The Civilian Radar Data for MH370

Civilian radar data after transponder was disabled. (Click to enlarge.)

We know that MH370 was captured by civilian and military radar sites before and after the transponder was disabled at 17:21 UTC. However, Malaysian authorities have chosen to release these data sets only as low resolution images that have imprecise position information with few timestamps. The DSTG did choose to publish in its Bayesian analysis the speed and track data that was derived from radar data that was provided to them by Malaysia. However, the DSTG presented the speed and track data after applying a Kalman filter to remove noise. It’s unknown whether that Kalman filter produced artefacts in the graphical presentation of that data.

We now have what we believe are the data sets for the primary surveillance radar (PSR) and secondary surveillance radar (SSR) from Malaysian civilian radar assets. The PSR data is of particular significance because it provides additional insight about how MH370 was flown after the transponder was disabled at 17:21 UTC. The data was publicly released by fellow IG member Mike Exner. The military radar data remains unavailable.

The data begins at 17:30:33 when the civilian radar installation at Kota Bharu Airport (WMKC) detected MH370 traveling back towards the Malay peninsula about 58 NM from shore. The last radar target was captured by the civilian radar installation at Butterworth Airfield (WMKB) after MH370 had passed to the south of Penang Island and was tracking northwest up the Malacca Strait towards Pulau Perak.

Some initial observations about the data:

  1. The PSR data is similar to the civilian radar data that was graphically presented in the Factual Information (FI) from March 2015. However, while the last civilian radar capture in the FI was at 17:51:47, the new data set has captures until 18:00:51.
  2. The path derived from the Kota Bharu radar data is not straight. More analysis is required to determine if this waviness indicates that there were pilot inputs from manual flying, pilot inputs to the selected heading with autopilot engaged, or inaccuracies of the radar data.
  3. The path was tangent to a 5 NM radius for both Kota Bharu and Penang Airports. This may indicate that these airports might have been displayed as fixes in the navigational display (ND) with a radius of 5 NM and used as navigational references.
  4. After passing to the south of Penang Island, the plane first tracked towards 301ºT, and then changed to 291ºT, which aligned with Pulau Perak and roughly towards VAMPI.
  5. The groundspeed data as derived from the radar data is noisy, reflecting uncertainty in the value of the timestamp as well as the range and azimuth for each capture. In light of the uncertainty, the average speed was calculated for five of the six segments of radar captures, and shown by the red line in the figure below. (The time interval of the shortest segment was only 24 s, and deemed to short to calculate the speed with a useful level of precision.) The average speed for the second and third segments are 527 knots and 532 knots, respectively, which suggests the plane was flying close to Mmo=0.87. For instance, with a tailwind of 12 knots and a temperature offset of ISA+10.3K, a groundspeed of 527 knots converts to M0.87. At the Mmo/Vmo crossover altitude of 30,500 ft, a groundspeed of 532 knots converts to M0.86. This suggests that after the aircraft flew past Kota Bharu, it was at the upper end of its operating speed range, and possibly at times beyond it.

Calculated groundspeed as derived from the civilian radar data. (Click to enlarge.)

I know that independent investigators that contribute here and elsewhere will continue to analyze the data to better understand how MH370 was flown before it completely disappeared from all radar sites.

Update on April 12, 2018: The plot of groundspeed was updated by removing the trend lines and replacing them with average speeds over segments. In light of the noise on the speed calculations, this is more appropriate. The estimated peak groundspeed reduced from 545 knots to 532 knots. The corresponding text in (5) was also updated to reflect this change.

Update 2 on April 12, 2018: Here is an Excel file for those wishing to see the basis for my calculations. Please let me know if corrections are required.

322 Responses to “The Civilian Radar Data for MH370”

  1. Rob says:

    @Nemo
    @David

    Apologies, carried over from previous post.

    A nefarious pilot might have wanted the cockpit door video system back up and running, or possibly electric power restored to the door lock mechanism?

    I seem to remember that the video security system is powered from the LH AC Bus, and controlled through the IFE switch. He may have wanted to see what was going on the other side of the door after repressurizing the cabin. He could at intervals, briefly power up the video system via the IFE switch to monitor the cabin, but only briefly because the SATCOM was also up and running.

    The door lock fails open when power is removed, and but can be locked manually. He may have wanted to restore power to the door lock for some reason.

    The IFE can be disabled from the switch on the overhead panel, ie it can be disabled without having to resort to disabling the SATCOM. The ACARS can be selected off from the cockpit, which prompts the question isolate the LH AC Bus in the first place?

    I think he isolated the AC Bus primarily to disable the SATCOM until he was out of primary radar range, firstly to prevent any incoming telephone calls from being acknowledged by the SDU. It would present MAS with a dead line as opposed to an unanswered call, which would suggest the plane had gone down when the transponder was lost. MAS would not then be prompted to ask the military to start a radar search. One hour later, the nefarious pilot deemed himself to be safely beyond Malaysian primary radar reach, and regarded it safe to reconnect the LH AC Bus.

  2. TBill says:

    @Victor
    Looks like potentially important data, thank you and ALSM for bringing the data forward.

    Questions:
    (1) Could the speed lead to incipient structural damage (eg; pre-dispose the flaperon and outer surfaces for later falling off)?

    (2) Does the high speed indicate descent from FL380-FL430?

    (3) If so, does that sound like zoom climb after IGARI accounting for the small radius of the turn at IGARI?

    (4) Overall I wonder the whole flight was heading settings vs. waypoints

  3. TBill says:

    @Ge Rijn
    PS- Correction my prior response last page “soul” searching.

  4. HB says:

    18:00:51 ??? If FI did not mention could it be another plane?

  5. Ge Rijn says:

    @TBill

    I did understand you I think. The whole point is this all is collateral information. Just like this updated radar-data. All nice and well but we already know the plane was flown deliberately and precise towards Penang and after. There’s no other sensible explanation.
    The exact details don’t matter that much anymore now.

    I feel it as kind of distraction on what is happening right now.
    I think @ALSM and others could do better work if also concentrating on the short search time left and start doubting there search-width assumptions now there is still time.
    And ofcourse starting to take the ‘Blue Panel’ and associated debris field more serious.

  6. Warren Platts says:

    @ Tbill, there is an obscure waypoint “ENDOR” that would give about the right distance if OPOVI was the next one.

  7. Tim says:

    @Victor,
    Good to have some more detail on the radar trace. Interesting to note the gentle turn at Penang, to me it looks like at least a 20nm radius.

    So what autopilot mode was used to make this turn? Turns in LNAV or Heading mode would produce smaller radii. I think it looks more like an ‘autopilot off’ flight, and the aircraft is just meandering. What does everyone else think?

  8. Ge Rijn says:

    @TBill

    According the best and latest drift-analysis (CSIRO/Griffin, Pattiarachi, Godfrey) all latitudes north of ~29S don’t fit the possible time-frames any more and/or coverage both of the Pemba-piece and Mosselbay-piece at those latitudes are impossible given the latitudes and time-frames.
    Even ~30S is allready problematic considering the flaperon beaching imo.
    Only including a ~140 days delay in a gyre would make this possible as far as I can see. Possible but in general unlikely.

    The drift along the Broken Ridge trenches was to the east after 8-3-2014 and weeks beyond that time.
    The ‘Blue Panel’ and 13 other spotted pieces were around 32.4S/97.80E at 28-3-2014.
    A simple reverse drift indication using the CSIRO KMZ-files tells you those pieces could well have drifted from closer to the 7th arc.
    I see 97.15′ as the minimal width in this region.
    We’ll see. I truly support OI will searched Victor’s debris-area.
    This can not be ignored anyway.

  9. Sabine Lechtenfeld says:

    @Victor, thanks for this interesting article. I wasn’t aware that the plane might’ve been flown faster than the normal envelope protection would allow.I remember that there have been early rumors after the plane vanished, that it had been flown at “break neck speed”, but later we were informed that these allegations were not correct.
    @Ge Rijn, analysing the primary radar data after the turnaround at IGARI might seem irrelevant to you. For others it’s not. As a propagator of the rogue-pilot scenario I wonder why the pilot (most likely ZS) might’ve pushed the envelope to such a degree.

  10. airlandseaman says:

    Ge Rijn: Sorry you don’t understand the importance of the new data and possible implications for the SC search area.

    The importance of the new data is (at least) two fold. For the first time, we have the level of detail needed to see that the plane was probably hand flown for most if not all of the time from 17:21 to 18:01. Victor, Andrew and I have discussed this, and have slightly different interpretations. I’ll let them elaborate on their views. But I think we all agree that it is likely the plane was hand flown towards Penang. Both the high speed build up and somewhat “wobbly path” are more consistent with a hand flown path (though not certain). At some point around the time of the Penang turn, the AP may have been set to TRK or HDG HLD, and then adjusted from ~301 to 292 circa 17:57 UTC. Hard to tell when the NAV mode change took place.

    I think the new data also removes any doubt about the possibility of an attempt to land at Penang.

    The speed build up also has implications for fuel consumption models, and therefore endurance, and possibly further evidence for a POI further NE than the original search further SW. Bobby has already made a few calculations on that subject.

    A speed of ~mach 0.90 has a number of implications for the understanding of what was happening. Such a high speed is not consistent with any SOP for an emergency. It may also give more weight to early reports that there was a descent along the path to Penang.

  11. Sabine Lechtenfeld says:

    @ALSM, thanks for the very illuminating comment. Very interesting…

  12. MH says:

    this make me even more suspicious of the fly back over Malaysia theory, the fly back data looks too inconsistent. perhaps MH370 never turned back.

  13. Victor Iannello says:

    @Sabine: More thought needs to put into the interpretation of the speed data, which was derived from the (time, range, and azimuth) radar data. If MH370 did actually fly faster than Mmo or Vmo, that could mean that the envelope protections were deliberately disabled. The easiest way I know to do that would be to disconnect the primary flight computers (PCFs) with the overhead switch, which would force the flight control mode to degrade from NORMAL to DIRECT. That seems like a drastic action to take.

  14. Victor Iannello says:

    @TBill: To answer your questions:

    1) Considering that the plane continued to fly for many hours, if there was structural damage, it would be minimum.
    2) The high speeds might be indicative of a descent, but that is not certain.
    3) I don’t know what the radius of the turn at IGARI was. We have no data. We are guessing based on a fuzzy image which might have been fabricated to serve as a replacement for missing data.
    4) We can’t rule out the possibility that none of the flight was flown with autopilot engaged.

  15. Victor Iannello says:

    @Andrew: There is an interesting video that might have been taken in a Level D simulator for some B777 version. With A/P engaged at FL340, A/T was disengaged and the throttles advanced to 100%. There was only enough thrust to reach M0.884, but then a V/S descent was initiated, and the speed reached M0.897 at which time overspeed alarms began. (The claim in the video is that Mmo=0.897.) During the descent, the speed continued to increase until [M0.920], and then the pitch increased and the thrust reduced to idle to reduce speed.

    What’s interesting to me is that flight envelope protection allowed speeds higher than Mmo. Is there validity to this video?

  16. Tim says:

    @All,
    So now we have a flight back across the Peninsula that is erratic. A wobbling track, unknown/changing altitude and now speed above Mmo. To me this is indicative of an aircraft that has suffered considerable damage and there’s no one in control.

    Re the drift analysis- I think we have to assume pieces were washing up long before they were found(1 or 2 months)Therefore, points further north become more acceptable. Remember, no one was searching those beaches when debris was actually washing up.

  17. Marijan says:

    I appologize to others who are involved in a more technical disscusion, but I have to ask one simple question. With such a high speed what would be the maximum range of the aircraft along the seveth arc? If the plane flew in the constant direction after FMT, then it has to be more south in order to match BTO. Yet, fuel economy would decrease, which might not allow long range to match BTO. Is there any discrepancy here or not? Thank you.

  18. Barry Carlson says:

    @Tim wrote, “To me this is indicative of an aircraft that has suffered considerable damage and there’s no one in control.”

    That statement is an oxymoron! For the aircraft to be flown in excess of Vmo speeds at FL350~ requires someone to be “in control”, and considerable damage doesn’t even fit the same flight envelope description.

  19. Victor Iannello says:

    Tim said: To me this is indicative of an aircraft that has suffered considerable damage and there’s no one in control.

    Funny, I came to the exact opposite conclusion. Despite the high speeds, the flight looks quite controlled.

  20. airlandseaman says:

    Barry Carlson &Tim: I agree w/ Barry. The speed is only consistent with a deliberate (extreme) act by the PF (whoever it was). I suspect it went something like this:

    Just past IGARI, turn off the transponder. Pull the throttles back and pull up to trade airspeed for altitude. Start a hard left turn during the climb. Roll out to take a look. Continue turn and round out on a heading toward Penang, start a descent and add power back until sometime circa 17:45-17:50 where the speed reached 565 kts. May have had to disable protection as suggested by Victor to get to .90. This was no accident.

  21. Tim says:

    @Barry C,
    The sort of damage I’m considering is not so much airframe, but electrical and pitot static supplies. Enough to render the autopilot into Direct mode. So there is no speed envelope protection.

  22. airlandseaman says:

    Tim: Try to reconcile that assumption with the fact that plane continued to fly for 7 hours.

  23. lkr says:

    @ALSM, VI, Andrew: I’ll be fascinated to see your respective analyses of this over coming days.

    To an amateur, it’s certainly consistent with 1) getting into the Andaman Sea as quickly as humanly possible, certainly consistent with avoiding intercept, 2) by going directly over two civilian airports, making it plausible that landing was intended, and 3) if flying beyond envelope protection, someone knew what they were doing. Doubt that a 9/11 half-term flight school hijacker would pull this off.

  24. Tim says:

    @ALSM,
    Consider this, the damage is mainly electrical, the aircraft has been trimmed for cruise. Even with no autopilot, and in secondary mode it will fly on until fuel exhaustion.

  25. David says:

    @Victor. “The easiest way I know to do that would be to disconnect the primary flight computers (PCFs) with the overhead switch, which would force the flight control mode to degrade from NORMAL to DIRECT. That seems like a drastic action to take.”

    I think turning off all generators is back in the mix, adding transponder off.

  26. Victor Iannello says:

    @David: Yes, by switching the left and right tie breakers to isolation and switching the left and right IDGs and the left and right backup generators all to off, the transfer busses would be unpowered, the pitot heaters would in turn be unpowered, and the flight control mode would degrade to SECONDARY. I didn’t view that as the easiest way to defeat the envelope protection, but it’s possible.

    But I’d also like to be sure that Mmo and/or Vmo cannot be exceeded in NORMAL flight control mode. It might be possible that with the A/T disengaged and the A/P engaged, it’s possible to apply full thrust, perhaps combined with a descent, and exceed Mmo and/or Vmo by some margin before envelope protection reduces speed. That’s what the video indicates, and that’s also the behavior of the FSX/PMDG777 model. It would be helpful to find any documentation on this matter.

  27. Sabine Lechtenfeld says:

    @Marijan, you asked a question re: the fuel range of the plane. If I understand you correctly you want to know if flying the plane at such high speed after the turnaround near IGARI means that there would have been more fuel used up and consequently less fuel left than previously thought for the final run into the SIO. That might indeed be so. In this case the plane might’ve ended up further north on the 7th Arc than the various latest calculations suggested.

  28. David says:

    @Victor. Irregular I know but I repeat a post from the JW site by @Gysbreght:
    “@Sunken Deal: “Can anyone make sense of this supposed new data that VI released on his blog today, via ALSM?”

    They finally understand that the airplane was not flown on autopilot. Perhaps some time they will understand that the ‘noise’ in the calculated speeds is due to rounding errors, for instance the primary radar UTC rounded to full seconds.”

  29. Paul Smithson says:

    @Victor, ALSM. Thank you very much indeed for sharing this.
    1. Could you please provide a little clarification on the method used to derive spot speeds in the second figure?
    2. Not knowing anything about PSR logic: is the slant range data in the csv is actually “raw” – or does the radar logic itself make some sort of “assumption” on altitude, from elevation or otherwise, to obtain a horizontal range estimate?
    3. For the derivation of lat/long presented in the GE figure, what altitude assumption is made?

  30. Victor Iannello says:

    @David: That’s a typical, snide, half-informed comment from him. The data is available to him to produce something of value if he chooses.

  31. Paul Smithson says:

    @ALSM Your second figure with the derived spot speeds in blue clearly shows multiple secondary “series” indicative of some sort of quantisation – whether due to the repetitive rounding errors on timestamps or otherwise. Can we extract a single “series” and if so, what does it tell us about speed?

  32. James Nixon says:

    You say: “The path derived from the Kota Bharu radar data is not straight. More analysis is required to determine if this waviness indicates that there were pilot inputs from manual flying, pilot inputs to the selected heading with autopilot engaged, or inaccuracies of the radar data.”

    When you imagine the other alternative: that the autopilot was actually disconnected; a whole new world opens to you.

    If you don’t choose to consider what heavy jet pilots do in Smoke Fire Fumes sim scenarios, and what the Captain did in UPS6, then you are missing what may well have happened with MH370.

  33. Tim says:

    Why would anyone want to fly faster than Mmo anyway. It doesn’t make sense. There would be no reason too. After all, it’s only a small percentage faster. Perhaps it will be this fact that points to this just being an accident.

    Trying to explain this away as Pijack is getting ridiculously convoluted and complicated.

  34. airlandseaman says:

    Paul Smithson:

    I derived speeds as follows:
    1. Convert all the raw slant range and az records to target Lat/Lon values. I did it using some basic algebra and trig math and simplifying assumptions. Victor did it using more elegant math and earth models. The 2 methods produced similar results, but Victor’s mythology is superior, so we are going with that.
    2. As noted, the raw data is noisy, so I used an 11 point moving average to filter the results. That method provides a better understanding of the trends. Although the 4 second data is noisy, the averaged data makes the general speed trend very clear.
    3. I then plot the averaged speed in Excel and add a second moving average filter (trend line) to smooth out the graphics.

    It should be noted that the noise is not indicative of actual aircraft motion. 4 seconds is a very short sample period, so a very noisy delta position is to be expected over 4 seconds. But positions differenced between, say, 60 or 120 seconds yield much smother results. Or a moving average over such a period.

    There are several factors affecting the accuracy. One is the accuracy of the radar range, probably OTOO 1%. Another is the accuracy of the azimuth, probably OTOO 1 degree. Additionally, the time stamps appear to be sync’ed to the antenna north position, not the target position. That’s a guess, but I hope to get that answered soon.

    I have .kmz files available if anyone wants to bypass the math and go to the good stuff.

  35. airlandseaman says:

    Paul Smithson: Not sure which figure you are referring to. Please provide the details.

  36. TBill says:

    @Victor. “The easiest way I know to do that would be to disconnect the primary flight computers (PCFs) with the overhead switch, which would force the flight control mode to degrade from NORMAL to DIRECT. That seems like a drastic action to take.”

    Victor- Let’s get you out of your B777 “piloting” comfort zone. let’s say the goal is to wipe the evidence. You’ve already visited the MEC Bay to take out the circuit breakers for the flight data recorders. Now the goal is to wipe the memory chips on the Flight Computers, or at least do not add any incriminating data.

    Now (speculating) if and when we find the aircraft, we’ll never know how it got there. I’ve been a bit influenced by the recent Aussie radio interview posted by @ventus45, which indicated that if the data recorder is *not* found, the other cockpit electronics can “data-mined” as a substitute. Not so fast, perhaps the pilot was thinking.

  37. Tim says:

    @victor
    @ALSM,
    Any idea why the last KL SSR data in your ‘data set’ is at 1706z and not 1720z?

  38. Mick Gilbert says:

    @Rob

    Re: ‘I seem to remember that the video security system is powered from the LH AC Bus, and controlled through the IFE switch.

    It’s not. This was discussed in some detail last July. On the MAS B777-200s power to the Cockpit Door Surveillance System camera is controlled via a switch separate to the IFE controls that is mounted in the center cockpit pedestal. The system is powered from the aircraft’s 28V DC RBUS.

  39. Andrew says:

    @Victor

    RE: “But I’d also like to be sure that Mmo and/or Vmo cannot be exceeded in NORMAL flight control mode. It might be possible that with the A/T disengaged and the A/P engaged, it’s possible to apply full thrust, perhaps combined with a descent, and exceed Mmo and/or Vmo by some margin before envelope protection reduces speed.”

    The simulator in the video is a B777-300ER (B-16701), operated by EVA Airways in Taiwan. The -300ER’s MMO (M0.89) is higher than that of the -200ER (M0.87). The autopilot overspeed protection operates as depicted in the video. The overspeed warning occurred at M0.897 (1:00) and the aircraft kept accelerating until it reached M0.92 (1:29), at which point the autopilot overspeed protection kicked in and raised the nose.

    I have not seen any published numbers, but anecdotally the overspeed protection in the -200 series aircraft works the same as the -300, albeit at a slightly lower Mach no. The overspeed warning occurs at about 0.877 and the autopilot overspeed protection kicks in at about M0.90. To answer your question: It is possible to exceed MMO by a small margin in NORMAL mode with the autopilot engaged.

  40. DrB says:

    @airlandseaman,

    The Range listed in your table cannot be the slant range between the radar and the aircraft because the very first entry is only 0.83 NM (I am using your XLSX file) . The altitude at FL350 is 5.76 NM, so a slant range of 0.83 NM is clearly wrong.

    If not slant range, what is it?

  41. airlandseaman says:

    DrB:

    The KL 0.83 NM range is correct. That range was taken as the plane took off, at the end of the runway.

  42. DrB says:

    @airlandseaman,

    I think I understand it now. That first bit of data was from KL, so the aircraft was taking off and climbing at the time. I mistakenly thought the data started at Bota Bharu. Never mind.

  43. Victor Iannello says:

    @Andrew: Based on your anecdotal evidence, I believe it is possible that the groundspeed of 545 knots was attained with the A/P engaged and the A/T disengaged, possibly while descending. I hadn’t thought it was possible to exceed Mmo with the A/P engaged until I found the video and tried a similar experiment with the FSX/PMDG777 model. Your anecdotal evidence is consistent with these simulations. That makes me doubt that drastic steps were taken to circumvent the flight envelope protection.

