Inmarsat’s Mark Dickinson holding the satellite data in an interview with CNN
Since we first learned of its existence, we’ve been asking for the complete record of the communications data between MH370 and Inmarsat’s satellite network. In May 2014, Malaysia released satellite data logs, but they were incomplete: fields of data were missing, and only a small number of data records from before the flight was made available. When pressed for the complete logs, Inmarsat and Malaysia both claimed the data had to be released by the other.
We now have what we believe is the complete record of communications between airframe 9M-MRO and the Inmarsat satellite network, from March 7, 2014, at 00:51 UTC, until March 8, 2014, at 01:16 UTC. This time period includes the previous flight from Beijing to Kuala Lumpur.
The satellite data was shared with me by a relative of a Chinese passenger on MH370. The data was given to him by Malaysia Airlines with the following email text:
Please find attached the Inmarsat data, for your info. Please note that these are raw data as you have requested. The authorities agree to release the data, on condition that:
- We will not translate the data into any meaningful information as the data is proprietary to Inmarsat. The Malaysian Investigation team does not have any experts to translate these data into any meaningful information.
- We will not translate the data into any other language, including Mandarin.
- These data are complete and obtained from Inmarsat. Please do not manipulate the data.
I know, by having these data, you will have more questions, but I have to say that we are providing these data to satisfy your request, but we cannot answer any questions on the data because we too, cannot understand it. Only the experts from Inmarsat can.
Hope you understand.
Thank you
I suspect the data will confirm some assumptions, and will raise even more questions. I hope the data can help us learn more about the disappearance.
Although not relevant to the above current topic, this article discussing the experiences
of some of the Chinese relatives of MH370 passengers is probably worth being more widely
known by VictorIs readers;
http://www.marieclaire.com/culture/news/a13397/malaysia-airlines-lost-flight-anniversary/
An alternative download URL for that article;
https://web.archive.org/web/20151001223050/http://www.marieclaire.com/culture/news/a13397/malaysia-airlines-lost-flight-anniversary/
My comments on the new, complete Inmarsat log are here: https://goo.gl/Th7QH1
ALSM
@ROB
On your previous comment about the cellphone in Flight-mode.
Flight-mode blocks all possible transmissions, so I don’t think this could cause a log-in somewhere. Rather a log-off but no log-in.
At least the log-in on WeChat indicates Z’s cellphone was not switched off while it should have been one minute before take-off.
And it probably further indicates the FO was the PIC during take-off and climbing to altitude till the first FL350 message from Z. to ATC.
After this I assume the FO was relieved by Z. and Z. took over control.
The second FL350 message was done by Z. 8 seconds after the final ACARS data transmission.
I would be curious if there was also a log-off registered by WeChat indicating the phone was switched of or put in to Flight-mode and if not this could mean the connection with WeChat prolonged during take-off and the early stages of the flight.
@ROB @others
Speculating about Z’s WeChat connection, using a Chinese server and encrypted messages, could it have been used to inform a Chinese contact about the faith of the plane under the name of ‘CMB’?
How could this ‘CMB’ have known at 3:30 in the early morning of 9 march 2014 there were 153 Chinese passengers on the plane and state that the plane was never going to be found if a contact was not informed by someone who had this information at that time?
@Ge Rijn
I think it was the other way round. Zaharie was PIC up to the point when (shortly before) the WeChat login occurred. After that, Fariq was PIC (for an unknown period of time). The login happens to fall in the time period when the change in PIC also seem to have occurred. This is because of the change of voice associated with the speaker who communicated to ground.
@ALSM
Nice. Thanks.
@ALSM
I’m not at an .xlsx enabled application device ATM.
I seem to remember that MH370 communicated to the satellite using the low-gain antenna,
then via the high-gain antenna – also, communicated initially with the POR, then switched
to the IOR.
If this is correct, could the ~1600 data point anomalies be the result of these occurences?
@GeRijn
Possibly I got confused. I was reading the earlier discussion iro whether or not a cell phone switch off causes a WeChat logon. As Mike Gilbert has pointed out, what exactly does FI mean when it states “Zaharie last WeChat login 40:02? Does it actually mean 40:02 was the last time Zaharie was logged on to WeChat? ie, he logged off (or his cell phone was powered off at that time? It’s yet to be clarified, think.
@ALSM
In the SUlog I noticed for both (attempted) phone calls towards the end:
Significant BER in combination with reducing C/No as well as reducing Rx power level. (No significant change in BFO)
Would you know how to explain this?
Here is a link to a complete decoding of all Initial and Subsequent Signalling Units from Hex to Ascii.
The first octet of each Subsequent Signalling Unit gives the message order, e.g. C8, C7, C6, C5, … etc., which is not always followed.
In each row of 12 octets, the first 2 octets are header and the last 2 octets are check sum.
I have therefore only translated the middle 8 octets in each row.
https://www.dropbox.com/s/8ngsielzp0fegct/ISUs%20and%20SSUs.pdf?dl=0
@Richard and @ASLM: Thank you for jumping on this so quickly and providing us with information.
@Richard
In your translation why is there the words “Pet Shop Boys”?
@Richard
This might be a silly explanation, but could it part of an Advert broadcast notice, because they were perhaps going to be live on tour in Malaysia later that year?
@Joseph,
The transmission containing the “Pet shop boys” string is that noted in the FI as pertaining to the IFE BITE channel. It’s an air-to-ground message.
Yeah, it’s just something the IFE sent to the ground when it started up.
ATSB did make this comment in the 2014 (Jun , revised thru Aug) Definition of Underwater Search Areas report:
The 1825 and 0019 SATCOM handshakes were log-on requests initiated by the aircraft. A log-on request in the middle of a flight is not common and can occur for only a few reasons.
Must not have looked at the prior flight, MH371, ZBAA to WMKK. The AES executed 22 Log Ons between OFF at ZBAA and ON at WMKK.
buyerninety:
Re: “I seem to remember that MH370 communicated to the satellite using the low-gain antenna, then via the high-gain antenna – also, communicated initially with the POR, then switched to the IOR.”
9M-MRO used the LGA and POR sat at 15:55:58.765 to log off. From 15:59:56.414 on MH370 used the HGA and IOR sat exclusively.
Re: “If this is correct, could the ~1600 data point anomalies be the result of these occurences?”
I do not understand what you are referring to. There were no “…1600 data point anomalies …” that I am aware of.
Niels:
Re: “In the SUlog I noticed for both (attempted) phone calls towards the end:
Significant BER in combination with reducing C/No as well as reducing Rx power level. (No significant change in BFO) Would you know how to explain this?”
The non-zero BER threshold was C/N0 = ~52 dB. For a data rate of 21000 b/s, that is about a 9db Eb/N0. I’m not up to speed on the FEC and other coding used on the C channels, but 9 dB is about right. (Don will be able to provide details I believe.) The system starts with a high AES EIRP (higher is needed for the 21,000 b/s channel speed). Then the GES sends commands iteratively to gradually reduce the AES uplink EIRP in order to minimize the required s/c downlink EIRP. The steady reduction to the min requirement and then slight increase is apparent in the following graph: https://goo.gl/QZ7lnV
@edmg
@Don Thompson
I understand guys thanks, a least over the years there wasn’t any conspiracy Nut, trying to link this to their song “Go West”.
@Joseph Coleman
There’s a story about the Pet Shop Boys conspiracy theory, but it will have to wait until the definitive history of MH370 is written. Mostly because I don’t remember whose theory it was.
It was a good one, though, at the time.
And it was “A New Life”, not “Go West”.
Niels:
I should have also noted that a BER of ~200 in 10^-6 (better than 10^3) is excellent for a typical coded voice channel.
Mike
@Victor: thanks for forwarding. Have Inmarsat publicly vouched for the authenticity of this data?
I downloaded the .xlsx file, and it seemed to retain the original metadata. The original timestamp on the file is 03:31 UT on Mar 8, 2014, barely 2 hours after the final transmission. According to this article:
https://corpcommsmagazine.co.uk/features-and-analysis/view/what-lessons-can-communicators-learn-from-malaysia-airlines-flight-mh370
from an interview with Chris McLaughlin, originally Inmarsat was asked for the data by SITA. It would appear that this spreadsheet is the file that was prepared at the time and sent off. According to McLaughlin, Inmarsat did not itself examine the data further until the afternoon of the next day (Sunday). Presumably it was Alan Schuster Bruce who did so, although he is not mentioned by name in the article.
It should be possible to fully model the BTO and BFO (which will require modeling the anti-Perth contribution more accurately, but I don’t the eclipse effect comes in – right?) Will take a bit of time to set it up.
@Brock McEwen: I have not formally asked Inmarsat, the ATSB or Malaysia whether the data is authentic. Considering the level of detail, the quantity of data, and the consistency with everything released to this point, I would be very surprised if the data was not authentic. That said, I would welcome any efforts on your part to obtain a formal statement from the authorities about the authenticity of the data.
@sk999: I agree that the creation time/date for the file is very interesting.
That’s no small task to get the BTO and BFO models right for POR in addition to IOR. I appreciate your willingness to try.
@sk999
I’d expect the POR pilot AFC reference to originate at Paumalu teleportin Hawaii (if that helps).
OK, I was just thinking of modeling the IOR data. Are there enough transmissions through that satellite to make it worthwhile? It looks the the SATCOM bounced between the two satellites during the flight. I don’t have TLEs for 3-F3 on Mar 7, and my space-track account expired ages ago, so I’d have to start over there. The location of the pilot signal transmitter is obviously important, assuming that the anti-Perth effect applies to it as well. The biggest amount of work will be validating the anti-Perth model (which I haven’t looked at in 3 years), pulling out yet more weather data, and putting together a realistic flight path. If the ACARS positions reports encoded in the data packet can be turned into readable tables, that would be a big help.
> Mick Gilbert says:
> Regarding deployment of the portable unit and antenna extension, it
> would appear that there are a variety of mounting and securing set-ups
> […]
> In both instances, however, note the plastic cover.
> […] from the MAS Safety and Emergency Services Manual it would appear
> that their portable ELTs were fitted with a cover. If it is the same
> as that shown in those photos then it encompasses the folded whip
> antenna.
> […] there also appears to be a lanyard connecting the beacon to the mounting bracket.
> Regardless of the configuration of the portable ELT on 9M-MRO one
> thing that is clear is that it is not designed to self-deploy.
Agreed. Great research!
The other type of ELT I referenced in my previous posting (“[…] designed to float on the surface of the water. The water usually dissolves a paper/cardboard collar holding a folded antenna in place. When the collar releases, the antenna springs up and the transmitter starts operating”) seems more useful to me than MH370’s ELT type, as it would more likely activate upon ditching.
Generally speaking, it’s frustrating for me that ELTs are so unreliable.
The FI report categorizes ELT failures in 173 accidents over the past 30 years as follows:
Operated effectively: 39 (22,5%)
Submerged: 1 (0,6%)
Terrain shielding: 1 (0,6%)
Internal failure: 5 (2,9%)
Damaged: 11 (6,4%)
Battery failed: 14 (8,1%)
Other: 21 (12,1%)
Not activated: 22 (12,7%)
Unknown: 59 (34,1%)
Given a less than 1 in 4 chance of successful ELT transmission upon crash, MH370’s lacking ELT signal unfortunately doesn’t seem to allow to draw any deduction. (If anything, the data suggests that no ELT signal would actually be the normal case and an ELT signal would be the exception.)
> Mick Gilbert says:
> while condensation would not be an issue for an internally mounted
> ELT, incorporating water activation would mean ELTA would be designing
> and manufacturing two quite different ELTs for fixed and portable
> applications. […] That one unit/two applications approach has a number
> of advantages for both suppliers and users.
IMO usefulness / fitness for purpose trumps commercial considerations (such as “it would be easier to design/manufacture”).
(following your argument, the same ELT would also be used for the life rafts)
@Victor: okay; anything to help. What is the full name and title of the MAS rep who sent the email? I’d like to cite the most upstream source you have when communicating with Inmarsat.
Brock:
I confirmed through an official channel that the file we have is identical to what ATSB received in March 2014.
@sk999 – on the subject of weather, do you have access to historic ECMWF wind data?
Indy says congratulations on acquiring the back side of the headpiece to the staff of Ra. Now let’s find the Ark itself.
@Brock McEwen: The name of the MAS official was stripped from the email forwarded to me by the Chinese NOK.
Based on the info that Mike supplied, I’m not sure it is worth your effort. But that’s your call.
Paul Smithson,
R.E. ECMWF, not I do not.
> edmg says (June 12, 2017 at 6:40 pm)
Huh, did anyone seriously consider a Pet Shop Boys conspiracy theory? Imagine if it had been Depeche Mode with “Enjoy the silence”…
@Don Thompson said, The AES executed 22 Log Ons between OFF at ZBAA and ON at WMKK. to demonstrate that ATSB’s statement that The 1825 and 0019 SATCOM handshakes were log-on requests initiated by the aircraft. A log-on request in the middle of a flight is not common and can occur for only a few reasons. seems contradictory.
I plotted the BFO for MH371 to show how many times the AES switched between IOR and POR. The variation in BFO is smallest in the middle of the flight, where turns and altitude changes are less likely. Also, under normal conditions, there appears to be no abnormal BFOs caused by an inflight log-on.
[I have removed a previous comment of mine until I can verify the timestamp information from the satellite data file.]
I suspect Inmarsat just created logs of all the data related to that aircraft, and didn’t actually look at them in any detail until the next day. There was already a search going on in the China Sea, so they had no reason to do so until someone decided to see if they could do anything to help locate it for the searchers.
In normal circumstances, you’d have expected it to be found by Sunday afternoon, by spotting wreckage or oil slicks. Only when it wasn’t found was there any reason for someone to take a close look at the logs.
@Victor
I anxiously await the plot of BFO error over time for MH371. Similar to figure 5.4 in “Bayesian Methods…”. I am too lazy to do it.
@DennisW: With the scarce data we have, it’s not trivial to do, and other things I’m working on have higher priority.
@ALSM
Mike, thanks for explaining the reduction of Rx power level and C/No during phone calls. While I don’t get all the details yet I understand the system deliberately reduces/optimizes AES uplink radiated power.
@VictorI
The timestamp info for the Inmarsat data file is indeed important. I hope you can somehow verify it.
@Niels: In a previous comment, Mike said, “I confirmed through an official channel that the file we have is identical to what ATSB received in March 2014.” That would imply that the creation date is correct.
@edmg
In one of the major MH370 TV documentaries, Inmarsat talks about their timing but if I recall correctly by late Sunday they were trying to get word thru their contacts to MY that the flight lasted hours longer than thought.
@all
I have some gut reaction to the comment to the NoK ” but we cannot answer any questions on the data because we too, cannot understand it. Only the experts from Inmarsat can”
…but is has been over 3 years since the accident, and Inmarsat has not displayed any reluctance to answer such questions to be of help. It implies
that many obvious avenues of investigation have not been done. Sorry to feel that way.
Re: File Creation date
I have confirmed via an official channel that the file creation date was 8 March 2014 03:21 UTC. Confusion about the date and time may arise because of the way Microsoft records and displays this date/time in Excel Files. The files contain the creation time and date in UTC. However, the date displayed on a users computer (in Properties) is displayed in then current local time. Thus, depending on where you are when you open the file, you may see a different date and time in Properties.
On my computer in Colorado (currently UTC-6), the properties for the file Victor shared shows 7 March 2014 9:21PM. This is the same as 8 March 2014 03:21 UTC. This is about 3 hours after MH370 crashed, and 10 hours after it went missing.
@Victor
“it’s not trivial to do, and other things I’m working on have higher priority.”
I used to have people for that, but no mas.
@Victor: that’s too bad. But no sweat: what was the name of the relative of who supplied you with the redacted email? I’ll ask that person for the MAS rep’s name.
Now that it is being widely reported, Inmarsat should go on camera and vouch for it. As a fellow pro bono researcher into the bizarre disappearance of MH370, I’m sure you agree we’ve all had enough dodgy “leaks” to last us a lifetime.
Thanks in advance.
Brock McEwen
Does anyone know
(1) the exact list of system’s condition to generate the message “unresponsive AES” (eg total loss of signal, invalid/corrupted AES ID, AES ID valid but no data … etc.)
(2) how is the normal log off sequence and why this message is not generated for the other log off events?
(3) there is an apparent conflict with the Factual Information stating that the last ACARS message, basically the fax from MAS ODC should be repeated every 2 min until 18:43:33 UTC p47 if no response from the AES. Why was 18:43:33 UTC mentioned – i cannot correlate this to the log? Any idea about that?
(4) there is a statement also in the factual information p43 saying that MAS should contact the plane via SATCOM if ACARS is silent for 30min. This apparently was not done at 17:37 ish: was this clarified with MAS as part of the investigation?
(5) is the there another log of satcom interface activities (print outs etc) on MAS side?
(6) does the satcom support multi tasks for instance can a fac be sent during an ACARS engine condition monitoring download which takes several seconds?
@all,
Here is the 12:50 POR Log-on BFO data plotted on top of the other log-ons:
https://twitter.com/DrBobbyUlich/status/874836356324872193
It is a perfect match to the OCXO transient curve.
Brock:
Why are you pursuing the source at MAS? Hasn’t it occurred to you that this source is better left unknown to the public? We already know it came from Inmarsat via MAS via NOK via VI and we know the file is authentic (confirmed same as ATSB’s file copy). Let’s encourage more cooperation between MAS and NOK. Exposing sources does not help anyone. Let’s get on with the analysis of the new data.
In addition to “pet shop boys” there are other seemingly strange messages, e.g., 16:06:32.405 there is a reference to some sort of special load:
NOTOC MESSAGE SPECIAL LOAD NOTOC FLIGHT DATE EDNO MH0370 /08 08MAR14 FROM/TO AC/REG KULPEK
This shortly followed by this seemingly bizarre message at 16:06:38.905 regarding lack of evidence of something:
THERE IS NO EVIDENCE THAT ANY DAM = 9M-MRO C1U QTY/TI IMP DESCRIPTION PEK —
followed by a description of over 4 tonnes of mangosteens (the exotic tropical fruit).
Then at 16:06:44.405 this seemingly ominous message caught my eye:
AGED OR LEAKING PACKAGES CONTAINING DANGEROUS GOODS HAVE BEEN LOADED ON THE AIRCRAFT THIS STATION. END ACARS NOTOC [NOtice TO Captain] !
Aged or leaking packages containing dangerous goods were loaded! This wouldn’t have anything to do with the disappearance, would it? Or so it was my first thought.
However, probably the two messages should be combined:
“THERE IS NO EVIDENCE THAT ANY DAMAGED OR LEAKING PACKAGES CONTAINING DANGEROUS GOODS HAVE BEEN LOADED ON THE AIRCRAFT THIS STATION”
I guess this is just a standard message routinely put at the end of special load manifests. So nothing here. Just putting this out in case anyone else gets confused.
@ALSM, @DrB
That is indeed a striking similarity in BFO curve shape/amplitude between the cold start POR logon 12:50 and the 18:25 logon.
It suggests that the “overshoot” value at 1825 is peak or close to peak of the curve. This pattern also pertains for the transient curves that Dr B has plotted from the Holland paper.
However, Dr B’s curve fit for 1825 logon places the “high” value half way up the spike toward the overshoot peak, rather than at the peak.
What do we think is the “proper” curve fit to the 1825 pattern? Can it tell us, what was the “real” underlying BFO value at 1825-1828 if the transient drift is excluded?
@Warren Platts
RE: “I guess this is just a standard message routinely put at the end of special load manifests.”
That’s correct. The phrase ““THERE IS NO EVIDENCE THAT ANY DAMAGED OR LEAKING PACKAGES CONTAINING DANGEROUS GOODS HAVE BEEN LOADED ON THE AIRCRAFT THIS STATION” is a standard declaration on every NOTOC (Notification to Captain). The NOTOC is a form given to the Captain before departure, notifying him/her of any dangerous goods loaded on the aircraft.
@Warren Platts
Hi Warren. So, probably no dangerous good on board. 😉
@DrB
The 18:25:27 BFO error was zero.
Actually not exactly correct. DG goods are controlled such that if something happens the consequence remains within the packaging so DGs do not present a hazard. That is why it is required to inspect the packaging and goods with defective packaging are not allowed on board. This follows IATA DG Regulations. For instance if batteries in significant quantities contain acid (corrosive Cat 6) if any leakage is observed or packaging damage is observed, they will not be transported. Nothing abnormal here.
So there are strong indications that this complete record of communications was shared with SITA early on March 8th. For me this raises several questions:
– for whom did they ask for this data / with which parties did they share it?
– what happened then between March 8th and say March 12th with the data through this SITA “channel”? I mean, you don’t have to be Einstein to see from the file that the AES was active for many hours after the aircraft had disappeared from radar. SITA and their “customers” should have been aware of this early on.
@Niels: I’m not sure that the complete record was shared with SITA on March 8th. The timeline seems to be something like this:
1. Plane disappears at 17:21 UTC on March 7.
2. SITA asks Inmarsat for data after disappearance.
3. Inmarsat supplies SITA with initial 1.5 hours of data.
4. Inmarsat creates complete data log at 3:21 UTC on Saturday, March 8, possibly from a facility at Perth.
5. Inmarsat (London) begins to study complete logs in afternoon of Sunday, March 9, and sees 7 hours of activity after disappearance.
