesia like @TBill suggested also.
Then made a smaller turn to the right before entering Indonesian radar range then heading towards the SIO.
The coincidence of the sat-call at 18:40 to catch the plane in a turn is just much more unlikely than the sat-call catching the plane in an ongoing and earlier started descent imo.
@Ge Rijn: The holding pattern is one of many possibilities. If you allow an ongoing descent at 18:40, the plane could be tracking towards Car Nicobar. Many of the great circle paths after 19:41 also extend back in time near Car Nicobar. A holding pattern connects the two flight segments. An excursion west past Car Nicobar and then back east before turning south is also possible.
@VictorI
I preferre the flight was as less complicated as possible.
If planned with the objective to deceive and avoid suspisious radar detection by India (Car Nicobar), Thailand or Indonesia it could have been a clever strategy. It stayed within Malaysian FIR at least till the final radar capture.
It would have looked like an outgoing normal commercial flight to the west and after the turn an incoming normal flight from the west to the east till vanishing by all other active radar stations.
Just flying straight towards 10N/90E (with a long descent after 18:28) and turning somewhere not too far before this point towards the south-east to produce the second arc at 19:41 could fit those legs in time without a loiter imo.
A second ‘real’ FMT is needed though to make the final slight right turn towards the SIO.
Just some thoughts.
Those would also be in line if an initial plan to fly towards 10N/90E was altered slightly by the not preferred circumstances of being a Beijing-flight and not a Jeddah-flight.
@GeRijn
Re: “There have been several window cracks as @Mick Gilbert (? no confirmation yet, please confirm) discribed in the past by failing window heating.”
There have been plenty of incidents where windows have cracked as a result of window heat problems. However, in most cases the cracks were caused by a defect in the heating block at the junction between the aircraft’s power supply and the window. The defect allowed electrical arcing to occur that weakened the outer layer of the window, causing it to crack. The cracks were not caused by a lack of heat to the window.
Even if a crack does occur, it’s not necessarily a major problem, apart from the reduced visibility through the cracked window. The windows have several layers and it’s usually the outer layer that cracks. The inner layer is perfectly capable of sustaining the differential pressure, provided it is undamaged. In that case there are no limitations on continued flight. The only time it’s a problem is when the inner ply is cracked or the window deforms or an air leak occurs. If any of those occur, the aircraft must descend to reduce the differential pressure and land as soon as possible
As you said in your comment, the biggest problem caused by a window heat failure is the reduced visibility caused by fogging and icing on the inside of the window.
@Victor
No, Victor, I was not referring to you in that comment.
@DennisW
As Victor has correctly surmised, political correctness plays no part in my analysis.
Further to the last paragraph of my previous post, the B777 has a backup window heat system that provides anti-fogging for the forward windows. Dispatch with the primary heat system inoperative is only allowed if the backup system operates normally. However, if the L AC transfer bus is not powered, then both the primary and backup window heat systems will be inoperative.
@Mick
As Victor has correctly surmised, political correctness plays no part in my analysis.
What parts do the timing of the diversion relative to the FIR boundary and the coordinates found on Shah’s simulator play in your analysis.
@all: While we wait for Victor’s new chapter — to me the past week has been ‘deja vu all over again’. Some fairly old back-and-forth on the various mechanically-determined scenarios. Since the latter either seek to explain the loss and recovery of left-bus power, or at least suggest this is a hole in deliberate-diversion scenarios, I wonder: is it possible or probable that re-energizing the left bus was just a matter of housekeeping?
For any diversion scenario, the PIC would have come off an hour of pure adrenalin — in rapid succession sealing the cockpit, depowering Satcomm and switching off the transponder [presumably in that order], turning back over the Malaysia-Thai border [perhaps in part at least flying manual] and almost certainly depressurizing the plane, then monitoring the approach and departure over Penang [the most likely place for an intercept.
It’s likely that the PIC would have been monitoring radio frequencies, and well past Butterworth would have decided there was no alarm of pursuit and relaxed, taken the time to program the rest of the flight. I’d guess that a tidy person would tend to housekeeping, and return most settings to normal — including the left bus. If it was originally thrown to disconnect satcomm [or several functions], it no longer mattered. And as Victor suggested a while back, at this point a sane person would take off his oxygen mask.
@IKR
While we wait for Victor’s new chapter — to me the past week has been ‘deja vu all over again’.