  44. Victor Iannello says:

    @James Nixon said: When you imagine the other alternative: that the autopilot was actually disconnected; a whole new world opens to you.

    If I recall your theory correctly, you believe the flight path was consistent with the autopilot disengaged and weather inducing turns while in NORMAL flight control mode. As we have discussed before, I really don’t think that meteorological conditions can explain straight segments connected by large turns, nor do I think that a B777 would fly for hours in NORMAL control mode. The inherent stability from the dihedral effect is easily overcome by asymmetrical effects such as rudder out-of-trim, thrust imbalance, and turbulence.

  45. Andrew says:

    @James Nixon

    RE: “If you don’t choose to consider what heavy jet pilots do in Smoke Fire Fumes sim scenarios, and what the Captain did in UPS6, then you are missing what may well have happened with MH370.”

    Would you care to elaborate??

  46. Mick Gilbert says:

    @Warren Platts
    @TBill

    ENDOR doesn’t come up often but it isn’t exactly obscure; it’s part of the Standard Terminal Arrivals (STARS) approach route to Penang’s RWY 04 for arrivals from the north-east known as BIDMO 1A (BIDMO-PUKAR-ENDOR-MEKAT-KENDI).

  47. Mick Gilbert says:

    @airlandseaman

    Mike, if you don’t mind sharing the .kmz file (or the lat/lon data used to construct it) that would be very much appreciated.

  48. Andrew says:

    @Victor

    RE: “I believe it is possible that the groundspeed of 545 knots was attained with the A/P engaged and the A/T disengaged, possibly while descending.”

    That does seem possible. Given the light winds, I think it’s likely the pilot would seek to increase speed to the highest possible TAS, assuming the intention was to cross the Malay peninsular and ‘escape’ as quickly as possible. That would require a descent to an altitude near the MMO/VMO crossover altitude (FL305), as previously discussed. Perhaps the pilot disengaged the A/T, set maximum thrust and conducted a shallow descent (500 ft/min??) to the lower level. The descent would certainly help the aircraft to accelerate to slightly beyond MMO. The engines would also produce a bit more thrust at the lower level, which would help to maintain the high speed once the aircraft resumed level flight.

    However, none of that explains why the radar path between Kota Bharu and Penang is so much more ‘wobbly’ than the path after Penang.

  49. Ge Rijn says:

    @ALSM

    I see the important relevance of this data mostly as further proof/indication the flight was well planned and flown by a very skilled pilot. He probably wanted to pass the peninsula as fast as possible for this would have been the most risky part of the journey (detection and interception).

    Interestingly the possibility of a high speed descent towards Penang comes in to explain the very high ground speeds. The FO mobile-phone detection comes in my mind right away. A lower altitude at Penang could explain the BBFARLIM2 detection better. Could there be a connection?
    Give the new data also more clarity about the flown altitudes?

  50. airlandseaman says:

    As requested, additional radar files derived from raw data here: https://goo.gl/nwRLnB

  51. DennisW says:

    @Victor

    The data above 550 knots should be discarded before performing the piecewise linear fit.

  52. airlandseaman says:

    DennisW: Bad idea. You need all the data to get the best fit to the average. Clipping the data will bias the results low.

  53. Mick Gilbert says:

    @airlandseaman

    Excellent! Thanks Mike. To the extent that you can share it, what’s the provenance of the data?

  54. flatpack says:

    Can anyone suggest why the pilot would seem to turn to pass Pulau Perak so closely?

    My first thought is that he wanted to be spotted heading north west.

  55. Richard Godfrey says:

    SC continues to make good progress into the Broken Ridge plateau area up to 31.3°S.

    By tomorrow Ocean Infinity will finish the 5th cycle of AUV launch and recovery, with 7 AUVs in each cycle. There were 2 ROV deployments on 10th April 2018 checking POIs from the previous cycle. The 6th cycle of AUV launches in the Broken Ridge plateau area has started.

    The weather is good, dominated by a high pressure, good visibility, with a 16 knot wind and a combined swell and wave height of 2.5m. There are no tropical storms in the region.

    https://www.dropbox.com/s/wht7eu5mfzieek8/SC%20Track%2012042018.pdf?dl=0

  56. Rob says:

    @ALSM
    @VictorI

    Hmmm…

    I can imagine the conversation between you two. It must have gone something like “we have to stop this meddling Stevens somehow, but I and save the (IG) empire, not to mention Dr B’s reputation. I know, said one, l’ll invent some rubbish from magically discovered” new” radar data suggesting he flew above Vmo by hand and even work in a descent near Penang. That will push the fuel consumption figures up through the the roof and force the search area further north. Those idiots will swallow it, I’m sure. Well something drastic has to be done!

    Problem is, I all this smoke and mirrors won’t find you the plane. Just the reverse in fact, the it will guarantee that the plane is never found.

    Rob, you’re banned.

  57. Paul Smithson says:

    @All. Before we all go leaping three steps forward to assume that a) we have derived accurate positions and speeds b) interpret what the plane appears to have been doing c) infer what was going on from control/pilot intent point of view, could I please appeal for some clarity on the data and speed/position derivations?

    1) Any transposition of a slant range and azimuth to lat/long position must make an assumption on altitude. It will also depend on whether we use a simplified “flat earth” or an earth model. What assumption & method was used?

    2) If (please clarify) speed has been calculated between every “point” then this will be affected by rounding errors on the timestamps. It would appear that we have an underlying rotation period on the radar of about 3.8 seconds. When time stamps are rounded to whole seconds, will get a rounding error of differing magnitude and a periodicity of about 20s. If we were to derive “speed” between every adjacent points, we will introduce unnecessary noise into the data from these rounding errors and smoothing using a moving average will only partially resolve this.

    3) Range and azimuth errors due to the accuracy of the radar will also contribute noise in the form of “fuzz” in the lat/long which would appears as zig-zag from point to point when magnified. If we implicity assume that this is real movement (by deriving speed between each data point) then we will overestimate distance travelled/speed by following the zig-zag rather than best-fit path.

    4) How sure are we that the slant range is really “raw” and has not been computed by the radar software? Isn’t a primary approach radar intended for targets at or below FL250?

    5) I cannot understand how we can reconcile the very high speed estimates being mentioned above with the time and distance from “abeam” KB to “abeam” Penang (or our best approximation of this). That calculation yields average speed of about M0.85 at FL340. So how is it possible for speed estimates derived from filtered radar data to be so much higher?

    6) Anyone making statments on airspeed/mach number: please include your assumptions on wind conditions and altitude. According to GDAS 1800Z 250hPa, the tailwind might easily have varied between 5 and 20kts (at FL350) over the flight segment between ~1730 and ~1800.

    So, before we all jump 3 steps ahead, could I please appeal for the maths to be shared and peer reviewed so that we can understand better the data that we are working with?

  58. DennisW says:

    @airllandseaman

    The argument of data editing prior to Kalman filtering has a long history. Yes, the notion of “there is no such thing as bad data”, and you need all the data to compensate symmetrical errors arises all the time.

    I am not going to get in an argument with you. You can take my advice or ignore it. I don’t really care.

  59. Tanmay says:

    Are we too much dependent on Inmarsat? We have spend 2 years and now few months following Inmarsat details and it has given us nothing. Cant the plane be somewhere near Mauritius? Why are we neglecting the eye witnesses?

  60. HB says:

    @Victor,
    It would be useful to superimpose the mil radar captures reported in the FI in your graphics together with the time stamps to enable a like for like comparison. Namely:
    * 17:30:35 231M, 496 kts FL357
    * 17:36:40 237M, 494-525 kts, FL311-330
    * 17:39:59 244M, 529 kts, FL311-330
    * Pulau Perak at 1802.59

    Also the timestamp of the FO mobile registration.

    I also note that this raw data set does not include primary radar capture beyond 17:06:12.6 to 17:19:45 (the latter is mentioned in FI), not sure why.
    There are also a number of discrepancies when compared to Figure 1.1E and Figure 1.1F of the FI in terms of time stamps and captures.
    * 17:43:07 to 17:44:24 gaps exist in F1.1F though those captures are reported in page 3
    * captures from 17:46:34 are new, not in the FI (why not in FI?)
    * captures from 17:51:47 are new, not in the FI (why not in FI?)(note mil radar has been reported in FI to cover this timing)

  61. Sabine Lechtenfeld says:

    @Rob at 05:35 am,
    I hope your last comment isn’t serious. If it is you’re really hitting below the belt. I know that the failure so far to find the plane is frustrating. But how exactly are “invented” data going to save the “IG Empire”, as you epress it?? Either the plane is further north or it isn’t. This scenario can actually be tested. Personally I have believed for quite some time that the plane might be further north along the 7th arc, and I said so before Victor published his new article.
    I hope that my irony detector was seriously compromised when I read your comment.

  62. Victor Iannello says:

    @Rob: You are a complete asshole with clear illusions of grandeur. I assure you that your name is never discussed in any communications I’ve had with Mike. Mike was persistent enough to obtain the civilian radar data, and released it so that people could independently analyze it. You can choose to do so or ignore it. Why anybody should be attacked for providing more information is beyond me, but that does seem to be a pattern.

  63. Victor Iannello says:

    @HB: Yes, a new figure with those annotations would be helpful. I encourage you to do so.

  64. Richard Godfrey says:

    Regarding the Radar Data, it was clearly filtered or processed by both Malaysia and DSTG. We still do not have raw data. We have less filtered and less processed data.

    @HB is correct to point out the discrepancies, but in my view we have genuine Civilian Radar data. We do not have the Military data.

  65. Victor Iannello says:

    @Paul Smithson: I can only speak for myself when I answer your questions:

    1) The conversion of slant range to horizontal distance was based on a (geometric) altitude of 36,000 ft, although it really only matters close to a radar site.

    2) Yes, there are rounding errors in the timestamps. The speeds are therefore inherently noisy. Calculating average speeds over longer time intervals reduces the noise.

    3) The extra distance induced by the waviness is very small, and does not explain the very high speeds.

    4) I don’t know whether or not slant was partially or fully corrected in the data set. I suspect it was not because the civil radar has no capability to measure altitude, and without applying a correction, the curvature near Kota Bharu is substantial.

    5) I am reviewing the technique I used for the linear regression. I think I can do better so that the average speed of the fit is forced to match the average speed (sum of the point-to-point segments divided by the time) for each segment of the piecewise fit. For instance, the segment after passing Kota Bharu seems to have an average speed that is 10 knots too high, despite the fit to the instantaneous speeds.

    6) I did state what tailwind, altitude, and temperature offset was used to convert groundspeed to Mach number.

    I’d also add that the analysis of the radar data is a work in progress. The goal was to put the data out there in raw form accompanied by initial observations and encourage independent analysis.

  66. TBill says:

    @Victor
    The other thing the data shows is a relatively limited civil radar range. I realize different installations have different ranges, but If Port Blair and Banda Aceh are similar radius, it would not be hard to avoid detection by them, not accounting for Sabang military.

    @flatpack
    On Google Earth if you draw a line from Penang to 1090E (which I postulate may have been one possible trajectory) it goes over Palau Perak. Also my house happens to be about 2 miles from an airway for jets going eg NY to Charlotte/etc, and it looks like the high altitude jets are going right over my house. But on FR24 there are offset.

  67. Paul Smithson says:

    @Victor. Thanks for those responses. Re your No.5 – yes, my preliminary poke at the data also suggests that the average speed after KB is lower than that derived from the fitted speed estimates. If the “average” method produces something like 515kts ground speed, that would be M0.84 at FL340 at ISA+10.8 and tailwind +17kts. Not such a crazy speed after all…

  68. Victor Iannello says:

    Update on April 12, 2018: The plot of groundspeed was updated by removing the trend lines and replacing them with average speeds over segments. In light of the noise on the speed calculations, this is more appropriate. The estimated peak groundspeed reduced from 545 knots to 532 knots. The corresponding text in (5) was also updated to reflect this change.

  69. Victor Iannello says:

    @Paul Smithson: When I have a chance, I’ll tidy up my spreadsheet and publish it so you can review the work.

  70. Ge Rijn says:

    @VictorI

    Maybe for reasons of comparising I thought it could be usefull to others to post a 2015 graphic from your hand:

    http://www.duncansteel.com/wp-content/uploads/2015/08/Fig1.png

    from the article you wrote back then:

    http://www.duncansteel.com/archives/1969

    To me at the new more complete civil PSR-captures don’t conflict in general with the ‘unknown’ military radar captures and the turn around Penang towards VAMPI. They actualy confirm now the turn and heading towards VAMPI took place and the plane did not cross Sumatra in a straight line after ~17:51 as some have suggested.

    I see also a descent below ~30.000ft at Penang at those air speeds would be highly unlikely if not impossible without damaging the plane.
    So the BBFARLIM2 connection remains what it was concluded on.

    Again, in all I see this information as further evidence the flight was flown in a planned and very skilled way. By someone who had complete control also on the outcome c.q. the end-of-flight scenario.
    Including fuel consumption control/endurance to a specific end-point.

    This might turn out to be the biggest issue if people (with all respect) keep clinging to simple fuel exhaust scenarios with uncontrolled (or controlled) high speed dive impacts without a specific, well thought end-point. Going all this lenght and then just crash somewhere without control in the SIO doesn’t make sence imo. The pilot might well be underestimated. He could have planned his end-of-flight as clever as he did after disappearing at ~17:21. If so; he was quite succesfull.

    But lets wait and see. SC is steadily moving towards 30S.

  71. airlandseaman says:

    Re comments and questions on the new radar data:
    We are learning more about the providence of the data. I am not at liberty to go into too much detail, but I can confirm the following:

    1. The range is the slant range, not the horizontal distance. So all the calc’s Victor and I have done are based on the correct interpretation.

    2. There are straight forward engineering and maintenance reasons for the BU drop outs. Nothing to be concerned about. It is an old NEC radar, with some Russian mods, not as new or sophisticated as KB or LGKW.

    3. The files I released contain the exact same values found in my source files. Those source files were generated by a software package used to read the raw data files coming from the radar heads. That software package has a different update rate (4 sec) from the radar scan rate (3.81 sec at KB). The details are still unknown, but what we do know is that this software introduces the apparent time stamp noise. This noise is effectively random noise, not a cumulative effect. IOW, the clocks are not drifting. The bottom line is that the data set is very reliable as long as you understand the fine scale timing errors. Thus, with appropriate smoothing, you get very accurate averages over periods of minutes, but not seconds.

  72. HB says:

    @victor, it was a suggestion. I have little spare time i am afraid.
    @Richard,
    The raw data indicates a continuity and i agree. I did not mean the added data was from other source.
    The mil data indicates the speed was initially higher at 496 than the computed average here.
    It also indicates 3 changes of directions.
    The magnetic heading in the mil data, the speed and altitude appeared to have been averaged to compare with the segments shown for the primary radar figures in the FI. These are no point capture. The indicator is that the mil data is given when available at the begining and end of the segment.
    So according to the mil data there is no exceedance of Mmo/Vmo and there has been a marginal increase in speed going from FL360ish to FL320ish in the first 6 min, then altitude appears to be maintained. Not sure if this could lead Mmo exceedence. The data post 17:40 is suddenly a skeletton mysteriouly falling from the cupboard and that part cannot be compared.
    The story from the mil data looks different regarding the flight envelope exceedence. However the various changes in headings over that period concur with someone in control.

  73. Victor Iannello says:

    @HB said: The story from the mil data looks different regarding the flight envelope exceedence.

    I’m not sure there is much difference between the military data and the civilian data if longer periods are used to calculate the speed, as the update to the post shows.

  74. Ge Rijn says:

    All I see as really new in this new data is the part between 17:51:47 and 18:00:51 compared to the 2015 data I referred to (where this part of the stretch was still blank).
    To me it only confirms the turn around Penang and the heading towards VAMPI again performed by a skilled and calculating pilot.
    Important other confirmation on what was already published and expected but no crucial implications on the flight or end-point after, being more north or south.

    To me it just shows again someone was in complete control of everything from beginning till end.

    I hope this new data will provide more proof to what actualy happened and to where the plane is resting. But I see nothing really substantial yet in this regard, compared to the data @VictorI had already provided back in 2015 on Duncan Steel’s site.

    Still the search is moving north nearing 30S and nothing has been reported yet..

  75. Victor Iannello says:

    Update 2 on April 12, 2018: Here is an Excel file for those wishing to see the basis for my calculations. Please let me know if corrections are required.

  76. GlobusMax says:

    Regarding the “most consistent” with hand-flown turn at Penang, I am reminded of Simon Hardy’s analysis of three years ago.

    http://www.bbc.com/news/magazine-31736835

    Being a waypoint proponent from the very beginning, if one believes the military radar data (I do), then it’s fair to say MH370’s path is most consistent with waypoint travel at VAMPI and MEKAR. IF it is also most likely that the plane was “hand-flown” to at least Penang at the speeds indicated, is it plausible a waypoint path could easily be entered and registered between Penang and VAMPI, timing-wise? What time is required to do this?

    Also, recently I was searching for information on a completely different topic, and was quite unaware that Inmarsat carries flight plan information in the clear per the following video:

    https://www.youtube.com/watch?v=psuEzxFJnZY

    I am not sure if any, the implications for MH370, but in the case it is useful to someone, there it is. Details of how this works are lacking, but my thoughts were why was the presumably new flight path not transmitted on reboot of the SDU? Reasons could be:

    1) SDU, on reboot does not check for changed flight path and depends on FMS to send if changed.
    2) MH370 used a different system
    3) Transmission is one-way, ground to plane
    4) etc.

    Apologies if this was hashed out years ago.

  77. Victor Iannello says:

    @GlobusMax: Regarding the time it takes to enter waypoints, there is no time constraint. If LNAV mode is not selected (whether or not the A/P is engaged), then the waypoints will not be followed until LNAV is selected, so waypoints could have been entered at any time. Even with LNAV selected, new waypoints can be entered, but the new route will not be followed until “executed” with a pushbutton on the CDU.

    Regarding a obtaining new flight plan, that would be manually initiated by a “request” on the route screen of the CDU, and would also require ACARS operability.

  78. Paul Smithson says:

    @Victor. Thanks for your update. Using your lat/long and [shortest] great circle distance over ground between start/end points I get average groundspeed of 531 knots over the 26 minutes between 17:35:34 and 17:51:35. With segments of ~5 minutes I get 534, 526, 515, 537. So I must concede that these data do indeed indicate speed of ~M0.87 if we assume an altitude of FL340, ISA +10.8 and average tailwind of not more than 15kts – and this conclusion will not be affected significantly by the considerations that I raised earlier.

    I also concur that the first ~three minutes from 17:30:33 show a much slower speed (I get 463kts groundspeed between 17:30:37 and 17:33:02) – with the change in speed appearing to start around 1734.

  79. Paul Smithson says:

    Apologies – correction to above – in the * 16 * [not 26] minutes between 1735 and 1751. since excel did not make the same error as my tired brain, the speed calcs above still stand.

  80. Victor Iannello says:

    @Paul Smithson: I’m glad we are in agreement. As you can see in the spreadsheet, the average speed calculations are independent of the lat/long conversions, but they were checked using a procedure similar to what you did.

  81. GlobusMax says:

    @Victor Thanks for the clarification. If the VAMPI / MEKAR waypoints were most likely entered pre-Penang (assuming they were entered), that makes the apparent “hand-flown” path around Penang a little more interesting. Actually, the second link above, plus your clarification would narrow the window for waypoint entry to also be post-IGARI, otherwise they would have been transmitted, I take it.

  82. Victor Iannello says:

    @GlobusMax: I don’t think that route changes would be transmitted from the aircraft. Basically, the system is meant to download company routes (and get weather updates). Others here might know more.

  83. James Nixon says:

    Hi Andrew,

    I did elaborate, in my book: http://www.The CrashOfMH370.com.

    I have long learned that no-one has ever changed their mind as the result of an argument, so won’t try to convince anyone who hasn’t flown a large airliner, of their dynamic stability with the autopilot off at high altitude.

    I was attracted to Victor’s comment that MH370’s progress over the Malay Peninsula was not perfectly straight. Coupled with the excursions in altitude it may point to my position that the autopilot had been disconnected.

    Investigators and pontificators have never considered that MH370’s Autopilot was turned-off. Until they do, they are not considering all the possibilities.

    It seems much easier to imagine a rogue pilot, than to imagine a determined crew doing what comes naturally, only to be overcome by toxic smoke, in a matter of minutes.

    Considering the number of smoke, fire, fumes events daily VS the number of suicidal-murdering pilot events since airliners were invented, I would have thought that Occam’s razor should have been applied long ago. Why not in this case?

    Nearly all the heavy-jet pilots I know support my theory.

    Cheers,

    James.

  84. James Nixon says:

    Hi Andrew,

    I did elaborate, in my book: http://www.The CrashOfMH370.com.

    I have long learned that no-one has ever changed their mind as the result of an argument, so won’t try to convince anyone who hasn’t flown a large airliner, of their dynamic stability with the autopilot off at high altitude.

    I was attracted to Victor’s comment that MH370’s progress over the Malay Peninsula was not perfectly straight. Coupled with the excursions in altitude it may point to my position that the autopilot had been disconnected.

    Investigators and pontificators have never considered that MH370’s Autopilot was turned-off. Until they do, they are not considering all the possibilities.

    It seems much easier to imagine a rogue pilot, than to imagine a determined crew doing what comes naturally, only to be overcome by toxic smoke, in a matter of minutes.

    Considering the number of smoke, fire, fumes events daily VS the number of suicidal-murdering pilot events since airliners were invented, I would have thought that Occam’s razor should have been applied long ago. Why not in this case?

    Nearly all the heavy-jet pilots I know support my theory.

    Cheers,

    James.