6. Inmarsat confirms 7 hours of activity on Monday, March 10.
7. Inmarsat notifies SITA of 7 hours of activity on Wednesday, March 12.
If McLaughlin’s narrative is correct, it appears that although the complete data logs were created just hours after the final satellite communications, SITA was unaware of the complete logs until several days later. What was initially shared with SITA were not the full communication logs.
@VictorI
Assuming the timestamp is as I saw it (and as Mike confirmed and explained, so 3:21 UTC March 8th not March 9th) I find this two-stage release of data to SITA unlikely. In other words I doubt your points 3 and 4 are correct.
@Niels: Yes, I typed the wrong timestamp date. Yours is correct. I fixed it in the comment to avoid confusion.
The timeline I proposed was based on McLaughlin’s comments. I have no way to know if the comments were accurate. I will say that when I submitted questions to him by email, I received a terse response indicating he had no intention to respond to independent inquiries. Whatever information Inmarsat shared with me was not from him.
@DrB
A fair bit to a lot of the discussion on the technical aspects of OXCO BFO error is beyond my grasp but would I be correct in inferring that the OXCO was likely to have been colder at the 1825 log-on than it was at the 1250 log-on? If that is the case, given the location of the SDU in passenger cabin, can we reasonably infer that the passenger cabin was colder at 1825 than it was at 1250?
@ALSM: I am simply trying to get everything above board. I am sick and tired of privately leaked evidence, when officially disclosed evidence should be the standard.
We need full names and titles of Inmarsat executives under-signing this data, or else it is not yet worthy of our trust. This is not a controversial point. At least, it isn’t in my industry.
What is the name of the official to whom you spoke, claiming a perfect match with what the ATSB received? I am happy to follow up directly with that person.
Brock:
The file is authentic. I verified it with an official that has a copy of the same file and we compared properties. They match. That should be sufficient. Focus on the new data.
@ALSM: what is the name of that official? Thanks in advance for your transparency.
Mick and Bobby:
We do not know what the ambient temperature was in the cabin at 18:25. It could have been lower than normal (which is typically +25C w/ AC on). But there is no data to tell one way or the other. It cannot be reliably estimated from the shape or timing of the BFO transient alone.
That said, I agree with Bobby that it would take longer for the oven to reach the set point temp (~+75C) if the ambient at 18:25 was very low, say -25C. That would nearly double the time to reach the set point temp. In such a case, the last SUD BITE check to Pass probably would be the oven temp, in which case it is more likely for the first transmission to occur while the transient is still “on the way up”. If the oven reaches the set point before other BITE tests pass, it is more likely that the first transmission will occur after the peak, on the way down.
But the timing of the first transmission following power on is a function of several software and hardware factors. It should be noted that the time difference between the first two BFOs (142 and 273 Hz) circa 18:25 was only 7 seconds. If the first transmission had occurred 10 seconds later, the 18:25 BFO transient would not have had a first value that happened to be close to steady state on the way up to the peak. It would have been near the overshoot peak. There are at least a handful of scenarios besides a super cold cabin that could explain this timing.
In sum, Bobby may be right. I have often speculated about the cabin going cold. If the left bus was off, and maybe the right bus too, it could have been cold. Decompression is another possibility. But we don’t know. Perhaps Thales would be willing to consider running a test in the environmental chamber to see if transient usually does look like 18:25 when the AES is very cold at power on.
@ALSM
Mike, so you are saying that there are a couple of additional variables that mean we cannot reasonably infer that the passenger cabin was colder at 1825 than it was at 1250?
@Mick Gilbert,
@ALSM,
There are three observed facts that strongly argue that the initial OCXO temperature at SDU power-up leading to the 18:25 log-on was the coldest of all the log-ons studied:
(1) The initial transmission at 18:25 (the log-on request) occurred at the earliest time in the BFO transient curve, and this is the only log-on event in which the first BFO error is near zero (instead of being the largest error observed, which happens in all other cases).
(2) The peak amplitude of the best-fit transient curve is the largest of all the log-on examples. Generally speaking, colder start-up temperature results in larger observed overshoot.
(3) The 18:25 event is the only one occurring in flight, and after a likely 1-hour power-off period.
ALSM believes the SDU OCXO temperature was the same sitting on the tarmac at 12:50 as it was in flight at 18:25. I don’t. I believe the -45C outside air temperature cools the aircraft skin considerably below the cabin temperature. I believe the SDU is located between the cabin ceiling and the upper skin of the aircraft. I have no idea how it is insulated, nor how it is heated or cooled, but it seems quite possible to me that an unpowered SDU would get passively cooled below the cabin temperature because of the proximity of the cold aircraft skin. Perhaps the loss of AC power to many equipment items (maybe the entire left AC bus?) affected the external heating/cooling of the SDU when it was unpowered. I would also ask if heat is supplied from an external source to the SDU when the unit is cold and unpowered. Maybe it is not. I invite anyone with knowledge of external heating/cooling of the SDU to address my questions above.
@DrB
The BFO value at 18:25:27 was virtually perfect. How do you explain that?
@ALSM,
I did not see your response to Mick until after I posted my response.
You said:” Perhaps Thales would be willing to consider running a test in the environmental chamber to see if transient usually does look like 18:25 when the AES is very cold at power on.”
I have already suggested to Ian Holland that he do exactly that. I have no word back yet on whether that might happen.
I was not considering a cold passenger cabin at 18:25. That might also affect the SDU temperature then. I think there was discussion on this point in the past. I seem to recall the cooling rate depended on the decompression rate.
@DennisW,
You said:”The BFO value at 18:25:27 was virtually perfect. How do you explain that?”
Your memory must be failing you since I have previously answered that question from you about five times (and the last time I promised never to do it again). Please consider how you can add signal instead of noise to this discussion. If you can’t follow the answer, then ask a question about the part you don’t understand. You keep doing the same thing but expect a different result. Here’s some good advice for participating in group activities: Lead, follow, or get out of the way. Please pick one.
@DrB
@ALSM
Thank you for your answers.
@DrB
RE: “I believe the SDU is located between the cabin ceiling and the upper skin of the aircraft. I have no idea how it is insulated, nor how it is heated or cooled, but it seems quite possible to me that an unpowered SDU would get passively cooled below the cabin temperature because of the proximity of the cold aircraft skin. Perhaps the loss of AC power to many equipment items (maybe the entire left AC bus?) affected the external heating/cooling of the SDU when it was unpowered. I would also ask if heat is supplied from an external source to the SDU when the unit is cold and unpowered. Maybe it is not. I invite anyone with knowledge of external heating/cooling of the SDU to address my questions above.”
The SDU and various other SATCOM components are located on the E11 equipment rack, immediately above the cabin ceiling near the door 3 area. The fuselage is insulated by fibreglass/mylar insulation blankets mounted next to the fuselage skin, as shown in the following photo:
B777 insulation blankets
The SATCOM equipment is cooled by the aft equipment cooling system, which uses the lavatory/galley ventilation fans to draw cabin air through the equipment. The exhaust air then discharged overboard through the aft outflow valve. A backup SATCOM cooling fan operates if the lavatory/galley ventilation fans fail. There is no other cooling or heating.
If the SDU was unpowered, then I imagine it would stabilise at a temperature similar to that of the cabin. The cabin itself would have to be extremely cold to significantly lower the temperature of the SDU.
Bobby, Andrew, Mick:
Thanks for the insulation Photo Andrew.
Bobby, we are generally in agreement about the cold start BFO transient. However, one thing you suggested above is not accurate.You wrote: “Generally speaking, colder start-up temperature results in larger observed overshoot.”
This is only true if the start up temp is within a few degrees of the setpoint. The overshoot will be the same for any initial difference greater than 5C or so. If the initial difference is greater than that, the loop will start in a first order mode which means the heater will be on at maximum, and stay on at max until close to the setpoint. Thus, the rate of change and overshoot will be about the same for all initial conditions except when the power comes on while the oven is already very close to the setpoint, in which case the loop is already switched to second order, and the heater authority is dialed back from max. Been there. Done that.
@DrB
“Your memory must be failing you since I have previously answered that question from you about five times (and the last time I promised never to do it again).”
I do remember your promise, but I don’t remember your answer to the question.
@DrB
“Here’s some good advice for participating in group activities: Lead, follow, or get out of the way. Please pick one.”
Good advice according to DrB.
I find it strange that in Dr. Holland’s paper “The Use of Burst Frequency Offsets in the Search for MH370” that the term “overshoot” does not appear even once. Holland had the benefit of peer review for his paper including the manufacturer of the AES who is part of the SSWG. Holland actually discards the 18:25:27 BFO as an outlier (as you probably read). Apparently, even the manufacturer does not understand how their equipment works.
I will follow your “good advice” above and take the “lead”. I am calling your overshoot/transient theory nonsense.
@ALSM. Thank you for that information.
Could you also inform us what is the typical duration of the transient distortion since I believe the x-axis was not quantified in Holland’s paper?
If your thesis is correct, why should duration / magnitude of transient distortion depend on power-off duration for any power-off where temperature has gone outside of the “5C or so”?
@Andrew,
Thanks for posting the photo and information on the SDU thermal control. It seems that an unpowered SDU in steady state would have to be at a temperature in between the lavatory/galley air and the aircraft skin and probably much closer to that of the galley air (assuming the exhaust fans were working).
@ALSM,
You said: “. . . the rate of change and overshoot will be about the same for all initial conditions except when the power comes on while the oven is already very close to the setpoint . . . .”
I agree. It appears to be “about the same” and yet not “exactly” the same for cold starts at somewhat different “cold” temperatures.
Part of that difference might be related somehow to the difference in the time required to complete the other BITE tests, especially loading the System Table. Certainly this time variability affects the observed BFO pattern. Yet we not only observe time-axis shifts, but also see a significant difference in the best-fit peak overshoot value. For instance, although the peak measured BFO errors at 18:25 (~110 Hz) and at 12:50 (~125 Hz) are somewhat similar, the best-fit peak overshoots are considerably different (~215 Hz at 18:25 versus ~125 Hz at 12:50). Why does this happen?
I also note that the 12:50 log-on has a smaller peak overshoot than Holland’s Log-on #3, so the 12:50 Log-on (= Holland’s Log-on #6) is not unique among the non-flight log-ons.
While I think we understand why the short-unpowered-time log-ons have smaller overshoots, the 12:50 and 18:25 events also have peak (fitted) overshoots that differ in amplitude by ~40%. This cannot be due to BITE timing variation. The peak overshoot value will depend on the velocity error when the servo is switched to second order. What could cause the OCXO heating rate (= “velocity” of the control parameter – temperature – in degrees / second) to vary between those two cases? I would guess that one explanation could be if the physical internal SDU temperature (i.e., the portion of the SDU surrounding the oven) were also changing at different rates in the two cases while the crystal is being heated inside the oven using the first-order loop. That would happen if the SDU were colder at 18:25 than at 12:50, which is almost certainly the case in my opinion, although the difference might only be a few degrees. I have never personally experienced a commercial flight where the cabin air was not noticeably cooler at high altitude (as it was at 18:25) than it was when parked at the gate (as it was at 12:50).
@DrB, @ALSM, @DennisW: Do we know the sign of the slope of the temperature-frequency curve for the OCXO under consideration? Does the sign change near the operating temperature? Understanding this relation would help us determine whether the approach of the frequency to its final value is a damped overshoot or a simple exponential decay.
@DRB
You said “I have never personally experienced a commercial flight where the cabin air was not noticeably cooler at high altitude (as it was at 18:25) than it was when parked at the gate (as it was at 12:50)”.
I hope you will for forgive me for now injecting a little levity into the discussion, but evidently, you weren’t one of my fellow passengers on the BA trans Siberian flight from Tokyo to Heathrow on 1st May 2006, where we roasted comfortably for 11.5 hours at altitudes of up to 39,000ft, or on a British Airtours Tristar charter flight from Gatwick to Heraklion on 16th June 1984, when due to the eccentricities of the Tristar’s air con design, my feet froze while my head boiled. (end of levity)
However, as Andrew has pointed out, the pressure cabin metal skin is fully insulated throughout. This would include the area in the immediate vicinity of the E11 equipment rack where the SDU is housed. So, if the logon characteristics at 18:25 do in fact point to a significantly lower SDU ambient temperature at 18:25 than at 12:50, then the most likely explanation, in my opinion, is that the cabin had been depressurized for an appreciable period prior to the 18:25.
@ Victor,
The sign is positive everywhere within the transmission-enabled band. Higher temperature = higher BFO.
@ROB,
You may be correct. I was reluctant to take that last step (leap?). However, environmental testing of the SDU at low temperatures could tell us if the 18:25 log-on can only be matched with very cold/thin cabin air. On that point I will say that reduced cabin air pressure will also lower the SDU temperature.
@DrB: Do you have a reference for this OCXO? If true, then the transient temperature profile represents an overshoot.
I’m following this specialists discussion with great interest.
Finally independent investigation possible on the original Inmarsat-data.
And it seems already a key-point of the puzzle has been found with comparing the log-ons.
Just to put a thought in the pocket I think Dr.B mentions something important about temperature and air-pressure.
Indeed the isolating properties of thin air at ~30.000 feet would be much higher tha on sea/land-level.
Warming-up something with air as an intermediate would take longer in a decompressed cabin at high altitude.
Maybe the air-pressure is even more decisive than the air-temperature.
Don’t know if this could have significant consequence in those values.
Just a thought.
A few facts:
Honeywell Frequency Reference Oscillator (OCXO) Assembly 81771-MBE
Honeywell Frequency Reference Oscillator Schematic 81771-WDME
Racal part number 81771-MBE
SC cut crystal ovenized oscillator manufactured by CQE.
The SC cut is chosen for a near flat turnover. The turnover point is ~90C.
Good luck tracking down any additional info. I spent a fair amount of time at it 3 years ago. The manufacturer has been out of business for awhile. No spec sheets found.
More details here: https://goo.gl/1Zx0WZ
@ASLM: So for Cut 0, we know that the frequency dependency on temperature is small at the operating temperature, by design. But do we really know if the slope of the curve is positive or negative? Bobby thinks it is surely positive. I am trying to understand why.
Victor:
All SC cut crystals exhibit an S shaped curve. They all cross at the inflection point around +92C. OCXO designers select a cut that provides zero TC at the turnover point. The turnover point is always selected so as to minimize the required oven temp for a given maximum ambient operating temp. The oven needs to operate about 20C above the maximum ambient temp spec. In this case, the maximum ambient operating temp is +55C, so I’m guessing the set point temp is +75-80C. For all SC cuts, for a temperature below +92C (see chart in Fig 7), the TC is positive below the setpoint temp. Nobody uses the turnover points above +92 unless the required ambient operating temperature is very high (like +90C). Again, referring to Fig 7, the best SC cut for a 75C oven is about +0.7 degrees (point where red line crosses 75 degrees).
@VictorI,
If I may add to Mike’s information, the set point is at +75 C and the turnover point is at +90 C. In other words, the slope does not go through zero and become negative until the temperature exceeds 90 C. The operating band (near the set point) is always on the positive slope. See Figure 7B on page 6 in this reference for an SC-cut temperature curve and explanation:
https://drive.google.com/file/d/0BzOIIFNlx2aUbERKaE03QThWMnc/view?usp=sharing
@DennisW,
In this situation one function of “a” lead person (not necessarily “the” lead person) is to propose a theory that explains all the data (or at least as much of the data as other theories can explain). The “data” in this case are the 18:22 radar location/track/speed and the 18:25-18:28 BTOs/BFOs. I have demonstrated and published an explanation that is entirely consistent with all the data. You have not.
You take the position that because the first BFO at 18:25:27 is close to the “expected value”, that means my theory is somehow incorrect. To the contrary, my theory shows under what conditions a small apparent BFO error can occur. In this case, a turn to the North (which is determined by the BTO data) happens to increase the BFO by roughly the same amount (about +25 Hz) as the transient error for the log-on request ( about -30 Hz).
You have not presented an explanation of why the 18:25:27 BFO (the log-on request) is good but the one 7 seconds later at 18:25:34 (the log-on acknowledge) is either bad or due to an aircraft maneuver during that 7 seconds. You can’t fall back on the “it’s unreliable” excuse (and neither can Ian Holland). In my opinion, NONE of the BFOs are unreliable – just not understood by everyone. In my opinion, no plausible B777 maneuver can produce a +130 Hz change in BFO in 7 seconds when cruising, as is needed to explain the second BFO (at 18:25:34) if the first one has no warm-up transient error (because the SDU had not lost power). If the first one is not affected by a warm-up transient, then none of them can be affected. I am still waiting for you (or Oleksandr or anyone else) to present a maneuver that will explain all the BTOs and BFOs from 18:22 (by calculation) to 18:25-18:28 (by measurement) other than a 15 NM right offset and an SDU warm-up transient occurring together. I won’t hold my breath.
@ASLM, @DrB: Got it. As long as the operating point is less than the turnover point (TC=0) and even further from the inflection point (TC<0), then TC should be positive. So it seems the observed transient behavior is indeed on overshoot of both temperature and frequency.
I would say thin air could result in either high temp or low temp.
The high temp possibility comes when the thin air is less conductive of heat away from the heat source. The low temp possibility comes if the the thin air is cooler.
Victor & Bobby:
Yes, I think we are all nearly on the same page. But to be clear, the inflection point is always near +92C for any SC cut. For cuts <0 degrees, there is no turnover point. All cuts 0 degrees, there will be two turnover points, one below and one above the inflection point. The one below +92C will have a positive TC below the turnover point, a negative TC between the 2 turnover points, and a positive TC above the higher turnover point. Typically, for operation up to +55C, an SC cut crystal will be specified to have a cut of ~+0.7 degrees, resulting in a lower turnover point of ~+75C. The goal is to match the turnover point to the set point temp so that the operating point at steady state is right on the “top” of the curve where the TC is zero. Obviously, every OCXO is slightly different, so some will end up with a tiny positive TC at steady state, and some will have a tiny negative TC at steady state. But in both cases, the TC will be positive approaching steady state from initial power on.
In summary, the the TC will be positive for all cases except possibly the last few Hz of the stabilization profile. There can be a tiny ripple at the end if the set point is exactly on top of the crystal curve, and the thermal control loop has a tiny bit of ripple closing in.
Hi All,
In the linked file below, I have decoded all the ACARS Messages from the Signal Unit data included in the full set of Inmarsat Satellite Data.
https://www.dropbox.com/s/8ngsielzp0fegct/ISUs%20and%20SSUs.pdf?dl=0
This includes the previous flight of 9M-MRO to MH370, which was MH371 from Beijing (ZBAA) to Kuala Lumpur (WMKK). The ACARS Messages include all the standard OUT, OFF, ON and INTO Messages, Position Reports, Engine Health Monitoring (EHM), Fuel Usage, Weather En-Route and Maintenance Messages after landing.
The ACARS Messages allow you to check the Fuel Usage in each Engine, Health of each Engine and the Aircraft Systems function on the previous flight and compare this data with the start of the MH370 flight.
There was a long list of Maintenance Messages after landing from Beijing:
MSG 2412080 – DB ELMS P210 ELECTRONICS UNIT
MSG 2123004 – DB CABIN TEMPERATURE CONTROLLER (R CHAN1)
MSG 2714012 – DB PRIMARY FLIGHT COMPUTER (RIGHT)
MSG 3158592 – DB CPM/COMM(M001) IN RIGHT AIMS
MSG 3230530 – DB BRAKE SYSTEM CONTROL UNIT (PRIMARY CHAN), DB BRAKE SYSTEM CONTROL UNIT (SECONDARY CHAN)
MSG 2112138 – DB ELMS P210 ELECTRONICS UNIT
MSG 2360591 – DB SATELLITE DATA UNIT (LEFT)
MSG 2342610 – DB OVERHEAD PANEL BUS CONTROLLER (R), DB OVERHEAD PANEL BUS CONTROLLER (L)
MSG 2355050 – DB AUDIO MANAGEMENT UNIT
You can also see the data from the Engineers trying out the SDU between flights.
I also detected a few minor typos in the Malaysian Factual Information in their reporting of the EHM.
For the EHM Parameters, please refer to the Malaysian Factual Information pages 133 and 134 (linked below).
https://www.dropbox.com/s/ghbkuv1xvpvf61a/EHM%20Parameter%20Key%201.png?dl=0
https://www.dropbox.com/s/72lfqyvzp08xq8l/EHM%20Parameter%20Key%202.png?dl=0
This file was checked against the Malaysian Factual Information pages 135 and 136 as well as pages 168 to 180.
There appear to be a few typos in the Malaysian Factual Information pages 135 and 136.
Then again, there might be a few typos in my file, although the decoding process was mostly automated.
@Richard,
Quite an achievement. Thanks for sharing. At last we have the means to do a proper validation/calibration of the fuel models using the previous flight data. I trust Dr B will be on to it faster than you can say Pet Shop Boys.
With regard to the numerous fault/error messages. That’s intriguing. I wonder how many of these would show up as caution messages to the pilots? @Andrew – does this number of fault/error messages surprise you?