I too am anxious for Victor’s “new chapter”. Not for the same reasons as the rest of you. Simply because the length of the comment section here is difficult for a person living in the boonies with low bandwidth.
@Mick
my question:
What parts do the timing of the diversion relative to the FIR boundary and the coordinates found on Shah’s simulator play in your analysis.
I don’t expect a reply. You simply have nothing to say on the subject. Even your stats statement is totally wrong. Wake up.
@Dennis: “Simply because the length of the comment section here is difficult for a person living in the boonies with low bandwidth.”
That too. But hey, Thanksgiving means most Americans had to loosen their belts a notch or two..
@DennisW
Really Dennis? This is what passes for collegial civility, is it?
Sorry I didn’t meet your cut-off for a response but I wasn’t aware there was a time limit; here are my answers anyway.
Much has been made of the turnback occurring at the near the Kuala Lumpur/Ho Chi Minh City FIR boundary. I don’t think that it is particularly notable for two reasons:
1. If you’d planned to disappear with a minimum of attention doing so right on the FIR boundary and right on handover to a new AATC actually isn’t your best choice. Apart from anything else it is one of the occasions on a flight when an air traffic controller is definitely expecting to hear from you. KL AATC had prepped HCC AATC for MH370’s handover a good 40 minutes before it approached IGARI. If HCC had have been doing their job the failure of the airplane to report in would have been noticed within a few minutes. Had the airplane have reported in to HCC near IGARI the next time HCC would likely have made contact with the airplane was for a frequency change as it approached Ho Chi Minh City, about 30 minutes later. It could have reported in and turned back a short time later and been relatively assured of a good 30 minutes head start. The actual 20 minute delay in HCC querying MH370’s failure to report in couldn’t possibly have been planned for.
2. Airplanes sometimes develop emergencies near FIR boundaries. Two examples bear this out:
(i) EgyptAir flight MS804 departed from its planned route virtually on top of waypoint KUMBI, right on the Athens/Cairo FIR boundary.
(ii) Similarly, Air France flight AF447 departed from its planned route as it approached waypoint TASIL, right on the Atlantic/Dakar FIR boundary.
The home flight simulator data falls somewhere between curiously coincidental and dammingly suspicious. I would like to have access to a more complete set of data relating to the half a dozen data points and have a better understanding of how Shah used his home simulator (currently we’re lacking any sort of behavioural baseline). I’m making some enquiries into the flight simulation program used and will get back to you in a couple of weeks.
And which stats statement in particular is totally wrong?
@Mick
I did not check your 0.5% pilot malice stat. I am assuming it is correct. However, it is modified substantially by the other priors which you have chosen to ignore.
The FIR choice is in line with an intentional diversion for the reasons you state. It was important that the plane could be confirmed as missing as early as possible to provide a maximum time for negotiation. An extra 30 minutes (or whatever the number) is a significant amount of time relative to the total time available.
@DennisW, @Mick Gilbert: Foul play involving a turn back near an FIR boundary is not unprecedented. For instance, the hijackers of AA77, which impacted the Pentagon on 9/11, chose to turn back towards Washington, DC, after passing from airspace controlled by Washington Center to airspace controlled by Indianapolis Center. After acknowledging clearance for a climb with Indianapolis controllers, hijackers disabled the transponder, and the aircraft turned back into Washington-controlled airspace. When the radar targets dropped from SSR, Indianapolis assumed either the plane crashed or it continued on its western track, and the search was conducted along those lines. In the ensuing confusion caused by the turn back at the FIR boundary, it took 36 minutes from the time the transponder was disabled until the time that the aircraft was identified on primary radar as traveling eastbound towards Washington, DC. At that time, an airborne C-130 was instructed to follow AA77. About 5 minutes later, the pilots of the C-130 witnessed AA77 crashing into the Pentagon.
@Mick
@Victor
“I’m making some enquiries into the flight simulation program used and will get back to you in a couple of weeks.”
Mick- what type of inquiries? I may have some questions too if you are establishing an official contact.
One thing about the Z sim cases, I almost never start a new flight from the runway (rather I start from an saved case already in flight). The only reason I take off from the runway is if I want the planned flight route to show up on the map. That way you can see where to move the icon, if you want to move ahead. Also I can see how close a turns ends up on the planned flight path.