  85. Mick Gilbert says:

    @Victor
    @airlandseaman

    Gents, I’m struck by the fact that in attempting to recreate the path of an object moving in three dimensions by using data that is essentially limited to two dimensions (slant range and azimuth but not elevation) you have to use an assumption. In this case the assumption is that the target maintained a fixed altitude of 36,000 feet. Constrained by that assumption you get an at times meandering lateral path that doesn’t appear to be consistent with an automatic flight mode (LNAV, HDG/TRK SEL/HLD). From that you’ve inferred that the airplane might have been hand flown.

    I’m wondering what might happen if you instead make your assumption that the lateral path should be straight (or at least straighter) and fit the data by varying the altitude. That approach would not be inconsistent with the limited military radar data provided in the FI that suggests that the target’s altitude was varying.

    I should have caveated this by stating I’m not a mathematician and might be totally off piste on this one.

  86. Brian Anderson says:

    I can’t say I am surprised at the potentially erratic nature of the flight back across Malaysia from IGARI. The relatively abrupt turn at IGARI and an erratic track back could fit either of the scenarios of some dramatic electrical/mechanical issue, or hijack, or rogue pilot.

    A track toward Penang doesn’t need waypoints. An experienced pilot could easily navigate that, at night, using familiar lighting patterns using just the MCP to set a heading. Altitude and speed variations might suggest the crew were intent on problem solving, or trying to cope with a hijack in progress.

    It takes only a handful of seconds to select a new track based on waypoints, and to activate that, if indeed that was done after skirting Penang. But, it would still be possible to continue to use the MCP to track toward familiar waypoints up the Malacca Strait.

  87. airlandseaman says:

    Mick Gilbert:

    re: Altitude assumption: Your question is a reasonable question, but there is a simple answer. At the speeds observed, the plane could only have been at a limited band of possible altitudes. In fact, at 0.90, a pretty narrow band close to 30,000 feet. Surely between say, 28,000 and 33,000. Except when the plane was close to the radar head, you can barely see the difference in the path arising from the wrong altitude assumption. It’s a small position error, except very close to the radar.

  88. David says:

    @Peter Norton. Below is a logic (and unsuccessful) flow of ‘likelies’ of a pijacker end-of-flight, intended to firm up on the recent ELT discussion and pijacker’s intentions.

    First point: if his intention was to ensure the aircraft position could not be reported by ACARS or anything else he would not have left the possibility of an ELT transmission to chance.

    Given the uncertainties of simulations, including their limitations, I doubt he would have satisfied himself that there could be no chance of an ELT triggering. Unless he had found and proved a way of disabling it which had no chance of discovery I think he would have put the nose down to make certain. From the earlier discussions I would put it as less than likely he would have been confident he could implement such a way.

    Supposing that, had there been a carefully planned pijack there would have been a pilot there at the end and a steep descent, pilot induced.

    That looks logical to me and, by itself, quite likely.

    Second point: that does not deal with why he would wait until fuel exhaustion to do that unless to extend range.

    However if range was an issue, why not pick another flight with more fuel and/or no back-and-forth across the Peninsula; or glide? As to the former it could be that he had a plan with no particular end point in mind, whose implementation was sparked by the events of 7th March, as per a @Donald comment. That would answer the likely no-glide (noting the final BFOs) also.

    Here though the logic-of-the-likelies breaks down. If he did not care about how far he got (within limits) why persist to fuel exhaustion?

    That collectively would suggest this was not a pijacking.

  89. Mick Gilbert says:

    @airlandseaman

    Mike, thanks for that answer. I can see that Victor’s spreadsheet has all the formulas in it so I’ll have a bit of a fiddle with that.

    What I’m struck by at the moment though is that you have two sets of data that are plotting location in three dimensions and you’re fitting them into a two dimensional lateral plot of position. At the very least that approach is forcing changes to position in the vertical axis (altitude) plus three dimension’s worth of noise into the two dimensional lateral plot. In other words you’re making the lateral plot noisier than it might actually be and then reading that as the target being hand flown. I think inferring much about mode of flight from that interpretation of the data is problematic.

    From my understanding of Victor’s revised calculation of speed the airplane was most likely never above Mmo so that likely makes the possible altitude band a shade wider.

    Regardless of altitude constraints, my reading of the data is that:

    1. For the first six or seven minutes the target is flying at around 270 KIAS and perhaps slowing down over that period. It is also heading towards where I would expect it to go if it was setting up for an approach to Kota Bharu’s RWY 10. So what’s going on there? Why so relatively slow? That doesn’t look like a get away.

    2. From about 10 nm NNE of Kota Bharu the target starts accelerating and we have that bit of a kick away to the north. Is that the start of a climb? It certainly looks like the start of an expedited transit.

    3. At or just after Kota Bharu the track changes to one that roughly aligns with what you’d expect for setting up for an approach to Penang’s RWY 04.

    4. A good 40 nm before it gets to Penang the target starts to slow down. What’s going on there? If this is a get away why are you slowing down before you get past Penang?

  90. Victor Iannello says:

    James Nixon said: Nearly all the heavy-jet pilots I know support my theory.

    Yes, Simon Hardy makes the same statement about his theory.

  91. Andrew says:

    @Victor

    So does Byron Bailey!

  92. William Shea says:

    There is more RADAR data.

  93. airlandseaman says:

    Mick Gilbert>

    It is important to understand how Victor revised his chart. He is averaging over several time blocks of about 2-5 minutes each. That has the effect of reducing the peak speeds. His math is not wrong, but I don’t think that type of averaging preserves the essential information about the trends, particularly the period between 17:30 and 17:42 UTC.

    I prefer to use a moving average filter, which clearly shows a stead increase in speed from ~470 kts to 545 kts (17:30 to 17:42). Obviously, if you average that period, the average will be lower than 545 kts. But I submit the trend is undeniable. See a graph of the moving average vs. the time block averages using Victor’s position reports here: https://goo.gl/AR9Vvd

  94. MH says:

    are you guys sure the speeds recorded are of a single aircraft/target?

  95. Tim says:

    So are these speed variations showing us the aircraft is flying a phugoid? With an altitude amplitude of perhaps 5000ft?

  96. Andrew says:

    @James Nixon

    Thanks for your reply.

    RE: ”I have long learned that no-one has ever changed their mind as the result of an argument, so won’t try to convince anyone who hasn’t flown a large airliner, of their dynamic stability with the autopilot off at high altitude.”

    I have logged almost 20,000 flying hours to date, including around 16,000 hours on wide-bodied airliners (B744, B777, A330, A340, A350) and a number of years as a training/senior check captain on the B777. I’d say that puts me in the category of someone who HAS flown a large airliner.

    The B777 is without doubt a pleasure to fly, but I do not believe the aircraft is so stable that it would continue flying more or less straight & level for many hours with the autopilot disengaged and no manual inputs. That is especially so if the flight control system were degraded, which would be likely if a major fire affected the MEC as you suggested. I also think it’s improbable that turbulence associated with cloud activity would cause the aircraft to first turn one way around the southern end of Penang and then the other way around the north-western tip of Sumatra.

    RE: ”If you don’t choose to consider what heavy jet pilots do in Smoke Fire Fumes sim scenarios, and what the Captain did in UPS6, then you are missing what may well have happened with MH370.”

    You suggested the pilot might disengage the autopilot to increase the angle of bank and reduce the turn radius. Perhaps so, but on the B777 (like other Boeing types), the pilot already has the facility to increase the bank angle to 25° in HDG SEL or TRK SEL. Increasing the bank angle further by resorting to manual flight could cause more problems at high altitude, due to the decreased buffet margin.

    There are obviously cases where pilots have chosen to disengage the autopilot during a smoke/fire/fumes event and it might even become necessary while completing the checklist on some aircraft types (eg A330). That is not the case with the B777 and I know I would prefer to keep the autopilot engaged, provided it is controlling the aircraft satisfactorily. Why complicate an already demanding situation by disengaging the autopilot?

    RE: ”It seems much easier to imagine a rogue pilot, than to imagine a determined crew doing what comes naturally, only to be overcome by toxic smoke, in a matter of minutes.”

    I have long wanted to believe that MH370’s disappearance was the result of a smoke/fire/fumes episode or some other event that led to the flight crew’s incapacitation. The cessation of communications and the aircraft’s subsequent turn back towards Penang could certainly indicate there was some kind of problem. However, it’s what came next that bothers me, together with the data that was recovered from the Captain’s flight simulator. How do we explain the aircraft’s flight path after passing Penang under a failure scenario, without resorting to contrived theories? How do we explain the simulator data?

    RE: ”Considering the number of smoke, fire, fumes events daily VS the number of suicidal-murdering pilot events since airliners were invented, I would have thought that Occam’s razor should have been applied long ago. Why not in this case?”

    I don’t think that any of the proposed scenarios satisfactorily explain all that is known about the aircraft’s disappearance. Nevertheless, on balance it seems to me that a pilot hijack/suicide is the simplest explanation. Would that not satisfy our friend Occam?

    RE: ”Nearly all the heavy-jet pilots I know support my theory.”

    I am obviously not one of them!

  97. Sabine Lechtenfeld says:

    @Mick Gilbert, you say that the pace after the turnaround was relatively slow, and that the plane seems to slow down when it closes up on Kota Bharu.You are even suggesting that there was the set-up for an approach of KB’s RWY10. I can’t judge myself if your interpretation is correct. But let’s say you are right: there’s a viable alternative to an attempted landing of a compromised aircraft. A rogue pilot might’ve tried to mask his intentions when he was about to enter one of the most critical stretches of his journey – the crossing of the peninsula. As you say, the way the plane was flown at that time doesn’t look like a getaway attempt or a threat. Exactly this impression might’ve been intended by a rogue pilot.

  98. Richard Godfrey says:

    @Victor, @Mike,

    The very first data point in time is 17:30:33 UTC. This data value includes the milliseconds value, which is 310 ms. The milliseconds value appear to have been stripped or truncated from all other time values.

    The difference between the first 2 data points is not 4 seconds, but 3 seconds 690 milliseconds.

    When the incremental time between one data point and the next is only 2 secs or 3 secs, then the truncating of the milliseconds will lead to errors in the speed calculation over that increment.

    Victor’s method of averaging over a larger time block will only be out by a second at the most. This smoothing results in speed ranging between 487 knots and 580 knots.

    Mike’s moving average will be distorted by these outliers, which are artefacts of the short incremental durations which have been truncated. This results in instantaneous speeds ranging between 247 knots and 940 knots. The moving average results in speeds ranging between 470 knots and 595 knots.

    Removing the outliers calculated over increments 3 seconds or less, results in instantaneous speeds ranging between 247 knots and 699 knots. The moving average results in speeds ranging between 440 knots and 570 knots.

    Which ever way you look at it, the speed was increasing from an initial value between 440 knots and 487 knots, toward Penang to at least between 570 knots and 580 knots and then slowed around Penang to between 510 knots and 520 knots.

  99. Richard Godfrey says:

    @Mick

    The first radar data point is 57.7 NM from Kota Bharu airport.

    I do not see a slow down towards Kota Bharu in the speed of MH370 either using a moving average based on all the data supplied or excluding the outliers.

    However, I do see a slow down towards Penang.

    Moving average based on all the data including outliers:

    https://www.dropbox.com/s/67xj1mstv8enzky/Instantaneous%20Speed%20including%20Outliers.png?dl=0

    Moving average excluding outliers:

    https://www.dropbox.com/s/tc1lypk6gysn59n/Instantaneous%20Speed%20excluding%20Outliers.png?dl=0

  100. Mick Gilbert says:

    @Richard Godfrey,

    You’re quite correct, Richard. I would have sworn that the trend line showed a mildly decreasing ground speed over the first 6.5 minutes or so. My mistake on that one.

  101. Richard Godfrey says:

    @Mick

    No worries!

  102. Sabine Lechtenfeld says:

    @Mick Gilbert, since you accept Richard’s correction, we can quite forget about my suggestion 🙂
    It’s great when people discuss the new data professionally and with an open mind. That’s why Victor has put up his article after all.

  103. Victor Iannello says:

    @Richard said: Victor’s method of averaging over a larger time block will only be out by a second at the most. This smoothing results in speed ranging between 487 knots and 580 knots.

    The segment of the radar data that produced an average speed of 580 knots was over an interval of 24 s. With a time resolution of only 4 seconds, I deemed that too short an interval to accurately calculate average speed, so I did not include that in the graph above.

    @All: My goal in devoting a blog post to the data that Mike released was to use the collective wisdom of contributors here to extract whatever additional information we can. I view the analysis that I performed as accurate but fairly rudimentary. I hope others will continue to analyze the data and share the results with the group.

  104. Mick Gilbert says:

    @Sabine Lechtenfeld

    Sabine, even Richard’s analysis of the data shows that the target’s speed for the first four to five minutes as it approaches Kota Bharu is relatively slow (around 270-odd KIAS) and relatively constant. It’s not consistent with a get away. And neither is the very apparent slow down before the target reaches Penang. Why start slowing down a good 40 nm before you get to Penang?

    As to the notion that behaviours that are antithetical to a quick get away and that are internally inconsistent were in fact part of some cunning plan is a testament to the almost infinite malleability of the rogue pilot theory. Your protagonist, Malus Homo, has a dramatic range to rival Daniel Day-Lewis and, much like an artist’s mannequin, you can have him do largely anything you want at any time you want because whatever you need done to fit the observation, well, tutns out that’s apparently what rogue pilots do. Frankly, it’s a nonsense argument.

    Time will tell whether you’re right or not; arguing further about it here does nought to refine a search strategy.

  105. DennisW says:

    @Victor

    @All: My goal in devoting a blog post to the data that Mike released was to use the collective wisdom of contributors here to extract whatever additional information we can. I view the analysis that I performed as accurate but fairly rudimentary. I hope others will continue to analyze the data and share the results with the group.

    I am in the process of being a good citizen and paying my taxes. Last year the IRS nearly took me to a basement in San Francisco for a water boarding session relative to some of my stock transactions. A terrorist gets better treatment than a taxpayer who is assumed guilty until proving their innocence.

    Back on track after April 15.

  106. Ge Rijn says:

    Just read something on the limitations of ATC-PSR:

    https://www.quora.com/Explain-why-primary-surveillance-radar-is-not-reliable-for-ATC-operation

    Then made a basic calculation about the distance travelled between 17:30 and 18:00. With messuring I came up with ~480km which makes 960km/h or 496 knots speed on average. The distance between Kota Bharu Airport and Penang Airport is 243km. Messuring the distances outside this track makes about the same distance added.

    I still don’t understand the fuzz really how this all can contribute to help the failing search so far in defining a better crash area. Also @DrB’s area has now been searched. Next of the very respected scientists who’s assumptions and calculations did not match the facts.
    Another push to the far north intended? Ignoring the drift-data above ~30S again which show arrival times of debris are much too soon?

    Still completely ignoring the ‘blue panel’ and associated debris field and the possibility of a recovery and glide outside the designated areas?
    Knowing all well now this flight was cleverly planned and executed from the start, there is no other sensible way. And it was as cleverly executed at the end-of-flight I’m sure. To decive us all.

    But linger on. When 29S has been searched without result (and I hope not!) I hope you all will start to consider those other possibilities more seriously.
    Remember it’s probably the final opportunity to find the plane.
    It’s a big responsibility you have here.

  107. Richard Godfrey says:

    @Ge Rijn

    Your “blue panel” has been mentioned 41 times in the last 3 posts.

    You obviously think you have failed to make your point, since you repeatedly repeat, what you have already repeated.

  108. sk999 says:

    All,

    For those wishing to look at “running averages” or other short-term behavior of speed, one should be aware that, because the timestamps are truncated to the nearest second, speeds computed over a short time interval – e.g., 4 seconds, will be biased high. For 4 second intervals, if the true mean speed is 520 knots, the average of many 4 second intervals will be 537 knots, a bias high of 17. The bias varies inversely as the square of the averaging interval. Thus, a minimum averaging interval of, say, 16 seconds would be recommended.

  109. DrB says:

    @All,

    A brief note on the estimated altitude when passing near Kota Bharu is HERE.

  110. Victor Iannello says:

    @sk999: Thank you. I noticed the high bias when averaging the 4-second data, which is why I opted to modify the post and report the results over the longer intervals corresponding to segments of (nearly) continuous radar data. I might have lost some of the trends of the data in the process, but I did remove the bias.

  111. Victor Iannello says:

    @DrB: That’s great. When I wrote the radar report some years ago, back before we had access to the data we have now, it disturbed me that even with the slant correction at FL340, I still saw some curvature, but I deemed the altitude to correct the curvature as too high, so I left it. With the new data, the effect is easier to discern.

    Others are arriving at the same conclusion by using the speed data, although that’s not surprising because the curvature in path also would cause an increase in speed because of the longer path length.

    At FL430, I estimate the temperature as 204.1K (ISA-12.55K) with the wind around 40 knots towards 290T. That translates to a tailwind of about 26 knots. If the groundspeed was 527 knots, that’s a true airspeed of 501 knots, corresponding to M0.90. The bottom line is that if MH370 was flying at FL430 past Kota Bharu, the speed was quite high.

  112. Ge Rijn says:

    @Richard Godfrey

    You don’t pick up on it while you stick to your ‘pre-calculated facts’ for about 3000 posts.
    Nothing you proposed or calculated has materialised yet so I guess you better hold your breath a bit.
    You never considered the blue panel seriously as far as I can see.
    That’s your handicap not mine.
    The search will tell. Not you or I.

  113. Paul Smithson says:

    @All.

    Many thanks again to Mike for sharing the radar data and to Victor for sharing his spreadsheet.

    I have developed a method of speed estimation that greatly reduces the noise in the speed data while still using all of the data points. This takes ten “steps” in the dataset (whether or not there is a gap in the data); then measure distance from start to end; and calculates speed (distance over time). Then assign that speed estimate to the mid-point of the start/end in question. This method is a bit like a moving average, but avoids contaminating that moving average with noise arising from very large errors on very small steps.

    The spreadheet used for these workings is here:
    https://www.dropbox.com/s/6jwh8evf22gprzv/2018-04-12%20VI%20PSR%20Calcs%2010-steps%20speeds%20FL440%20composite.xlsx?dl=0

    And the resulting speed profile chart is here:
    https://www.dropbox.com/s/119sl6z7rnzuiag/groundspeed%201731-1759.pdf?dl=0

    In the course of this exercise it became clear that the data was good enough to make a “speed bump” clearly discernable at Kota Bharu. The size of this speed bump is greatly affected by assumed altitude. At altitudes below 40,000 you get an “excess speed” anomaly close to Kota Bharu. At altitudes of greater than 45,000 this “inverts” into a speed dip. At around 44,000 the anomaly disappears and produces a smooth fit with adjacent segments. You can play with this yourself in the linked spreadsheet to see how altitude affects the “speed bump”.

    I then extracted a kmz file from the lat/long positions with different altitude assumptions (thanks to VI for the spreadsheet shared earlier). At 45000 (my initial best-effort fit) the lateral path appears to be smooth and undistorted by a altitude error.

    I am therefore minded to believe that this radar data provides good circumstantial evidence that the aircraft was close to 44 or 45kft geometric altitude at the time it passed Kota Bharu.

    Other observations from the results:
    1) Ground speed when the aircraft first enters KB detection range is very low – somewhere close to 460kts
    2) There appears to be a steady accelleration from 1732 through to 1736 at the rate of about 12kts per minute.
    3) The data between 1736 and 1748 is very noisy but shows a trend that is very close to flat (mean 530kts groundspeed, increasing 0.8kts per minute)
    4) There is a clear decelleration between 1749 and 1753 – from around 530 to around 510
    5) The trend from 1753 to end again seems to be nearly flat (and will surely be statistically no different from “flat”).

  114. Victor Iannello says:

    @Paul Smithson: Thank you for sharing. I think we are making good progress at extracting more information.

  115. Paul Smithson says:

    @Dr B. Your method to minimise a path anomaly in vicinity of KB radar is analagous to my method to minimise a speed anomaly. Both methods arrive at the same conclusion.

    Note that my speed estimation method uses straight lines start to end (not sum of the steps) and is therefore nearly unaffected by lateral path distortion. It would still show up the speed distortion even if the path went directly overhead of the radar.

    I am also struck that the number we have independently arrived at is very close to that on the RMP file annotation of radar points close to Penang (FL447) that I had previously regarded as nonsense.

    I will be very interested to hear from pilots/aviation experts:-

    a) what max altitude was attainable in a 772 at this weight
    b) why you might want to go to max altitude
    c) whether the rate of acceleration indicated 1753-1756 is consistent with flat acceleration at altitude or climb and accelerate. I am presuming the latter since I’m guessing you can’t even fly at 460kts groundspeed (?450 airspeed) at >FL430 and that weight.

    I do think this data is starting to raise some very interesting questions about what was going on and why. My money is still on fire.

  116. Sabine Lechtenfeld says:

    @Mick Gilbert, you are right insofar as I fired too quick a shot. Sorry for that. However your following diatribe was totally unwarranted. The rogue pilot scenario ist supported by tons of circumstantial evidence. I truly don’t believe it’s necessary to regurgitate it here since it has been discussed ad nauseam. The scenario doesn’t stand or fall with these new radar data, which still need to be fully analysed.
    I trusted your take that the plane slowed down towards Kota Bharu btw. That’s why I tried an explanation – a little too quickly. But apparently you just didn’t look carefully enough, and you readily admitted that there was no slowing down after all, after Richard pointed this out. You were equally quickly making unfounded assumptions.
    I will refrain for the time being from trying a quick explanation of the new radar data. It’s not necessary. But I will certainly continue to propagate the so called rogue pilot scenario which stands on many well founded legs. You are entitled to your opinions. But you cannot tell me to hold back either.

  117. TBill says:

    One wonders what those fisherman off KB really saw

  118. Sabine Lechtenfeld says:

    @TBill, I often asked myself the same question. There aren’t just the reports of those fishermen. There are many other eyewitness reports from the eastcoast of strange, lowly flying planes. You can almost create a corridor if you put all these sighting locations onto a map. They are more credible than many other accounts insofar as these very early reports were made when it hadn’t been made public, yet, that the plane had turned around and had re-crossed the peninsula. Therefore they cannot have been influenced by later media reports.