Perhaps we may be seeing multiple symptoms of common fault/error? I see from the discussion linked below that multiple messages might be explained by common fault at bus controller: “something went wrong in the bus controllers and the first thing the maintenance system “noticed” was that it couldn’t see the component that runs through them. Maintenance message logic is *extremely* sensitive to timing when it comes to the order effects show up.” http://www.airliners.net/forum/viewtopic.php?t=768565 that multiple messages
Perhaps somebody with access to the 777-200 Fault Isolation Manual could look those up and see if they can make sense of them.
ps: Is “audio management unit” not the piece of kit required for functionality of ALL radios, VHF and HF? Just saying 😉
@Paul Smithson
RE: “@Andrew – does this number of fault/error messages surprise you?”
No, the maintenance computer generates quite a few messages at the end of every flight, but most of them are minor and of no consequence. Unfortunately I don’t have access to the FIM so can’t decode the messages in Richard’s file. However, anything that had a ‘flight deck effect’, such as an EICAS warning, caution, advisory or status message should have generated a separate ACARS report at the time of the occurrence. The fact there were no such reports suggests the messages were of no consequence to the operation of the aircraft.
@Richard: Thank you for your hard work.
@All: Here are three lines of inquiry based on information extracted so far from the complete satellite data set:
1. The reason for SATCOM’s numerous switching of links between the IOR and POR satellites during flight MH371 (previous to MH370).
2. The mean and standard deviation of the BTO offset for a log-on request. Inmarsat has advised using a mean value of 4600 μs with no advice about the variation. However, the data from MH371 suggests a mean of about 4550 μs with a significant variation. This could impact both the location and error we associate with the 7th arc.
3. The meaning and significance of the maintenance messages generated when 9M-MRO landed in Beijing.
@Victor
“1. The reason for SATCOM’s numerous switching of links between the IOR and POR satellites during flight MH371 (previous to MH370).”
You can find the reason in:
“Aeronautical Air-Ground Data Link Communications” by Mohamed Slim Ben Mahmoud, Christophe Guerber, Nicolas Larrieu, Alain Pirovano, Jose Radzik
The pertinent information is in the Satcom Section 1.3.3 paragraph 1.3.3.4
“AMSS does not implement actual handover procedures as in mobile networks.
However, it may be necessary for an AES to move from one satellite to another
one (or from one regional beam to another one). One of the following events may
trigger the handover procedure: P-channel degradation (detected either by loss of
clock synchronization for more than 10 s or failure of log-on renewal), satellite
below elevation handover threshold with another satellite being at least 1° higher
than the log-on satellite for more than 10 s and user command. As a result, AES
proceeds with log-off (except P-channel degradation) then connects to the new
GES applying the procedure presented in Figure 1.18.”
Here is a link to a preview:
https://reader.bookshout.com/books/834451/book_data/preview
George/Victor…
From ZBAA, the AES antenna pointing angles were as follows:
AZ EL
IOR 243.7 19.7
POR 109.1 12.9
The elevation angle was better (>1 degree) for the IOR bird all the way to WMKK. For these relatively low elevation angles (especially to the POR s/c), there may have been some multipath issues on the ground at ZBAA. However, I would not expect multipath to be much of an issue above 10 degrees while in the air. The coding should take care of that. P-channel degradation is one possible cause. Collisions on the random access R channel is another.
Hi All,
I have been asked by some of you for an Excel spreadsheet version of the data that I published earlier today as a .pdf at 02:35am.
Here it is:
https://www.dropbox.com/s/ra3x6lzba91kybz/ISUs%20and%20SSUs%20Export.xlsx?dl=0
@Paul Smithson
The reason for sharing the data is so that multiple people can pursue different lines of investigation simultaneously.
As Victor has pointed out already, there are a number of different avenues to explore.
Anyone of us can only properly analyse a limited number of ideas at one time.
The fuel analysis is only one aspect out of many, that can now be re-analysed based on the actual facts from the previous flight. The engines were not changed between flights MH371 and MH370 on 7th March 2014. The serial numbers are identical for both flights and they are still ESN 51463 Left and ESN 51462 Right.
It would be good to have a thorough analysis of the Engine Health Monitoring at 01:34:19 UTC and 01:43:52 UTC as compared to 16:41:58 UTC and 16:52:21 UTC.
An analysis of APU usage would also be helpful.
An analysis of the Maintenance messages between the flights may be very revealing.
Even an analysis of the In-flight Entertainment Equipment (IFE) messages regarding the “Pet Shop Boys” might tell us something we do not know.
@ALSM
I wonder if the switching between satellites on the previous flight was a symptom of an impending hardware failure in the SATCOM or power feed to the hardware…
Did MAS maintenance do any diagnostics on the SDU during the lay-over or just the normal between flight stuff?
it is remarkable that a number of these systems in the maintenance messages, have been suspected to be isolated or failed or modified during the flight. Is that a coincidence or is there a possible link?
@Richard. “The reason for sharing the data is so that multiple people can pursue different lines of investigation simultaneously.” Indeed – and many thanks for making this important contribution.
George: The frequent s/c swaps look more like network issues, not AES hw or sw issues. I would like to know what the sdu squawk was about.
@ALSM,
You said: “In summary, the the TC will be positive for all cases except possibly the last few Hz of the stabilization profile. There can be a tiny ripple at the end if the set point is exactly on top of the crystal curve, and the thermal control loop has a tiny bit of ripple closing in.”
This would explain why some SDUs show overshoot and some do not, depending on the exact temperature setpoint made by electronic adjustment in the temperature control system. This is an issue for thermal testing of SDUs to understand the 18:25 BFO transient. Since we don’t have the 9M-MRO SDU to test, one must be used that behaves similarly or is adjusted to behave similarly (with overshoot).
Bobby:
I don’t think the last few seconds and Hz matter. It’s the first few minutes that we need. I would set up the whole AES (except antenna) in the chamber and run several power on tests at different temps. They should measure the SDU 10.08 MHz OCXO frequency vs. time every second, recorded with a counter locked to a rubidium (or similar) standard. Also record the timing of all the logon related events using a simulator like the one manufactured by Square Peg, or just put an antenna outside and use the satellite/GES. Do the test at +25C, 0C and -30C. The goal would be to see if the OCXO warm-up transient timing changes relative to the R600 logon timing, as a function of cold start ambient temp.
Bobby:
I would add…If Thales would agree to conduct this test, it could potentially provide a very important clue. If the tests confirm that the SDU was probably VERY cold at 18:25, then we could narrow down the onboard scenarios that might have taken place on the aircraft between 17:21 and 18:25.
> Andrew says:
> The fuselage is insulated by fibreglass/mylar insulation blankets
> mounted next to the fuselage skin, as shown in the following photo:
Here is a higher resolution photo:
http://airchive.com/blog/wp-content/uploads/2013/04/EVERETT-2013-777-FUSELAGE-INTERIOR.jpg
@ALSM
Just in case it could be usefull I add this thought to your suggestion of testing the OCXO/SDU at different temperatures:
Could it also be usefull to test the OCXO/SDU in a simulated high altitude (~35.000ft) thin air/low pressure environment?
I mean in such an environment the transference of heat would probably be less efficient cq. slower?
I did some interesting reading on OCXO’s. I put it here for others to read also:
https://www.vectron.com/products/literature_library/ocxo.pdf
@Ge Rijn. Thanks. p7 Orientation effect, “When the physical orientation of an oscillator is changed, there is a small frequency change…, due to
the change in stress on the crystal blank resulting from the gravitational affect upon the crystal supports.”
As an extension of that pulling g in a high descent rate theoretically could have an effect.
David; Ge Rijn
I do not believe the gravitational effect is significant at 00:19 compared to the descent rate induced BFO change. I remember looking at this in depth 2-3 years ago. Can’t find any notes now, but I remember the result. According to Greenway:
“The magnitude of these frequency shifts is determined by the quartz crystal’s acceleration or “g-sensitivity” vector and the characteristics of the applied acceleration force. The range of typical g-sensitivities for bulkmode quartz crystals can span several orders of magnitude, from less than 1×10-10 per g for a carefully made precision SC cut…”http://www.greenrayindustries.com/library/accsens_sglpage.pdf
This report infers <1Hz/g at L band.
Heat transfer within the OCXO is almost entirely via conduction and radiation, not convection, so I don't think a lower pressure environment would have much effect on the warm-up timing. The crystal itself would be in a hermetically sealed nitrogen filled package.
That said, if Thales had a thermal-vacuum chamber, they could check the frequency vs. pressure easily. That test could be suggested, if they have not already done so during certification.
@ALSM. Gravitational effect. Thanks for that.
@Andrew said, However, anything that had a ‘flight deck effect’, such as an EICAS warning, caution, advisory or status message should have generated a separate ACARS report at the time of the occurrence.
Here are ACARS messages for UA930, which was a B777 flight from San Francisco to London that returned to San Francisco after experiencing problems. Notice that there is the following message:
MSG 2360181 I 2020 02SEP97 CL I 1 PL
DB SATELLITE DATA UNIT (LEFT)
Satellite data Fault 2360181 seen here must be more serious than Fault 2360591 seen on MH371 as it generated an ACARS message, as did many other faults.
@ALSM, DrB, All
ALSM said “Bobby, I would add…If Thales would agree to conduct this test, it could potentially provide a very important clue. If the tests confirm that the SDU was probably VERY cold at 18:25, then we could narrow down the onboard scenarios that might have taken place on the aircraft between 17:21 and 18:25”.
Indeed! It could be one of the most significant clues to emerge to date. Because, if it can be shown that the SDU must have reached a very low temperature prior to the 18:25 logon, it would be persuasive evidence of deliberate cabin depressurization. If the aircraft had suffered an accidental depressurization, the crew would have immediately carried out an emergency descent. Obviously,this didn’t happen. In fact, the aircraft maintained its cruising altitude and followed what looks suspiciously like a preplanned flight path, avoiding Indonesian airspace.
If the aircraft carried out an offset manoeuvre at around 18:25, while just out of primary radar range, it would show that the PIC was still a PIC at this time, ie still fully in control.
@AlSM
Thanks explaning. I later read in another paper the same as you state.
Most heat transfer is by conduction.
Although in this particular OXCO there is some minor heat transfer by convection with air as an intermediate between the heater and the resonator: page 56 – 59, figure 4.6 and 4.7.
https://etda.libraries.psu.edu/files/final_submissions/3071
But as you say the OCXO used in 9M-MRO is a sealed unit filled with nitrogen then the air pressure around it would make no difference for the volume or density of the nitrogen inside won’t change.
@VictorI
On the ACARS message from UA930:
‘DB SATELLITE DATA UNIT (LEFT)’
Does this mean there were two SDU-units on that plane (LEFT and RIGHT)?
And if so could this have been the same for 9M-MRO?
@Ge Rijn: I’ve seen no evidence to suggest there were two SDUs on 9M-MRO. A reference to LEFT doesn’t mean there was a RIGHT.
@Andrew
I’ve seen a suggestion the EFB can display Airplane Condition Monitoring Function (ACMF)
messages. Does it also contain a look-up table that lists all the message numbers & their
causes and effects?
(Asking because we don’t have access to a Honeywell ‘Aircraft Diagnostic Systems Engineer’.)
@Andrew
With ADIRU inoperative, the SAARU provides heading & attitude, but not correction for wind
acting on the airframe and not correction for Coriolis effect – Yes?
The FMC makes no correction for Coriolis effect – Yes?
________________________________________________________
(@VictorI
Maintenance messsages, vide;)
http://elektroarsenal.net/fault-reporting-and-correlation.html
@ALSM,
You said: “I don’t think the last few seconds and Hz matter. It’s the first few minutes that we need.”
I’m not sure I understand your reference to the last few seconds. My point was that according to Ian Holland’s paper, each SDU has a different transient curve. Presumably this depends on the exact temperature set-point relative to the crystal characteristic. I think that if you want to convince anyone that you are faithfully recreating the BFOs after start-up from various temperatures, you need to use a SDU that has a similar shape of transient error as the SDU in 9M-MRO, especially so during the first 2-3 minutes after LOR.
Another benefit of thermal testing would be a more accurate estimate of the time power was actually applied to the SDU prior to 18:25.
It seems possible to use the log-on BFO error pattern as a thermometer of the SDU/OCXO temperature at power-up. We just need to calibrate that thermometer with lab testing of a similar unit.
Bobby:
Good suggestions.
@Victor,
Reading the timeline of the ACARS msgs related for the 2 Sep 1997 UA930 event, and the subsequent maintenance release for the re-scheduled departure, my interpretation is that N788UA lost power to the L AC Bus (due to GCU issue first noted at 20:13) subsequent to take off (at 20:12). The maintenance messages indicate detection of a power interruption by the various systems.
An inadvertent/non-normal loss of an engine IDG power supply while airborne is not mitigated by the ‘no break power transfer’ (NBPT) design of the electrical system. The NBPT design is intended to mitigate interruption when transferring supply from two concurrently active sources when on the ground.
At 20:20, a related SDU message is generated (but not relayed air-to-ground until 20:22). If the power break exceeded the SDU’s capability to hold-thru, a reboot will have ensued.
I note also that the airphones were placarded as inop since 4 Aug 1997.
Don
@DrB
“You have not presented an explanation of why the 18:25:27 BFO (the log-on request) is good but the one 7 seconds later at 18:25:34 (the log-on acknowledge) is either bad or due to an aircraft maneuver during that 7 seconds. You can’t fall back on the “it’s unreliable” excuse (and neither can Ian Holland). In my opinion, NONE of the BFOs are unreliable – just not understood by everyone. In my opinion, no plausible B777 maneuver can produce a +130 Hz change in BFO in 7 seconds when cruising, as is needed to explain the second BFO (at 18:25:34) if the first one has no warm-up transient error (because the SDU had not lost power)”
I agree. I have no explanation for the 18:25:34 BFO value. I remain troubled by the accuracy of the 18:25:27 value. My only admonition to you is that your explanation requires a bit of luck. That does not mean it is incorrect.
I also agree that testing by the manufacturer would be an excellent idea, and I suggested the same thing myself. I can’t recall if it was here or in a private email to Victor. Holland’s paper could have been so much more valuable with that information.
@ROB
Re: “It could be one of the most significant clues to emerge to date. Because, if it can be shown that the SDU must have reached a very low temperature prior to the 18:25 logon, it would be persuasive evidence of deliberate cabin depressurization.”
As was pointed out to me when I was contemplating the likely cabin temperature subsequent to a depressurisation event, the end-state temperature is largely a factor of how rapidly the depressurisation occurs. Deliberately depressurising the airplane by manually selecting the outflow valves to open is unlikely to depressurise the airplane rapidly enough to achieve a very low temperature.
Re: “If the aircraft had suffered an accidental depressurization, the crew would have immediately carried out an emergency descent.”
The nature of the accident, the presence of concurrent or rapidly escalating issues, the capacity of the crew to react and the status of airplane systems would all impact upon whether an emergency descent was initiated and whether the airplane responded.
@buyerninety
RE: “I’ve seen a suggestion the EFB can display Airplane Condition Monitoring Function (ACMF)
messages. Does it also contain a look-up table that lists all the message numbers & their
causes and effects?”
The Tech Log function of the EFB might display maintenance messages associated with existing flight deck effects, but I’m not sure because our aircraft don’t have an EFB. However, all existing maintenance messages and associated information can be displayed on the Maintenance Access Terminal (MAT) located next to the second observer’s seat in the flight deck. The maintenance engineers interrogate the MAT during every turn around to check for faults. That said, I don’t think it allows you to look up faults that haven’t already been detected by the system. I believe you’d need the Fault Isolation Manual (FIM) to find that information.
RE: “With ADIRU inoperative, the SAARU provides heading & attitude, but not correction for wind
acting on the airframe and not correction for Coriolis effect – Yes?
The FMC makes no correction for Coriolis effect – Yes?”
Correct. The SAARU heading information is only valid for 3 minutes after the ADIRU fails. The heading must then be updated periodically by entering the standby compass magnetic heading in the FMC POS INIT page.
@Andrew
G’day Andrew. You said, “The SAARU heading information is only valid for 3 minutes after the ADIRU fails. The heading must then be updated periodically by entering the standby compass magnetic heading in the FMC POS INIT page.”
What happens if the heading is not updated manually? How might the lack of updates to the heading affect an airplane flying to a CMH?
@Mick Gilbert
The SAARU’s initial heading is based on the ADIRU heading immediately before the failure. After the failure, the SAARU has no way of compensating for changes in the magnetic variation; it is simply a glorified directional gyro with no magnetic reference. Consequently, its heading output must be periodically updated using the magnetic compass. If that isn’t done, then the SAARU heading output will be in error by an amount equal to the change in magnetic variation since the ADIRU failure.
In other words, in terms of heading reference, it behaves the same way as a basic gyro compass in a Cessna 172!
Don Thompson said: An inadvertent/non-normal loss of an engine IDG power supply while airborne is not mitigated by the ‘no break power transfer’ (NBPT) design of the electrical system.
Are you saying that you believe that a flameout of the left engine, with the right engine running and the tie breaker functioning, would cause the SATCOM to reboot?
@Mick Gilbert. “Deliberately depressurising the airplane by manually selecting the outflow valves to open is unlikely to depressurise the airplane rapidly enough to achieve a very low temperature.”
Turning off bleed air also would accelerate depressurisation and surely the aircraft would get cold then even if some electric heaters remain, that is if not shed/deselected?
@Don Thompson,
What about a failure of the left IDG rather than left engine flame-out? Would that cause the SDU to reboot?
@Andrew
Thanks for those answers regarding the SAARU heading output. Would it be correct to say that absent any manual heading updates, the CMH output by the SAARU will start to approximate CTH?
@David
Even with bleed air off the rate at which you can deliberately depressurise the airplane is not likely to be rapid enough to cause a really substantial drop in temperature. I’m pretty sure it was Gysbreght and TBill who had provided the background information about the rate of depressurisation and some end-state estimates (I’ve been trawling through old posts to see if I can find their original comments without success so far).
@Mick. I hope they will correct me as needed but I imagine they were talking about adiabatic expansion and conduction through the skin plus heat added from bleed air during that expansion. If the outside air is cold as at altitude, bleed air is turned off, if other internal heat sources contribute comparatively little and it is at night, according to Newton the temperature inside will drop exponentially to that outside.
@Mick Gilbert
RE:“Would it be correct to say that absent any manual heading updates, the CMH output by the SAARU will start to approximate CTH?”
If the variation at the point where the ADIRU failed is small, then the magnetic heading at that point will approximate the true heading. If the magnetic variation subsequently increases but the SAARU heading is not adjusted to compensate, then the SAARU heading will continue to approximate the true heading.
@Mick Gilbert
@David
RE: “Even with bleed air off the rate at which you can deliberately depressurise the airplane is not likely to be rapid enough to cause a really substantial drop in temperature. “
The sudden loss of cabin pressure will cause a drop in temperature. If the air conditioning packs are ON, the cabin temperature should recover somewhat as the air conditioning system automatically pumps in warm air in an attempt to regulate the temperature. However, if the packs are OFF, then the temperature will continue to decrease as cabin heat is lost to the outside atmosphere.
@David
My thought process was very similar to yours but what I was ignoring was the fact that we’re not just talking about a tube of air, we’re talking about an insulated tube of air with a lot of contents (seats, panelling, passengers, etc) that are all at or above 25°C to start with. Further, we’re talking about only an hour or so between any likely depressurisation event and the 1825 UTC log-on.
@TBill
I think that you provided some estimates of end state temperatures for a few different depressurisation scenarios; might I trouble you please to repeat those.
@Mick Gilbert
Sorry but you a wrong on both counts. If the outflow valves are selected open and at the same time, the aircon pack inflow valves are selected closed, the cabin will depressurize to ambient in a remarkably short space of time, a few minutes only.
An accidental, sudden depressurization could in theory happen quickly enough to prevent the crew from taking emergency action, I am careful to say in theory because such a situation has never happened on a large, civil airliner. In every case, the crew were able to take appropriate action before they were overcome by hypoxia. The Helios accident is often cited when discussing this subject, but it is not commonly appreciated that the Helios accident was not a full depressurization. The faulty outflow was only failed open 12% of full open setting, and the air pack inflow valves remained open throughout.
Loose the yoke of denial, and see the situation for what it was.
With MH370 what is significant is the sequence of events following the takeover – the events do Not in any way indicate or suggest an aircraft flying out of control with the crew slumped on their seats. On the contrary, the aircraft is observed to make a series of controlled manoeuvres, as it maintained altitude and speed, and carefully observed FIR boundaries, as it flew its way with the help of selected waypoints, to a position whereby it could turn south into the SIO (hopefully) undetected, and continue in a straight line until fuel exhaustion!
…”depressurization could in theory happen quickly enough to prevent the crew from
taking emergency action”…
I don’t think Mick specifically said anything about sudden depressurization.
…”because such a situation has never happened on a large, civil airliner.”
But for the training/quick thinking of only the co-pilot, this example would
disprove that assertion ( – some might suggest this example supports Mick’s line of
enquiry is not unreasonable…);
https://www.fss.aero/accident-reports/look.php?report_key=1059
@Andrew, Thankyou for that info.
I notice David said;
“Turning off bleed air also would accelerate depressurisation and surely the aircraft
would get cold then even if some electric heaters remain, that is if not shed/deselected?”
Is the aircraft air heated by ‘electric heaters’, or is it heated by something like a
‘heat exchanger’ transfering the heat from the hot air (sourced from the engine{s})
pressurized bleed air?