Seems to me the turn at 10N ends exactly on the DOTEN to NZPG great circle, which I do not know how to conduct an exact turn like that except via trial and error.
@TBill
I think far too much emphasis is being placed on the detailed simulator functionality. Does it really matter? What does matter are the coordinates – the hard numbers. As I said before, they would have the same impact if they were scribbled on a piece of paper in Shah’s trash. Who cares how the coordinates were generated? It is their existence that matters. Not trying to diminish the efforts Victor put in which only strengthen the case.
Questioning the simulator data is the standard drill of the failure scenario advocates (we now have the “lack of a behavioral baseline” question added to the pathetic list of questions raised so far).
@Victor
“Pentagon on 9/11”
We just visited Flight 93 National Memorial a few weeks ago, and also my cousin was an air traffic controller that day. Apparently the Trade Center flights also turned off their transponders (I am not sure if this was at FIR boundary). Sounds like ATC could see 2nd flight heading down Hudson on their primary radar, and asked other pilots to report back, they said they could see it at low altitude.
Flight 93 memorial is quite impressive…had no idea how big it was. PAX deserve it for saving the Capitol. Tower of Voices to be completed in 2018. I am a founding contributor to the memorial – found my name on the list they have.
“Frankly, I am open to hearing what recommendations others here might have.”
Speaking of possible Antarctic aiming points, if it were the case that the PIC was angry over the Malaysian policy of jailing people for being gay, someone pointed out a long time ago that -69,69 would be as logical as any other point. It would be easy to enter into the computer, and actually fits rather well with the following waypoint path, with tolerable BTO errors IMO: NILAM POVUS ISBIX MUTMI RUNUT -69,69. There also happens to be Chinese base in the same general direction (Zhongshan).
NILAM POVUS ISBIX MUTMI RUNUT -69,69″
So you’re saying 40S on Arc7…
@Andrew,
Do you know how a B777 executes at SLOP? For large distances (say 15 NM), does it turn to a maximum relative angle to the airway track and then fly straight for a while before turning back to meet the offset path without overshoot? Do you happen to know what that maximum angle is? Would the maximum bank angle typically be 25 degrees?
Victor,
R.E AA77, my rule of thumb (subject to wild variations) is that it takes ~40 minutes to cross an FIR. This is based on analyzing the FFP of MH370. In the case of AA77, the hijacking started ~11 minutes after crossing the FIR boundary (based on cursory research of the AA77 timeline). Not particularly close in time. Further, the aircraft HAD checked in with Indianapolis, so there wasn’t any question of who was responsible.
A closer case is Egyptair 804. It, too, disappeared from SSR at an FIR crossing, approximately 30 seconds after passing KUMBI. However, loss of communication occurred BEFORE it crossed the FIR boundary.
Conclusion: AA77 is not particularly anomalous. Egyptair IS somewhat anomalous, but given the number of flights that have “vanished from radar” in the past 5 years, perhaps it is not entirely unexpected.
If MH370 really disappeared 2 seconds after passing IGARI***, it still stands out like a sore thumb.
*** IGARI is the “transfer of control” point, where control shifts from KL to HCM. It is a few NM away from the actual FIR boundary (which is actually between FIR Singapore and FIR Ho Chi Minh – isn’t aviation bureaucracy wonderful?)
@sk999: I didn’t mean to imply that AA77 went dark right before the FIR boundary. As I said above, it was in contact with Indianapolis for clearance to a higher altitude. What made AA77 difficult to find was the turn back into the preceding FIR, which caused confusion because the main options considered were continue flying west, or crash. A turn back towards the east was not considered until much later, and valuable time was lost. A similar situation occurred for MH370, where the controllers were looking to the east and to the sea surface rather than to consider that MH370 was flying back towards the west.
@vICTOR,
You asked people to nominate a new search area for OI after doing Dr David Griffin’s “next best quess”.
I nominate “E2” (94.469 -43.487).
The reason, in a nutshell, is, that it fits the recorded 00:11 BTO of 23,000.
I know that the IG swears by the existing published ATSB BTO’s, but I don’t.
I know that what follows will be dismissed out of hand by all the “experts”, but that does not worry me either.
My take on the last three and a half years can be simply summarised as:-
“the experts have come up empty, so a rethink is required”.
GOING BACK TO SQUARE ONE.
In the early days, Inmarsat put a very strong caveat on everything they said, about their data. They repeatedly cautioned, that their own system logs could have been hacked.