  119. Andrew says:

    @Paul Smithson

    RE: “what max altitude was attainable in a 772 at this weight.”

    The LRC Maximum Operating Altitude tables for the 772ER shows that the maximum altitude at 215T, ISA+10 or below is about 40,600 ft, giving a speed of M0.838. I think DrB used the M0.84 tables to obtain a similar result. The LRC Maximum Operating Altitude tables also show that the aircraft is thrust limited at that altitude. In other words, the aircraft would be limited by the available thrust rather than airframe considerations. It would not have sufficient thrust to fly much faster than about M0.84 at 40,600 ft.

  120. Donald says:

    @Mick Gilbert

    I’ve not seen even the least bit of objectivity displayed by you during your participation on this thread. While there are other contributors here who inexplicably FAVOR other scenarios OVER the rogue pilot theory, they, unlike you, are not observed assailing every new and potentially further incriminating discovery pointing at ZS and deliberate sabotage.

    You make some interesting observations and add valuable insight with your deep knowledge about aviation and all things MH370, but you fail the objectivity smell test miserably. It’s clear you have an agenda, period.

    @All

    Setting aside the drift models (which I like much like Rob find dubious) and fuel models (will these be needing revision in light of the new speed and altitude?), I really believe we are allowing our confirmation biases and some questionable science to lend to some serious myopia.

    If ZS didn’t have any fascination with hiding the plane by way of underwater feature, but instead was satisfied with ‘almost as south as possible into the vastness of the SIO’…then I fear this whole notion of being further North on the arc is misplaced.

    Unlike most on this blog, I am as sure as I can be that ZS was alive and in control until impact. An action like the one undertaken is predicated on revenge and control. This control would not be relinquished until a perfectionist, task-minded type like Z was simply no longer capable of retaining it. This occurs at the POI, NOT at the FMT! I cannot stress this enough.

    Gliding was a true passion of Z’s until his injury. Performing a ‘stunt’, while incorporating one’s passion, would be how I would expect him to spend his final minutes. I’m not qualified to take final BFO and make a determination, but I would caution those who believe this to definitively rule out a glide to be wary.

    Reminds me of hearing ad nauseam about a how a t7 couldn’t zoom climb to anywhere near approaching FL450 with the weight it was carrying at that point in the flight. And how the PSR return of FL450 could simply not, no way, impossible be accurate.

    *ZS also appears to have a fixation with ice insomuch as quite a bit of his social media content features ice.

    @Tbill

    Always believed the KB fisherman. Only 1st person account I gave much credibility.

  121. Mick Gilbert says:

    @Donald

    Once again you have me confused with someone who cares what you think. I don’t.

  122. Andrew says:

    @Donald

    RE: “Reminds me of hearing ad nauseam about a how a t7 couldn’t zoom climb to anywhere near approaching FL450 with the weight it was carrying at that point in the flight.”

    It can’t, PERIOD. What does that tell you?

  123. Christine L says:

    I am sure insignificant but has anyone ever collated the supposed eyewitness statements?

    Thanks for an awesome blog and everyone who has put in the technical work. I have read and followed since day 1. I can’t contribute other than saying your work is greatly appreciated!!! Keep up the amazing work and know you are helping all those whose families were onboard!

    THANK YOU

  124. Mick Gilbert says:

    @Paul Smithson
    @DrB

    Gents,

    Thank you both for the further analysis of what Mike and Victor kicked off.

    Can I just get some clarity on the exercise at hand here please? You are analysing 258 data points. 13-15 data points present as an anomaly; the KB volcano, an incongruous spike in derived ground speed when the target was within 13-14 nm of Kota Bharu. You know that those data points are associated with the target passing close to the source radar. You should know the limitations of the radar in terms of its ability to ‘look up’ accurately. In other words, of all your data, this 5 per cent is almost invariably the worst in terms of accuracy.

    Am I missing something here or are you trying to achieve an overall solution (viz invoking an improbable very high target altitude) just to accommodate the worst 5 per cent of data?

    A few practical filters probably need to be laid over the pure maths; the limitations of the equipments involved, the airplane and the radar, for starters. With regards to the airplane, I’m sure Andrew can offer his professional observations but an acceleration of 50-odd knots over 4 minutes doesn’t sound like what you’d expect to see from a B777-200ER at MH370’s weight climbing towards (or even at) its maximum achievable altitude. Don is the go-to guy on radar but from my rudimentary understanding most ATC PSRs have a typical beam elevation range of between 3° – 30°. From between around 17:36:20 to 17:36:43 UTC a target at FL430 would have been at elevations above 30° from KB; that accounts for about half of the anomalous data points.

    According to the FI between 1736 – 1740 UTC Malaysian military radar had the target at ground speeds ranging between 494 – 529 knots. In other words, broadly consistent with ground speeds derived from the ATC PSR data sans the KB spike. It is worth noting though that military radar had the target at altitudes in a tightish range between 31,100 and 33,000 feet during that time period, not at 40,000+ feet. Bear in mind that military radars are designed from the get-go to resolve targets in 3D (ie azimuth, range and elevation), ATC PSRs are not.

  125. TBill says:

    @Andrew
    Perhaps a tad faster if bleed air is off

  126. Barry Carlson says:

    @airlandseaman @VictorI,

    In the Kota Bharu null return area and close to it, perhaps some consideration needs to be given to the affect of the radar head 3D side lobes and their relationship to the noisy data recorded. The actual returns may not always represent the assumed head azimuths with consequences to slant/ranges.

  127. Victor Iannello says:

    @Andrew: An aircraft at 480 kn and level flight could reach an altitude 10,200 ft higher in a rapid zoom-climb, assuming a speed of zero at the top of the climb. Of course, it would then descend. Did this happen? I doubt it.

  128. Victor Iannello says:

    @Christine L: In the early days, there was much work trying to reconcile witness statements. Unfortunately, most reports are mutually exclusive, and few can be reconciled with the satellite data, the radar data, and the drift analyses, all of which most here view as more reliable. I know that view upsets many people.

  129. Victor Iannello says:

    @Donald said: I really believe we are allowing our confirmation biases and some questionable science to lend to some serious myopia.

    Re-read your entire comment, which reeks of confirmation bias. I doubt you can see that, but most here can.

  130. Christine L says:

    @victor

    Thank you, just wondering if there had been anything that aligned. Data is without a doubt the most reliable option. Malaysia has been no help and I doubt any transparency will occur until their hand is forced. Hopeful for the coming days and weeks of the search!

  131. Victor Iannello says:

    @Andrew said:It would not have sufficient thrust to fly much faster than about M0.84 at 40,600 ft.

    And even less likely to reach FL430 and M0.90.

    So the altitude analyses from the radar data at Kota Bharu are not correct. It would be interesting to understand why.

  132. Andrew says:

    @Victor

    RE: “An aircraft at 480 kn and level flight could reach an altitude 10,200 ft higher in a rapid zoom-climb, assuming a speed of zero at the top of the climb.”

    Ok, but that would require an instantaneous vertical speed of 480 kt (810 ft/sec), would it not? I hardly think that’s a realistic scenario, given that an aircraft in level flight is not a ballistic missile!

    RE: “And even less likely to reach FL430 and M0.90.”

    Correct.

  133. Donald says:

    @Victor

    If you’re suggesting my confirmation bias is that I am wedded to the scenario that the PIC commandeered the aircraft and successfully executed his plan to fly deep into the SIO, then I am guilty as charged.

    Not sure why such a prickly retort? By opining about the possibility of the flight ending up further south 38>, and that a glide should still not be ruled out, I now have confirmation bias?

    I’m trying to impart a tad bit of psychology and how someone who in the midst of a mass murder/suicide may be motivated. And what choices and decisions he would likely make when executing such a plan.

    Such as neutralizing all threats (killing everyone) as quickly and as efficiently as possible, for example.

    @Rob

    Oh well.

    @Andrew

    I said “Anywhere near” FL450. Maybe I should have said FL430? Paul’s analysis suggested to me that flight at FL450 was possible, but I surely misunderstood.

  134. DennisW says:

    @Donald

    Do you think mass murder and suicide were the plan from the get-go, or do you think it was plan B resulting from a failed plan A? How carefully have you profiled ZS in that regard?

  135. DennisW says:

    @sk999

    Your opinion please? Before filtering, either Kalman or simple low pass what is your opinion on data editing? By that I mean discarding values which are physically impossible (i.e. > 600 knots airspeed). Physically impossible values cannot really be classified as outliers. There is not a whole lot of of definitive opinion in the literature on this question. My own experience is that we obtained better results editing “out of reality” data values.

    Another option is the reduce the “R value” of the Kalman filter for these data points, but that sort of tuning is something I have not tried.

  136. Andrew says:

    @Victor

    RE: “So the altitude analyses from the radar data at Kota Bharu are not correct. It would be interesting to understand why.”

    The altitudes derived from the radar data are geometric, as Paul Smithson mentioned. However, the aircraft (and the performance data) uses pressure altitude. In other words, the aircraft altimeter is measuring a pressure level, not the absolute altitude above sea level. If the column of air in which the aircraft is flying is warmer than ISA, the pressure altitude will be somewhat lower than the geometric altitude.

  137. Andrew says:

    @Donald

    RE: ‘I said “Anywhere near” FL450. Maybe I should have said FL430? Paul’s analysis suggested to me that flight at FL450 was possible, but I surely misunderstood.’

    I understand Paul’s analysis suggests a geometric altitude around 44-45,000 ft. However, that’s not the same as the pressure altitude used by the aircraft and the performance data (or ATC for that matter). The performance data shows the aircraft could not maintain a pressure altitude much more than 40,600 ft and at that altitude its zoom potential would be very limited in any realistic scenario. However, the aircraft’s geometric altitude (ie the actual altitude above sea level) could have been higher than 40,600 ft if the atmosphere was warmer than ISA (which it was). That would certainly account for some of the difference between the altitude analysis and the performance manual data.

  138. DrB says:

    @Mick Gilbert,

    All I have said was that, if you ASSUME a straight path past Kota Bharu, that implies a fairly high geometrical altitude of 40’ish thousand feet. The pressure altitude may be several thousand feet lower than that, so it probably could be flown at a speed slightly higher than M0.84.

    I have not yet analyzed the ground speed versus time, but I plan to do so using a different method than what I have seen so far.

    I also think the wind shear at high altitude could be contributing to the high ground speeds more than originally thought, and this may reduce the estimated air speed. I plan to apply the full 4-D GDAS winds to get the most accurate air speeds possible. We’ll see how much of a difference it makes, but since I have not addressed the air speed yet, I don’t have any information on that subject at this time.

  139. TBill says:

    @Andrew
    How far could the altitude reading be off? 5000-ft?

  140. Andrew says:

    @TBill

    No, I don’t think it wouldn’t be that much. More likely around 2-3,000 ft, depending on the atmospheric conditions. See the following:

    Use of Barometric Altitude and Geometric Altitude Information in ADS-B Message for ATC Applications

  141. Andrew says:

    Oops – make that “I don’t think it would be that much…”

  142. Sabine Lechtenfeld says:

    @Christine L, while I find some eyewitness reports very intriguing -especially the sightings near Kota Bharu, because the witnesses went on record before it even became known that the plane had turned around – Victor is unfortunately right. There are too many sightings which are either mutually exclusive and/or are at odds with other data we have. This doesn’t mean that all of them are wrong. But they can’t be used for finding the plane.

  143. Richard Godfrey says:

    SC continues to make good progress up the Broken Ridge plateau area to 31.0°S.

    The weather is marginal, still dominated by a high pressure, reduced visibility, with a 13 knot wind and a combined swell and wave height of 2.8m. There are no tropical storms in the region.

    https://www.dropbox.com/s/3z400mkz8838tmq/SC%20Track%2014042018.pdf?dl=0

  144. airlandseaman says:

    Victor, Paul, Bobby, Andrew:

    I want to thank everybody for jumping on this new data, and confirming my analysis, which came to the conclusion that the geo altitude was ~43,500 feet going by KB. That altitude is not much different from the Boeing FL406 upper limit estimate, given the surface pressure at KB. (Closest pressure reference I have found so far is Phuket 00Z radiosonde 0 ft agl pressure=1012 hPa. Temp at 44300 was -67.8C.)

    It is especially noteworthy to see that Bobby’s method of minimizing the straight line path error produces nearly the exact same result that Paul and I computed by minimizing the altitude anomaly error near KB.

    My revised speeds are about the same as Paul’s. MH370 accelerated between 17:30 and 17:37 from GS= ~460 to GS~= 530 kts. Using Bobby’s handy dandy GDAS lookup tool, I found the tail wind at KB to be ~14 kts at 34000 feet and 28 kts at 44000 feet. So, considering the tail wind at 43500, the max estimated TAS was about 502 kts (nearly the same as VI’s calc’s).

    But note too that this wind speed means the TAS at 17:30 was very low, around 430 kts, consistent with a possible chandelle type turn at IGARI to trade TAS for altitude. If that happened, it could explain the abrupt IGARI turn depicted in various documents.

    In short, I think we are on to something quite revealing. I’m sure the analysis will continue to be refined, but I think it is clear from the 3 independent studies, all finding essentially the same results, by 3 methods, that MH370 was at a high altitude at 17:37 and started very slow at 17:30, accelerating to a high speed by 17:37.

    I’ve asked ATSB for feedback.

  145. Don Thompson says:

    @Mick Gilbert commented on the capability of ATC PSRs.

    The PSRs involved, Kota Bharu & Butterworth AB, are described as Terminal Area Radars or Air Surveillance Radars. They typically exploit two beams and a cosecant² reflector to form the antenna. The main beam provides the ‘flatter’ lobe of coverage out to maximum radial range while the auxiliary beam extends the vertical detection envelope and minimises the cone of silence. The auxiliary beam will provide coverage beyond 45,000ft close to the radar head.

    The Kota Bharu TAR is a Selex ATCR-33 but I have recently learned that the Butterworth TAR is an upgraded NEC ASR, modernised circa 2008 by Eldis. However, the capability and antenna performance is similar for both (designed to satisfy ICAO requirements).

  146. Richard Godfrey says:

    @Mike, Victor, Paul, Bobby, Andrew,

    Many thanks for the excellent collective analysis.

    I started yesterday to try and fit the last known ADS-B data just beyond waypoint IGARI to the start point of the radar data without success.

    Given the last known ADS-B position, speed and altitude, using 15 and 20 degree turns. I could not find a fit with normal turns.

    I think you guys are on to some really new insights and I would be interested to know how you find a fit to the prior data from waypoint IGARI.

  147. airlandseaman says:

    I posted a summary of my analysis of the new radar data here: https://goo.gl/k1VYpo

  148. Victor Iannello says:

    @Andrew said: Ok, but that would require an instantaneous vertical speed of 480 kt (810 ft/sec), would it not? I hardly think that’s a realistic scenario, given that an aircraft in level flight is not a ballistic missile!

    No, I don’t think the pure vertical speed analogy is appropriate. The zoom-climb calculation assumes that the drag and the thrust are roughly equal when averaged (by distance) over the length of the climb so that total energy (kinetic plus potential) is conserved. Lift is perpendicular to the flight path, so it doesn’t change the total energy, and the climb could be achieved at a reasonable flight path angle. However, the maximum altitude change corresponds to zero final speed, which would render the aircraft uncontrollable. As I said, it’s unlikely this occurred.

  149. Victor Iannello says:

    @Andrew, @DrB, @airlandseaman: Using the 1200z radiosonde data for Kota Bharu, the geopotential altitude at FL432 is 45305 ft. At FL405, it’s 42703 ft.

  150. formula says:

    @ Donald “If ZS didn’t have any fascination with hiding the plane by way of underwater feature, but instead was satisfied with ‘almost as south as possible into the vastness of the SIO’…then I fear this whole notion of being further North on the arc is misplaced.”

    Although if satisfied with anywhere in the SIO vastness, further North on the arc might not be misplaced if the perpetrator anticipated and was concerned about discovery of floating debris. Then, selection of an end point as far east as was consistent with debris tracking westward (to then maximize the passage of time before landfall in the hope the incident would have by then lost attention and any search would have ended meanwhile) would seem plausible.

  151. airlandseaman says:

    Thanks for that estimate Victor. It looks like a pull up and turn maneuver (chandelle) trading some airspeed for altitude, combined with max available thrust to reach ~43000 feet.

  152. paul smithson says:

    @Richard G. You’ll find quite a long time ago I did a path fit from 1706 to 1735 and posted the kmz and interpretation. My conclusion was an immediate slowdown at time of disappearance to about M0.7 at 35000, 25 AOB turnback through 180 degrees, then course adjust to point at KB. This provides excellent fit to the apparent diameter of the turn Back, the trajectory from there to 173033 and correct time of arrival at 173033. I further observed that the aircraft must then have speeded up (I estimated at 1734 or 1735) to about M0.85 (assumed fl350) and adjusted course more towards Penang. The path modelling included winds.

    Now that we have better primary radar data I’d like to repeat and refine that analysis.

    Note also that sk999 separately concluded a major slow down after disappearance using the DSTG filtered data.

  153. airlandseaman says:

    Paul: Be careful with the SK999 filtered digitized data. There are huge Kalman Filter artifacts (ringing).

  154. Victor Iannello says:

    @Paul Smithson said: Note also that sk999 separately concluded a major slow down after disappearance using the DSTG filtered data.

    @sk999 directly used the graphical speed and track data that was presented in the DSTG report to calculate path. Barry Martin extracted the embedded digital information from the figure. The embedded data shows a minimum groundspeed of 190.5 kn at 17:23:48. @sk999, by digitizing the graph, presented a minimum groundspeed of 194.6 kn at 17:23:30. Those are unrealistically low speeds, even if there was a rapid climb. I’ve long suspected there were timing errors between military and civilian radar sites that caused the large (apparent) speed dip.

  155. Victor Iannello says:

    The radiosonde data for WMKC (Kota Bharu) at 1200z is found here. For FL350 and under, the geopotential altitude Hg relates to the pressure altitude Hp as follows: Hg(ft) = 1.0616 Hp(ft) – 95.6, i.e, the geopotential altitude is about 6.2% higher than the pressure altitude. However, the relationship deviates from linear at higher altitudes, as the ISA temperature offset is not constant. At FL350, the offset is +10.0K. At FL453, it’s -13.3K.

  156. paul smithson says:

    For those of you with 777 simulators could you see what it predicts for max steady/sustained acceleration and climb capability, starting from 450kts TAS at FL340, 215T(?), assuming calm conditions?

    Dr B. What does your fuel model predict gross weight should be at 1730?

  157. Victor Iannello says:

    @Paul Smithson: The PMDG777 model is for a B777-200LR, with higher thrust engines than for the B777-200ER. We’d have to derate the engine thrust in the simulation. Hand calculations might be more appropriate.

  158. TBill says:

    @Victor
    >Do you now see any similarities to the sim data going to FL400 at N10?
    >I assume lack of bleed air optionally could give more thrust.

    I hate to be jumping to conclusions, but perhaps the perp had to go higher altitude to get the lower atmospheric pressure desired for an intentional depressure, whereas all these calcs are basically showing something like FL350 geometric might have been survivable because the pressure altitude was lower this day.

    These new calcs are extraordinary but so far tend to confirm past info. For example, Ewan Wilson in his Sept_2014 book said ascent to FL380 for intentional depressure. Somebody apparently clued him in, so now we are getting this info out in the public, perhaps in prep for release of the final report by MY. If this data is in there, that report draft is being fairly widely circulated for review right now.

  159. Victor Iannello says:

    Assuming a groundspeed of 530 knots and a track angle of 241°T, and using the KB 1200z radiosonde data for meteorological conditions (which I think is the best we have), we can find the Mach number at various altitudes:

    FL, Hp(ft), TW(kn), M(-)
    FL305, 32274, 5.3, 0.868
    FL352, 37198, 13.1, 0.878
    FL403, 42703, 19.9, 0.894
    FL432, 45305, 28.9, 0.891

    Unless the groundspeed is in error, that’s very fast, no matter what the altitude.

  160. Richard Godfrey says:

    @Paul

    I did the same exercise long ago as well. I did not account for an altitude change and the resulting wind effects.

    I look forward to your revised analysis in due course, based on the latest data.

  161. Victor Iannello says:

    @TBill: The data is getting a good review here by many knowledgeable people. I think this data is much more helpful than the speed/track data presented in the DSTG report, as that data was the output of a filter. I think we are not yet ready to make conclusions using this data. It wouldn’t surprise me if none of this appears in Malaysia’s final report, as the data was available for some time before the FI released in March 2015, and there was no mention of it.

  162. oriondt says:

    @Sabine, @Christine

    Regarding the eyewitness reports, the ones from Kelantan always intrigued me. At the time these reports were made, SAR was focused on a crash in the SCS- yet these witnesses say they saw a plane flying back the other way. A couple of years ago, I compiled these sightings and overlaid them on the FI radar tracks available at the time. I’ve included the compilation below for those interested. I don’t want to distract from the discussion, as I feel significant progress is being made to understand all of the information currently at hand. I continue to follow with great interest and appreciation for those who continue to analyze and re-analyze every piece of data in hopes of solving this mystery.

    Example Flightpath illustration combines the radar information and the locations of 5 possible eyewitnesses sightings in the Kelantan area:

    https://www.dropbox.com/s/5oven4vnczejs3l/1736-ge-path.pdf?dl=0

    Eyewitness Account summary:

    A – Two fishermen approx 14.4km from Pantai Cahaya Bulan (Moonlight Beach). A plane flies ‘crazy’ low overhead. Lights ‘as big as coconuts.’

    http://translate.googleusercontent.com/translate_c?depth=1&hl=en&prev=search&rurl=translate.google.com&sl=id&u=http://www.thestar.com.my/News/Nation/2014/03/11/Kelantan-duo-report-seeing-lights-falling-at-high-speed/&usg=ALkJrhgKoCu4HXlpICpS-WOLoaD-ZMGUiQ

    B – Pantai Geting Tumpat, low flying plane with bright lights.