(Note, for clarity, the question disregards any references to heating by the electric
water heaters (galley), seats (pilot) heating or cockpit windows, etc.. )
@ROB
Thank you, you actually neatly illustrate my point for me; deliberately depressurising the airplane is unlikely to depressurise it rapidly enough to achieve a very low temperature.
By your own estimate, the fastest possible deliberate depressurisation utilising flight deck controls would take “a few minutes“. A 7.5 psi depressurisation over a period of a few minutes is not particularly rapid and it would not cause significant cooling, certainly not to the extent contemplated to achieve a very cold ambient temperature for the SDU (~ – 25°C) in only 60 minutes or so.
If we look at an accidental depressurisations on the other hand, such as QF30 where only 41 seconds elapsed between the hull breach and depressurisation to ambient, the cabin gets colder much faster. Accordingly, if the SDU is determined to have been very cold at the 1825 UTC log-on then an accidental depressurisation is more likely to have been the cause.
Regarding the contention that “because such a situation has never happened on a large, civil airliner” that it is theoretical, well, the history of aviation safety is replete with examples that bear out the adage that there is a first time for everything; BOAC781, TK981, TWA800, UA585, AF4590 are just a few accidents where the fact that “such a situation has never happened on a large, civil airliner” didn’t matter a jot – theoretical turned to practical in the twinkling of an eye, killing a good many people in the process and in most cases confounding aviation safety experts for quite some time.
As for that hackneyed spiel that the airplane made a “series of controlled manoeuvres … there were three; the initial turnback which was entirely consistent with the response to an inflight emergency, the turn from south of Penang that may well have been the result of an LNAV Discontinuity Error and an incapacitated crew, and the final turn south;
… as it maintained altitude and speed … did it? that is highly conjectural, there is evidence that the airplane’s speed and altitude at the turnback and back across the Malay Peninsula varied and, by some accounts, varied considerably, and there’s nothing to suggest these variations didn’t continue as it tracked up the Straits of Malacca;
… and carefully observed FIR boundaries, … really? the initial turnback took the airplane across the Kuala Lumpur/Bangkok FIR boundary at least twice;
… as it flew its way with the help of selected waypoints, … really? which waypoints? there is no conclusive evidence that the airplane navigated by any waypoint, selected or otherwise, subsequent to the turnback;
well that narrative was found wanting on the first day it was articulated and time and evidence have done it no favours.
Since we’re handing out gratuitous advice, apart from exercising some courtesy, you might also try picking up the glasses of objectivity; the view is a little bit more complex but it is far more instructive than blinkered myopia.
@Mick Gilbert
You’re talking complete cobblers. Do yourself and the rest of us a favour and get yourself a thinking brain 😊
@Buyerninety
Thank you for the valuable clarification. Welcome, as ever.
@Mick Gilbert said: there is evidence that the airplane’s speed and altitude at the turnback and back across the Malay Peninsula varied and, by some accounts, varied considerably
Which accounts? Other than early reports that were later corrected, I’m not aware of evidence that the altitude might have varied considerably.
@Dr B & Victor,
I wrote that N788UA, UA930, “lost power to the L AC Bus (due to GCU issue first noted at 20:13)“.
Each GCU controls its Bus Tie Breaker (for supply from the opposite engine IDG, or APU, via the Bus Tie Bus) and its Generator Control Breaker (for supply from its IDG). A GCU fault will revert both the BTB and GCB to open.
If both the GCUs are operating normally, and an IDG supply fails, the switchover is not ‘no break’ but occurs within the hold up period that is defined for the SDU. From AMM, Chapter 24,
When the ac system changes from one power source to another in the air, it does break power transfers. On the ground, it does no-break power transfers. The system momentarily connects two power sources to one bus so there is no interruption in power. A GCU electronically adjusts an IDG speed to match the power of the two sources to do a no-break power transfer. For transfers between external power and the APU, the APU controller adjusts the APU speed to do the no-break power transfer.
N788UA experienced a GCU issue, temporarily isolating the L AC Bus. It appears N788UA’s crew manually intervened to restore supply to L AC Bus.
There’s nothing in the N788UA example to contradict the accepted sequence of events for 9M-MRO: first engine flamed out; that engine’s GCU closed its Bus Tie Breaker; AC bus supply restored within the avionics hold up period.
@Don Thompson: OK. It’s the GCU fault that caused the problem on N788UA.
VictorI
Perhaps Mick is refering to the FI, page 3 – altitude variations, 35700, 32800, 31100 to 33000 ft.
@Mick Gilbert
I’ve calmed down enough to give you a relatively reasoned response to you criticisms.
When I said such an event has never happened to a large civil airliner, I was referring to a case if sudden depressurization that incapacitated the crew which the crew before they were able to don oxygen masks and initiate an emergency descent, in an otherwise still controllable aircraft. I was not referring to cases of rupture of the airframe or airframe disintegration that resulted in the aircraft crashing out of control. If such a fate had befallen MH370, the wreckage would have been found in the South China Sea.
Your criticism has no credibility. You did not read my post. Your’s is a classic case of myopia, which is the very attribute you have kindly bestowed on me.
The remainder of your critique is simply not worth the effort of a response.
@buyerninety
Alternatively, perhaps Mick was just being economical with the truth, to suit his narrative.
FYI, the apparent altitude excursions derived from the primary radar tracking, and reported in FI, were more likely due to insufficient calibration in elevation of the radar antennas, nothing more.
@buyerninety: I would not consider those to be considerable variations. In fact, those variations are probably barely detectable by the military radar.
@Rob: I’ve yet to see a narrative that doesn’t have major holes or inconsistencies. After three years, we’re still left with choosing the best among some questionable scenarios.
[2nd try – typo in email the last time]
All,
The following is a draft report on flight path reconstruction and BTO/BFO calculations for MH371 (IOR points only). Bottom line – lots of outliers, but no large Mumbai-like drift.
https://docs.google.com/document/d/14hleZyx1pUPL44yaeHKt6jnSQ3DbgRq2zibbKkFLq2c/edit?pref=2&pli=1
[Caveat Emptor – since this is a draft, I reserve the right to change anything in the future, including the bottom line.]
@sk999: That’s an impressive and very helpful piece of work. Thank you for completing it and sharing it.
@sk999. Very nice work. Interesting to see that BTO “drift” mid-flight of ~ -40 microsecs. Do you attribute that to the BTO drift +/- 10 microsecs described in DSTG or to errors on the satellite position predictions?
@sk999: In the DSTG Bayesian analysis, it advises that the BTO outliers can be corrected with a term N*7820 μs, where N is an integer. I have found this correction to work for all the points I have tested, i.e., the corrected points fall within the expected deviation from the mean of the sequential burst. It would be interesting for you to recreate your plot with the outliers corrected.
Why this is significant is it provides justification for using the outlier “log-on acknowledge” BTO value at 00:19:37, which should be more accurate than the “log-on request” BTO value at 00:19:29 because the standard deviation for an anomalous R1200 channel value is 43 μs versus the 62 μs observed for an R600 channel. In addition, the log-on request at 00:19:29 has to be corrected by the offset of 4600 μs, which might also have an associate variation.
@Victor
That’s fine. I look forward to studying SK999’s work when I get to a desktop PC.
There is still much useful work to be done iro fuel flows and path reconstructions West of the Malacca Strait, but I will have to leave that to the “experts”
@sk999
Thanks!
@Mick
I have previously given the following numbers for inside AIR temp:
(for depressurization from FL060 to FL350 from 70 deg F)
Explosive Decomp (Adiabatic): -85 deg F (-65 deg C)
Rapid Decomp (Isentropic): -27 deg F (-33 deg C)
Slow (isothermal): No change
But this above is only the instantaneous temperature drop of the air inside the cabin. What happens next is the air warms back up because of temperature exchange with the surroundings (seats, PAX, walls, etc.). So I have suggested that the final temperature of the air in the cabin might be 10-20 deg F (5-10 deg C) lower than before depressurization.
In the chemical process industry we have fairly complex decompression calculation models that take into account the heat exchange with the surroundings. This is done for equipment safety reasons to calculate how low the temperature could go for embrittlement of valves and piping during a loss of pressure. Therefore I have suggested Boeing may similarly have complex models for aircraft temperature upon depressurization.
Separately I have estimated depressuring rate could be quite rapid if the outflow valve was set to OPEN and the bleed air was set to OFF. In other words, the outflow valves are quite big if they are full open. This contradicts the recent book that said depressurization would be very slow. But the book was apparently not contemplating a worst case intentional depressurization scenario.
@TBill
To shime in on this with a question at the end.
In any case, explosive, rapid or slow, also after a ‘slow’ full decompression, the decompression will be complete in a few minutes.
I read considerable drop in temperature is already happening with a leaking door seal (Helios flight report; earlier leaking problems).
With explosive or rapid decompression, temperatures will drop instandly or quite fast to well below zero C (you mention -65C and -35C).
And with the bleed air/heating closed this drop will be even faster.
I don’t think the stored heat in the plane’s materials and in the body’s of the people in the plane can compensate a -65C or -35C to a +5 or 10C level. But if so this could only have been during several minutes for this stored heat would be lost very soon.
Imo in any case if the plane got decompressed fully at ~35.000ft shortly after the IGARI turn the temperature drop would have become unbearable/unsurvivable within at max. an hour if no emercency descent was made (which was not as far as we know now). Probably much shorter if also the bleeding air was shut off. So I assume the latter did not took place.
For this would also affect the PIC imo in which he could not have made a controlled flight till at least 18:25 or even till Penang.
But this is just my guess.
What is your view on this?
Do you see any option for a controlled flight till 18:25 or Penang under full decompression and shut-off bleed-air? Or after an explosive decompression without emergency descent?
@buyerninety
The American Trans Air Flight 406 depressurization incident report confirms that a combination of OPEN outflow valves and reduced bleed air can quickly decapacitate the PAX.
This contradicts the recent book “THE CRASH OF MH370” by retired airline pilot James Nixon. Nixon essentially claimed that it was not reasonably possible to intentionally and rapidly depressurize commercial airliners. He said it would be a very slow process and therefore not a reasonable possibility for decapacitating MH370 PAX (paraphrasing here).
Thank you for the Link. I feel cabin air temperature and pressure should be monitored and reported by ACARS if they are out of bounds.
@Ge Rijn
I am not an aircraft engineer, but I feel the extreme low temperature would probably be a transient. I believe the Captain could optionally selectively bring warmer bleed air into the cockpit. Remember the thinner air does not have as much heat transfer ability to cool off your body.
In the Helios incident, there was a widely circulated and bogus fake news report that the PAX were frozen in their seats. Upon autopsy the PAX were apparently only unconscious at the time of the crash. So there is this tendency to assume deep freeze conditions, but I don’t think so. Now if you left the “heat” off for a long time, then the inside of the aircraft would eventually cool off to ambient. Sounds to me like a pilot could in theory take a few moments to decapacitate the PAX and bring the bleed air back on.
This is one reason why the powers that be (airline industry) have no interest in finding MH370 and potentially showing the public what could be done by a pilot. We do not know what happened on MH370, and many would like to keep it that way.
@All:
Duncan Steel has created files in ECEF and LLA coordinates for the IOR and POR satellites for 25 hours starting at 0:00 UTC on March 7, 2014, in 1 second increments. He is making those files available here:
https://www.dropbox.com/sh/ogh8o1z5sm3n5un/AAB9n7O44ZmzC7zF0fFE_mOsa?dl=0
In Duncan’s words:
Both [IOR and POR data sets] are in one-second steps (hence large files: around 6MB), based in the SGP4 integrator, backwards from orbits with epochs on March 09 [sic] as defined by USSPACECOM hence Spacetrak hence agi.com (whence I induct them into STK). Screen grabs as PNG files in the above Dropbox location indicate which reference orbits I used. The essence here is that I am assuming that there were no station-keeping thrusts (i.e. artificial orbit changes) applied to either satellite between the start of the period of interest (beginning of March 07) and the epoch for each satellite orbit (65-71 hours later).
For those that are using @sk999’s excellent orbital model, I have fit the POR satellite data supplied by Duncan to the orbital model. I find an excellent fit with the following parameters:
POR parameters:
lsat = 178.078 deg
i = 1.0354 deg
e = 0.000519
rs = 42164.2 km
uto = 6.418 hr
utp = 0.0689 hr
Victor
@Victor
Is there any data from the SU log not included between row 5821 and 5822?
@Victor
Re: “Which accounts? Other than early reports that were later corrected, I’m not aware of evidence that the altitude might have varied considerably.”
As well as the PSR variations referred to by buyerninety there is also Gysbreght’s extrapolation of the Figure 4.2 data from Bayesian Methods in the Search for MH370.
@Joseph Coleman: I don’t understand your question. To the best of our knowledge, the SU log is complete. What leads you to believe that data is missing?
@Joseph Coleman
Line 5818: 08:02:27 was the final transmission from the AES before the aircraft was powered down after completing the ZBAA-WMKK MH371 service.
Lines 5819-5821: 09:01:28, 09:01:39, and 09:01:49, show the failed Log On Interrogations sent by the GES (failed, as the aircraft was powered down).
Line 5822: 12:50:19 is a Log On as consequence of the aircraft being powered up.
Why might you expect any AES activity to be logged between 08:02:27 and 12:50:19?
Don
Victor,
Thanks very much for those orbital elements.
@buyerninety
RE: “Is the aircraft air heated by ‘electric heaters’, or is it heated by something like a
‘heat exchanger’ transfering the heat from the hot air (sourced from the engine{s})
pressurized bleed air?”
Two air conditioning packs cool the bleed air from the engines to a usable temperature. Each pack cools the hot bleed air by passing it through two heat exchangers and an air cycle machine. The cabin is divided into zones that can be individually temperature-controlled. The pack outlet temperature is determined by the zone that requires the coldest air. If the other zones require warmer air, then hot trim air from the bleed system is mixed with the conditioned air that supplies those zones.
@ROB
“The remainder of your critique is simply not worth the effort of a response.”
That’s essentially my view on much of your post. You set out saying that if the SDU was “very cold” (~ – 25°C) at the 1825 UTC log-on then that pointed to a deliberate depressurisation. I pointed out to you that the rate of depressurisation that can be achieved by manual means from the flight deck made that unlikely. You said I was wrong while at the same time providing information that supported my position and contradicted yours.
When I get something wrong, and I frequently do, I usually accept that I was wrong, thank the person who has corrected me and apologise for any confusion that I may have caused.
As to the matter of events that have “never happened on a large, civil airliner.” I was making the point that simply because something has never happened before doesn’t mean that it can’t. You criticised me for not reading your post, you clearly haven’t read mine. The examples of “first of” accidents were not direct analogies for MH370; I wasn’t suggesting that MH370 suffered the same fate as BOAC781 or TWA800 and it is disingenuous to misrepresent me as doing so.
As to “… perhaps Mick was just being economical with the truth … ” perhaps you might be a little less economical with courtesy? I share what research I have on MH370 regardless of what camp it might support; for example, I most assuredly would not have pointed out that the 10N and 45S1-2 data points from the Captain’s flight simulator can be joined by a simple CMT of 180° if I was being “economical with the truth“. My interest is in dispassionately and objectively assessing the data. I have never discounted the possibility of malicious deliberate action with regards to MH370; events may have unfolded in that fashion but equally they may not have. As Victor has pointed out any number of times both the malicious deliberate action and escalating inflight emergency narratives have weaknesses. If you want to settle on malicious deliberate action and ignore the deficiencies in that narrative then that’s fine and beaut … for you. Don’t expect others to do so and kindly refrain from ad hominen attacks and insults when they don’t.
I don’t think that anything further can be reasonably gained by continuing this particular exchange so I won’t be.
@TBill
Thank you for repeating that information on depressurisation scenarios and likely temperature drop.
@Mick Gilbert said: As well as the PSR variations referred to by buyerninety there is also Gysbreght’s extrapolation of the Figure 4.2 data from Bayesian Methods in the Search for MH370.
As I said, the altitude variations from military radar were modest, and probably at the limit of the altitude resolution of the equipment.
As for Gysbreght’s analysis, if I recall correctly, he assumed the total energy, i.e., potential plus kinetic energy, was constant after 17:21. While that might be an acceptable approximation for a short-lived transient such as a zoom-climb, the only way that approximation would be accurate over the course of an hour would be if the engine thrust exactly balanced the drag. (Perhaps that’s what you are proposing?)
Not to mention that I believe that speed graph from the DSTG report is wrong, as it doesn’t even match the known speed before 17:21 when ADS-B coverage was available.
@Mick Gilbert said: As Victor has pointed out any number of times both the malicious deliberate action and escalating inflight emergency narratives have weaknesses.
It would be an interesting exercise if contributors here were first asked to choose what they believe is the most likely scenario, and then had to make a list of every weakness of that scenario.
@sk999: Regarding the orbital elements, I did not derive the parameters from the TLE for POR. Rather, I looked at the 26 position vectors on the hour over the course of 25 hours and determined the orbital elements that minimized the square errors of all the position components as compared to the STK prediction.
@Victor
“It would be an interesting exercise if contributors here were first asked to choose what they believe is the most likely scenario, and then had to make a list of every weakness of that scenario.”
I think it is equally important to have a set of boxes that a scenario has to check. Focussing on weaknesses is a good thing. Focussing on strengths is equally or perhaps even more important, IMO. There will always be weak links, but there is a lower threshold for a minimal checking of boxes.
Most people would never even consider the questions:
1> Why the flight to Beijing?
2> Why the almost nonexistent Malay response?
3> Why the coordinates on Shah’s simulator?
@Victor
Re: “I would not consider those [altitude variations of 35700, 32800, 31100 to 33000 ft.] to be considerable variations. In fact, those variations are probably barely detectable by the military radar.”
Victor, a few points if I may:
1. If the PSR altitude data in the FI was derived from military radar then the variations seen significantly exceed the height accuracy range of the radars, they are most assuredly “considerable” and well within the detection capabilities of military radar. The Selex AMS RAT-31DL at Western Hill and the Martello S-743D at Gong Kedak are designed from the get go as military-grade primary radars; tracking a target like a B777 (at least twice the radar cross section of a Tu-22M Backfire) at 35,000 feet at ranges of less than 100 nm would have been a doddle; it would have taken only three sweeps to lock it up and they would have then tracked it to the horizon. They are designed to track targets above 100,000 feet so extreme elevation/slant range tends not to be an issue; the target elevation from Gong Kedak would have been less than 10°, well within the capabilities of the S-743D. If the FI PSR altitude data came from military radar then the airplane almost certainly changed altitude.
2. I suspect that MH370 was not tracked by Malaysian military radar at any time rather the FI PSR data comes from the civilian radars at Kota Bharu and Butterworth (a joint use Alenia-Marconi ATCR-33S). The incomplete tracking, short traces and possible slant range issue just north of Kota Bharu (where the target elevation would have exceeded 20°) are far more likely to be associated with civilian rather than military radar.
3. While there may be differing views on the basis and accuracy of the altitude variations in the PSR data and Fig 4.2 interpretation they are nevertheless “accounts” of variations in the altitude of the airplane, as is Gysbreght’s extrapolation of the Fig 4.2 data. You can dismiss, ignore, rationalise and/or explain those accounts away but there is no way that anyone can say conclusively that MH370’s altitude did not vary as it tracked back across the Malay Peninsula.
@Mick Gilbert
That’s absolutely fine my me.
@victor
@Don
Thanks for answering the question in detail.
I presume after the last failed Logon interrogations from GES there is no other hourly interrogations.
@Joseph Coleman,
You asked, “I presume after the last failed Logon interrogations from GES there is no other hourly interrogations.”
Yes, after a defined number of failed interrogations the GES marks the AES as logged off & initiates no further contact with the AES.
In the AMS(R)S specification to hand, dated 2007, it’s defined that after a period of no datalink activity the GES will make five Log On Interrogations at 10 sec intervals. In the Log we see 3 interrogations. The Log On Interrogation is a GES Management Function: that Inmarsat may have changed the function to make 3 rather than 5 failed interrogations, since 2007, is of no consequence here.
Don
@Mick Gilbert: You can dismiss, ignore, rationalise and/or explain those accounts away
Yes, “explain” is the right word.
I believe that radar-derived altitudes are inaccurate. Early reports, later dismissed due to inaccurate radar data, had the plane climbing and diving near IGARI. The RMP report included radar data showing an unrealistically high and steady altitude of FL447 near Penang.
As for any analysis that derives altitude by assuming total energy is constant, I believe that is only a valid approach over a relative short period of time.
No, I can’t conclusively say the altitude did not considerably vary while MH370 flew back over Malaysia. However, I am not aware of credible evidence that it did. That was my point.
All,
I added a link to the complete ACARS data, now nicely formatted. Dry weight was 175.5 tons, about 1 ton more than MH370.
@SK999
Thank you for producing a consolidated & tabulated FMS position report.
A gross weight of 490320 is repeated over four reports, perhaps a cut and paste error?
It has allowed me to make a quick check on the initial conditions (IC), climb (CL), and enroute ER) ACMS/engine status reports which are recorded through the report. The ER reports appear to be released after Top of Descent.
Don
@sk999
Great work, I just don’t understand why MAS didn’t just release the easier interpretation of the MH371 ACARS, it’s from the same plane. Perhaps because it wasn’t a specific request.
@Don
Thanks again for another detailed explanation.
@sk999. How do the fuel burn numbers on MH371 compare to the model that you had derived and validated against the flight brief (fuel plan). Do you still get near-perfect fit, or is your model a bit on the high/low side?