PHASE ONE – up to IGARI.
The existing flight path to IGARI is agreed, as is all the BTO analsis and calibrations at Gate C1, and the ACARS points and data en-route to IGARI.
PHASE TWO – post IGARI.
The hour or so post IGARI was “the dark time”.
Initially we had the “south china sea” search.
Then we had the first RMAF Radar “possible turnback”.
Then we had the “mallacca strait” search.
Then we had the Thai’s saying (apparently at he “urging” of the malaysians) that their radar had detected what they “thought” was MH370, but that it was “not a normal return” near Igari.
Then we had the LIDO slide, the last “confirmed” return at Palu Perak, the “white hole”, and then the other “returns”, to ten miles past Mekar, then a gap, and then the supposed 18:22 return.
Around this time, there were the first “unconfirmed reports from intelligence sources” that Hamid’s phone had been detected at Penang.
Then we had the first crumbes of the Inmarsat data, the 40 degrees elevation, the two north and south corridors. Later crumbs gave us the time that the SDU came back up, at 18:25, and then came the “flying leap of logic”, that the 18:22 radar return was “consistent with” the 18:25 SDU reboot, and so the whole reconstructed path story goes from there. In amongst all this, an Indonesian Police General said that he “knew” what had happened to MH370, and was then promptly fired.
My analysis says the BTO’s were indeed “hacked”, and in fact, it went SOUTH from Igari, NOT west.
The proof of that, is the 00:19:29 BTO itself.
It was recorded as 23,000, and it was, I mean, it actually was correct, it, and the 00:19:37 were “NOT HACKED”.
Why ?
Simple, because whoever “hacked the log” did it “before” they realised that there was anything post about 00:12 – 00:15.
Why ?
Two reasons.
ONE, they knew that the fuel would have run out round 00:00 – 00:15 anyway, and it would therefore have surely crashed by then, so there could be no more handshakes of any kind post 00:11 (they were badly wrong as we now know).
TWO,
Because they knew the second phone call had reset the system “ping stay alive” for another hour past the 23:14 phone call, which again was way past fuel exhaustion, AND around 00:15, so “done deal”, that will do – log off now !
This means, whovever “hacked the log” did so between 23:14 and 00:15.
It also means, that whoever it was, must have had an intimate satellite communications enginnering knowldege of the system, (obviously) and access to it. If only “the hacker” had stayed on line another five minutes. His plan would have been complete, and perfect. But alas, he was too sure he was on top of his game, and too impatient.
With it’s dying breath, 9M-MRO sent it’s “Last Will and Testament” at 00:19:29, and foiled his plan.
This means, that the ONLY Inmarsat data that is correct is the data up to the last ACARS inbound Igari, and the 00:19 data.
All the intervening Inmarsat data, ie, post the 18:25 logon and up to and including 00:11 (the 6th arc) is FALSE.
The 7th arc 00:19:29 data, that data that was, you will all remember, in the early days “not understood”, was in fact, correct after all.
I will repeat what I said at the beginning.
GOING BACK TO SQUARE ONE.
In the early days, Inmarsat put a very strong caveat on everything they said, about their data.
They repeatedly cautioned, that their own system logs could have been hacked.
I now think they were correct, and I hve a rationalle for that.
Without going on at length about how I eventually worked all this out, I will just simply give you all the answer(s).
The simple answer is, “the BTO’s from 18:25 to 00:11 inclusive were simply hacked by ONE NUMBER, and that magic number is “minus 4600us”.
This means that to get the true BTO’s, as “originally recorded” in the log file, up to 00:11, ie, before they were hacked, we have to ADD 4600us, and for 00:19, the ATSB had to SUBTRACT 4600us to get a figure that “they wanted”.
(Just as an “aside”, it was the fact that I never swallowed the ATSB’s 7th Arc, that was “corrected” in so many ways, to get their 18410, that was not credible to me, that really got me “digging”).