    (Link now broken)

    C – Tumpat Kelantan Beach. Very low flying aircraft overhead. Very bright lights ‘as big as watermelons.’

    http://www.themalaymailonline.com/malaysia/article/kelantan-police-hand-over-witness-reports-to-dca

    D – Kampung Pasir Kasar Sering. Low flying aircraft with bright lights.

    http://translate.google.com/translate?hl=en&sl=ms&u=http://www.utusan.com.my/utusan/Dalam_Negeri/20140312/dn_07/Lagi-individu-dakwa-lihat-MH370-terbang-rendah&prev=search

    E – Kampung Kadok Ketereh. Plane with bright lights going down towards the sea.

    https://sg.news.yahoo.com/man-claims-saw-plane-descending-160100245.html

  163. Victor Iannello says:

    @All: It looks like the scanning is approaching 31S latitude. I haven’t seen evidence of high interest contacts so far. [I corrected the latitude.]

  164. Ge Rijn says:

    The impressive data-analysis done here seems to confirm those very early reports that the plane climbed to ~45.000ft after IGARI according not disclosed military data:

    https://www.theaustralian.com.au/news/inquirer/missing-flight-mh370-can-only-be-explained-by-pilot-control/news-story/df6b2e8e700e9232d0f3e9078c8d5000

  165. TBill says:

    @oriondt
    Thank you for the references.
    According to several of the articles, the direction of flight was stated to be 350 deg so almost due north towards the open waters.

    When you look at FlightRadar24 that time of day, there are very few commercial flights. But when you hear eye “witnesses” like Kate Tee, it sounds like several aircraft flying and via strange routes compared to commercial airways. Not to mention the oil rig worker off-shore Vietnam. I tentatively conclude perhaps air traffic is heavier than we know, for example Singapore airborne radar assets etc. I have to admit it is wild and crazy how many (mutually exclusive) sitings of rouge and/or distressed aircraft were seen around the globe that nite.

  166. sk999 says:

    Victor,

    The GDAS tables include geometric altitude for all tabulated pressure levels. I compared the 18Z values at Kota Bharu with the 12Z values in the table that you linked to for the 150, 200, 250, and 300 mbar levels (rougly FL450, FL390, FL340, and Fl300 respectively). For 150 mbar, the GDAS altitude is 28 meters lower than the tabulated values in your table, for all other levels it is 10 meters lower. Seems like there is no problem using your table.

  167. Victor Iannello says:

    @sk999: Thank you for checking. Anytime I’ve checked, the radiosonde and GDAS data sets are close, and vary little over 12 hours. The meteorological values collected during the climb of MH370 are also close to the GDAS tables.

    Have you begun to analyze the radar data? Please share any insights you may have.

  168. airlandseaman says:

    I’m wondering now…is there one more nugget in this data. Figuring out how to compute the altitude at KB was an important finding. Paul and I derived it by minimizing artifacts in the computed speed. Bobby verified it with an independent analysis that minimized the path anomalies at KB. So, can we take it a step further by combining the information in both methods, along with estimates of the aircraft performance limits, estimated IGARI turn geometry, etc. to squeeze out an estimate the vertical speed from 17:30 to 17:37? If it was at 43500 ft at KB, how high was it at 17:30? At 17:25? The acceleration from GS=460 kts to 530 kts over 7 minutes, ending at 43,500 feet, suggests that the altitude was even higher at 17:30, probably higher yet at 17:25. In other words, the acceleration from 17:30 to 17:37 must have come from a combination of high throttle setting and a gradual descent to 43,500 ft. So, can we estimate this vertical speed?

    As discussed with Victor and Andrew, I do not believe the Boeing FL406 (about 42800 feet) figure is a limitation on the maximum altitude MH370 could have reached in a chandelle type turn (pull up with turn). FL406 is the max sustainable altitude (ROC=300 ft/min). But it is not the maximum peak altitude that could be achieved. I believe, based on my own pilot experience, that such a pull up could have reached a significantly higher altitude in the hands of an experience pilot. The airspeed can drop well below the stall speed (200-300 kts?), and the aircraft will still be controllable, as long as the wings are unloaded (<1g). I do it all the time. It's fun.

  169. Victor Iannello says:

    @airlandseaman: I don’t think that acceleration is too high for level flight. Here’s why:

    Let’s assume the plane can cruise at M0.84 at FL406, as per performance tables. By definition for a B777, that means there is enough extra thrust for a 300 fpm (2.962 kn) climb. Now, M0.84 at FL406 and ISA converts to TAS = 482 kn. The flight path angle for a 300 fpm climb at 482 kn is asin(2.962/482) = 0.352°. But if that excess thrust is used to accelerate instead of climbing, the acceleration would be (a/g) = 2.962/482 = 6.145e-3, or 6.028e-2 m/s2, or 7.03 kn/min (assuming I did the math right).

    So, over a 7 minute interval, the groundspeed could change by 49 kn (assuming the tailwind is constant). For a final speed of 530 kn, it could have been at 481 kn 7 minutes sooner.

    Now, I made some simplifying assumptions, such as constant drag at M0.84. But the speed started less than M0.84 and ended faster than M0.84, so it might not be a bad first pass.

    The bottom line is I’m not sure a descent is required for the estimated acceleration.

  170. Paul Smithson says:

    @ALSM – DESCEND to 43,500ft? Can I have some of what you are smoking 😉

    Who am I to say what a 777 does performance wise (that’s why I asked for input earlier)? But it seems to me that the radar data tells us that the aircraft reached an altitude that was at or above normal operations max altitude for that weight. And for the 5+ minutes beforehand exhibited a sustained acceleration of +60 groundspeed (perhaps +50 TAS).

    By the looks of it, the only way you are going to get to there (at least 43000ft) and stay there is a hard and steady acceleration and climb somewhere close to the limit of the aircraft’s capability. I presume that you need to increase speed to generate sufficient lift rather than relying on brute thrust to achieve the climb? So I envisage combination of acceleration and climb until the max altitude is achieved. And, by implication, I’m imagining that the aircraft could not have already been high at 1730Z and 460kt groundspeed. I’d love to see a simulation of what the aircraft CAN do (compared to what you ought to do to stay within normal operating envelope) – even if this is a different variant of the 777,

    @Victor. thanks for those calculations. If I have understood you correctly, they are not going to do the trick, are they? You need 7 minutes (vs 6 observed) to add +50kts TAS. And ALSO need to climb through at least +7500ft geo altitude, which takes more 25 mins at 300fpm. Do I understand you correctly that you believe you can’t BOTH climb and accelerate with the available thrust? I thought that these were massively powerful engines that have lots in reserve during cruise (normally only used at takeoff)?

    You can see that I’m out of my depth on this. Somebody please put me out of my misery with some authoritative estimates of a) acceleration and climb achievable at the top end of the normal operating envelope b) acceleration and climb achievable at the top end of the aircraft’s capabilities (and to hell with the rule book as long as it is still achievable in extremis).

    @Andrew, Victor, Bobby. If we are correct that groundspeed was 465kts or less prior to 1730, what is the max altitude that could be maintained at this speed and weight?

  171. airlandseaman says:

    Victor: Your response is exactly what I am trying to stimulate. As I said, I envision a combination of thrust and possible descent to accelerate from 460 to 530 kts in 7 minutes. If you think it was possible using thrust alone starting at ~43500, that gives us an estimate that the descent rate was ~zero. That is what I’m looking for. If that is corrtect, it probably means something close to 43000 was maintained until the job was done…say 18:xx?

  172. Victor Iannello says:

    @Paul Smithson: No, I was not proposing a climb and an acceleration. Supposed it climbed between 17:21 and 17:30 from FL350 to FL406 at M0.81, averaging 620 fpm. That would put it at 462 kn TAS, or about 482 kn GS. Then, full throttle to accelerate from 482 kn to 530 kn between 17:30 and 17:37. These are all rough numbers, of course. (FL406 corresponds to around 42,800 ft.)

  173. Victor Iannello says:

    @airlandseaman: I’d say it’s possible it was level during the acceleration. More work required.

    If the goal was to gain altitude as quickly as possible, it would be advantageous to limit the Mach to something like M0.81, which was the Mach number before 17:21. Then, once the desired altitude is reached, acceleration to the final speed could occur at constant altitude. Whatever reason for the climb, there was probably an urgency to get the target altitude fast, so it’s not surprising that the speed was not initially high, but then there was acceleration.

  174. sk999 says:

    Victor,

    I have not done any analysis of the radar data due to having been off the last few days exploring a missing person search area characterized by being devoid of humans and cell phone coverage while being populated by rattlesnakes.

    Upon further review of the impact of UT quantization on the short-term speed calculation, I find that the bias is not quite as severe – perhaps 7 knots, instead of 17 as previously stated.

    DennisW – r.e. outlier rejection, it is a subtle topic. Every situation needs to be evaluated on its own. Just throwing out seemingly anomalous data points is not enough – one should try to understand why they are anomalous (and why the other “good” data points are not.) When large data sets are involved, the causes are often well understood, and outlier rejection using automated algorithms is well justified, robust, and often essential. Life gets more interesting when the “outliers” are actually the signal you are looking for – how do you show that they are true signal and not outlying noise? Anyway, it is a rich topic that cannot be addressed in one post.

  175. airlandseaman says:

    BTW…I still think the peak altitude was at least a little higher than the KB altitude, whatever the true value was there. To get a plane up to it’s top speed following a climb, it is often necessary to get it up “on the step” as they say. In essence, it means start a shallow descent to get the speed above your best level speed, then level off slowly. I can’t explain why it works aerodynamically, but pilots know about the step.

  176. DrB says:

    @Paul Smithson,

    You said: “Dr B. What does your fuel model predict gross weight should be at 1730?”

    215.6 tonnes

  177. Paul Smithson says:

    @Victor. As you know I earlier produced a path model from IGARI onwards compatible with both military and civilian radar traces. I conclude that the only way to do it is a low speed from IGARI onwards. If not, it is impossible to arrive back at 173033 position without massively overshooting the turback position/time, exceeding its apparent diameter, coming back in on the wrong trajectory to meet up with the KB radar trace, arriving at 173033 position “on time” – or failing on all of the above solution constraints.

    My solution:
    Complete the IGARI turn on to 059 for BITOD; reduce speed from M0.821 to M0.78 over 40 seconds from 17:20:31. Commence a 180 turnback with AOB 25 degrees at 17:22:06 and continue at M0.78 all the way back to 17:30:33. That work (done using GE transposition of Fig 1.1E, F and the DSTG/ATSB military trace depiction) turns out to have been remarkably good versus the new radar data. That lateral offset of my predicted path vs KB radar is <0.5NM and my timing for the first KB primary radar positions matches to within 3 seconds.

    kmz's are here

    Path model for IGARI to 173445 with 1s time resolution
    https://www.dropbox.com/s/2dieskbgvx7uw7n/IGARI%20turn%20172015%20turnback%20M0.78%20to%20173445.kmz?dl=0

    military turnback representation
    https://www.dropbox.com/s/tskaeg9077r1wyj/Fig%202.1%20turnback%20representation.kmz?dl=0

    KB primary radar trace with timestamps (from ALSM/VI)
    https://www.dropbox.com/s/ax1qnc057byrb3i/20180412102347-32044-map.kmz?dl=0

    Its interesting that the "predicted speed" required for this fit happens to match up very nicely with observed speed at the beginning of the new radar data (M0.78 at FL340 gives 471kts groundspeed at that position using GDAS 1800Z winds and ISA delta).

    You might be able to attain an even better match if you drop this speed by a few knots and start your turnback a few seconds earlier – that would avoid overshooting to the NE and NW on the shape of the turnback and still get you back to 173033 on time.

    In short, my contention is that major slowdown commenced at time of disappearance and stayed that way all the way through to the start of the KB radar trace (at which time he was pointed at Kota Bharu). It might not have escaped your notice that this speed also matches that magic number – ECON descent speed (IAS 271 at FL340, ISA +11).

    I sense that the time is now ripe to dust that study off and share it here for peer review.

  178. Paul Smithson says:

    @Victor. Thanks for your response re acceleration and climb. As you see from my last post, my working hypothesis is level flight at around FL340 and M0.78 between 1720 and 1730. That would mean climb and acceleration has to happen between 1730 and 1737. I’m not sure if it is even possible to make (and sustain) the climb earlier eg from 1721 without increasing speed as well?

  179. Paul Smithson says:

    Thanks for the weight, DrB.

  180. DrB says:

    @Paul Smithson,

    You said: “@Andrew, Victor, Bobby. If we are correct that groundspeed was 465kts or less prior to 1730, what is the max altitude that could be maintained at this speed and weight?”

    Based on perusing various Boeing tables, especially Holding, I would guess in the neighborhood of FL330 for level flight at 215 tonnes and close to M0.75.

  181. Victor Iannello says:

    @Paul Smithson: I think it is more likely that there was a climb then an acceleration. To get to M0.89, maybe at a bit less than maximum cruise altitude. Still thinking…

  182. MH says:

    The fishermen eye witnesses near KB would have difficulties seeing MH370 with the elevations that are being analyzed here on the turn back.. If they saw anything it would be a low flying aircraft in a difficult situation or maybe the SAR aircraft where already looking for the missing MH370…

  183. Mick Gilbert says:

    Gentlemen,

    I think that you are letting a mathematical solution that satisfies 100 per cent of the data but that is practically improbable trump practical solutions that are supported by independent measurements that satisfy 95 per cent of the data.

    The overarching practical consideration is the airplane’s performance. The simple fact of the matter is that the B777-200ER with Rolls-Royce RB211 Trent 892B-17 engines is thrust limited at altitude. In simple terms as the airplane approaches maximum altitude there’s very little left in the tank thrust-wise and when it gets to maximum altitude there’s nothing left in the tank. It’s a lack of thrust that prevents it getting any higher and, by corollary, it’s a lack of thrust that prevents it getting any faster once it gets there.

    Whichever way you look at it the observed acceleration of 50-odd knots over 4-5 minutes approaching Kota Bharu is a big problem. You couldn’t possibly get that sort of acceleration in a climb at that weight at that altitude – you’re heavy and high and going up hill; you’re not going to go faster. Accordingly, you’d have to assume that the airplane was at or near 40,000+ feet when the acceleration started. Even if you say 20 knots worth of the increase was due to stronger tailwinds that still leaves 30 knots you need to squeeze out of the airplane at pretty much maximum altitude. Technically you have 300 fpm worth of excess thrust at the nominal ceiling but good luck translating that into an extra 30 knots of speed. It’s nigh impossible.

    Let’s not lose sight of the fact that all this hubbub is about 5 per cent of the data; all of it clustered within 15 nm of the radar head. Knowing what we know about radar and close range, high elevation targets you have got to consider instrument error as being a, if not the, factor. Bear in mind that if you set aside the data from within 15 nm of KB the altitude issue goes away.

    Also bear in mind that the assumption that the airplane was at or above 40,000 feet between 1736 – 1740 UTC is directly contradicted by the military radar data presented in the Factual Information; military radar placed the airplane between 31,100 and 33,000 feet. I would argue that it is not coincidental that that altitude band is roughly where you would put the airplane to extract maximum speed out of it.

    And there’s got to be at least a feint sense of déjà vu with this discussion. The notion of a climb to 45,000 feet was floated very early on in the piece. I know that many observers like to think of the Malaysian authorities as blundering dolts but on the basis that they have had this data from the get go, it would be just a tad arrogant to think that they didn’t run a similar analysis, that they didn’t see the same problem with the ‘KB volcano’ and that they didn’t arrive at a similar resolution; that the target was at 45,000 feet. That conclusion was largely discounted years ago for a variety of reasons, mainly relating to the performance limitations of the airplane. However, it seems that now we’ve got the data and we’ve done the maths, the whole matter takes on a different perspective.

  184. Mick Gilbert says:

    @Paul Smithson

    Re: ‘It might not have escaped your notice that this speed also matches that magic number – ECON descent speed (IAS 271 at FL340, ISA +11).

    That is a very interesting observation, Paul. At IGARI the airplane would have been well inside the descent point for Kota Bharu. I’m wondering if commanding a diversion to Kota Bharu at that point would have caused a deceleration to descent speed?

  185. airlandseaman says:

    Mick Gilbert: I can understand the skepticism. But I am reasonably confident that the plane was unusually high and fast at 17:37 UTC. How it got there is open for debate, but 3 people have independently arrived at substantially the same result using the same data and independent methods. Don and I have discussed the providence of the data with my source and we are sure it is 100% authentic and as accurate as the system is capable of producing, which for KB especially, is good.

    One component of the explanation may be that the GDAS estimated wind at 43000 was low by, say, 10 kts. I have a couple of decades working with met data models. Believe me, it is possible.

    Another is the assumption that this plane performed exactly like the book. I’ve owned a number of planes over the last 50 years. None have performed exactly like the book. Some were better, and some not. Point is, I would not trust the Boing manual and the forecast WX data to 3 significant digits this close to a theoretical limit. If the book says FL406 with 300 ft/min climb rate, and the met data says FL406=42,800 feet, an ex fighter pilot could conceivably reach 44000 or 45000 ft with a chandelle.

  186. Victor Iannello says:

    @Mick Gilbert: This discussion obviously distresses you. Please let it happen. Yes, the available thrust is an issue. We have possible conflicting evidence that we are trying to better understand. There is no reason to try to shut down the discussion. And your comment about not being able to translate 300 fpm of climb into 30 knots of (ground)speed is not correct. It’s the high Mach number that is more concerning.

  187. Victor Iannello says:

    @Mick Gilbert: Let me add that first we are trying to understand the radar data. Then, we are matching that with aircraft performance and possible manoeuvers to find a scenario that is consistent. Either we develop a consistent story or we don’t. We’ve just begun to analyze this.

  188. MH says:

    With radar data under suspicion I suggest the turn back be re-analyzed as the turn
    Back was based on matching to the suspect radar data which was the best
    Scenario that was available. I also suggest to review all scenarios if the turn back can’t
    Match with the new radar data in case mh370 never made that manoeuvre.

  189. Mick Gilbert says:

    @Victor Iannello
    @airlandseaman

    Victor, distressed? Hardly. Bemused would be more accurate. As to trying to shut the discussion down?! Good grief! I don’t think that I’ve even vaguely alluded to that. As a matter of fact I thought that I was at least contributing to, if not simulating, the discussion. However, if you’re just looking for sagacious nods of agreement, well then, to borrow a line, what I should have said was nothing.

    Regarding surplus thrust being converted to speed, well, I’ll guess we’ll see. At forty-odd thousand feet you need around 18 KIAS to give you 30 KTAS; that’s still a bit of an ask in a thrust limited airplane unless you start going down the hill. And yes, whatever which way, you’re going to be banging up against Mmo.

    Mike,

    My comment was at least in part driven by your contention that there was confirmation that the airplane was at around 43,5000 feet passing Kota Bharu; it had a bit of a ‘Mission accomplished!’ feel to it. I think there’s a bit of water to go under the bridge yet.

    And I don’t think that saying that 3 people have independently arrived at substantially the same result using the same data and independent methods is correct.

    The issue is the 15 or so data points captured within 15 nm of the Kota Bharu radar head, specifically where the lateral plots for the slant range/azimuth data pairs land. For fear of stating the obvious, at lower elevations (ie lower altitudes) the plots are more widely splayed laterally. Because the plots are all generated from one point (viz the radar head) the splaying manifests itself as a curved track away from the radar head. As the data points are all equally spaced in time, the further apart they are the higher the ground speed that is needed to join them all up. So, close to the radar head for the same set of slant range/azimuth data, lower altitudes equals higher ground speeds and a more curved path, higher altitudes equals lower ground speeds and a straighter path. Shape of path and required ground speed are just two manifestations of the same issue and both, not surprisingly, are solved by the same solution; assuming higher elevations/altitudes. Not detracting from the work put in but that’s not independent methods solving independent problems.

    Any old how, two questions for you please:

    1. Do you accept that the quality of the data is likely to be degraded in close proximity to radar head?

    2. You made reference to 2 anomolus records (outliers) being deleted from the data set; what were they please?

  190. David says:

    @Andrew. While a speed exchange with height could lift altitude temporarily, return to the previous speed with no thrust increase would be at a lower altitude pending making up the net energy losses resulting from the manoeuvre.

    However according to FCOM the RR EEC can be selected to alternate mode, allowing EPR and N1 to N3 limits to be exceeded. I imagine that doing this with throttle levers fully forward would increase climb rate and ceiling, (even if decreasing time to overhaul!). That with bleed air and IDGs de-selected would assist with sustained climb rate and ceiling/speed.

    If it comes to getting aircraft performance to match the observed maybe steps like this might need to be looked into, while leaving aside what the purpose might have been.

    I imagine there to be no quantification of what the aggregate gains might be from selecting that mode with throttles fully advanced while also deselecting parasitic engine loads but if so do you have any qualitative feel for that please?

  191. David says:

    @Andrew. FCOM should say something to that effect but what in fact I was referring to was Smart Cockpit, 777 Engines and APU, pages 8 and 9;

    https://www.scribd.com/document/212412011/Untitled

  192. David says:

    @Andrew. A follow up.

    My memory has it that bleed air cost accounts for around 2½% of fuel consumption. Taking the IDGs off line and reducing generation by say 100 KW would save about 60 lbs/hr of fuel (say 30% thermal efficiency).

    Supposing thrust is roughly proportional to fuel flow at high thrust, it appears that thrust rise would be appreciable from those steps alone.

  193. Victor Iannello says:

    @David: Reducing bleed air, reducing power consumption, and selecting EEC ALTN mode are all interesting ways to increase thrust.

  194. Andrew says:

    @David

    Yes, if the EECs are in ALTN mode, the engines’ maximum rated thrust will be achieved at a thrust lever position less than full forward, as stated in the manual you cited. Pushing the thrust levers further forward will generate more thrust, at the risk of overboosting the engines. I do not know of any data you could use to compute the thrust increase from turning off bleeds, IDGs, etc.