@sk999
Yes, very impressive work.
Do you think there is any future possibility of the systematic BFO errors being understood to the point that they permit the actual navigation parameters (as supplied to the SDU) to be reconstructed, and accordingly the actual flight path?
You point out that both ECON and LRC modes require a complete flight plan, including an end of descent. Might make these modes less likely on the night in question
@sk999 per @ROB
…also, sk999 I was struck by the statement made somewhere that only the MH371 BFO’s from level flight could be fit well. Is that true? and is there a way to correct those “off” points by realizing the actual flight path and seeing why the deviation (Predicted vs. Actual) is happening?
@ROB
RE: “You point out that both ECON and LRC modes require a complete flight plan, including an end of descent. Might make these modes less likely on the night in question”
That’s not strictly true. VNAV only needs the end of descent point to calculate the descent path and a top of descent point. VNAV works fine in the cruise even if an end of descent point has not been defined by entering an arrival/approach in the FMC. ECON and LRC cruise modes are still available.
@Andrew
Thanks for clarifying the situation on VNAV and availability of ECON and LRC.
However, it’s still clear to me how ECON and LRC cruise function in the absence of a destination point in the FMC. As I understand things, VNAV has to be engaged to enable the FMC to perform a step climb during the flight, to optimize cruise altitude and speed. But I cannot see how the FMC could perform this function without having a target point to aim for.
Thanks
Rob
Rob
@Andrew
Re 2nd para of my prev post: of course I meant “it’s still not clear to me”.
Thanks,
Rob
@Rob: With VNAV engaged, the FMC does not automatically perform a step climb. In VNAV and ECON or LRC modes, the FMC advises the optimum, recommended, and maximum altitudes, as well as when to perform an altitude change. If LNAV is not engaged, or if LNAV is engaged but there are no altitude restrictions associated with waypoints, then the Top of Descent (TOD) is not calculated in VNAV. As Andrew said, the plane can continue at ECON or LRC speed without a descent plan.
@Victor
Thank you for the explanation. Much appreciated.
Rob/Victor:
Re “With VNAV engaged, the FMC does not automatically perform a step climb”
In fact, no plane can “automatically” perform a step climb regardless of the NAV mode. Step climbs must be authorized by ATC in realtime, so they cannot be programmed to occur in advance.
@ROB
Apologies for the delay in replying.
Expanding on Victor’s comments, the FMC breaks the flight into different phases (eg. climb, cruise, descent) and optimises those phases separately in a bid to minimise the overall cost of the flight. The derivation of the cost function used by the FMC can be found in the Airbus publication Getting to grips with the cost index, but it boils down to:
τ = ΔF + (CI x ΔT)
where
ΔF = trip fuel
CI = cost index
ΔT = trip time
Over a given sector length (ΔS), the cost function can be expressed as:
τ/ΔS = (FF + CI)/Vg
where
FF = fuel flow
Vg = ground speed
For a given sector length and cost index, the FMC only needs to look at fuel flow and ground speed to determine the optimum altitude and cruise Mach no., using the aircraft’s weight and wind/temperature data. It then calculates optimum step climb points by using the step size entered in the FMC. That step size defaults to ‘ICAO’ (4,000 ft), but can be zero (ie no step) or any multiple of 1,000 ft up to 9,000 ft.
@all
What we need is a new fuel range analysis. Never mind that Boeing was a member of the SSWG.
Does that not matter to anyone? Do we really believe we can out analyze the manufacturer of the aircraft when it comes to fuel range or flight dynamics/parameters. Why are we beating this drum?
@Andrew
Many thanks. it’s a lot clearer to me now. In particular, step climbs are optional when flying ECON/LRC on a long haul sector, not obligatory. Furthermore, a top of descent point is not a necessary prerequisite.
@DennisW
Agree, a new fuel range analysis would be very welcome at this point. Although Boeing was a member of the SSWG, they are primarily a commercial organization. Their first priority is to stay in business – going the extra mile to find MH370 is not high on the list of corporate responsibilities.
I think it was rather telling that when the search was called off, and they (Boeing) were pressed for a response, their only reply was that if the crew choose to disengage ACARS, then there was very little that could be done (in so many words)
@ROB
Re: “I think it was rather telling that when the search was called off, and they (Boeing) were pressed for a response, their only reply was that if the crew choose to disengage ACARS, then there was very little that could be done (in so many words).”
It’s interesting that Boeing would make any comment as to possible crew actions when their company position is usually to not comment on open investigations. Do you have a link or reference for that reply from Boeing suggesting that the crew chose to disengage ACARS?
@Mick Gilbert
No Mick, sorry but I can’t remember the actual item where I got that from. However, I do remember them being reported as saying it at the time.
@ROB
Okey doke, thanks, but it would have been sometime around 17 January this year when the search was officially suspended?
Andrew said to Oleksandr (last month);
“The SAARU sends inertial data on the center flight controls ARINC 629 bus. The SAARU data goes to:
– Left and right AIMS cabinets
– Left, right, and center primary flight computers (PFCs)
– Left, right, and center autopilot flight director computers.”
@Andrew, I’m somewhat hazy on what’s occuring here – I would have assumed the aircraft ‘present
position’ was held by/at the AIM(s), and forwarded from there to other logical units for their
use/calculation/display.
An example question I could ask is;
Can GPS (update of position) Updating be selected to be inhibited in only certain of these units,
(which might allow, for example, the pilots to see what the affect is on aircraft {displayed} position
in one PFC {with GPS ‘in the mix’}, compared to the aircraft {displayed} position in another PFC {with
GPS inhibited -‘out of the mix’} )??
If the above question is not how it works, could you comment; if GPS position updating is selected to
be inhibited, is it inhibited in AIM(s) + every unit, or only in some of these units?
@Andrew, I forgot to specify in the above question, for simplicitys sake
in your answer, please regard the ADIRU as non-operational.
@ Mick Gilbert
@Rob
“Boeing said it accepted the conclusion of the authorities leading the search”
http://mobile.reuters.com/article/idUSKBN1510GO
Not sure if Boeing actually said this, I’ve not seen any official statement from them.
@Andrew said: That step size defaults to ‘ICAO’ (4,000 ft), but can be zero (ie no step) or any multiple of 1,000 ft up to 9,000 ft.
Minor question: Would a pilot more likely choose RVSM (2,000 ft steps between FL290 and FL410) instead of ICAO as the step size? Or just choose 0 so that the FMC doesn’t assume a stepped climb in its fuel and time calculations?
@Mick Gilbert
As I said, I don’t remember the particular report, only that I remember reading it. 😁
@Mick Gilbert
If I may add a bit more (I write a post, I sit back and think about the problem, as you do and then I remember something else I wish I’d said at the time).
Although I can’t remember the particular report, I do remember being taken aback at the time. I remember thinking “how could they?, what a cop out, to absolve themselves in that way”.
I wasn’t surprised that Boeing referred specifically to ACARS being switched off by the crew because to be honest, the world and his wife already knew that’s what happened. In a press conference just after the plane disappeared, the Malaysian government said that ACARS was switched off and the radar transponder(s) was switched off. They have never changed their story, right to this day.
@Rob
I do believe Boeing acted in good faith relative aircraft performance estimation. Certainly their tools and knowledge base are better than anything we could hope to replicate here.
Just trying to stir the pot back to path and terminus considerations.
@ALSM @Victor
“In fact, no plane can “automatically” perform a step climb regardless of the NAV mode. Step climbs must be authorized by ATC in realtime, so they cannot be programmed to occur in advance.”
That is interesting.
Victor I know in PSS777 we can go in LEGS screen and set speed and altitude for each leg, but so far I can’t get the aircraft to adhere to that pre-set change instruction.
@DennisW
I hadn’t got you down as a stirrer 😆
For myself, I was hoping the recently released ACARS data on the previous flight might might lead to a more definitive MRC.
@TBill: In a VNAV climb, the altitude won’t exceed what is in the altitude window of the MCP or whatever altitude restrictions are associated with waypoints in the route. (The altitude in the MCP can be set to whatever altitude is cleared by ATC, for instance, to follow a plan yet ensure compliance with ATC instructions.) It may be possible (I haven’t run this down) to schedule automated climbs by associating altitudes with waypoints and ensuring the selected MCP altitude exceeds the waypoint altitudes. When you did your PSS777 test, was the MCP altitude properly set?
@Andrew,
As a side issue to the step climb questions, I wonder, if there is any way, or any mode, in which the FMC could, either “default to”, or be “programmed to”, “indulge” shall we say, in a classic “optimal cruise climb” as Gross Weight decreases with fuel burn ?
“When you did your PSS777 test, was the MCP altitude properly set?”
Not sure…but I may have been trying to exceed the altitude. One thing I had in mind was pre-programming the MH370 wind data to SIO in thin layers and then using pre-programmed minor altitude changes to change the wind along the route.
But also more importantly it would be interesting to know what could be pre-programmed ahead of a long ghost flight, besides LNAV of course.
Re Step Climb comment…I should make clear that I was not referring to what the equipment may or may not be technically capable to doing. I’m not sure about that. I was pointing out the operational limitations. So, regardless of the technical capability, step climbs can only occur following a request to ATC and clearance to proceed. They do not automatically approve. Sometimes, especially when it is very busy, step climb requests are delayed or modified to a different FL. This is what I meant when I stated it is not automatic.
@buyerninety
RE: “I’m somewhat hazy on what’s occuring here – I would have assumed the aircraft ‘present
position’ was held by/at the AIM(s), and forwarded from there to other logical units for their
use/calculation/display.
An example question I could ask is;
Can GPS (update of position) Updating be selected to be inhibited in only certain of these units,
(which might allow, for example, the pilots to see what the affect is on aircraft {displayed} position
in one PFC {with GPS ‘in the mix’}, compared to the aircraft {displayed} position in another PFC {with
GPS inhibited -‘out of the mix’} )??
If the above question is not how it works, could you comment; if GPS position updating is selected to
be inhibited, is it inhibited in AIM(s) + every unit, or only in some of these units?”
Just to be clear, the inertial data the SAARU sends does NOT include position information because the SAARU does not compute position. If the ADIRU fails, the SAARU will output inertial data including pitch & bank angles, heading, accelerations, etc. That data is output on the centre flight controls ARINC 629 bus and used by those systems that need it.
Also, the PFCs are part of the primary flight control system (ie the ‘fly by wire’ flight controls); they have nothing to do with navigation or the display of navigation data and they do not use GPS data. Navigation is handled by the Flight Management Computing Function (FMCF) within AIMS. Normally, the FMCF uses a combination of ADIRU, GPS and radio position data to compute aircraft position (primarily the GPS because it is the most accurate). If the ADIRU is not available, then it will continue to use the GPS data if it’s available. Inhibiting the GPS in the FMC only affects the FMCF’s use of the GPS data. As far as I’m aware, it is not possible to inhibit GPS data on one side only.
@Victor
RE: “Would a pilot more likely choose RVSM (2,000 ft steps between FL290 and FL410) instead of ICAO as the step size? Or just choose 0 so that the FMC doesn’t assume a stepped climb in its fuel and time calculations?”
Yes. The pilot would normally choose whatever step size suits the airspace. Some one-way routes even allow 1,000 ft steps. Another way of doing it is to enter a step size of 0 and then manually enter the step altitudes against the waypoints, as per the operational flight plan. It’s also possible to enter the next required step altitude at 1R on the VNAV CRZ page. The FMC will then compute the optimum point to climb.
@Ventus45
RE: “I wonder, if there is any way, or any mode, in which the FMC could, either “default to”, or be “programmed to”, “indulge” shall we say, in a classic “optimal cruise climb” as Gross Weight decreases with fuel burn ?”
No. The minimum step size that can be entered in the FMC is 1,000 ft.
@Andrew said;
“Inhibiting the GPS in the FMC only affects the FMCF’s use of the GPS data.”
The above statement might be open to misinterpretation, so to clarify, could you answer this;
Assuming GPS ‘position updating’ has been inhibited, (and allow a non-short time period has
passed), what position is being passed from the AIM(s) to the SDU? (- the position with GPS
derived input ‘in the mix’ or the position that is calculated without GPS ‘in the mix’?)
Again, consider the ADIRU has been/is non-operational.
@Andrew said;
“If the ADIRU fails, the SAARU will output inertial data including pitch & bank angles, heading,
accelerations, etc.
OK, could you clarify, does the SAARU sense accelerations on the airframe caused by wind, i.e.
does it calculate & adjust for wind action on the airframe?
@ROB
Re: “I wasn’t surprised that Boeing referred specifically to ACARS being switched off by the crew because to be honest, the world and his wife already knew that’s what happened.”
I am very surprised that Boeing would offer any comment as possible causation regarding an open investigation, particularly given their typically taciturn approach to commentary regarding MH370 from day one. If you come across a reference for the Boeing statement I’d be grateful if you could let me know.
The very simple fact of the matter is that nobody (or their wife) can know what caused the transponder signal failure and the interruption to the SATCOM connection and ACARS transmissions. You can speculate till the cows come home but as Tom Sawyer observed, saying so don’t make it so.
URrrggg, Mick, (hopefully, to greatly short-circuit the liklihood of discussion of this
matter of) who it was that said ‘the crew chose to disengage ACARS‘, – it was probably actually Tim Clark, President of Emirates Airline, in an interview with Der Spiegel, and
duly translated?/mistranslated?/reported?/misreported? in the DailyFail ;
http://www.airliners.net/forum/viewtopic.php?f=3&t=577505&start=50#p8745633
@buyerninety
Thank you for that reference. I have the transcript of the Tim Clark – Andreas Spaeth interview of November 2014 (that’s more than two years earlier than when ROB thinks Boeing made their statement) and while Clark makes a number of observations about ACARS he doesn’t say that he suspects the crew of deliberate malicious action. In fact, Clark states that while he believes that “probably control was taken of that aeroplane” you’re left with the impression that he believes it was someone other than the flight crew;
“… the events that happened during the course of its tracked flight will be anybody’s guess of who did what and when. I think we need to know who was on this aeroplane in the detail that obviously some people do know, we need to know what was in the hold of the aeroplane, in the detail we need to know, in a transparent manner.”
Clark goes on to largely discount pilot suicide;
“If you eliminate the pilot on a suicide mission, I’m sure you could have put the aircraft in the South China Sea, rather than fly it for seven hours. So if he was on a suicide mission, he would have done it then.“
Don Thompson and I have been looking at fuel flow information in the “unredacted Inmarsat Logs”. My summary follows here:
https://goo.gl/fx4xdh
Credits to Richard Godfrey and Don Thompson for cracking the HEX codes and Gysbreght for suggesting the 6xxx figures were fuel flow (WF values).
ALSM et al,
Nice work on L/R fuel burn. I finished a preliminary fuel burn model for MH371 (while I was at 37,000 feet this evening – quite appropriate, one would think) and hope to have written up in a few days.
Here is my 2 cents on a few earlier posts. No intention on my part to step on anyone’s toes. The main reason flights west e.g. to Jeddah or Amsterdam, would not have worked IMO is because 3 in the cockpit is a crowd. Chances of a single person taking control of the aircraft would drop exponentially. Secondly, downing an aircraft with mainly PAX from either of these sovereign countries, lined with very deep pockets, may have resulted in never ending searches and/or these sovereigns taking control of the investigations. Not desirable if the aircraft was meant to disappear for good.
If the PIC is indeed the offender in this tragic event, he would know MY, MAS, ATC and the area like no other. Response times could be attributed to initial denial anything was amiss, lack of practice as it relates to emergency protocols etc. The intent seemed to be to cause mayhem and confusion as to what was really going on. It worked.
The turn at IGARI and subsequently flying back over mainland MY is very risky when you have 238 PAX/crew with workable cell phones. It would take just 1 phone to connect to a cell tower to relay some kind of message and this is definitely possible even at high altitudes. If PAX/Crew were not immediately incapacitated, it begs the question were they a threat to the PIC in any way? The FO would have been well aware what was happening which is probably why his cell phone was switched on and was later detected over Penang.
Even the most seasoned bankers – those that are well versed in the complexities of executing international wire transfers – would be struggling to extort funds from any government successfully.
Electronic wire transfers require proper authorizations, a minimum 4 eye principal, security tokens, signatories and sometimes call-back procedures to verify the legitimacy of large transfers. This is because the people that own the money will go to great lengths to protect it. Trying to move large sums of money out of any bank account is no walk in the park even if books of fiction makes one believe otherwise.
The safe return of PAX/crew is only likely if the PIC was willing to sacrifice himself for the sake of all others. The only fate awaiting him would be immediate arrest, extradition and subsequently the death penalty. These countries dish out the death penalty for much lesser offences every day. It is doubtful he would have been hailed a hero and his family would not only have been deeply shamed in MY society but branded by his actions for the rest of their natural lives. It seems the intention was to make the evidence disappear and, to date, it worked.
You guys are the smartest guys in the room! You will find MH370.
@ALSM and others you acknowledge.
Nice work. What a stonking PDA on the right engine. From the few data points in the summary table it looks like R:L slightly greater than 1.03 and this could obviously be refined using all MH371 data points. With slightly lower initial fuel in R tank and total flight time of ~7.6hrs, you would expect MH370 fuel exhaustion R to occur about 15-17 mins before left. Very interesting. I recall that Dr B’s fuel numbers from ATSB (from MH371?) also indicated much greater PDA R:L.
@Irthe Turner
Right on man! That’s slightly more than 2cents worth, though. The vexed question of the PAX mobile phones has been much discussed, as you would guess.
It’s one reason why the pilot kept his plane at FL350. Picture this, the Captain makes the cabin crew go carefully through the plane, making sure all personal equipment is switched off or on flight mode to prevent “interference with the onboard navigation systems” with the promise that they will be able to use them once they are established in the cruise. That chance never comes, however, because as soon as the FO is locked out of the cockpit, the Captain depressurized the cabin. It’s the element of surprise that overtakes them all. It’s the element of surprise that lets the Captain get into the SIO undetected. Well almost. Things didn’t go 100% to plan.
@buyerninety
RE: “Assuming GPS ‘position updating’ has been inhibited, (and allow a non-short time period has
passed), what position is being passed from the AIM(s) to the SDU? (- the position with GPS
derived input ‘in the mix’ or the position that is calculated without GPS ‘in the mix’?)
Again, consider the ADIRU has been/is non-operational.”
The SDU receives ‘raw’ ADIRU position information via the AIMS. If the ADIRU is inoperative then the SDU does not receive any position information.
RE: “OK, could you clarify, does the SAARU sense accelerations on the airframe caused by wind, i.e.
does it calculate & adjust for wind action on the airframe?”
Amongst other things, the SAARU outputs backup heading, track, along track & cross track horizontal acceleration and flight path acceleration. I’m not sure what you mean by ‘adjust for wind action’. The SAARU simply calculates the inertial data and outputs it for other systems to use; it doesn’t ‘adjust’ anything.
If the ADIRU is inoperative, the only lateral AFDS mode available is HDG SEL. The pilots must steer the aircraft by selecting headings to maintain the desired track.
@Victor
A correction to my previous comment about the FMC default step size: The default step size can be ICAO, RVSM, or 0, as selected by the airline in the FMC’s airline modifiable information database.
Concerning cellphone connect.
The goal for a cell base station antenna is to provide maximum coverage at ground level, not 35,000ft. However, the planar array antennas used to form the radiated power into a shape resembling a segment of a squashed torus also produce anomalous lobes radiating at high elevations. Imagine the anomalous lobe as a ‘thick walled dish’.
At 01:52:27MYT, the time of the cellphone network registration, 9M-MRO had initiated its turn around Penang Island. For approximately a minute, the flight path resulted in a consistent range from the BBFARLIM2 cell base station site.
If the flight path coincided with the high elevation lobe, I suggest this enabled the phone registration with the network LBS.
@Buyerninety
It might be worth clarifying that AIMS is a platform and, itself, does not perform a function. The platform is a collection of processor, associated data bus comms modules, and inter-connections between the two AIMS cabinets. AIMS hosts many separate avionics functions, each of which is strictly partitioned within the hardware components of AIMS.
When it’s described that a particular data path routing involves AIMS, that data path routing involves a specific function hosted on AIMS. It should not be inferred that the data path routing with AIMS involves distribution to very function hosted on the platform.
Here is an updated summary of the MH371 fuel flow analysis:
https://goo.gl/UJTm6J
The data tends to confirm that the fuel flow sensors are quite accurate. At least, the sum of the left and right rate sensors agrees within 0.13% with the dFWT/dT.
@ALSM. That’s very nice. So now we have delta GWT (lbs), delta fuel remaining (kgs) and flow rate R, L, total that all appear to be mutually compatible/consistent.
Now, @sk999, @Victor, @DrB: How do these empirical burn rates compare to your fuel flow models f(weight,altitude,M,temp)?
@Andrew, Don
Yes, thanks, that has clarified the question of the IRS source for the SDU.
@Don T
Re: your latest post above
Is there any doubt that the cellphone registration occurred?
@Don Thompson
I wonder about this still regarding the altitude and distance the FO’s cellphone was detected.
BBFARLIM2 cell tower is in a south western suburb of Georgetown to the north east of Penang. Surrounded in the south and west by hills with only a more open line of sight to the north east.