Thus the reconstructed BTO values are:-
UTC ATSB +4600 TRUE
00:25 12480 +4600 17,080
19:41 11500 +4600 16,100
20:41 11740 +4600 16,340
21:41 12780 +4600 17,380
22:41 14540 +4600 19,140
00:11 18040 +4600 22,640
Now, 9M-MRO’s “LAST WILL AND TESTAMENT” was at 00:19:29
UTC TRUE ADJUST ATSB
00:1929 23,000 -4600 18400
00:1937 23,010 -4600 18410
Thus, the reconstructed flight path coordinates for the TRUE BTO’s are:-
UTC Lon Lat
18:28 105.324 000.000 (Equator)
19:41 102.069 -9.107
20:41 100.028 -16.617
21:41 98.875 -23.402
22:41 97.405 -31.299
00:11 94.636 -42.917
00:1929 94.351 -43.960
00:1937 94.345 -43.984
My end point is near enought to “E2” (94.469 -43.487) that it doesn’t matter.
Case Solved.
I therefore suggest David Mearns eventually searches that area (he does not like “pins in charts”).
CORRECTION:
The reason, in a nutshell, is, that it fits the recorded 00:19:29 BTO of 23,000. (not 00:11)
@TBill
Bill, regarding the flight sim, I’ve asked some questions relating to how the simulation models the autotune function of the real airplane, the extent of the simulation’s navaid database and the extent of its navigational (waypoints and airports) database. I’ll shoot you the contact details separately.
With regards to trying get the turn at 10N to fit the DOTEN-NZPG great circle route, I’d suggest that the problem lies in the fact that the turn wasn’t initiated at or near 10N; based on the navaid settings for the 10N data point the simulation airplane had been placed in that 20° AOB turn over 500 nm away, somewhere over in the Straits of Malacca near VAMPI. The simulation airplane had most likely been placed in that turn, allowed to reach a heading of around 255° (which would have it heading towards or in the general direction of Banda Aceh) and then it was “dragged” to 10N.
@Victor
@sk999
Your reference to AA77 illustrates my point that taking the time to check in with and being accepted by the “next” AATC before initiating a turn back is the best course of action. Failing to check in with HCC AATC should have raised a red flag within minutes; deliberately failing to do so doesn’t appear to be consistent with a meticulously planned diversion.
Mick,
You say, “Your reference to AA77 illustrates my point that taking the time to check in with and being accepted by the “next” AATC before initiating a turn back is the best course of action.”
Glad to know that you are an expert at hijacking aircraft. Too bad you weren’t on board to provide advice. However, whoever diverted the aircraft succeeded anyway (whether or not it was “near” to an FIR boundary).
“Failing to check in with HCC AATC should have raised a red flag within minutes …”
Well, it did – 18 minutes later.
————
Appendix 1.18G DIRECT LINE COORDINATION COMMUNICATION KL ATCC SECTOR 3+5 PLANNER
1739:03 UTC
[0139:03 MYT]
KL ATCC Lumpur
1739:06 UTC
[0139:06 MYT]
HCM ATCC Any information on Malaysian Three Seven Zero sir.
1739:08 UTC
[0139:08 MYT]
KL ATCC Malaysian Three Seven Zero already transfer to you
right
1739:12 UTC
[0139:12 MYT]
HCM ATCC Yeah yeah I know at time two zero but we have no just
about in contact after… BITOD we have na… radar
lost with him the other one here to track identified on
my radar.
@Mick Gilbert said: The simulation airplane had most likely been placed in that turn, allowed to reach a heading of around 255° (which would have it heading towards or in the general direction of Banda Aceh) and then it was “dragged” to 10N.
I agree.
@ventus45 said: I therefore suggest David Mearns eventually searches that area (he does not like “pins in charts”).
That’s unlikely to happen. Your scenario means that Inmarsat lied about the repeatable 4600 μs adjustment at log-on, the US helped falsify the radar data, the Malaysian cell phone company produced fraudulent records, the BFO values were also hacked to match the hacked BTO, the debris was planted to look like a more northern impact…in fact, from what I can tell, the only evidence that you claim supports this theory is the acoustic event.
@Mick Gilbert: I find it a bit amusing when somebody offers evidence that the disappearance wasn’t intentional because a particular action should not have worked (but did). Examples are not checking in with HCM ATC and flying near Butterworth.
@Victor,
I am not surprised that you disagree. The kml’s for what they are worth.
DropBox-V45-BTOs-E2
@DrB
Re: “Do you know how a B777 executes at SLOP? For large distances (say 15 NM), does it turn to a maximum relative angle to the airway track and then fly straight for a while before turning back to meet the offset path without overshoot? Do you happen to know what that maximum angle is? Would the maximum bank angle typically be 25 degrees?”