  195. Andrew says:

    @Paul Smithson

    RE: “Do I understand you correctly that you believe you can’t BOTH climb and accelerate with the available thrust? I thought that these were massively powerful engines that have lots in reserve during cruise (normally only used at takeoff)?”

    Turbofans accelerate large masses of air to produce thrust. The mass flow through the engines decreases as altitude increases, because the air density decreases. Consequently, at high altitude the engines can’t produce anywhere near the thrust they can produce at sea level.

  196. Paul Smithson says:

    Thanks @Andrew. I do understand that. So, if your intent was to get to maximum altitude and stay there, starting from 460 TAS at FL340, with gross weight 215.6T and ISA +11, how do you do it, how long does it take you to get there and what maximum altitude is achieved?

  197. Ge Rijn says:

    I don’t know if you noticed but the search is reaching it’s final stages without results yet.
    This discussion is very interesting but won’t add anything new to a more specific possible crash-site. Like @DrB already mentioned regarding fuel consumption.
    All it’s indicating with even more evidence; the flight was deliberate and well planned and executed by a very skilled pilot.
    Indicating to me the end-of-flight must have been as well planned and executed with a specific goal. Not just ending up in the middle of nowhere somewhere close to the 7th arc with a dive.

    It’s about time to seriously consider why the searched has failed so far and think about alternatives after SC has scanned ~30S before they go even farther north (which would be invane I’m sure).

  198. airlandseaman says:

    Mick asked:

    1. Do you accept that the quality of the data is likely to be degraded in close proximity to radar head? Answer: Absolutely not! The opposite is true. Especially WRT the az angle, the closer you are, the more accurate the observation. (Did I mention: I was a radar operator and tech backing the late 60’s.)

    2. You made reference to 2 anomalous (sic) records (outliers) being deleted from the data set; what were they please? Answer: There were two records as I recall. One was the AZ value at 17:41:01. That value is obviously wrong, and the error is obviously a missing character (9). The correct value would have been 249.5. In the other case, a single time stamp was off by exactly 1 hour. Anomalies occurring in a time series like this are obvious and correctable.

    17:40:57 32 249.8
    17:41:01 32.5 24.5
    17:41:05 33 249.4

    Nothing of importance or relevance to the topic at hand was deleted.

  199. Victor Iannello says:

    @airlandseaman: I should mention that in the Excel file that I supplied, I corrected that anomalous value of azimuth to 249.5. The correction seemed obvious, although I don’t know how a character was dropped.

  200. airlandseaman says:

    MH: “With radar data under suspicion…” What are you talking about? Which data are you referring to? I certainly don’t consider the newly released KU or BU PSR data under suspicion. It is under serious consideration for all the information we can squeeze from it.

  201. airlandseaman says:

    Victor: People here need to give you (and me) some respect when it comes to data analysis. Mick’s inference by question #2 is particularly insulting to me. We are not idiots, or hiding anything. Fixing an obvious anomaly is not a crime. It is part of the responsibility of making sure the data is clean.

    That said, I do plan to inquire further about the two cases I know of (out of many thousands of characters) where a character was dropped or a value changed. These two cases I know of were obvious, and obviously unintentional. It is hard to imaging how they could have happened within the automated recording system or communications link. I suspect that they may have happened after the data was exported to excel, caused by fat fingers accidentally. But that is only a guess. I will inquire further.

    As anyone familiar with the analysis of data like this will know, data QC is important. We do not rely on every value. We rely on patterns. Anomalies that don’t fit patterns constrained by physics are easily detected. (Planes can’t turn from 249 to 24 and back to 249 in 8 seconds.)

  202. Victor Iannello says:

    @airlandseaman: I fully accept that this is not the business to be in if you want respect…

    We are fortunate that MH370 was flying nearly straight and fairly close to a radar head. This may allow us to for the first time use the data in our hands to discriminate altitude. Part of that exercise is to understand the limitations of the data. Yes, it’s true that if we “set aside the data from within 15 nm of KB the altitude issue goes away”. This is exactly what we should not do.

  203. Victor Iannello says:

    Seabed Constructor trackers report that it spent some hours at (-31.106, 97.1461) before moving on, which might have been an ROV deployment. That’s only about 1.5 NM from the 7th arc. We’ll see if SC returns to this location.

  204. TBill says:

    @Andrew
    “I do not know of any data you could use to compute the thrust increase from turning off bleeds, IDGs, etc.”

    Re: Bleed – I think I yesterday bumped into a number 1%N1=2.4% thrust which was a totally different aircraft and engines, so I did not bother to record my source. We would need to ask Rolls Royce for a 9MMRO number?

    @Victor
    “Reducing bleed air, reducing power consumption, and selecting EEC ALTN mode are all interesting ways to increase thrust.”

    Re: Gross weight-
    Yes and for what it’s worth, I estimate optionally subtract 1-tonne for the air that could be missing from a depressurized aircraft

    I am also wondering what the impact of depressuring is on the diameter of the
    fuselage, and if this could weaken the external honeycomb composite

  205. airlandseaman says:

    Confirmed: SC was looking at rocks at -31.106, 97.1461.

  206. Richard Godfrey says:

    SC continues to make good progress up the Broken Ridge plateau area towards 30.5°S.

    The ROV was deployed for 5 hours 25 minutes at -31.1060 97.1460. As Mike reports, just rocks!

    The weather has improved, still dominated by a high pressure, good visibility, with a 15 knot wind and a combined swell and wave height of 1.7m. There are no tropical storms in the region.

    https://www.dropbox.com/s/23mmp1pwbf9mwi9/SC%20Track%2015042018.pdf?dl=0

  207. TBill says:

    @Richard
    Good luck on your pin!
    I liked a recent post by someone- “…seek and ye shall find.”
    Best we can do.

  208. MH says:

    @alsm- all the radar data even new PSR is under my suspicion of not being from MH370!

  209. Michael John says:

    Just out of curiosity why didn’t Mh370 carry on flying slightly more North & cut West over Songkhla? This route looks more direct without the need for excessive turns not to mention cuts out a good chunk of the Malacca Strait.

  210. flatpack says:

    @TBill

    “I am also wondering what the impact of depressuring is on the diameter of the fuselage, and if this could weaken the external honeycomb composite”

    The fuselage may be regarded as a pressure-stabilized monocoque to some extent. So the risk of buckling may increase during extreme maneuvers or turbulence.

    Presumably the chandelle did not induce global buckling.

  211. Mick Gilbert says:

    @airlandseaman

    Mike, I can assure you that there was no stated or implied suggestion of anything untoward in my question. Your note 4 to the data stated ‘2 anomolus records (outliers) were deleted‘; I was simply curious as to the nature and timing of the anomalies.

    Further, I do not think that either you or Victor are idiots; far from it.

  212. DrB says:

    @airlandseaman,
    @Victor Iannello,

    In my previous note I said that, if the route across the radar “hole” were assumed to be fairly straight, the best fit to that straight path was at a high altitude (roughly 40,000 feet), and speed was not considered at that time. I am now coming to the conclusion that the path was not straight, and therefore the altitude might not have been that high. I say this for two reasons.

    First, extending the two tracks toward the center of the gap does not produce an intersection within the gap. That means there was not a single turn. In fact, to make the two tracks meet up with the correct locations and courses requires two minor turns, one to the right, followed by one to the left. It can also be done by flying an arc roughly centered on Kota Bharu (what I previously called an “orbital” turn. So, some of the “curvature” visible in the positions at the end of the approaching segment may be due to the aircraft turning (and some is certainly due to to the altitude/slant range effect.

    Second, when assuming a very high altitude, the air speed I see at the very end of the approaching segment diverges rapidly, and does not match the air speed I see at the start of the receding segment. I should say here that I have a new method working to estimate the air speed. It avoids some of the noise and many of the artifacts caused by boxcar averaging. I’m trying to automate this speed estimation process so I can find the altitude which gives a smoothly varying speed curve without a large discontinuity at the radar hole. Then, once I have a reliable ground speed curve, I’ll remove the tailwind to get air speed. Then I can find the Mach and see if it ever gets outside the achievable range. This process is pretty straightforward if the altitude is constant, but it gets complicated quickly if the altitude changes with time. I’ll try a constant altitude first and see how good the fit is. That may tell me whether or not a changing altitude is required to match the observables. To start with, I’m using just the Kota Bharu data. If that works out, I’ll add the Butterworth data and see how well it matches up with the Kota Bharu data.

  213. TBill says:

    @Michael John
    As you know, anything we guess is only speculation. Cutting more directly west was an active early theory, especially as it related to the shadowing of SIA68. But the radar data – from MY and maybe Thai not sure – eventually showed where MH370 apparently went, and the SIA68 shadow theory was ruled out within a week or two.

    Advocates of an accident scenario would say emergency landing at KB or Penang was the rationale.

    Advocates of intentional diversion would speculate keeping along the boundary of the countries is a common way to avoid alarming the radar operators. Maybe some show-boating or taking a last look a Penang was a goal. That route resulted in a very important confirming data point (the FO phone connect).

  214. David says:

    @Andrew, Victor. Re added thrust, thank you.

    @TBill. Butting in. Lightening of the aircraft by de-pressurisation.
    Yes, though that would entail manual opening of the outflow valves too if it is not to be very slow (they will close automatically before much cabin altitude rise otherwise).

    The fuselage shell, alloy I think, should be less stressed when depressurised.
    Honeycomb exposed to ambient should stretch with altitude depending on flight loads and cooling of entrained air.

    You wrote, “Bleed – I think I yesterday bumped into a number 1%N1=2.4% thrust which was a totally different aircraft and engines, so I did not bother to record my source. We would need to ask Rolls Royce for a 9MMRO number?”

    We (@Andrew in particular) went into this in detail a few months ago here using bleed flow rates and other aircraft as analogies. I believe Dr B has been using the outcome, 2 ½ % as I recall.
    That is compressor energy input unrecovered in the turbine, thereby reducing thrust and increasing fuel consumption.
    As to getting answers from Rolls Royce, I have received no help from there. Though not a part of the SSWG they may be, or see themselves, as lips sealed.

    An exact figure is of little value if unknowns in the other possible contributors to thrust increase are large. The scope of that and IDG de-selection are at least bound but we have no feel at all for what selecting the EEC to ALTN might bring (and, incidentally, for where any EGT limits might fit in). Currently these are all curiosities and ‘break-glass-if-needed’ but all the same is there any chance you could find the time to take a look as to your simulator’s reaction to that, out of interest?

    @Mick Gilbert. Your 6:08 PM, well put.

  215. DennisW says:

    @Victor/Mike/Paul

    So I’ve been distracted by my desire to avoid an IRS audit. It would be number 10. Lost 3 and won 6 coming into this tax year.

    I took a quick look at the raw data provided to Mike. I don’t like Victor’s data since there are obvious signs of tampering (editing). The figure below based on the raw data is about all you can conclude, IMO. The azimuth data coming into KB and leaving KB flattens, and the range change data is very linear. Using the linear portions of the range data at relatively constant azimuth shows a ground speed of 456 knots heading toward KB, and a speed of 504 knots heading away from KB. Absolutely no filtering or data editing was done.

    https://photos.app.goo.gl/Wo90EwYryEKipTuo2

  216. Victor Iannello says:

    @DennisW said: I don’t like Victor’s data since there are obvious signs of tampering (editing).

    Really? How so? The columns labeled DATA are identical to the raw data supplied by Mike.

    Absolutely no filtering or data editing was done.

    You’ll have to explain what filtering of the data I performed to calculate the average speeds for the segments towards and away from Kota Bharu. The average speeds were calculated by the total distance (sum of the incremental distances) divided the total time (stop time minus start time).

  217. DennisW says:

    @Victor

    Azimuth interpolation was apparent in your spreadsheet.

  218. Victor Iannello says:

    @DennisW: No, you are mistaken. No interpolation at all. The columns labeled DATA are the raw data values.

  219. DennisW says:

    @Victor

    I’ve been mistaken many times before. Going back and looking at your data versus raw I cannot find any examples so I apologize. I must have been looking at it incorrectly.

  220. DennisW says:

    @Victor

    I understand how you did your speed averaging, and I have no quarrel with it. My values are close to yours and assume no azimuth speed component (which is not correct but close) just the slope of the range change. The slight azimuth variation would add speed so I am assuming your values are correct.

  221. DennisW says:

    @Victor

    My point in posting was not to refute your work in any way. It was merely a very simple way of looking at the raw data. Extracting incremental speed values from the raw data introduces a lot of noise i.e. your ground speed figure above. There is no evidence of this noise in the raw data. It introduced by the sampling process.

    The data as I have shown it shows a simple fly-by of KB with a speed up along the way.

  222. Andrew says:

    @Paul Smithson

    RE: “So, if your intent was to get to maximum altitude and stay there, starting from 460 TAS at FL340, with gross weight 215.6T and ISA +11, how do you do it, how long does it take you to get there and what maximum altitude is achieved?”

    That’s not an easy question to answer. I’m not a fan of the zoom climb/chandelle manoeuvre that has been suggested. I think a ‘steady-state’ climb would be more likely, but that’s not going to get the aircraft to the peak altitude suggested by the current radar analysis. It has been suggested that packs off, IDGs off and EECs in ALTN mode would provide more thrust, which is true, but I don’t know any way to calculate the climb/cruise performance in such a configuration. I’ll be interested to see the results of DrB’s analysis; perhaps the altitude wasn’t so high after all.

  223. Paul Howard says:

    @All

    Before coming to any conclusion from perceived altitudes,speeds and maneuvers, Primary Radar identification methods should be considered.They are explained here; http://tfmlearning.faa.gov/publications/atpubs/ATC/atc0503.html

    None of those methods were available for the primary traces of an assumed single track. The ONLY identification method remaining is an exhaustive Elimination Of Known Traffic. That requires collation of data from all relevant ATS units. It is a painstaking, time consuming method and there was NO mention of it having been done in FI2015. FR24 coverage is incomplete and it should be noted that the track was wholly within the confines of B219(VKB-VPG) an ATS route established for the purpose of separating expected traffic orientation. At night with less traffic, aircraft are permitted off-route & given direct route to waypoints so an angular distance from B219 centerline could imply an ATC instructed direct routing.

    Identification is not just needed for the whole track but for each section of unbroken trace. Where altitude & speed is different from one unbroken trace to the next, assuming an odd maneuver between can only be certain if looking at the same aircraft.

    To conclude, because of lack of knowledge of all other aircraft in the airspace at the time, there is a possibility that at least parts of the track were not MH370.

  224. ventus45 says:

    I have been reading the results of the analysis, and am beginning to wonder, if “the problem” is in the apparent acceptance of the azimuth data with an “implied angular azimuth precision” of decimal one degree.

    If you took that at “face value”, you might think that you had 360° * 10 = 3,600 azimuth “bins” available for analysis.

    Most Spec sheets that I have seen for typical commercial ATC PSR’s, suggest that they typically have a “raw” Azimuth Beam Width Resoultion of around 2.8º.
    This gives only 128 “raw azimuth bins” around the circle (360°/2.8° = 128) for discriminating a reflection returned off a target “for any individual single pulse”.
    You can only get “finer” azimuth details with a lot of signal processing, off a quick succession of multiple pulses reflected from your “target”, as the antenna “sweeps past it”.
    Example, if the antenna is rotating at 15 rpm, one revolution is 4 seconds, ie, it is scanning 90° per second.
    For the 2.8° wide beam to “sweep past a target” takes 2.8°/ 90° = 0.031 seconds.
    If the PRF (pulse repetition frequency) is say 400/sec, then that “target” is “illuminated” with only 400 * 0.031 = 12.4 pulses per sweep, so let’s say 12 pulses per sweep.
    You then have 12 pulses in a 2.8° wide “patch” or bin.

    Those pulses are then “processed” by the reciver, the details of which are design specific to every individual radar receiver type.

    The strength of the return from each individual pulse will be lowest at the beginning and end, and strongest in the middle of each sequence of 12 pulses per sweep.
    Let’s assume that the signal processing of these 12 pulses is able to effectively halve the beam width that it eventually assigns this “group” of pulses.
    Thus, each “azimuth bin” becomes 1.4° wide, resulting in only 360°/1.4° = 256 azimuth bins that a “processed target return” could be recorded into.
    Thus, there are only 256 azimuth bins, NOT the 3,600 you may have thought you had with 0.1 degree resolution.

    Let’s assume that the instrumented range of the PSR is 60 nautical miles.
    The circumfrence at 60 nm is approximately 377 nautical miles, meaning that each “bin” as viewed from the radar head at that slant range is about 1.47 nautical mile wide, or nearly 9,000 feet, or looked at another way, about 45 B777 wingspans wide.

    This surely must have profound implications for analysing the data we have, would it not ?

  225. Victor Iannello says:

    @DennisW: I think we are all in agreement that much of the speed noise is due to uncertainty in the timestamp. I said that in observation (5) in my post above.

  226. Paul Howard says:

    Apologies for spacing in previous post, not intended.

  227. DennisW says:

    @Victor

    Sure, but my range rate lines (unfiltered) are very smooth. I think most of the noise is in the azimuth quantization.

  228. Barry Carlson says:

    @Victor,

    @DennisW wrote,” I think most of the noise is in the azimuth quantization.”

    … which is what I implied in a previous post some time ago.

  229. DennisW says:

    @Victor

    So I stopped being lazy and instead of “eyeballing” the speeds off my graph I went to the tables and obtained values of 480 knots before KB and 522 knots after KB. Acceptably close to your values of 487 knots and 527 knots. The reality is a simple flyby, IMO. Don’t try to read too much into it. We are past diminishing returns.

  230. DennisW says:

    @Ge Rijn

    All it’s indicating with even more evidence; the flight was deliberate and well planned and executed by a very skilled pilot.
    Indicating to me the end-of-flight must have been as well planned and executed with a specific goal. Not just ending up in the middle of nowhere somewhere close to the 7th arc with a dive.

    It does not take much of a plan or skill to fly by a radar site. Your are hopelessly committed to a scenario which has no merit. There is no evidence whatever indicating a specific goal with respect to the terminus.

  231. DennisW says:

    @all

    I finished my taxes, and have been drinking heavily. I may re-evangelize my CI scenario. It would be fun actually. 🙂

    The reality is that I am very confident of the 30S terminus.

  232. Ge Rijn says:

    @DennisW

    RE: “Your are hopelessly committed to a scenario which has no merit. There is no evidence whatever indicating a specific goal with respect to the terminus.”

    Not hopelessly committed but sure a bit frustrated the area I proposed (around 32.26`S/~97E) based on the indirect evidence I tried to bring forward for so long, has not gained any serious support here.
    I think this relatively small area just outside the +/-25Nm area should have been searched even if only based on the ‘blue panel’ and associated RNZAF spotted debris field at 28-3-2014.
    Other ‘warm spots’ have been searched based on weaker indirect evidence (CSIRO satelite image spots f.i.) also outside the +/-25Nm zone.

    I hope it turns out unnecessary to take a closer look at this scenario and area later.

  233. Victor Iannello says:

    I received an email from @Gysbreght with the following comments:

    In your Update 2 on April 12, 2018 to your recent post you request comments on your Excel file of PSR Calcs. I would like to submit two observations. I hope you will take these as constructive and not as criticism of your work.

    1. In Column I you calculate the horizontal distance to the target from the slant range and the altitude difference between target and radar. I would think that the horizontal distance is the projection of the slant range on the horizontal plane at the radar site. Due to the curvature of the earth surface, the height of the airplane above that horizontal plane is less than the altitude difference.

    2 Cell T105 is empty but would otherwise have shown an incremental distance of 20.767 NM for the interval 17:36:43 – 17:38:55, corresponding to a groundspeed of 566.4 kts in that interval. In the light of recent discussions on your blog, would that not have merited mentioning?

    1) Over a range of 60 NM, the surface of the earth drops about 3170 ft due to curvature. However, the difference between slant range and horizontal distance becomes small far from the radar head, so there is little change in calculated horizontal distance due to earth curvature. At 60 NM, I calculate a change in horizontal distance of 102 m for a target at 40,000 ft. So yes, this effect could have been included in the spreadsheet, but the effect would be very small.

    2) The speeds in the spreadsheet were average speeds calculated for each continuous segment, and used in the figure in the post. The average speeds for the gaps, including the one over Kota Bharu, were not included in the figure, but could have been, and may give some indication of altitude. (We’d have to make an assumption that the path was straight during the gap.) I think other methods reported by Mike Exner, Paul Smithson, and Bobby Ulich might be more useful ways to estimate altitude.

  234. DennisW says:

    @Victor

    I made a slight edit to my radar figure – simply removed the line joining the range data near the KB site. It was misleading since there is no data there – it was an artifact of the graphing process. Anyway, editing the figure made the link change. New link below.

    https://photos.app.goo.gl/nkuJkr3vkqRX1oZj1

  235. @all
    Thanks to all for the impressive work.

    @DrB
    Your “orbital” turn notion is very interesting. May ask you this:
    Operationally, from all the results one can derive that the aircaft was not descending to land at Kota Bharu, but kept an en-route altitude. As Kota Bharu is not an en-route waypoint, would it be worth considering that she flew over one on the closest en-route waypoints (GOLUD, ABTOK or KADAX) ? KADAX is interestingly almost just on the envisaged straigth path during the “KB Volcano” crossing.

    @all
    In the same operational perpective close to Penang Island and considering the radar plots, it is interesting to see that the path overflies ENDOR and OPOVI en-route waypoints during its turn South of Penang.

    I think this is not pure coincidence but probably reveals that LNAV was in operation. What is turned on just before KADAX explaining the “orbital turn” ?

    Thanks 🙂

  236. Ge Rijn says:

    I have to mention @VictorI mentioned this general possibility in his previous post.
    So at least I have to mention the scenario has not been completly rejected here:

    “There is also the possibility that the previous search was as the correct latitude along the 7th arc, but the width of +/- 25 NM from the 7th arc was not sufficient. The final two BFO values indicate a steep, increasing descent that if continued would mean the plane impacted close to the 7th arc. The debris is also consistent with a high-energy impact. However, it is possible, albeit unlikely, that a skilled pilot carefully recovered from the high-speed descent, regained altitude, and glided for some distance beyond 25 NM.”