In a city environment a cell tower has a detection range of a few km and on an elevation with undisturbed line of sight a max of ~25km.
I think this max line of sight range could only have been to the north east with undisturbed line of sight.
Which is hardly imaginable regarding the location of BBFARLIM2.
To the south and west the hills would block its line of sight soon imo.
What would the detection range/diameter of this anomalous ‘disk’ be from the BBFARLIM2 location?
@Irthe Turner @ROB
I am in total agreement as far as most likely scenario. However, this is not much new info. Your analysis is essentially equal to what the book Goodnight Malaysian 370 by New Zealand pilot Ewan Wilson and Geoff Taylor said in July_2014.
I would like to know if Wilson/Taylor have any updated thinking, but I feel their book stands the test of time. It has long been my adopted hypothesis.
@Don Thompson
Like to add that in the flight tests they did afterwards there were detections by several celltowers but none was detected by BBFARLIM2 and as far as I remeber none at ~35.000ft.
If I remeber it well the highest detection was at ~22.000ft.
@Ge Rijn: The tests that were conducted by Malaysia were at lower speeds, lower altitudes, and not exactly the same path that MH370 is believed to have flown near Penang. A connection was detected at the highest altitude flown (FL240), although not for the BBFARLIM2 tower. It would be very difficult to use these results to determine if a cell phone connect was possible for the speed, altitude, and path of MH370.
@Rob, Tbill, Thanks. Not read the book yet but you piqued my curiosity. Will defitely pick it up.
Ge Rijn:
Information wrt Cell Phone Registration is here:
https://goo.gl/j9PUAK
The plane was within range (26 km), and the path was line of sight with sufficient margin for a connection.
All:
BTW…The cell phone tests conducted by the Malaysians were poorly conceived and poorly executed. It is almost trivial to show by link analysis that the cell phone could connect as long as the Doppler was not too high, and the B777 window loss was not over ~25 dB. The plane was only 26 km from the cell tower at the time of registration, within the 32 kn system spec. But none of their tests really addressed these two unknowns.
@DennisW – Why the Beijing flight? In addition to the above suggested reason to restrict the flight deck to a 2 person crew, how about, “So S&R would waste a week looking in the SCS?”
Possible caption for your cartoon, “..And they said we wouldn’t find this place either”
@Lauren H.
Yes, the two person crew is a biggie that I had not considered.
@ALSM
It is really hard to find decent experimental data on aircraft cell phone connections. I think it is somehow discouraged for the public domain. Used to be a that Google search would bring up the experiment of a couple of farmers from Ohio who tried to call their wives without success from a Cessna that one of them owned. The Malay experiment was not much better.
@Don Thompson,
With the aircraft banking to the right turning around the south end of Penang Island, the person sitting in the FO seat with a cell phone in his pocket has an (almost?) unobstructed line of sight to the cell tower through the right side window. That seems like the most likely seat and time for a cell tower connection to have occurred during this flight, so it’s not surprising to me that it did occur.
@DennisW
Doubt? No, at least, not on my part. I can’t now recall what motivated me, earlier today, to post a comment about it.
@Paul Smithson,
You said: “Now, @sk999, @Victor, @DrB: How do these empirical burn rates compare to your fuel flow models f(weight,altitude,M,temp)?
My fuel flow model in level flight agrees within 1% with both the MH370 Flight Brief and with a prior flight (not MH371) for which ATSB has provided me with downloaded ACARS and FOQA data. I am checking the MH371 fuel flows now.
The R Engine Fuel Flow Sensor agrees within a few tenths of 1% with the slope of the R Tank Fuel Quantity Sensor.
The L Engine Fuel Flow Sensor reads about 0.5% lower than the slope of the L Tank Fuel Quantity Sensor.
The ratio of R engine Fuel Burn Rate to L engine Fuel Burn Rate in cruise is 1.021 +/- 0.004, based on my analysis to date.
Corrections to predicted fuel flows include weight, static air temperature, pressure altitude, tailwind, and Cost Index. The Cost Index correction for fuel flow and Mach relative to LRC tables depends in a complex way on Mach, weight, and altitude.
Based on my analyses so far, the Cost Index of 52 may have been used for all analyzed flights, and the average PDA is very near the MH370 Flight Brief value of 1.5%. The L Engine PDA is near 0.4% and the R engine PDA is near 2.6%. The ratio of R/L FF Sensor readings is 1.033 +/- 0.002 in cruise. The ratio of R/L engine fuel burn rates is 1.021 +/- 0.004.
I also found that the fuel parameters are quantized in different sizes of steps: Fuel Quantity in 100 kg, gross weight in 40 pounds, and Fuel Flow in ~7 kg/hr. It is much better to estimate total fuel weight using the gross weight and subtracting the Zero Fuel Weight than to use the TOTFW parameter. Unfortunately, the L and R and Center Tank fuel quantities are always rounded to the nearest 100 kg.
The bottom line:
(1) the Fuel Flow sensors are quite accurate (within 1%), but probably not quite as good as the Fuel Quantity Sensors,
(2) when tailwinds are high, corrections must be made to the predicted Mach and Fuel Flow because the FMC reduces Mach (and thus Fuel Flow) depending on the tailwind and the Cost Index,
(3) after applying numerous small corrections, the measured and predicted fuel flows are in excellent agreement, including the Boeing LRC FF table, the MH370 Flight Brief, and a prior flight of 9M-MRO some days earlier (and my MH371 comparison is not yet complete).
@VictorI @ALSM
I commented on the ‘cellphone’-link @ALSM also provided on Jeff’s blog.
I think the information in the link is not all correct.
Ge Rijn:
I replied on JWs blog. The base station coordinates stated are correct.
@ALSM
I did the same in return.I guess my Dutch GoogleEarth works the same as yours..
@ALSM, @Ge Rijn: I’m not sure we are certain of the location of the cell tower. Don believes it is on the St John’s Ambulance building based on cell tower information he found. On the other hand, if you look at the center of the cell coverage sector from the map in the RMP report, the location does not appear to coincide with the ambulance building. I never resolved this. Perhaps somebody else has.
@Andrew,
I apologize for being silent for a while – a bit busy with relocation.
You wrote: “If the ADIRU is inoperative, the only lateral AFDS mode available is HDG SEL”.
According to FCOM, besides HDG SEL there are several more roll modes available when the ADIRU fails: HDG HOLD (if magnetic heading is entered as POS INIT page), rollout (irrelevant to our case), and the ATT. Do you agree that it is possible to set a bank angle of, say 10 deg (>5 deg), and leave the plane on its own? This will be the ATT mode, affected by wind (see my analysis of EY440 pattern) etc. In my understanding, there was no definite conclusion with regard to what happens if the plane is left at the bank angle of 0.1 deg: either the AFDS rolls to wind level, but cannot switch to HDG HOLD, or it keeps 0.1 deg because it ‘knows’ about the failed ADIRU.
Regarding SAARU to SDU data flow. If I recall correctly, the diagram you posted mentioned inertial data, but not the ADIRU specifically. Furthermore, I recall later we figured out that the SAARU data are also sent to the AIMS, but the SDU was not listed as a recipient. This does not exclude, however, such a possibility, right?
Re: “The SDU receives ‘raw’ ADIRU position information via the AIMS. If the ADIRU is inoperative then the SDU does not receive any position information.” I recall the SDU receives time data via GP channel, and the time is sourced from GPS. Also, while it was stated that the SDU receives time data, was it confirmed that the SDU cannot receive position data via the same GP channel, especially when inertial data is not available? Finally, it is not clear what would happen if only position data are not available to the SDU.
The cell tower is perhaps this one:
goo.gl/sTQqKG
I finally got aroud to making a comparison of ACARS weather with GDAS. The following numbers are in the sense ACARS-GDAS:
SAT: Mean difference 1.0, stdev 1.0
E-W wind (knots): Mean difference -1.1, stdev 4.5
N-S wind (knots): Mean difference -0.3, stdev 4.6
These differences are consistent with prior estimates – in particular, the rms error in the GDAS wind (1-d) is of order 5 knots. For reference, Baysian Methods used a steady-state error of 5.7 knots.
Addendum: SAT = Static Air Temperature (deg C).
@ROB
Re: “Picture this, the Captain makes the cabin crew go carefully through the plane, making sure all personal equipment is switched off or on flight mode to prevent “interference with the onboard navigation systems” with the promise that they will be able to use them once they are established in the cruise.”
What exactly are we picturing here? Turning off portable electronic equipment is part of the standard pre-take-off briefing. Passengers can turn their gear back on once the seat belts sign has been turned off, typically as the airplane passes FL150; that would have been about 10 minutes after take-off, about 20 minutes before they reached IGARI.
Or are you suggesting that the Captain issued some sort of special instruction for passengers to keep their portable electronic equipment off for longer?
@DrB
“With the aircraft banking to the right turning around the south end of Penang Island, the person sitting in the FO seat with a cell phone in his pocket has an (almost?) unobstructed line of sight to the cell tower through the right side window. That seems like the most likely seat and time for a cell tower connection to have occurred during this flight, so it’s not surprising to me that it did occur.”
Snap! That was also my conclusion and it suggests or is at least not incompatible with crew incapacitation.
sk999: It should be noted that commercial aircraft have been supplying near real time met data to NOAA, ECMWF, etc. for decades. (I used to work with people at NOAA and NCAR that pioneered the idea.) Now it is SOP everywhere. They not only use the cruise level data, they also use the climb and descent vertical profiles (like radiosondes). Therefore, it is no surprise that the MH371 met data is in good agreement with GDAS. GDAS data is a product that is derived in part from commercial aircraft flying that route.
https://amdar.noaa.gov/docs/bams/
https://amdar.noaa.gov/FAQ.html
https://www.wmo.int/pages/prog/www/GOS/ABO/
Mike
@Oleksandr
Perhaps I should have been more explicit in my reply. HDG SEL is the only available lateral mode that might be used by the pilots to ‘steer’ the aircraft along a defined track.
RE: “Do you agree that it is possible to set a bank angle of, say 10 deg (>5 deg), and leave the plane on its own? This will be the ATT mode, affected by wind (see my analysis of EY440 pattern) etc.”
ATT mode engages when the autopilot is first engaged or when the flight director is first turned on in flight. If the angle of bank is between 5-30 degrees, the AFDS will hold the bank angle and will not roll wings level. If the bank angle is less than 5 degrees, the AFDS will roll wings level.
However, I believe you’re considering a scenario where the ADIRU fails? If that occurs while LNAV is engaged and the aircraft is established in a turn, then the AFDS remains engaged in an “attitude stabilising mode”. That condition would be annunciated on the PFD by an amber line drawn through the LNAV mode annunciation. If the condition persists, my understanding is that the aircraft would continue in the “attitude stabilising mode” with a constant bank angle. ATT mode would not be annunciated on the PFD in that scenario.
RE: “Regarding SAARU to SDU data flow. If I recall correctly, the diagram you posted mentioned inertial data, but not the ADIRU specifically. Furthermore, I recall later we figured out that the SAARU data are also sent to the AIMS, but the SDU was not listed as a recipient. This does not exclude, however, such a possibility, right?”
It has already been stated, several times, that the SDU receives inertial position data from the ADIRU for beam steering. The SDU does NOT receive data from the SAARU.
RE: “I recall the SDU receives time data via GP channel, and the time is sourced from GPS. Also, while it was stated that the SDU receives time data, was it confirmed that the SDU cannot receive position data via the same GP channel, especially when inertial data is not available?”
Yes, the SDU receives date/time data from the L AIMS cabinet via the GP 1 data bus. The AIMS cabinets receive date/time data from the multi-mode receivers (ie GPS). The GP 1 data bus does not transmit position data.
RE: “Finally, it is not clear what would happen if only position data are not available to the SDU.”
The position data is used by the SDU for beam steering. I’m not sure exactly what happens if that data is lost, but if the SATCOM doesn’t fail immediately, I assume it will eventually ‘lose’ the satellite as the aircraft position changes.
@Andrew: Position, groundspeed, and track data are used for pre-compensation of the L-band Doppler shift. Even if the low gain antenna (LGA) is in use, which requires no beam steering, position information is required.
@Pax Lambda: Welcome to the discussion.
ALSM,
Yes indeed, I am aware that ACARS data are ingested by NOAA, etc. and your comments and references are very relevant. You stop short of asking the next question – how good are the wind models over the SIO, where commerical flights are few and far between? I have no good answer – it could be that the models are as much fancy as they are fact. Now I do have a scheme to find out …
SK999:
Yes, commercial flights are few and far between in the SIO. But…The GPS/MET demonstration project and later COSMIC systems that I worked on 1992-1997 have revolutionized weather prediction in data sparse areas like the SIO. There are quite a few radio occultation payloads in orbit now, but the one I managed to get launched on MicroLab-1 back in 1995 was the first. Radio occultation payloads observe the GPS L1/L2 signals as they “slice through the atmosphere” when a LEO payload rises or sets relative to the observed GPS satellite. Each LEO payload can observe several hundred vertical temperature and pressure profiles daily.
With many LEO satellites now carrying GPS radio occultation payloads, the number of soundings in the SIO is now quite dense. From these soundings, the global models develop “geostrophic winds”. It is very cool technology, contributing to the accuracy of winds in the SIO.
Short Video produced by UCAR & NSF: https://goo.gl/DvuZDH
http://www.cosmic.ucar.edu/
http://www.cosmic.ucar.edu/gpsMet.html
@sk999,
Did you figure out the correct gross weight values for MH371 at 2:04, 2:34, and 3:04. I think Don T asked about this. My apologies if you posted something that I missed.
@Rob, Am hopeful the data will eventually unravel this mystery. If one were to speculate you have to put yourself in the PIC shoes and think through what he would do and why. The ultimate end goal, disapearing forever, is key imo. I agree with you that eliminating the main threat from the get go is critical to the success of said end goal.
@sk999. re wind model error magnitude. A couple of months ago I used windytv.com which offers GFS and ECMWF to look at difference in (current) winds 250HPA every 1 degree of latitude along a path from NW Sumatra to 7th arc at 38S. Findings: neither systematically lower/higher than other. RMS difference on wind strength 8.0 kts, maximum difference 16kts. RMS difference on wind direction 15.3 degrees. No correlation between magnitude of difference between models and wind strength.
@Irethe Turner
Yes, my approach has been exactly the same as yours, ie. to try and see the situation from the pilot’s point of view and ask the question “if I wanted to do this, how would I go about it”. Needless to say, the plan demanded getting as far into the SIO as possible, as efficiently as possible, which rules out any loitering in the area west of Sumatra. Every minute spent loitering, would increase the chance of being identified.
Personally, I am confident he was aiming for the area centered on S38, E89 (the Bayesian Hotspot) because this flight path turns out to be synchronized with a low sun angle at flameout, in such a precise way as to rule out coincidence. The big question at the moment is “did he reach his intended terminal area, of did things go seriously wrong following the FMT, and the aircraft ended up on constant heading/track mode, and ended up closer to S35. The BTO favours S38, but the BFO is more persuaded toward S35.
this
@VictorI said;
“Even if the low gain antenna (LGA) is in use, which requires no beam steering,
position information is required.”
Wasn’t it determined long ago, (by Don or ALSM?) that the comms log indicated that it
was the High Gain Antenna(s) that was/were in use?
@Mick Gilbert
Ok, we have to address the question why (apparently) to cellphone messages got out during the flight, apart from on reported message while still on the ground. This in itself if a highly unusual situation, even for a redeye flight taking off after midnight.
It’s a sad fact, but we will probably never know exactly what went on in the passenger cabin as this flight unfolded,but as the evidence stands at present, no messages got out after takeoff. The FO’s phone made a fleeting contact with the outside world as the plane skirted round Penang Island, but there was no message sent. We will never know if the FO was trying to contact the ground at that time, or if he was already dead by then. He would have switched his phone off prior to takeoff. My guess is that as soon as he realized what was happening, ie the Captain had locked him out of the cockpit, was depressurizing the plane and diverting it from it’s planned course, he being second in command would deem himself responsible for trying to make contact with the outside world. No other cellphones made contact as the plane passed Penang. What does that tell you? It tells me that the passenger and cabin crew were in no fit state to engage in the luxury of turning their phones on.
@Mick Gilbert
That should read why No cellphone messages got out.
Probably because cell towers are scarce in Taman Negara & Tanjung Mentung. I imagine Celcomm
found the rate of mobile phone uptake by Lar Gibbons to be particularly disappointing.
Mick, r u hearing a dogwhistle?
@ROB
Re: “we have to address the question why (apparently) [no] cellphone messages got out during the flight, apart from on reported message while still on the ground. This in itself if a highly unusual situation, even for a redeye flight taking off after midnight.”
Why do you consider it “highly unusual” that no cellphone messages got out during the flight? Given the restrictions on the use of portable electronic devices from doors close, the time of departure and the time at the destination, I would expect that no cellphone activity would be normal on the outbound leg.
On the leg back to Penang, getting a cellphone connection would be problematic at the best of times. As some other contributors have observed, the banked right turn south of Penang opens up the line of sight from the right side of the airplane to the ground making that the most likely place and time to get a connection. And that’s what happened for one cellphone that might reasonably be expected to have been on the right side of the airplane.
“He would have switched his phone off prior to takeoff.”
We have no way of knowing that. Ask flight crew how many times they have forgotten to turn their cellphones off prior to departure; it’s not uncommon.
“No other cellphones made contact as the plane passed Penang. What does that tell you? It tells me that the passenger and cabin crew were in no fit state to engage in the luxury of turning their phones on.”
It tells me the pretty much the same thing. However, it tells me absolutely nothing about how or why that situation had come about.
If you’re trying to look at this through the eyes of a malicious perpetrator, and if getting as far into the SIO as possible was important, why would you deliberately fly the airplane all the way down to Penang, with the increased risk of detection or someone making contact with a cellphone, and then back up the Straits of Malacca? Why wouldn’t you save time, fuel and greatly reduce the risk of detection by cutting straight across Malaysian airspace from near LOSLO/BIDMO direct to MEKAR?
Re: “I am confident he was aiming for the area centered on S38, E89 (the Bayesian Hotspot) because this flight path turns out to be synchronized with a low sun angle at flameout, in such a precise way as to rule out coincidence.”
I don’t know what level of precision you’re talking about such that it rules out coincidence because there is only seven minutes difference for sunrise across the entire 2,000 kilometre expanse from one end of the possible impact zone – 27°S 100°E – to the other – 40°S 85°E.
@Rob said: Ok, we have to address the question why (apparently) [no] cellphone messages got out during the flight, apart from [one] reported message while still on the ground.
We don’t know whether the cell phones of passengers connected to any cell towers. The RMP report is silent on this. The FI didn’t even mention the cell phone connect of the First Officer. (Why is still a mystery.) I have reason to believe that the Malaysian authorities never collected the cell phone numbers of passengers, which would be necessary to check for any cell phone registrations during the flight.
@buyerninety: During the flight, yes.
The MH150/three crew member discussion is interesting but seems to be based on at least one false premise. While MH150, being over 8 hours but not more than 12 hours, would most assuredly require three flight crew, there seems to be an assumption that the third flight crew member would be on the flight deck; that is not the case.
The purpose of carrying extra flight crew on longer flights is to ensure that the limitation on the maximum time (viz 8 hours) that two pilots can be in the seat on a single sector is not exceeded. In order to accomplish that there is a requirement that “there will be for the crew member resting a comfortable reclining seat, or bunk“, that is a seat in business class or in the crew rest area. Accordingly, securing the flight deck on MH150 would be no more difficult than asking the First Officer to go and fetch his relief from business class and then latching the flight deck door behind him; a process that is certainly less unusual and probably somewhat less affronting than asking him to play waitress and go and fetch a coffee.
Even with an additional crew member on board, MH150 presents itself as an ideal flight to deliberately divert if mysterious murder-suicide ending with an undetectable impact in the Southern Indian Ocean was the plan. That is because MH150 flies through a radar and VHF blind spot over the Bay of Bengal; it starts on N571 about 50 nm past BIKEN and then extends for about 200 nm (the blind spot is actually shaped like a corridor roughly 150-200 nm wide running north-south). Quite coincidentally, if not conveniently for a malicious perpetrator, MH150 reaches that blind spot about 2 hours after take-off which is precisely when the first relief crew change would typically take place. It presents as an ideal opportunity for securing the flight deck and diverting the airplane at a time when there is no radar or VHF radio coverage. Furthermore, by turning to roughly 178° from around the middle of the blind spot, with the fuel onboard, you could fly straight down the corridor completely unobserved by radar and out of VHF range all the way to somewhere near 50°S 91°E.
@IrntTurner
You said “Mick, ru hearing a dog whistle?”
Woof! Woof!
@ROB
“The BTO favours S38, but the BFO is more persuaded toward S35.”
The path is really the only part of your argument I have trouble with. BTO only favors 38S based on ATSB-like assumptions of a quick FMT near Indonesia and straight level flight. I feel maneuvers are apparent up to at least a little after 19:41 and seems to me a descent and slow down after Arc5 to reduce visual profile as sunrise approaches.
@Mick Gilbert
Mick, 7 minutes difference across the search area? Do me a favour mate. 1 hour would be more like it. The morning terminator was advancing across the ocean at latitude S37 at the rate of 13.5 miles/minute, so would have advanced westwards by 95 statute miles in 7 minutes.