Yes, the aircraft will turn and then fly a straight segment before turning again to intercept the offset path. It’s been a while since I’ve flown the B777, but from memory the intercept angle is about 45° and the maximum bank angle is typically 25°.
@sk999
Steve, my point is that if you want to draw fairly prompt attention to yourself, failing to make scheduled contact with ATC at a transfer of control point is generally a good way to accomplish this. You do not have to be an “expert at hijacking aircraft” to understand that, virtually every qualified pilot, private or commercial, knows it.
@Victor
And I find it a bit amusing when somebody offers evidence that the disappearance wasn’t accidental because a particular action, such as a mayday, didn’t occur. I guess some people will think that we’re easily amused.
@DennisW
Dennis, for a generally plain-speaking fellow you can be hard to follow at times. The statistics relating to murder/suicides by commercial pilots using a commercial flight are relatively easy to calculate. There have been a grand total of six such incidents in the history of contemporary commercial aviation (five at the time that MH370 flew). To 2016 there had been 910 hull losses of commercial jet aircraft (I highlight “jet” because one of the commercial pilot murder/suicides, the 1994 Royal Air Maroc Flight 630 incident, involved an ATR 42-300 turboprop). You can roll commercial turboprop hull losses into the mix if you want; for simplicity I removed the Royal Air Maroc incident to get an incidence rate of 0.549%.
What priors would you have me consider? In a grand total of none of the six incidents did the airplane make any significant deviation from its planned route apart the obvious one in the vertical plane. And, on no occasions did the time from take-off to impact exceed 1 hour and 45 minutes. The average elapsed time from take-off to impact was 47 minutes.
And for someone who has been scathingly critical of the ATSB’s decision to embark on an underwater search with insufficient information and who also emphasises the importance of considering priors in analysis, it’s just a tad odd that you would then brand my desire to have more information with regards to the Captain’s flight simulator usage so as to be able to consider prior behaviour as “pathetic”. Each to their own, I guess.
Any old how, I’ll be watching the cricket this afternoon so responses will not be timely; considered responses even less so.
@Mick
Priors in this context refer to relevant information you had before you declared a 0.55% incident rate. The most significant prior is the coordinates found on Shah’s simulator. A second prior is the lack of communication followed by a lengthy flight continuation. A third prior being the timing of the diversion relative to the FIR.
It is not possible to assign numerical modifiers to these priors, but it is easy to see that they are very significant. The probability of a diversion initiated by Shah and unrelated to any aircraft issues is very near 100%.
I think what troubles me the most about failure posters is that they do not even mention the simulator data until challenged. I would frankly be embarrassed to make posts about various failures without having a strong “canned” response to why the simulator data should not be considered.
@ventus45… i noticed the a possible north endpoint is near Xinjiang by switching (-43.487, 94.469) to (+43.487, 94.469)… especially if the hacking or spoofing method was to make a northern flight look like it went south
@Mick Gilbert said: The simulation airplane had most likely been placed in that turn, allowed to reach a heading of around 255° (which would have it heading towards or in the general direction of Banda Aceh) and then it was “dragged” to 10N.
@Victor said: I agree.
>>You guys have some explaining to do.
@DennisW
The reason for study of the sim data is to see if Victor/Yves got all of the findings out of it. They did pretty good, but @Mick saw something in the radio settings.
@TBill
I fully support the efforts of Victor, Yves, and anyone else who studies the simulator data. My comments are intended to deflect posters who want to invalidate it based on the nuances of how it might have been created.
@All
Something for Sunday morning:
Go to the Movable-Type Scripts online Vincent calculator, scroll down to the Direct Solution box, enter 07 01 25N, 94 36 08E as the start point, bearing 186 48 25.66, distance 5305132.87 metres, and see where it goes to. 0.0012 arc sec is inch at S40.50!
S40.50, E88.00 is 173NM downrange of fuel exhaustion UTC 00:17:30. The track passes within 5NM of the Bayesian hotspot bullseye.
But how did he get to our start point at N07 01 25, E94 36 08? Well, he left the N571 12NM right offset at 18:29 and flew directly toward ANOKO. 20 NM before reaching ANOKO, he redirected his aircraft to S40.50, E88.00 manual waypoint. Flying at M0.84, at FL350, he reach the turning point at 18:35.67, the 7.5NM radius turn took about 1.4 minutes, turning through 81.5deg to align with the manual waypoint. As soon as the turn got under way, he began a slowdown to M0.67, to increase his endurance time by a few minutes to make sure he didn’t flameout before sunrise. 23 minutes later, he increased speed to M0.82 and climbed to FL390 for the journey south, touching the 19:41 arc at S01 02 00, E93 39 00.