    Felt the need to add this to be fair.

  237. Richard Godfrey says:

    SC continues to make good progress up the Broken Ridge plateau area towards 30.5°S.

    The ROV was deployed twice on 15th April 2018 for around 5 hours each time.

    The weather is good, still dominated by a high pressure, good visibility, with a 8 knot wind and a combined swell and wave height of 3.2m, which is quite high. There are no tropical storms in the region.

    https://www.dropbox.com/s/8ih1y9mocczu06r/SC%20Track%2017042018.pdf?dl=0

  238. ventus45 says:

    @Richard

    Can you provide an index and explanatory note to all the “A##” points please.

  239. Ge Rijn says:

    Wake up guys, time is running short. This is not your regular fishing panel. It’s exactly like something specific floating up side down.. Enhanced once again in a different spectrum:

    https://www.dropbox.com/s/ywj150hmfvcf3rd/%20flaperonred.jpg?dl=0

  240. David says:

    @Ge Rijn. With trailing edge intact. The left therefore do you mean?

  241. Richard Godfrey says:

    @ventus45

    The points marked A## are the AUV launches on this tour.

  242. Ge Rijn says:

    Yes @David, the left.
    All the features are in this image. The curves, the trapezium shape, the lines, the sections and holes at the right places on that inboard edge.
    And it was reported by the crew on the RNZAF plane to be about 4m2 in size which fits also.
    And it was spotted at 32.4S/97.8E on 28-3-2013 which fits an origin closer to the 7th arc on 8-3-2014 according the latest CSIRO-drift-analysis used on the satelite images. The drift along the Broken Ridge trenches during that time were to the east.

    I know this would be too good to be true but it would be just stupid to blindly ignore it considering what’s at stake now just out of disbelieve or denial.

  243. Victor Iannello says:

    If Seabed Constructor continues scanning at this pace, it should reach 29.5S latitude before the end of this swing. That’s an impressive pace.

    Ocean Infinity has also silenced the naysayers that claimed the technology was too complicated and failure-prone to achieve these amazing scanning rates. Other than a temporary setback from one problem AUV and then one ROV, the progress has been to plan. Whether or not OI finds MH370, it has raised the bar in achievable seabed scan rates and cost efficiency.

  244. Ge Rijn says:

    @VictorI

    They’ve reduced the search width quite considerably also it seems.
    Do you know which width they are taking now and how many days they’ll need to finish 29.5S?

    And indeed OI has shown /proven it’s capabilities beyond many expectations.
    Hats off in all respect. But they are there to find the plane.
    Technical ability is one thing. If not making the right choices at the right time those abilities are useless in respect to the goal.

    In the end it’s about OI people making choices and decisions. They’ve already proven no-one can blame their technology if they fail.

  245. TBill says:

    @Victor
    “If Seabed Constructor continues scanning at this pace, it should reach 29.5S latitude before the end of this swing. That’s an impressive pace.”

    …and then we get one more swing- Site4? Sounds like they could get up 27S or better if all goes well? Water gets deeper again in the orig McMurdo scenario. I’d be curious how the under water temperature is varying at the various depths of the search.

    Note they have added Site4 in the recent report. There is Arc8 (a typo? or what they are calling ALSM’s Arc7 20000-ft). I think I am perfect agreement with where they decided to go more narrow search area at around 31.5S.

    Also the latest map show the BR search area a little more clearly.

  246. Ge Rijn says:

    Put it another way.
    What would be the statistical chances something with the same shape and features like an up side down left wing flaperon floating in that area at that time? Among 13 other observed pieces of debris around the same location? Which the RNZAF crew called; “I think we’ve entered a debris field”?

    And then by change this location also fits all the Inmarsat-data, drift-data, fuel-data, possible motivation of the culprit (hiding the plane), the kind of found debris, the lack of crush-damage, the intact leading-edges of flaperon and flap-section, all those trailing edge/wing related pieces, the nose-gear door piece, the engine cowling pieces.

    It’s just all so obvious. The plane must have glided after the 7th arc and ended in a ditch-impact. Maybe losing its tail section like Asiana 214 in the event or breaching the hull in another place.

    A high speed nose down impact close to the 7th arc is just impossible considering this all.
    But stay on. Within a week or so opinions have to be evaluated.

  247. Victor Iannello says:

    @TBill: I think if progress continues at this pace, SC might get to 29.5S during this swing, and perhaps to 26.5S the next. After that, if there is no debris field, we’ll all have to re-assess where to look next, if there is that opportunity.

  248. Nederland says:

    @Ge Rijn

    The blue panel was actually found based on the assumption that MH370 crashed close to the arc at around 31S, the area currently being searched. It was found on the first day once the search had moved to that area.

    https://s3-ap-southeast-2.amazonaws.com/asset.amsa.gov.au/MH370%20Day%2011/Charts/Charts2/2014_03_28_cumulative_search_handout.pdf

  249. Ge Rijn says:

    @VictorI

    After 26.5S there will be no time left to search somewhere next. You should know. You want OI to search till there?
    Your ‘debris-point’ at ~29.5S is the final possible point based on possible hard evidence. The rest north becomes increasingly impossible due to drift-analysis constraints and also Inmarsat-data expectations. Even 29.5S is already problematic it this regard.

    You want this search to fade out? Or take real challenges?
    I hope OI does not share your point of view.

  250. Victor Iannello says:

    @Nederland: Yes, you are right. The aerial search pattern was based on the predicted location of debris on the day of the search assuming an impact along the 7th arc. So by definition, if debris was found during the aerial search, it would correspond to an impact point somewhere along the arc, as predicted by the drift models. I’ve made the point many times that OI would be scanning the part of the arc corresponding to the “blue panel”, even if we don’t conduct our own drift studies to determine where exactly that point is along the 7th arc.

  251. airlandseaman says:

    Ge Rijn:

    As previously reported, the search width is ±22nm, centered on the IG (and now also the DSTG) 20,000 foot 7th arc. The DSTGT arc agrees with the IG arc to 70m. The current 20,000 foot reference 7th arc and ±22nm arcs are here: https://goo.gl/xHYAgU

  252. GlobusMax says:

    OI is definitely working hard and moving fast. With the new Site 4 extension, I have their chances from here on out at up to 25%. If they finish what is indicated, they will have searched an area on par with the total area searched 2014-2017, by my estimate. Well done, OI.

  253. Victor Iannello says:

    Right as we are touting the capabilities of Ocean Infinity, they have made a new offer on Twitter:

    @Armada_Arg, @MindefArg, we are willing to search for #ARASanJuan offering NO CURE NO PAY. Our #multiAUVfleet is highly effective and fast. Read more about MH370 https://bit.ly/2qErRZZ . Please get in touch. @Ocean__Infinity

  254. GlobusMax says:

    I hope the offer is accepted. No Cure, No Pay is definitely innovative. If a public prediction market could be added, there would be even more incentive and cooperative effort to find MH370. Malaysia could fund the “pot,” the public could place their bets, and firms like OI could take the counterbet for each area searched to subsidize their effort. I know I’d have placed some substantial “bets” over the years.

  255. TBill says:

    @Victor
    We have 2 possible outcomes:
    (1) MH370 is found this search
    (2) MH370 is not found this search

    If Item (2) we get:
    (a) the Malaysia final report which could be significant, and
    (b) a whole lot of Pin proposals need to be re-done (including mine).

    But I always thought there was some merit for what I call the vector L894 vicinity 20-23S. I recently noticed a slow 360 knot path to L894 tends to work and most BFO’s up to are off by about constant +10 vs. observed.

  256. DrB says:

    @Jean-Luc Marchand – CAPTIO,

    You said:

    “@DrB
    Your “orbital” turn notion is very interesting. May ask you this:
    Operationally, from all the results one can derive that the aircaft was not descending to land at Kota Bharu, but kept an en-route altitude. As Kota Bharu is not an en-route waypoint, would it be worth considering that she flew over one on the closest en-route waypoints (GOLUD, ABTOK or KADAX) ? KADAX is interestingly almost just on the envisaged straigth path during the “KB Volcano” crossing.

    Here is what I said in September 2014:

    “5.3.2.7 Arrive Kota Bharu Airport
    The nearest airport to 9M-MRO at the time of diversion is Sultan Ismail Petra Airport in Kota Bharu, Malaysia (VKB / WMKC). It has a 7,900 foot runway and commercial airline service. It appears that the MH370 flight crew initiated a path to one of the aviation waypoints immediately to the north of the airport. These waypoints form a tight cluster and include ABTOK, GOLUD, and KADAX. It is not necessary for my analysis to discern which waypoint was selected since the actual flight path is extremely close to all of them. I have chosen to use GOLUD at (6.285N, 102.278E), which is 8 NM north of Kota Bharu Airport. This location matches the radar track in the ATSB Report Figure 2.”

  257. Victor Iannello says:

    @TBill: If MH370 is not found after searching to 26.5S latitude, there are the following options:

    1) Search further north along the arc
    2) Search further south along the arc
    3) Search further out from the arc
    4) Re-scan what was previously scanned
    5) Look elsewhere

    I doubt a strategy will be followed where people conjecture about a particular scenario and then only that hypothetical endpoint is searched. Considering how many individual scenarios have been proposed and have proven wrong, I doubt there will much patience for more guesses about specific scenarios. Nor should there be.

    We still have a lot more of the 7th arc to be scanned before the search is completed for this season.

  258. DennisW says:

    @Victor

    Considering how many individual scenarios have been proposed and have proven wrong, I doubt there will much patience for more guesses about specific scenarios. Nor should there be.

    I have never proposed a scenario that has been proven wrong.

  259. GlobusMax says:

    > I have never proposed a scenario that has been proven wrong.

    You have company there, but to the credit of the authorities in charge, I’m not sure their searches have ever been driven completely by any single point of interest. The planned searches have always been somewhat broad. Search was arguably extended south to cover the IG hotpot in 2015. Even OI planned initially to search more than just the CSIRO hotspot at 35s. But both of these were firmly in what were broader hotspots indicated by satellite and drift/debris data, respectively.

  260. David says:

    @Ge Rijn. As you know there were numerous pieces in the debris field of the purported flaperon. HMAS SUCCESS and a Chinese ship recovered and assessed debris there. Nothing of interest was found. One possible explanation was that this area was a local concentration of general flotsam such as Dr Griffin has recently described, but unrelated to MH370.

    Missing are any sightings in that area of the numerous other MH370 parts which later drifted ashore, many of which would have been floating high and lightly coloured including a large engine panel, a large part of a flap and other flight wing parts. There may well have been more which have not been recovered.

    Granted the search was at wide spacing, though some areas were aerial searched multiple times.

    The flaperon should float well out of the water. This is not evident and I think some of what you see about it could be artefacts.

    In summary it is not so much that it couldn’t be the left flaperon but that the prospects of it being so are limited by it not having washed ashore anywhere and by no other debris having been located during that search which had good prospects, flotation in particular, of being from MH370.

    You have been seeking a positive response but I put some reasons why I for one do not share your enthusiasm.

  261. David says:

    @Ge Rijn. In para 2 I missed adding the right flaperon.

  262. DennisW says:

    @all

    It has gone pretty quiet on the radar data so I’ll add some thoughts. There was certainly a speed increase of some 40 knots in the vicinity of KB. The radar data is very clear on that. The rest – maneuvers, altitude changes,… are much less clear. The difference in slant range at the loss of radar entering and leaving KB is not too conclusive. Stroboscopic effects associated with the rotating position of the antenna and the time resampling could account for a part of it. The simplest assumption is a flyby at nearly constant altitude with a speed change. If one extends the range data entering and leaving KB you find the intersection at about 7nm. This distance represents the slant range at closest approach. Since the aircraft did not fly directly over the radar head, the slant range at closest approach is not purely altitude. Allowing for this offset results in an altitude of about 6nm or about 36,000 feet.

    I know, arm waving, but it hangs together reasonably well. I estimate 36,000 feet and a straight path over KB.

  263. formula says:

    Concerning @Victor’s further search option “4) Re-scan what was previously scanned” are there any views please on the prospects that: –

    (a) volcanic activity and/or undersea avalanches (mud slides)might have obscured or wholly concealed the aircraft wreckage; and

    (b) the scanning might after all have missed identifying wreckage, the apparent thoroughness and high quality of the searches notwithstanding?

  264. sk999 says:

    All,

    I have (finally) finishsed a first cut at analyzing the radar data. As has been noted by many, jitter is introduced by quantization in time, range, and azimuth. Errors in range and azimuth are correlated over spans of time of up to 40 seconds, making a determination of speeds on short timescales (such as a minute) problematic. I have filtered the range and azimuth data as best as possible, but, similar to Victor, I think one can, at best, divide the data into three time intervals and determine an average speed for each. I find as follows:

    17:30:00 to 17:37:12 481 knots
    17:38:24 to 17:48:35 523 knots
    17:51:00 to 18:01:11 513 knots

    The global average speed is 517 knots (261 nm in 0.505 hours). For reference, I used an altitude of 34,000 feet (geometric). I hesitate to assign credible errors to any of these speeds.

    Anyone wishing to derive information about altitude, climbs or descents, or exceeding aircraft performance limits based on short-term patterns within the data needs to demonstrate that such conclusions are not impacted by the squirrely quantization errors present in the data. I tried but abandoned it.

  265. GlobusMax says:

    @formula

    a) undersea volcanoes. This is extremely remote. There are volcanoes, but I have not heard of any being active. Think about how active volcanoes are on land and you won’t be too far off undersea. Then consider the portion of the search area subject to activity – probably a fraction of a percent. The answer when you multiply those probabilities by the probability MH370 is there is virtually nil.

    b) Definitely more of a worry. I have a Bayesian model that computes this based on published numbers of detection ability, gaps, etc (and my interpretation of the prior probabilities that data models indicated). For example, the 120,000 +/- km^2 searched from 2014-2017 now has a residual ~9% chance of containing MH370.

  266. Victor Iannello says:

    @sk999: Thanks for your results. There is a small group that has been working together offline trying to reconstruct the timestamps and improve the speed calculations. If successful, those results will be shared.

  267. sk999 says:

    GlobusMax states, “… undersea volcanoes. This is extremely remote. There are volcanoes, but I have not heard of any being active.”

    Listen again. Three months ago …

    “We All Nearly Missed The Largest Underwater Volcano Eruption Ever Recorded”

    https://www.sciencealert.com/almost-nobody-noticed-largest-underwater-volcano-eruption-ever-recorded-havre-seamount

  268. GlobusMax says:

    @sk999

    My statement applied to the search area, not the whole world. 😉 That is a nice big volcano, but in a much different area geologically. New Zealand is just a big friggin volcanic Island, especially the North Island. The search area is not all that active tectonically, as I understand.

    https://en.wikipedia.org/wiki/List_of_submarine_volcanoes

    Your link says 70% of all volcanism is submarine (they mean 70% of magma production); coincidently, 71% of Earth’s surface is ocean.

  269. formula says:

    Thanks for responding @GlobusMax. The “residual ~9% chance” is worryingly high.

    Thanks to you also and to sk999 concerning information about volcanic activity. The Havre caldera provides an interesting example.

  270. DennisW says:

    @sk999: Thanks for your results. There is a small group that has been working together offline trying to reconstruct the timestamps and improve the speed calculations. If successful, those results will be shared.

    Why I am laughing?

  271. Ge Rijn says:

    @David

    According the news at the time several observations were made in the region by different planes. One of those spotted two rectangular grey/white panels among ~13 other floating pieces including the ‘blue panel’.
    Haixun 1 was sheduled to try and retrieve this debris. They did not find those panels and associated debris again as far as I know.
    The news at the time is a bit messy about what was spotted where, when and by which plane and about what was retrieved by which ship.
    But the ‘blue panel’ was not retrieved and the observations made by this particular RNZAF Orion flight on 28-3-2014 is well documented (by Bernard Lagan f.i.):

    https://www.salon.com/2014/03/28/malaysia_airlines_flight_mh370_update_multiple_planes_sight_objects_in_new_search_zone/

    http://www.ibtimes.com/malaysia-airlines-flight-mh370-search-planes-spot-multiple-objects-various-colors-new-northeast

    Then indeed the ‘blue panel’ is floating ‘flat’. While the found flaperon is sticking it’s trailing edge (what’s left of it) above the surface.
    But think about the weight of the missing trailing edge is removed here.
    If the found flaperon had it trailing edge still complete it would aslo float much more flat (that weight pulling its trailing edge down).

    Whatever this spotted pieces have been there’s no way to tell it could not have been from MH370. Assuming it could not have been, is like taking a huge risk in missing a realistic opportunity to find the plane.

  272. Richard Godfrey says:

    SC continues to make good progress up the Broken Ridge plateau area and has reached 30.5°S.

    Ocean Infinity are now in the 8th cycle of AUV launch and recovery, with 7 AUVs per cycle, since the start of the Broken Ridge area on 31st March 2018.

    I expect Ocean Infinity to reach 29.5°S before leaving to Fremantle for crew change and resupplying.

    The weather is good, dominated by a high pressure, good visibility, with a 9 knot wind and a combined swell and wave height of 2.5m. There are no tropical storms in the region.

    https://www.dropbox.com/s/iqy5ovzzpmz12cs/SC%20Track%2018042018.pdf?dl=0

  273. love all you guys and comments please keep looking.
    The pilot had to be at somewhere he chose and with the problem of fuel reserves.
    I have found all of Inmarsats numbers fine ( convert 7.14825) except the ending hard left after 18:25′ best to ignore.The conversion BTO off the planet, had to be ignored ariel problems. I found the turn south- west deep 346 nm 61 min before heading 180 degrees to Broken Ridge,passing east of Runnut. The pilot used fuel calculations times speed to approximate cruise target 488nm kts 158.66 mins.
    Here I would like you guys to work out distance between U18040 and U18400 this tells you how fast the plane was traveling near the end point. Lodgic tells me a call was made at U18040 from the operations room then 8’39 mins later nothing. I have MH 370 nearside to comsat close to arc when right motor expires 15 nm.Which is exactly where Infinity is now along the 7th Arc but inline with those drift photos It must have crossed the Arc.(Yes I have it ditching with fuel in left motor flap broke away struck tail assembly and flop cracked back end allowing 41 D seat to breakaway.
    AlBaz

  274. David says:

    @Ge Rijn. Yes the records of “what” was recovered and assessed (HMAS SUCCESS, at least, kept one which has not been located) and maybe that would include “where” anyway but nevertheless the conclusion was that there was nothing from MH370. There would have been various items even if the “flaperon” was not located that is unless the flaperon were shed before the aircraft crashed. However if solitary like that its location would be where MH370 wreckage wasn’t.

    I do think the trailing edge would be buoyant in net being honeycomb and would stick out of the water as would the flaperon generally. Yes I think all of us are well aware of the Bernard Lagan remarks.

  275. Victor Iannello says:

    @DennisW said: Why I am laughing?

    Probably because you missed comments with extra information that help us to understand the time step in the underlying data.

  276. Ge Rijn says:

    @David

    Main point I try to make clear is whatever the ‘blue panel’ and associated debris field was, there’s no reason to treat this documented observations with lesser care than the CSIRO satelite images or @VictorI’s spotted debris around 29.5S.
    It’s possible hard evidence which as well justifies serious investigation and a wider search width than random locations/latitudes.
    It should not be ignored the way it has been. There’s no logical or legitimate reason I can think of. And there has been no acceptable explanation why it should be ignored.

  277. Ge Rijn says:

    Then the latest discussion is all very nice and interesting but does not add to the real problem now: Where to look closer?

    In this regard it’s a distraction from the real problem: Why is the search failing so far? Why is the plane not close to the 7th arc so far (after 4 years)? This discussion is avoided. Why?

    But keep on going. Your general confirmation-bias has showed no results yet. I hope it has when ~29.5S has been searched. But if not, then keep on going till 26.5S or even farther north before you surrender to your defeat.
    Ego’s consider themselfs sometimes more important than the reality of possibly have been wrong. Despite the drama all involved suffered and still suffer.

  278. Victor Iannello says:

    @Ge Rijn said: Main point I try to make clear is whatever the ‘blue panel’ and associated debris field was, there’s no reason to treat this documented observations with lesser care than the CSIRO satelite images or @VictorI’s spotted debris around 29.5S.

    Despite all your ramblings, what is you say patently false. The impact location associated with the “blue panel” was searched to the same extent as the CSIRO impact sites and the debris fields will be searched. In fact, the search width has now narrowed to +/- 22 NM, so future latitudes are getting less attention than previous latitudes. I think everybody here is able to comprehend that except you.

  279. sk999 says:

    All,

    Here is another bias to be aware of. In comparing my long/lat coords with Victor, I found excellent agreement on average, but with some jitter, presumably because I smooth the az and range values first. The jitter in the derived long/lat coords in the absence of smoothing has the effect of increasing the total path length due to artificial motion perpendicular to the direction of travel. It is not much – about 1% – but it means that one will overestimate the ground speed by about 5 knots.

  280. DennisW says:

    @VictorI

    Probably because you missed comments with extra information that help us to understand the time step in the underlying data.

    I don’t think so. The data looks very clean to me. Your manipulations are creating the artifacts.

    https://photos.app.goo.gl/SlatMm16LnjmThsE2

  281. Victor Iannello says:

    @DennisW: We are trying to estimate the speed profile.

  282. Victor Iannello says:

    @sk999: Agreed.

  283. David says:

    JW has posted about the search extension north, No.4.

    For those who have not been able to access Operational Search Report 12:

    https://www.dropbox.com/s/rq8dy9qo9iho06u/Operational%20Search%20Update%20%23%2012.pdf?dl=0

  284. sk999 says:

    All,

    Hopefully someone can check the following. As MH370 passed the KB primary radar, the relation between slant range and physical distance on the surface of the Earth depended very much on the altitude of the aircraft. At least, for the KB primary radar. Essentially no such dependence existed for the military radar at Western Hill (130 nm away).