If you had actually taken the trouble to check it out (like I did) you would find the flight path with 186deg heading, the IGOGU/ISBIX/S38, E89 flight path ran almost exactly parallel to the advancing morning terminator, diverging from exactly parallel by less than 1deg during the final 2.5 hours of the flight. This alignment meant that at 00:19, the Sun was about 4deg above the horizon at sea level, at all points along the flight path, which meant the pilot only had to wait until fuel exhaustion to get the right lighting conditions for a ditching. He didn’t have to bother about adjusting the cruising speed as he wasn’t trying to hit a particular spot, he only had to wait for fuel exhaustion, and “bingo” (if you pardon the pun)
With this flight path he would be in darkness for all but the last half hour or so, just enough time to make sure he wouldn’t be coming down next to an ore carrier, if they ever get down that far. No other flight path had this lighting arrangement while at the same time realized the range potential afforded by the particular fuel load. If you try to approach the sunrise zone from either the east or the west, it would be like trying to hit a fast moving target (moving at 13.5miles/min, and you would never do it.
@Victor
The reason why the RMP only mention the FO phone contact was because it must have been the only one, in my opinion. If thee had been others, we would have heard something by now.
@Mick Gilbert
Did you spot the deliberate mistake!? Who would ever have wanted to approach from the east? They would have been in daylight for far to long. He could have manoeuvred to approach from the east, but he would have had trouble hitting the spot at the same time as he ran out of fuel, and when you manoeuvre you unavoidably rate into the range potential.
@Mick
My typing is atrocious. He could have manoeuvred to approach from the west, not from the east, but it would mean he didn’t get as far into the SIO, and he would have trouble hitting the spot with the right lighting conditions.
I’m now going to give this a break, and take a walk in the country to clear my head. 😎
@Rob: If they didn’t collect passenger cell phone numbers from the NOK, the authorities would not know whether other cell phones registered on cell towers.
@Victor
It is also not clear how many of the Chinese PAX phones would operate on GSM or LTE. My guess is few to none. Most of the China telecom operators use some variation of CDMA. The PAX would need to rent phones in KL.
@Rob
If you are interested in the terminator positions, at various altitudes, and how to plan to track parallel to the advancing terminator, and how to descend unseen until the last moment, I laid it all out, over 17 months ago now.
See here: http://www.auntypru.com/forum/showthread.php?tid=28&pid=3569#pid3569
and here: http://www.auntypru.com/forum/showthread.php?tid=28&pid=3585#pid3585
and here: http://www.auntypru.com/forum/showthread.php?tid=28&pid=3656#pid3656
@ROB Don’t forget that 38S definitely causes problems with drift patterns [specifically W Australia], and 35S isn’t much better. There really isn’t a single solution that fits everything we know [or think we know].
@DennisW: Yes, I agree that a large portion of Chinese cell phones would be incompatible with GSM networks in Malaysia.
@Victor
“We don’t know whether the cell phones of passengers connected to any cell towers. The RMP report is silent on this. The FI didn’t even mention the cell phone connect of the First Officer. (Why is still a mystery.) I have reason to believe that the Malaysian authorities never collected the cell phone numbers of passengers, which would be necessary to check for any cell phone registrations during the flight.”
@Dennis
“It is also not clear how many of the Chinese PAX phones would operate on GSM or LTE. My guess is few to none. Most of the China telecom operators use some variation of CDMA. The PAX would need to rent phones in KL.”
Excellent points Victor and Dennis. Though, I will point out we only (at least me) have access to the RMP folders leaked to me and others. I don’t know what the PAX folder contains and whether detailed assessment was made of their cell phones. The released network data, analysis from several providers and tests carried out, *might* indicate that no effort was made to subject the cell phones of PX in the way cockpit and cabin crew were. Also, the RMP report remains a snapshot in time – 2014. I don’t know if the RMP, post 2014, pursued their criminal investigation into the period 2015-17.
I tend to go with Victor’s assessment that they likely did not and we would have heard something by now. Remember, back then – 2014 – it was clear the focus was on the cap and FO.
But the point Dennis makes is equally cogent – that even if it was (RE: GSM or LTE), the chances of a positive ping/cell phone detection significantly decreases.
All that said, we did have PAX in the cabin who were business people, clearly technically-minded, and must have been well-travelled.
But I hear the echoes of Jeff Wise’s comment – when I recently interviewed him for radio – that the (RMP) criminal investigation may have been somewhat “half-assed.”
@Mick Rooney: “Half-assed” is an understatement. The RMP report is shoddy, incomplete, and raises many more questions than it answers. The description of the cell phone testing is just one of many examples of this. However, the report does present evidence that is not documented elsewhere, such as the contents of the flight simulator files, and the record of the cell phone connect.
@Dr B. Thanks for your feedback on fuel. I look forward to hearing if there is any tweak once you have looked at the MH371 numbers more closely.
Re cell phones
I expect that the reality is that MY cellular operators do not routinely log the basic device registrations for service on their networks. Such data would present little, or no, value. Legislation in the UK, and I believe EU wide, requires mobile call data records (CDR) to be maintained for 18mths, that is, records of call history. MY’s legislation is unlikely to be different, in terms of the scope for data retention, if any exists at all. The cost of implementing a unique regime would be the issue, not the ability to sort/retain.
My recollection of the RMP report details concerning IP connections from smartphones to social media accounts was that investigation was mostly inconclusive as the operators didn’t record IP address leases to specific devices. While the socmedia services logged inbound IP addresses, the connecting ‘link’ to device ID was absent.
@Don Thompson said: I expect that the reality is that MY cellular operators do not routinely log the basic device registrations for service on their networks.
How do you explain the registration of the First Officer’s cell phone at Penang? And if this was event was recorded, isn’t it possible that other connections from aboard the plane were also recorded?
@Andrew,
Re: “However, I believe you’re considering a scenario where the ADIRU fails? If that occurs while LNAV is engaged and the aircraft is established in a turn, then the AFDS remains engaged in an “attitude stabilising mode”. That condition would be annunciated on the PFD by an amber line drawn through the LNAV mode annunciation. If the condition persists, my understanding is that the aircraft would continue in the “attitude stabilising mode” with a constant bank angle. ATT mode would not be annunciated on the PFD in that scenario.”
Yes, I consider the ATT mode active under the failed ADIRU assumption, as otherwise the ATT would only be a transient mode. I have a long lasting interest in the ATT mode because there are trajectories confirming BTO and BFO data. And given that these trajectories are subjected to wind and Coriolis, and in addition they are consistent with the drift studies, I believe this is a remarkable coincidence. Note that the impact of the Coriolis is equivalent to flying in the constant gyroscopic heading mode – this what SAARU provides.
Re: “It has already been stated, several times, that the SDU receives inertial position data from the ADIRU for beam steering. The SDU does NOT receive data from the SAARU.”
Could you please remind where it was explicitly stated that the SDU receives position data from the ADIRU only? The SAARU does not output position data, but GPSs do provide, and I have not seen explicit statements that the SDU cannot use GPS data when the ADIRU fails. FCOM (11.10.10), for example, states that a pilot can select altitude source for the transponder: ADIRU or SAARU. If I am not mistaken in the diagrams and descriptions you posted it was never mentioned that the SAARU data are supplied to the transponders. The absence of evidence is not the evidence of absence (D.S.).
Re: “Yes, the SDU receives date/time data from the L AIMS cabinet via the GP 1 data bus. The AIMS cabinets receive date/time data from the multi-mode receivers (ie GPS). The GP 1 data bus does not transmit position data.”
Again, where was it explicitly stated? Absence of the position data in the description lists does not mean that such a data is not supplied via GP channel. Especially in case when ADIRU data is not available. From my point of view it would be logical for reliability reasons at no additional cost.
Re: “The position data is used by the SDU for beam steering. I’m not sure exactly what happens if that data is lost, but if the SATCOM doesn’t fail immediately, I assume it will eventually ‘lose’ the satellite as the aircraft position changes.”
I have not seen any proper study. If the SDU can keep in its memory the last position, in-principle it could use it. The error in steering angle would be negligible over several minutes of flight if not hours. This is in contrast to the attitude data. I don’t know how much is the tolerance error in the steering angle: perhaps somebody can comment on this topic.
@ROB
You’re quite correct, it’s an hour and 7 minutes from one end of the zone to the other. My mistake, I had missed the time zone change, my apologies.
Isn’t the problem with this supposedly precision flight path along the terminator that when the impact point was searched thoroughly, the airplane wasn’t there?
@Victor,
The interaction with the FO’s phone involved the Location Based Service, it’s my understanding this service is involved in the process that provides cellular smartphone subscribers with useful supplementary information such as the nearest coffee/pizza/donut vendor when they execute a search on their device.
Don
@Oleksandr,
“The error in steering angle would be negligible over several minutes of flight if not hours.”
Seriously, no, not negligible.
The expanded GES log, the subject of the post to which we are commenting, illustrates how sensitive the AES is to accurate tracking of a satellite.
@Don Thompson,
“Seriously, no, not negligible.”
I think you are confusing contributions of the attitude and position, and respectively sensitivity to these two factors. For example, recall that the satellite also moves: displacement along Z-axis (in ECEF) ranged from 390 to 1206 km according to Tab. 3 from ATSB June 2014 report. Did this cause significant impact on the ability to transmit/receive signal due to the error in antennae steering? The answer is obvious – no. Similarly, the same impact (or its absence) could be expected in the case of airplane’s displacement of order 800 km, which is equivalent of 1 hour of flight.
@All
Come on guys. As problematic as the RMP ‘report’ is, I’m a wee bit incredulous that we would not by now heard heard about any other pax or crew cell phone connects. Surely if they had occurred, word of such an occurrence would have leaked from NOK. And surely other investigative agencies have done their due diligence on the matter.
There is clearly a significance to only the FO’s cell phone making a connect…the most logical being a desperate attempt to contact someone after being locked out of the cockpit. And he was 100% locked out as he posed the greatest risk to Z…and I think it’s safe to rule out a physical assault or pick your poison, as anything other than a locked out FO would be far to risky in regard to neutralizing the FO.
Let’s not kid ourselves about the import of the cell connect, the lack of any other pax or crew connects, and the story this tells.
Mick@, In a few hours, I will be on a 10 hour flight. Behaviour of a 3 person flightdeck crew is highly unpredictable. They have their own resting area which is definitely not in BC on a 777. Often all 3 are in the cockpit until well in the flight. They hang around the galleys and rotate a few hours rest when needed . The point being , you can’t plan on the unknown with 3 pilots on board.
@Irthe turner
Malaysia Airlines’ Ops is quite specific as to how the Captain is to organise crew resources and manage the timing of crew changes.
“When a set of flight crew consisting a relief Captain is required for a flight, the hours for the flight will be shared equally. For example, in a 9 hours flight, the hours will be shared as follows … :
First 2 Hours – Capt A & Co-Pilot
Next 3 Hours – Capt A & Capt B
Next 3 Hours – Capt B & Co-Pilot
Last 1 Hour
– Capt A & Co-Pilot”
MH150 is a nine hour flight. It can’t be much clearer than that.
Whether the relief crew sit in Business Class or the crew rest area would largely depend on the configuration of the airplane (not all have a crew rest station) but it would ultimately be at the Captain’s discretion whether the relief crew member is ensconced on the flight deck.
@VictorI @ ALSM
On the ‘poorly conducted flight-tests’ regarding the FO cellphone connection. I think you might be right for those test were conducted on (far) lower speeds and altitudes than MH370 was supposed to fly on.
But then; is it not the more suprising BBFARLIM2 did not detect or connect any cellphone during those tests?
Chances would be far better than with a plane passing by at ~35.000ft/500knots.
Still it did not happen even on far lower altitudes and speeds in the tests.
But the FO-cellphone on MH370 did anyway.
Imo this indicates MH370 must at least have flown on a lower altitude and probably also a more northern route passing Penang over land to make the detection of BBFARLIM2 possible.
@Oleksandr
RE: “The SAARU does not output position data, but GPSs do provide, and I have not seen explicit statements that the SDU cannot use GPS data when the ADIRU fails.”
You won’t find such a statement. I have already provided you with a diagram that shows all the systems that interface with the SDU. The GPS is not depicted. Do you not think that such an interface would be shown or described somewhere in the text, if it existed?
RE: “FCOM (11.10.10), for example, states that a pilot can select altitude source for the transponder: ADIRU or SAARU. If I am not mistaken in the diagrams and descriptions you posted it was never mentioned that the SAARU data are supplied to the transponders.”
If I remember correctly, the previous discussion simply stated that SAARU data is output on the centre flight controls ARINC 629 data bus. It did not consider all the systems that might or might not use that data. Further, the discussion had nothing whatsoever to do with the transponder, so why would it have been mentioned? If you’d asked, I could have given you references from both the FCOM and the AMM that show the transponder can use SAARU data as an alternate source for altitude reporting, if selected by the pilots. The same does NOT apply to the SATCOM.
RE: “Again, where was it explicitly stated? Absence of the position data in the description lists does not mean that such a data is not supplied via GP channel. Especially in case when ADIRU data is not available. From my point of view it would be logical for reliability reasons at no additional cost.”
Again, you won’t find a statement that says “the GP 1 data bus does not transmit position data”. The manuals describe the type of data that is transmitted to the aircraft systems via the various data buses. They don’t explicitly state the data that is not transmitted. Again, do you not think that GPS data would be mentioned in the manuals if it were sent to the SDU via the GP 1 data bus?
Consider what happens when the aircraft is on the ground with the ADIRU selected OFF. According to your theory, the SDU would be provided with position data from the GPS and other inertial data would be provided by the SAARU, correct? So SATCOM voice communications using the HGA should be possible on the ground when the ADIRU is selected OFF, correct? I can assure you, based on many years experience of operating the aircraft, that is NOT the case. SATCOM voice communications are NOT available when the aircraft is on the ground with the ADIRU selected OFF. Why?
@Donald
Re: “There is clearly a significance to only the FO’s cell phone making a connect…the most logical being a desperate attempt to contact someone after being locked out of the cockpit.”
How is that “the most logical” interpretation? It might be an interpretation that fits your preferred narrative but it is hardly “logical”. As DrB has observed the banked right turn south of Penang opens up the line of sight from the right side of the airplane to the ground making that the most likely place and time to get a connection, particularly from a phone that was located on the right side of the airplane. And it appears that’s what happened for one cellphone, the First Officer’s, that might reasonably be expected to have been on the right side of the airplane.
Re: “And he was 100% locked out as he posed the greatest risk to Z…and I think it’s safe to rule out a physical assault or pick your poison, as anything other than a locked out FO would be far to risky in regard to neutralizing the FO.”
That doesn’t make much sense. If the First Officer was the greatest risk, why would you have him somewhere beyond your control? Locked out of the flight deck the First Officer would have been free to alert the cabin crew, try to alert the authorities or, worse still for a malicious perpetrator, access the Main Equipment Centre and start disabling critical flight deck support systems such as the flight crew oxygen system. Moreover, if you did determine that you were going to lock the First Officer out, why would you then bring the airplane with in cellphone range of Penang?
Re: “Let’s not kid ourselves about the import of the cell connect, the lack of any other pax or crew connects, and the story this tells.”
Well, what story exactly does it tell? If the First Officer was locked out of the flight deck yet still able to use his phone as the airplane rounded Penang why weren’t any members of the extraordinarily experienced cabin crew (the average length of service was over twenty years, the Inflight Supervisor had 35 years experience and even the most junior member had 13 years experience) able to do the same? Had the First Officer been locked out as you’ve suggested, he would have been able to coordinate with and organise the cabin crew and you would have expected to see multiple cellphone registrations not just one.
I think that a single cellphone registration from a phone that you’d expect to be on the right side of the airplane as it executed a banked right turn does tell a story; a story of happenstance (in that the First Officer had left his phone on) and his possible incapacitation while still in his seat.
Ge Rijn said: But then; is it not the more suprising BBFARLIM2 did not detect or connect any cellphone during those tests?
Chances would be far better than with a plane passing by at ~35.000ft/500knots.
Not necessarily. It depends on the radiation pattern of the cell tower antenna, and where the lobes are at various elevation angles. Because of the lobes, a higher elevation angle does not necessarily translate to a lower gain. As for speed, if the plane is traveling tangentially to the antenna, the line-of-sight speed is much lower than the groundspeed.
@DennisW
I seem to recall unsubstantiated info in the press that there may have been a few other flight crew cell connects.
@VictorI
I asked about the reach of those lobes in altitude and in diameter.
Got no answer yet.
It seems highly inefficient to me those celltowers radiate so much energie vertically that they can detect a cellphone at 35.000ft/10km. And this would be only if the plane flew straight over the celltower.
From a necessary lign of sight the distance to the celltower would even be much greater and this ‘lobe’ should be able to detect the cellphone from that distance also. It seems all very unlikely to me and far fetched.
Those antennas are designed to radiate their energy in a narrow band directed mostly horizontal towards the ground.
In a city area the power required to cover a certain city area is only to cover a few miles at most.
I would like to see more detailed information about those ‘lobes’ at 35.000ft.
@TBill
I don’t recall other connections being mentioned.
As far as the base station location, when I use ALSM’s (all the digits coordinates) I end up in a tree using the new Google Earth version on my Chromebook. BTW, the Chrome version of Goggle Earth is truly spectacular, and much better than previous versions. Probably there are small differences in the coordinate math.
@Ge Rijn
The basestation antenna is a rectangular radiator. The lobes are a consequence of that geometry.
BTW the ‘cell tower’ depicted in @ALSM’s link (St Johns Ambulance Building) is not a ‘cell tower’. It represents the comman 3 section cell-antennas you see everywhere on buildings in city areas. And it’s not high above the ground either.
Those are not high powered high cell towers which you can find in less dense populated areas.
@DennisW
I would be glad to read more details about those ‘lobes’. I cann’t find them. If you have any please post them.
On the other cellphone connections of other crewmembers
I recall two were mentioned long time ago.
One of them was from Penang Bridge (the first Penang bridge not the second).
@Ge Rijn: The lobes depend on elevation angle, not altitude. And I never said the plane was flying through the vertical lobe when the connect occurred.
Do an internet search on radiation patterns of cell tower antennas and you will see that typical patterns have lobes at various elevation angles above the lowest, main lobe. This is not really debatable.
@Mick Gilbert
Yes I admit, the negative search result has been a bit of a downer for my theory. My original theory also proposed an extended glide that followed flameout and regrettably the search stopped short – a 16:1 glide would finish several km outside the search zone.
Is a piloted glide likely though? The BFO at 00:19 is still a problem for it, the high descent rate seems rule it out, so does the APU lighting up after flameout. The question being would the pilot allow the LH engine to flameout with the APU not run up in readiness, he deliberately staged it to look as such, but this is mere speculation.
There are aspects of the debris finds that seem to suggest a severe overspeed during descent: items 9 and 15 from identical locations on the upper trailing edges of RH and LH wings respectively, could have been forced of by excessive air loads in a supersonic dive, as could the RH horizontal stabilizer panel (also on the upper skin)and the verical stabilizer piece also, not to mention our old friend the RH flaperon, whose neatly fractured hinges look suspiciously like a case of flutter.
So what is the alternative? Well, if revised, updated fuel endurance figures do in fact allow the aircraft to reach S37/S38 with MRC/LRC, then the BM hotspot it still definitely a runner, Imo. But if it transpires the plan could not have made it that far south, then the CMH or a co-contender, ending near S35, becomes much more likely. If that’s the case, then how did the BM get so far off track? Well it could be that the BM hotspot was the pilot’s originally intended track, but before reaching ISBIX, he was incapacitated in some way, for example by hypothermia as a result of having to extend the depressurization phase (this has to be speculatory, but possibly the door was in danger of being forced unless he kept the plane depressurized for longer than originally planned) and the journey south ended up as a ghost flight. The BM analysis was successful in defining its position and heading at 19:41, because the 2nd arc closely limits position in the east-west direction at that point. Then the failure to detect any changes of direction subsequently due to the ambiguity of the BFO, and over reliance on an unknowingly inaccurate MRC range limit, resulted in a hotspot ending up too far west along the 7th arc.
But here again, the aircraft obviously cannot be at either S35 or S38 after burning the same amount of ⛽ fuel, if it had been in LRC/MRC all the way, because of the total covered are different, which means to reach S35 at 00:19, the speed has to be slower (and possibly lower) LRC, and less efficient. Unless a loiter is assumed west of Sumatra
At this point you might be justified in thinking I have got myself hopelessly confused, such is the seemingly intractable nature of the problem.
@VictorI
Thanks for the suggestion for searching on ‘radiation patterns’.
I found this and I think it’s quite informative in this case.
Lobes and all, the article reflects cellphone connections are very unlikely to be picked up from a plane by a celltower above 8000ft:
http://www.datasync.com/~rsf1/cell-air.htm
@VictorI,
@Ge Rijn,
As was mentioned previously (perhaps by VictorI), the Doppler shift of the cell phone transmission observed at the cell tower would also be minimized for a circular path flown by 9M-MRO around (the southern end of) the island. That also helps the connectivity. I don’t think the later test flights followed the same path as MH370.
As far as I know, the NOK have no means to check for cell phone registrations (only attempted calls).
It would be interesting to know the last time the FO’s phone connected to a tower at Kuala Lumpur. Was it on after take-off? I can’t recall if this was addressed in the RMP Report.