This was a procedure he had practiced on the simulator on 2nd Feb.
@All
But how did he avoid the search area, BFO at 00:19 shows he was descending rapidly?
Well we shouldn’t underestimate his capabilities, or his calculated cunning. He may have known that SATCOM transmissions compensated for contacting horizontal velocity only (he didn’t know about the stationary satellite assumption, though) So if he timed a short steep descent to coincide with the SDU logon 8sec snapshot, he could make it look as if the plane was descending out of control. Clever, eh? Or possibly, a glide from FL390 allows a brief steep descent early on, and still gets downrange of the search area. Anyway, however he did it, he did it!
@All
Here are the relevant range and endurance figures:
My flight path from 18:29 to 00:17.50 is 2761.5NM (air miles, the Vincent calculates ground miles, btw) to convert, use factor.
Dr Bobby’s fuel model is 2788NM MEFE 00:18 for M0.82 at FL390, or 2774NM 00:16 at FL380. My path is 27NM or 12 NM less than predicted, depending on whether he flew at FL380 or FL390 in the night. Difference is due to him not attaining final cruising altitude at M0.82 until about 19:10.
The Mach 0.82 cruise and the S40.5, E88.0 manual waypoint when taken together constitute a smoking gun. A smoking Glok.
Chasing down BFO errors is pointless task.
The drift results are clearly completely fabricated to take the heat off the ATSB. The biggest elephant in the room has always been the deliberate, pre-planned pilot action(for what ever reason, take your pick)
You are letting yourselves be led astray, following each others tails. You are now so far down the wrong path, it’s impossible for you to turn back.
Good luck.
@VictorI
I’m also curious about your anwser to @Mick Gilbert;
‘…and then it was “dragged” to 10N.
@Victor said: I agree.’
I wonder if your anwser was serious or kind of cynical.
@Ge Rijn: I was serious. We know that at 5N, the plane was exactly tracking towards VAMPI (despite claims otherwise from people that don’t know the difference between track and heading). We also know that the plane was dragged to position 10N just before the save. @Mick Gilbert astutely noticed that the VOR frequencies were consistent with a position near VAMPI. (Although I believe his theory about a simulated flight near Colombo is false.) So I think the observation that Mick makes is likely correct.
@VictorI
Clear. But then I think he first initiated a turn to the south-west at 5N around the tip of Sumatra (or towards Banda Atjeh as @Mick Gilbert suggested) and then moved this turn towards towards 10N/90E.
To me this looks like he could have been considering two options; an early FMT at 5N or a late one at 10N/90E.
Does this make any sence to you?
to add.. Better to name it a MT instead of an FMT in my previous suggestion..
@Ge Rijn: I don’t know. I have a side theory about the simulator data that explains both their existence and their over-writing, but it is pure conjecture. Perhaps at a later time I’ll present it.
@Ge Rijn
They’ve (@Victor. @Mick) got some explaining to do because the turn at 10N seems to me perfectly timed for a turn onto DOTEN/NZPG, so they have to convince me the structure of an earlier turn. What I want to know is if Z had a calc or PSS777 version that knew where to start a turn.
to add something more;
This would also delete the possibility his initial target/destination could have been Colombo. The turn at 5N just wasn’t changed when moved to 10N.
His initial/first intention was to turn towards the tip of Sumatra and probably the IO at 5N it seems to me.
@VictorI
I look forward to see that side theory.
Now to me the heading towards Sri Lanka/Colombo at 10N/90E makes absolute sence. It’s just coincidence.
The initial turn to- or around the tip of Sumatra just wasn’t changed and moved towards 10N/90E.
If I’m definitely wrong I’m glad to hear.
@TBill
Like you I also suggested a late (F)MT, before- but near 10N/90E quite some time ago.
The two legs necessary from 18:22 till that turn back and to the second Arc could fit the time, general speed and distances needed to make the data fit without a loiter imo. A more simple and logical solution too imo.
I assume it would have been no problem for Shah to calculate where to turn anywhere. The turns at IGARI and Penang show this clearly imo. But I could be wrong ofcourse.
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