    Many moons ago I integrated Figure 4.2 of Bayesian Methods and produced a model for the military radar track that matched the ATSB version of this track pretty well (outside of the major turns); the big gain was that I now had timing information. We have timing information for the civil radar as well, so we can match them up. By requiring that there be no timing discontinuity as the plane passed through the “cone of silence”, we might learn something about the altitude.

    [It should be noted in advance that the ground tracks of both the civil and military radar are very closely aligned – mean perpendicular offset of 0.5 nm.]

    To start, let us take an extreme case where the altitude is 0. I find that at 17:30, the initial civil radar point, the timing offset between the civil and military tracks is -20 sec, in the sense that the civil radar shows the plane passing a particular location earlier than does the military radar. At 17:37, just as the plane entered the cone of silence, this offset is now +10 sec (reflecting the fact that the speed indicated by the military radar is higher than that from the civil radar.) At 17:39, the offset is back to -18 sec. Thus, the offset has jumped by -28 sec during the passage through the cone of silence.

    How about 30,000 feet? The discontinuity is now -11 sec, better.

    How about 41,000 feet? Now the discontinuity is 0. Even higher altitudes might be indicated.

    Oh yes, by the time the plane reached the Strait of Malacca, the timing offsets are close to zero.

    [All the above is based on me eyeballing graphs. YMMV.]

  285. DennisW says:

    @sk999

    I estimated the altitude crossing KB using the extension of the slant range data and the offset of the crossing with respect to the radar head. 36000′ is close. The polynomial in my graph is 10th degree but you can extend the straight lines to ~7nm. The offset from directly overhead indicates an altitude of ~6nm.

    https://photos.app.goo.gl/Tjid7FPg9nP13ICf1

  286. Mick Gilbert says:

    @Globus Max
    @formula
    @sk999

    Regarding undersea volcanoes in the search area, let’s not forget that back in January 2016 Furgo Discovery lost a tow fish when it struck an undersea volcano and separated from the vessel. I recall that it was described as a ‘mud volcano’ at the time. I can’t recall any discussion as to whether it was active or whether activity (viz changing height and shape due to mud flows) might have contributed to Furgo towing the sonar vehicle into what should have been an already surveyed feature.

  287. TBill says:

    @Mick Gilbert
    When the accident happened, I recall on the USA news (CNN) there was a lot of talk about the ocean bottom being covered with a thick layer of muck, such that the wreckage might sink in and be hidden. I have not heard so much discussion of that in later years.

  288. David says:

    @TBill, Mick Gilbert. Talking about mud.
    The photo of the Fugro Discovery towfish on the bottom at 2550 metres on 3rd February, 2016, apparently having hit a mud volcano on 24th January, is void of mud.
    Volcano:
    https://www.atsb.gov.au/media/5768541/MH370%20Operational%20Search%20Update%2027%20JAN%202016.pdf

    No mud (towfish negatively buoyant):
    https://www.atsb.gov.au/media/5768562/mh370-operational-search-update-10-february-2016.pdf

    Yet after the cable of the Dong Hai Jiu 101’s towfish parted, on 21st March, 2016, as seen on the bottom on 18th April (at 3700 metres) there was plenty of mud.
    See the depressor two-thirds buried (this towfish buoyant):
    https://www.atsb.gov.au/media/5770142/mh370-operational-search-update-20-april-2016.pdf

    The depressor ‘weighs’ 800 Kg (less water buoyancy of it) and even though ‘towing’ the towfish (and its buoyancy) down it would have impacted at speed. Still as I have raised before to bury itself so deeply suggests deep mud. That almost certainly would attenuate sonar returns from wreckage buried in it, reducing or more likely nullifying them.

    All the objects photographed on the bottom during that search were without appreciable mud. That might be because there was little and Dong Hai coming across it was a fluke. However another possibility is that any in mud escaped detection, particularly if they had settled deeper into it over a year or two.

    Would the anchors and cables have been found in muddy areas for example?

  289. Don Thompson says:

    @David,

    Comparing the towfish depressor and, say, an engine core is reasonable. If one considers that an engine core might also ‘torpedo’ its way to the seafloor and partially embed in a sediment bottom, the resulting position might present a good target for side-scan sonar if part of the object remains exposed above the seafloor. Even should its impact embed deeper, you’d expect a crater that would be also be detectable as good target among a debris field and an abyssal bottom.

    Lighter debris fragments scattered on the seafloor, which a typical field would comprise, will also be a good target environment presenting highly contrasting backscatter.

    The Geoscience Australia backscatter map, derived from the initial multi-beam echo sounder (MBES) survey, shows the Broken Ridge Plateau as an intrinsically low backscatter area – that is good to maximise the probability of detection.

  290. Richard Godfrey says:

    I have run the Kota Bharu data based on both 3.8145s and 3.812s rotation time and do not see a difference. I have tried target altitudes between 36,000 feet and 45,000 feet and get the best fit at a constant 36,000 feet. I used a 10 data point moving average. I made a timing adjustment of 4s at 17:31:38 UTC and another timing adjustment of 6s at 17:38:55s.

    In my view, MH370 was increasing in speed throughout both the inbound and outbound leg of the Kota Bharu area, from around 460 knots to 530 knots. There is only a small difference between the last ADS-B recorded speed of 471 knots at 17:20:35 UTC and the first 10 data point moving average speed of 465.5 knots at 17:31:11 UTC. There was no discontinuity between the inbound and outbound speed.

    Fig.1 – Speed vs Time as captured by the Kota Bharu radar:
    https://www.dropbox.com/s/l7r00ickr4gnhuk/Kota%20Bharu%20Primary%20Radar%20Data%20-%20Speed%2036K%203.8145s.png?dl=0

    Fig.2 – Track as captured by the Kota Bharu radar:
    https://www.dropbox.com/s/0hdtcg48atkgp1t/Kota%20Bharu%20Primary%20Radar%20Data%20-%20Track%2036K%203.8145s.png?dl=0

  291. Paul Smithson says:

    @Richard. Thank you for posting and I am encouraged that we are now obtaining similar findings.

    I agree that you get those shapes if you assume your altitudes. If we left it at that, who is to say which altitude is best fit – except to point out that 540kts looks a bit unlikely with the tailwinds at FL340.

    Please calculate speed across the gap and see whether it fits speeds on either side.

    Across-gap speed has greatly suppressed noise associated with high-temporal resolution speed estimates so it “ought” to be a solid speed estimate if the path across the gap was straight or nearly straight.

    Some would argue that it wasn’t straight or might not have been straight. Fine. Add appropriate distance for that scenario and calculate that speed as well as a sensitivity test.

    In either case, I think you will find that altitude must have been substantially higher than your scenario above.

  292. DennisW says:

    @Paul

    Some would argue that it wasn’t straight or might not have been straight.

    Who is arguing that the path was not straight?

  293. DennisW says:

    @Richard

    Your graph reminds me of a bit of mathematical trivia – there is no known way to compute a best fit using two straight lines to model data.

  294. Victor Iannello says:

    @Richard: Thanks for posting your results. I agree with the trend of increasing speed and the difficulty in extracting altitude information.

    @DennisW: I believe there was a turn before the gap over Kota Bharu and a turn during the gap. I’ll explain why later.

  295. DennisW says:

    @victorI

    @Richard: Thanks for posting your results. I agree with the trend of increasing speed and the difficulty in extracting altitude information.

    @DennisW: I believe there was a turn before the gap over Kota Bharu and a turn during the gap. I’ll explain why later.

    I stand by my altitude estimation of ~36,000′, and I see no evidence of any turns.

  296. David says:

    @Don Thompson. As you say, bits sticking up provide good contrast in a smooth low backscatter field but I think there is a risk that maximum range could be reduced. In the below I address sensitivity to that.

    References are to the ATSB’s Operational Search for MH370 of October 2017.

    In this there is no mention of the possibility of burial of wreckage in whole or part, as neither there is of bottom hardness being a characteristic measured during bathymetry or any other assessment. It may be that there was complete confidence that this was not an issue but then again the depressor photograph suggests that the bottom could have been soft at least here and there.

    At Fig 28 the ATSB alludes to, “underwater landslides of sediment that travel for kilometres along the sea floor.” At page 49, specifically of north of Broken Ridge it says, “The seafloor in this region is covered in a layer of sediment up to 300 m thick and is subject to extensive seafloor landslides, some of which are kilometres long”. There is no detail on how soft that might be or what bumps, ridges and boulders it might include.

    More broadly, at page 54 the report depicts AF447 engines on the bottom, largely unburied if at all. Above this the ATSB describes a “feature detection capability, or resolution, of two cubic metres” as the minimum to be expected from a B777 engine on the bottom, also presumably unburied and in like condition.

    As targets (page 61) they utilised 2m cubed crosses and cubes, which presented flat steel to the sonar, plus a similarly sized cylinder on end yet supplemented by a flat reflector on top. There were no shapes like oleos or rubber as with tyres, so the detection was aimed just at the engines.

    An underlying assumption is that the No.1 spool shaft in a 3 spool engine would remain intact; and most probably the fan stator vanes and shroud would be retained as per the Air France engines.

    In the test range off the WA coast the bottom was hard. In a test (Fig 44) at depth the same applied. Also note that in the figure above there is no mention of the cylindrical target. Presumably it would have been part of the trial but if so was undetected.

    Whereas a 1700 metre search line spacing applied in that search with detection range at 1000 metres being seen as reliable, that 300 metres reduction in line spacing was to allow for side-to-side wander of the tow fish. Indeed detection of those reflective targets placed on a hard bottom was “intermittent” at 1100 metres (page 61) so there is not much “fat” there to cope with weaker echoes.

    At page 89 tow fish altitude testing is described, over “a fairly benign sea floor”.

    To me the trial targets selected together with proving conditions and results’ assessment are not robust enough to make allowance for major items possibly being part concealed in some places and the general debris field likewise.

    At page 80 the ATSB says, “At the time of the first principles review an area of nearly 120,000 km² covering more than 85 per cent of the highest probability flight paths had been searched to a level of confidence greater than 95 per cent.” (Subsequent searching was confined to looking at some sonar gaps and specific spots.) That suggests the chances of the wreckage being missed or outside the search area yet within the assessed probability area is one chance in six to seven. Were there some soft sediment in the search area that prospect could well increase.

  297. Richard Godfrey says:

    SC continues to make good progress up the Broken Ridge plateau area and has reached 30.18°S.

    Ocean Infinity are now in the 9th cycle of AUV launch and recovery, with 7 AUVs per cycle, since the start of the Broken Ridge area on 31st March 2018.

    There was another ROV deployment yesterday at 30.4848°S 97.7340°E for 3 hours 30 minutes.

    The weather is mediocre, dominated by a high pressure, good visibility, with a 16 knot wind and a combined swell and wave height of 4.3m, which is high. There are no tropical storms in the region.

    https://www.dropbox.com/s/wmc5802nxnldu95/SC%20Track%2020042018.pdf?dl=0

  298. Gerald says:

    As the search goes on, the more I get the feeling that MH370 will not be found. Despite all calculations by experts and amateurs the hotspots are not hot, the promised high probabilities have been proven wrong and now OI is moving northwards which seems to be our last Hope. But where is the mistake. Lets hope and pray for a finding in the northern sector, because otherwise we really have a problem concerning aviation safety. Me as a normal pax and layman I always try not to think about MH370 when boarding a long haul flight which of course doesn’t work.
    Thanks to all for your great work and enthusiasm.

  299. Richard Godfrey says:

    @Gerald

    Please do not be pessimistic.

    Ocean Infinity are just starting to search the most probable area.

    There was previously too much silo thinking and false assumptions in the ATSB/DSTG/CSIRO calculations.

    However, it will still take several weeks to reach 26.5S.

    I appreciate that $200M has been spent of tax payers money without result, but Ocean Infinity are currently footing the bill not the tax payer.

  300. Don Thompson says:

    @David,

    no mention of […] bottom hardness being a characteristic measured during bathymetry or any other assessment.

    You appear to have missed the discussion of Backscatter analysis on page 51-52 (PDF 60-61 of 440 pgs)

    A backscatter image is published by Geoscience Australia in their MH370 archive hosted on the National Computational Infrastructure.

    The comment about the Broken Ridge Plateau and landslides could only refer to the slopes of the Gulden Draak and Batavia seamounts: it is a plateau, very flat. I recently generated a 3D rendering of the seafloor in the vicinity of a PoI, the bathymetry is quite clear. That image is generated from Geoscience Australia’s 45m resolution (XY) MBES derived data, my understanding is that the elevation resolution is sub 1m.

    While ATSB’s benchmarking of side-scan performance was based on three dimensional reference targets of approx 2m³ volume, the reality of discriminating a target is typically a result of the side scan sonar detecting backscatter from a distributed field of debris, examples include the remnants (anchors, nails, water box) of the decomposed wooden vessel and the many geological features investigated.

    The track spacing and overlap allows the extremities of the side-scan sonar swath to be covered from both directions, ensonifying poorly resolved objects and shadows from two sides.

    I’m not contending that large debris items may lie in shadow areas but I expect any identification will be led by recognition of a side-scan sonar image anomaly that extends over a area, 10s to 100s of metres.

  301. Don Thompson says:

    @Richard G wrote that Seabed Constructor appeared to conduct an ROV dive between 2018-04-19 20:30UTC and 23:59UTC.

    It returned to a second site approx 2000m northwards along the arc at 2018-04-20 at 11:15UTC.

    Bathymetry rendering of this area here.

  302. Ge Rijn says:

    While the main structures of the plane will be largely intact and together on the ocean floor, detection was- and is no problem at all.
    The problem is when your search is- and stays based on limiting and wrong assumptions, you won’t detect anything.
    And this is what reality shows till now.

    When @VictorI’s debris point won’t give results also, your assumptions and calculations on the crash and crash-areas have failed. Plain and simple.
    Holding on to this ‘close-to-the-arc-high-speed-impact’ believe will turn out completely useless after @VictorI’s debris point has been scanned.

    It’s becoming sad in a way to watch you cling to your own straws while still not seriously considering other possible (and more likely) alternatives.

  303. Don Thompson says:

    @Ge Rijn,

    Was the above an interjection to the conversation initiated by @David, or simply a psychotic reaction to mention of the likely characteristics of a debris field?

  304. ArthurC says:

    It’s always good to have an antagonist, it keeps the dialogue going.

    At least @Rob has disappeared (at least for now)…

  305. airlandseaman says:

    The evidence is growing that MH370 was in fact at a high altitude (~43500 feet) and TAS (~500 kts) passing KB. My latest analysis results are here: https://goo.gl/AvDg88

  306. Richard Godfrey says:

    Further to my post yesterday, I have included the Butterworth Radar data in my analysis and used the same methodology with the 10 data point moving average. I get a better fit at 36,000 feet than other higher altitudes. The track at 36K feet altitude and a rotation time of 3.8145 seconds is shown below.

    The speed appears to increase towards the overflight of Malaysia and then reduce again as Penang and the Malacca Strait is in sight. The gap between the Kota Bharu and Butterworth radar is as follows:

    The last radar data point from Kota Bharu is at 17:44:24 (63863.4275 secs), with the position 5.723098°N 101.367002°E.

    The first radar data point from Butterworth is at 17:46:34 (63994.0000 secs), with the position 5.575565°N 101.093790°E.

    The distance between the two points is 18.574514 NM and the elapsed time is 130.5725 secs, giving a speed of 512.1 knots. This gap calculation is dependent on both radars being synchronised to UTC. A speed of 512 knots would suggest that the graph below shows an exaggerated curve and the maximum speed reached is less than the 530 knots indicated.

    Fig.1 – Speed vs Time as captured by the Kota Bharu and Butterworth radar:

    https://www.dropbox.com/s/mz6eh1m0cq8jjoz/Kota%20Bharu%20and%20Butterworth%20Primary%20Radar%20Data%20-%20Speed%2036K%203.8145s.png?dl=0

    Fig.2 – Track as captured by the Kota Bharu and Butterworth radar:

    https://www.dropbox.com/s/y32qeu7husf8jff/Kota%20Bharu%20and%20Butterworth%20Primary%20Radar%20Data%20-%20Track%2036K%203.8145s.pdf?dl=0

  307. DennisW says:

    @ALSM

    The evidence is growing that MH370 was in fact at a high altitude (~43500 feet) and TAS (~500 kts) passing KB.

    ??? Can you share your evidence?

  308. airlandseaman says:

    Dennis: Did you bother to look at the link? (https://goo.gl/AvDg88)

    I think the speed profiles at 30,000 feet, 37200 feet and 43500 feet clearly point to the higher altitude scenario. At lower altitudes, the speed is unrealistic, especially when the tail wind is considered.

  309. DennisW says:

    @ALSM

    Yes, I looked at the link. I get a GS of 519 knots across the gap at 36,000. I will write it up in some detail when I finish my honey do list. What value are you using for tailwind across the gap?

  310. DennisW says:

    @ALSM

    Never mind the wind question. I did not look at your table included in the figure. Duh!

  311. DennisW says:

    @ALSM

    What is the source of your speed variations (at a given altitude) across the gap? There is no data from which to derive varying speeds.

  312. Gerald says:

    Why should this bird have been flown up to 43500ft? This seems to be very unrational by the Pic cause this will lower his endurance because of fuel burn. So scenarios way up north seem to become possible as this thread goes on and nothing is found. Well, maybe some people are thinking of ways to find arguments. Just my two cents.

  313. paul smithson says:

    @Dennis. What’s wrong with distance over time to derive speed 😉

  314. Victor Iannello says:

    @Don Thompson: Two contacts spaced about 1.2 NM apart and about 1.2 NM from the 7th arc is very interesting. We’ll have to watch the near term behavior of Seabed Constructor.

  315. DennisW says:

    @Paul

    That is the way I do it as well.

  316. airlandseaman says:

    Dennis:

    The calculations were done with a very precise spreadsheet developed by Victor. It properly takes into account the altitude in a 3D model, including the curvature of the earth. The raw range and az are converted to Lat/Lon values. The SASS-C 4 second stamps in the file were replaced with the true N*3.814 second radar head time stamps derived by careful analysis of the residual timing errors. Then the distance and time differences for each 4 minute period were used to plot the moving average (dS/dT). Using a 4 minute average has the advantage that we can see the average speed before, during and after the “cone of silence”.

  317. Victor Iannello says:

    @Dennis: If you take the raw range and azimuth data before and after the gap above Kota Bharu, you can calculate the distance for a given (geometric) altitude. Using the timestamp data, we know the time interval, and can calculate the mean speed.

    However, doing this for an altitude of 36,000 ft produces a speed of 566 knots, assuming a straight path in the gap. There are only really three possible explanations for this high speed:

    1) The uncertainty of the range and azimuth data is much higher than we believe.
    2) One or both timestamps are in error, and the interval is longer.
    3) The aircraft was at a higher altitude (43,000+ ft).

    I view (1) as unlikely and haven’t decided on (2) or (3). Mike’s work is based on (3).

  318. @all

    In all the computations presented so far, none is comparing its output with the Malaysian military radar with modern 3D+Time capability thanks to its “digital” phase array antenna.

    Is there a particular reason to put aside the values given by the Factual Information report para 1.1.3 a) ? A correlation would probably bring valuable info.

    I would think the military technology is much more precise than the analogic one of the old KB civil radar. Thus it could serve as a kind of a baseline, couldn’t it?.

  319. airlandseaman says:

    Good summary of the options Victor. I agree that #1 is unlikely. WRT #2, it is also unlikely given (1) the continuity with the ButterWorth data and (2) the knowledge we have that the radar antenna was turning at a near constant rate of 3.814 seconds.

    Re #3. I think it is almost certain now…better than 95% certain by my estimate…that (1) there was a speed increase of ~70 kts between 17:30 and 17:39 from ~460 to ~530 kts, and (2) the altitude at KB was ~43,500 feet. Lower altitude assumptions produce unrealistically high speeds (GS=556 kts; TAS = 546 kts at 30,000 feet). Higher assumed altitudes are not realistic given the B777-200ER performance envelope. In fact, the estimated speed and altitude at KB are very consistent with the max B777-200ER performance given the OAT at the time.

    Implications: The speed analysis suggests that the aircraft made a full throttle climbing left turn at the best rate of climb speed for those weight and enviro conditions (430 kts?), followed by a round out on a course of ~231 degrees. Somewhere near KB, the course changed to ~239 degrees.

    It is almost impossible to imagine an accident scenario that is consistent with this data.

  320. DennisW says:

    @Victor

    The time stamps do not have to be in error, but they have 3.8 second resolution meaning any given measurement can be off by 3.8 seconds. The gap timing of 132 seconds could be in the range of 139.6 seconds to 124.4 seconds. Assuming your 566 knots is geometrically correct the speed could be in the range of 539.2 knots to 605 knots.

  321. David says:

    @Don Thompson. “You appear to have missed the discussion of Backscatter analysis on page 51-52 (PDF 60-61 of 440 pgs)”

    Thanks, though had I looked attentively as these pages and the GeoScience archive. The word hardness in quotation marks is used but from the description below and at the dot points this alludes to reflectivity not the propensity for part burial. The focus is on whether the background reflections could drown out wreckage echoes and create misleading impressions.

    Putting it another way, was there any indication that where the depressor was two thirds buried that that area was “soft”? Indeed was there any indication of any areas being “soft” in the part burial sense? I have found none.

  322. airlandseaman says:

    Jean-Luc Marchand: The path derived from the “new PSR data” is almost identical to the the path in the FI, ATSB and DSTG reports. Virtually no difference. I have posted comparisons. It is also consistent with several independent analysis (sk999, etc.). The thing that is new is access to detailed target positions every 3.814 seconds. This in turn allows us to compute speed estimates we have never been able to derive from publicly available data. Yes, there have been long baseline estimates made from the publicly available data, but for the first time we can see fine details details we have never seen before.

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