@Ge Rijn: I’m glad that now you agree that the concept of elevation lobes in the cell antenna radiation pattern is not “far fetched”. In fact, it is a consequence of the wave nature of the radiation.
In order to use the results of that study you cite, you have to put the results in the correct context:
1. In that study, one criterion used for the suitability of a connection was based on the time to transit a lobe while flying at constant altitude. A connection time of 26s was deemed unacceptably short. While it might be not be possible to complete a call with a connection time of 26s, that is much longer than the minimum time to register a connection on a tower. (The FO’s cell phone did not complete a call. We don’t even know if a call was attempted at the time of the registration.) Also, a plane at constant level and on a track that is tangential to the cell tower would not transit the lobe in the manner described.
2. The other criterion used in the study is based on “Doppler blockage”. However, if the path of the plane is tangential to a tower (such as the suspected turn around Penang), the Doppler shift would be very low, and Doppler blockage would not occur.
Do you believe the radar data of the plane flying south of Penang Island at high altitude and high speed is fabricated? We might quibble over the exact altitude and speed, but do you really think the plane was flying at low speed and low altitude?
As for the claim that there was a connection to a cell tower on a Penang bridge, that is based on the following comment on reddit:
I saw an internal memo from Abdul Farim Fakir Ali, CTO of Maxis, saying that they picked up a call attempt from a “crew member” originating on a cell tower covering Perhentian Besar. He also implied that Digi may have something from a different crew member near or over Jambatan Pulau Pinang.
The comment was posted by an anonymous commenter calling himself (herself?) “karl-erik”. This was his first and only post on reddit. The claim was never reported in the media, which has a very low threshold for reporting rumors related to MH370. There is an individual on Twitter that repeated this claim many times as though it is fact. I see zero basis for believing this claim.
Re Cell Phone Registration:
I will post shortly a more complete note on the cell phone connection at 17:52, but in the mean time…a couple of words on the connection.
1. We know it happened because the RMP Folder#4 reports document that fact in detail. The independent engineering evaluation is useful to determine if it was possible to have connected and stay connected longer.
2. The base station (BBFARLIM2) was at the “‘Grain Loaf” (5.388290, 100.282694), not the one 2 km away at St John’s Ambulance Society as first assumed. I’ll explain the confusion in the note.
3. MH370 was at 5.2334, 100.2961 at 17:52:27. That put MH370 well within the BBFARLIM sector 2 antenna area of coverage at a distance=17km, az=175 degrees, el=31 degrees.
4. MH370 was headed on a track of 259.5 degrees at that time, making the track almost orthogonal to the line of sight bearing. Thus, the radial velocity was 30dB assuming omni antennas at both ends of the link. Assuming B777 glass loss=10dB, there was still a lot of margin. Assuming a low gain Base station antenna with no sidelobes, there was plenty of margin. Assuming a high gain phased array (19 dB), the plane could have been in the first side lobe with plenty of margin, or down 30 dB on the main lobe, and there was still plenty of margin.
BTW…all phased arrays have side lobes. The number and angles and gain relative to the main lobe are a function of number of elements, element spacing, phasing and more. The GE street photo of the antennas suggests a medium gain phased array…probably ~16 dB.
The previous post was somehow mangled after #3. It should read:
4. MH370 was headed on a track of 259.5 degrees at that time, making the track almost orthogonal to the line of sight bearing. Thus, the radial velocity was <50 kts, well within the Doppler capability of the base stations demods.
5. The link margin was greater than 35dB assuming omni antennas at both ends of the link. Assuming B777 glass loss=10dB, there was still a lot of margin. Assuming a low gain Base station antenna with no sidelobes, there was still margin. Assuming a high gain phased array (19 dB), the plane could have been in the first side lobe with plenty of margin, or down 30 dB on the main lobe (net gain -11 dB), and there was still plenty of margin.
BTW…all phased arrays have side lobes. The number and angles and gain relative to the main lobe are a function of number of elements, element spacing, phasing and more. The GE street photo of the antennas suggests a medium gain phased array…probably ~16 dB.
Victor: Are the characters “” special HTML characters? I think the use of those characters in my previous original post cased the text to be mangled.
That answers it! can’t use less than and greater than symbols…
<&rt;
< Yes you can > with escape characters
@all: in my opinion, the alleged Metéo report, the alleged RMP report, and the alleged raw Inmarsat data clearly cannot be trusted or used until Metéo, the RMP and Inmarsat, respectively, publicly endorse them as authentic.
Until such time, we have nothing to distinguish them from the many bits of DIS-information to which we’ve been treated on the MH370 file.
I think best practice, at this point, is for us to go back over the very earliest reports of MH370’s disappearance. Perhaps the truth was only visible until professional disinformers had time to get their operation up and running.
@ALSM
Street view of your new base station location.
http://tmex1.blogspot.com/2017/06/base-station-street-view.html
@ALSM says:
“The base station (BBFARLIM2) was at the “‘Grain Loaf” (5.388290, 100.282694), not the one 2 km away at St John’s Ambulance Society as first assumed. I’ll explain the confusion in the note.”
After much fiddling around in Google Earth, the best view of the Grain Loaf tower is obtained by:
(a) Input Position as: 5°23’18.54″N 100°16’58.27″E
(b) Enter “Street View” at that position.
(c) When street View opens, swing left to look back up the road onto heading 270 (west – ie have the “N” indicator at the 3 o’clock position).
(d) Pan Upwards.
(e) Bingo
Grain Loaf tower https://www.dropbox.com/s/c6o0nlpurelwrcs/V45-Grain-Loaf-Tower.gif?dl=0
Some interesting beam pattern and power level details for towers (pages 15, 16, 18, 19, 20) and power level / range requirements for a mobile phone to work reliably (page 30).
https://s3.amazonaws.com/ppt-download/gk-radiationnorm-btua-110130132947-phpapp01.pdf?response-content-disposition=attachment&Signature=DUhbFSI26awJyzw1HJCcanXmRlw%3D&Expires=1498441966&AWSAccessKeyId=AKIAJ6D6SEMXSASXHDAQ
@ASLM: The characters < and > delimit tags in HTML. If you wish to use these characters in text, you can use the HTML code sequences < and > , respectively.
@ROB
“… such is the seemingly intractable nature of the problem.”
On that point we are most assuredly in agreement.
This GE Image combines my background map with Don’s BBFARLIM2 overlay from RMP Folder#4 Diagram 3 plus Steve Kent’s digitized primary radar track. A second map tack at 17:53:27 illustrates how fast the window comes and goes. Not much time for a low Doppler state.
https://goo.gl/KWodLh
@Ventus45 @DennisW @ALSM @VictorI
Thanks for the confirmation on the new celltower location in Bandar Baru Air Itam. I checked over and over and knew I had to be right on this one when I started questioning the ‘St. Johns building’ celltower location.
I’m glad this seems to be solved now and it’s another case of the importance of reviewing all ‘evidence’ if there is good reason to doubt and question it.
I think it’s very positive people here are willing and able to solve this kind of questions together.
Implications are IMO the primary line of sight changes for with the new location this is blocked by the ~200 meter hills to the east and south.
As @ALSM and @VictorI explained earlier and I understand better now by the linked article, the detection could have been made when the plane was flying through one of those lobes.
I still question though if this was possible from the new celltower location regarding the hills and distance and altitude MH370 was supposed to fly at that time.
@Ventus45
And I like to say it was nice to see you found the new celltower location with the same GE-notation I used in reply on @ALSM on Jeff’s blog june 23.
I noted there an area around 5.23’11N 100.16’55E in Bandar Baru Air Itam but could not find a building there like the St Johns Ambulance Building while searching at all streets. Now I understand why.
But afterall I was quite close it turns out.
The different notation used by @ALSM gave some confusion otherwise.
@VictorI
On your question:
“Do you believe the radar data of the plane flying south of Penang Island at high altitude and high speed is fabricated? We might quibble over the exact altitude and speed, but do you really think the plane was flying at low speed and low altitude?”
I won’t say the radar data were fabricated but I indeed seriously doubt at least the route south around Penang.
When I look at the Lido-radar tracks I see the first track after Penang starts way west above see west of Penang. It seems to me the plane became only visible there for the Butterworth radar station after it past the western hills of Penang.
Further when you draw a straight mediate line through that first radar track towards Penang it crosses the island over land, not south over the see.
The second Lido-radar track past Pulau Perak puts the route even more north across the Island when you draw a straight line through it.
It leads directly over Georgetown to Butterworth.
Like you suggested before in another topic; maybe we are even dealing with two planes here. One crossing the island south and one (MH370) crossing the island north.
The north route over Georgetown could explain the cellphone detection better than the south route IMO. Although a south route over Penang would make odds of detection also more likely than the current route over see.
I think it is also important to find out in which direction section 2 of the BBFARLIM2 antenna is directed.
@Brock McEwen
I fully agree on the need to revert back to day 1 and not only reassess the evidence but question the validity and provenance of all the evidence.
Since the MY authorities from the very outset have mislead I question everything they offer. Too much of our crowd-sourced talent has blindly followed the crumbs placed by the MY authorities and gone down the rabbit hole.
Brock McEwen says:
June 25, 2017 at 5:47 pm
@all: in my opinion, the alleged Metéo report, the alleged RMP report, and the alleged raw Inmarsat data clearly cannot be trusted or used until Metéo, the RMP and Inmarsat, respectively, publicly endorse them as authentic.
Until such time, we have nothing to distinguish them from the many bits of DIS-information to which we’ve been treated on the MH370 file.
I think best practice, at this point, is for us to go back over the very earliest reports of MH370’s disappearance. Perhaps the truth was only visible until professional disinformers had time to get their operation up and running.
– sorry about the finger trouble above ….
@ALSM says: Re Cell Phone Registration:
“I will post shortly a more complete note on the cell phone connection at 17:52”..
Hopefully with a reference as to where the exact location is plainly stated to be,
so we can put this matter of the Cell tower location to bed. Permanently.
________________________________
@Ge Rijn said;
“the other cellphone connections of other crewmembers. I recall two were mentioned long time ago.”
VictorI replied;
“As for the claim that there was a connection to a cell tower on a Penang bridge, that is based on
the following comment on reddit:
(karl-erik)..”saw an internal memo from Abdul Farim Fakir Ali, CTO of Maxis”
I see zero basis for believing this claim.”
Perhaps Ge Rijn would like to chase this up, as it bothers him so much, to see if this individual ever saw any such memo or made any such post…;
http://www.digi.com.my/aboutus/corporate_overview/senior_management_team.html
https://my.linkedin.com/in/karl-erik-brøten-0b04552/de
@buyerninety
We’ve been through this other cellphone connections long time ago on Jeff Wise´s blog.
I’ve searched back then for this Abdul Farim Fakir Ali, CTO of Maxis and I found his curriculum vitae some where and indeed has been a CTO of Maxis at the time.
I suggested to Jeff Wise back then if it would be possible for him, being a journalist, to contact this man. I suppose he wasn´t and there the lead stopped as far as I was concerned.
buyerninety:
I gave you the references above (“…RMP Folder#4 Diagram 3 plus Steve Kent’s digitized primary radar track…). The ambulance site was originally thought to be the most likely basestation site meeting the publically available description… until the RMP files were leaked. Once we had Folder #4, we had the detail needed to locate it more accurately. It is the RMP map that tells us the Grain Loaf was the BBFARLIM2 basestation site. Don’s overlay nails it. Steve’s radar track nails the position of MH370 at 17:52:27. The rest is math.
The BBFARLIM2 basestation location confusion arose because the Grain Loaf is not (or was not at the time) a Celcom site. It is a Maxxis site. The ambulance site is a Celcom site. (Must have had some sharing agreement?) Anyway, they are only 2.5 km apart. The basic link analysis is unaffected by a 2.5 km difference (0.5 dB and 3 degrees in el angle). So nothing important changes from learning that the true location was the Grain Loaf. The link analysis I did last year is still valid. It shows that the connection was technically possible, the location of the plane at the time of the connection was in fact the ideal location for minimum Doppler.
@buyerninety §VictorI
I did a quick search in Linkedin.
Carl Erik Broten is still a CFO at DiGi Telecommunications Malaysia like he was when MH370 disappeared.
https://www.linkedin.com/in/karl-erik-br%C3%B8ten-0b04552/
He has a premium Linkedin account so I cann´t send him a message this way to ask about the other cellphone connections.
Maybe someone with a premium Linkedin account can send him an in/mail message.
@ALSM. With a cellphone location derived for purpose of “location based service”, how accurate would you anticipate that location is in range/azimuth from the tower that it connects to? Do you reckon that range would be better than +/-1km? I also wonder if the report writers were diligent enough to translate a slant range into a horizontal range with altitude assumption?
@Ge Rijn
Then the matter stands exactly as VictorI stated;
“I see zero basis for believing this claim.”
SO there is no need for you to keep bringing it up again, as you have
done about every 3 months in the past, unless you actually have new
evidence about it.
@ALSM
Sorry, that’s not a reference, that’s an opinion based on a map the size
of Penang, and a radar track determined by someone named ‘Steve Kent’ that
you gave no reference as to where it might be found, resting on math that
you did not refer to where it may be found so it can be checked. Some
scepticism is in order.
Paul Smithson: The accuracy is really not that important wrt the link analysis. The connection was possible from horizontal distances between ~5 and 32 km. It would have been strongest at the maximum possible distance (due to the antenna pattern), which is 32 km, limited by the network timing protocol.
buyerninety:
What are you trying to prove? What is your point? Are you disputing that the cell phone registered at 17:52:27? Are you disputing the validity of the RMP reports and maps that clearly show the BBFARLIM2 sector 2 area of coverage and the BBFARLIM2 location? Are you disputing the digitized primary radar track (which is almost identical to the track in the RMP overlay)? What exactly is it that you are still skeptical about?
It seems to me that the technical questions are answered. The connection was confirmed by Celcom logs and the RMP. The independent technical analysis shows it was definitely possible. It also shows that there was only a narrow window of time…maybe 1 minute at most…that the phone could have been connected (due to AOC and Doppler). The important questions that remain concern not the technical feasibility, but instead, what was going on in the airplane at 17:52:27? Was the connection a failed attempt to make a call? Was the connection simply an automatic registration resulting from a incapacitated FO leaving his phone on? Probably won’t be able to answer these questions unless the black boxes are recovered.
@Ge Rijn: There is an email address on this page if you wish to follow-up:
http://www.mnbc.com.my/www/lang/en/show.do?page=11;15
@VictorI
Thanks. I emailed him.
This is my mail to him:
Dear Karl Erik Broten,
Let me first introduce myself. I am Ge Rijn from Holland. I am as a private person very interested in the whereabouts of MH370 since it disappeared 8 march 2014.
Now in a discussion your name comes up again as the man who posted a message on Reddit long time ago in which is stated that you saw a memo from Maxis CTO Abdul Farim Fakir Ali.
This memo was telling at least one more cellphone connection from other crewmembers was made from a celltower on Penang Bridge.
Many people seem to think the message was a hoax and the messenger a fake using your name.
Could please confirm to me if the message and it’s contence was genuine and you posted it back then?
I would really appreciate it for then we can put this important information in perspective one and for all.
With kind regards,
Ge Rijn
For those that missed it…the digitized primary radar (originally calculated and posted by sk999 in Jan 2016 and in .kmz format by me in May 2016) is here:
My .kmz file: https://goo.gl/fkFZ7s
sk999 original spreadsheet: https://goo.gl/CkcUsR
@Ge Rijn: By the way, the poster on Reddit never claimed to be the Maxis executive you identified. The Reddit poster used a first name that coincides with the first name of this individual. Is there further evidence to make this association?
And why do you assume the connect was made with a cell tower on a Penang bridge? There is no mention of this in the Reddit post, although a Twitter user continues to make this claim.
[Added]
OK. I now see that Jambatan Pulau Pinang is translated as the Penang Bridge. But that reference to a third cell phone connect on a Digi network is a rumor that was reported in a rumor. That makes it even less credible than second connect on the Maxis network.
@ALSM
You declined to provide the informational items I enquired about. To short circuit our
discussion, I will state I am extremely happy to accept that is the location of BBFARLIM2,
if Ge Rijn accepts that is its location, and therefore never again has to post
questioning ‘where is BBFARLIM2’. I feel I speak for DennisW, who I fear after having to read
about this question raised again, has put his Glock 21 to his temple and blown his
brains out in exasperation.
@David
Abdul Farim Fakir Ali was a CEO of Maxim. I looked it up back then and found his CV.
Penang Bridge was named specifically among other location(s). I don’t know where anymore. There was even a GE graphic with the location of the celltower on the bridge.
We’ll see if and what Karl Eric Broten will reply.
I don’t have other clues either.
@VictorI
Sorry that post was for you not for @David. Just ended a post to @David on Jeff’s blog…
@buyerninety: We already have agreement on the location of BBFARLIM2.
@Ge Rijn: See what I added to this post.
@buyerninety
Sorry but you are not correct. This time @Don Thompson brought up the cellphone and tower subject june 23. And I’m glad to for at least it has cleared up another matter it seems to me.
But I had a big laugh with your comment speaking for @DennisW..:-)
@Ge Rijn @Victor @DennisW
OK that is the obscure reference to possible crew member cell phone connects that is was remembering…thank you. Supplemental to that, was there also a mention in the RMP police report that flight crew member cell phone connects were searched for? As opposed to PAX, which Victor suggests the PAX cell phone connects may not have been searched for.
@VictorI
I’ll reserve my reply for in ‘3 months time’…
@Oleksandr
Did you progress further with your “trivial” reason for the FMT (of 180°), and did you
come to this reason through reading my previous suggestions (and does the reason come
about as a result of removal of waypoints?) ?
Just one more thing on the cell tower. Hope @buyerninety doesn’t hit his head against a wall..
I think I found the direction of sector 2 from BBFARLIM2. Those antenna sector directions seem to be standarised.
Sector 2 is covering the 90 degree south/east region. Which than indeed would be directed towards the flight path MH370 is supposed to have taken south/south-east of BBFARLIM2.
See page 37 in this link:
http://wispd.org/attachments/2015Conference/pdf/Mattert_Weitz_Understanding%20and%20Plotting%20Cell%20Phone%20Information.pdf
@Ge Rijn
Thankyou for your link in regard to U.S. cell tower/antenna sector information.
I believe I will be contacting the author(s) at the email address therein, in
regard to another unknown location/missing mystery (totally unrelated to MH370).
In regard to MH370, may I politely suggest the direction of sector 2 is more
likely to be that as shown in the RMP report ‘Folder Appendix (1).pdf’, Appendix
K-2, Google Earth picture 2.
Cheers
Sector 2 covers nominally 120 degrees from ~160 to ~280 degrees. Look at the Celcom coverage map (Folder 4, Diagram 3, Page 21) and as posted here: https://goo.gl/KWodLh.
@ALSM
Yes, ofcource 120 degrees (not 90..). But would ~160 to ~280 degrees not be sector 3 that covers the south west section?
I cann’t see the sector in your posted link.
@VictorI
I found the source and contence of the Reddit message.
I copied it myself from Reddit in november 2016 and posted it on Jeff’s blog:
‘From the current Reddit-discussion I copied the following:
“I saw an internal memo from Abdul Farim Fakir Ali, CTO of Maxis, saying that they picked up a call attempt from a “crew member” originating on a cell tower covering Perhentian Besar. He also implied that Digi may have something from a different crew member near or over Jambatan Pulau Pinang.”
Perhentian Besar is an island on the north-east coast of Malaysia not far from Kota Bharu.
Jambatan Pulau Pinang is the northern 13.5km long Penang Bridge connecting Penang Island to mainland Malaysia.
@Ge Rijn: This discussion is going in circles. See here and here.
Perhaps you’ll get a response from the Digi contact.
@ALSM
Mike, for the sake of clarity can I please confirm that “the digitized primary radar” refers to a digitized version of “Fig. 4.1 Primary and secondary radar data available for MH370.” from the Bayesian Methods paper, sometimes referred to as “the 10 second radar data”.
Mick:
Yes, you can read more about sk999’s analysis here: https://goo.gl/zFPTKd
The link to his digitized route can be found on (unnumbered) page 3.
All (except for Brock, since I don’t have full names of anyone behind the data, so it is not worth your bother):
Updated MH371 BTO/BFO analysis available at the usual URL:
https://docs.google.com/document/d/14hleZyx1pUPL44yaeHKt6jnSQ3DbgRq2zibbKkFLq2c/edit?pref=2&pli=1
Addendum:
For those in search of digitized radar data, check out the additional links labeled “Data Source” and “RADAR”.
For those who asked questions that I have not yet answered – it’s a busy time of the year.
@sk999. “The BTO turns out to be not quite as well-behaved as we thought”. Indeed! Very valuable analysis and thought-provoking. I hope that a suitable peer can reproduce and confirm.
@sk999
Thank you for your Updated MH371 BTO/BFO analysis. I’ll happily admit that a lot of the technical discussion is beyond me but I think I understand what you are getting at. If you have a moment could I please trouble you to expand on the last sentence,
“We are still waiting to see a situation where the drift is as systematic as is required for the uncommanded autopilot routes that end at -38 deg latitude.”
Many thanks.
That sounds plausible. But they could have collected the numbers via NoK after the fact. Cell phone connections would be an important part in understanding what happened and even where it happened.
@Peter Norton: When you consider that the FO’s cell connection was never mentioned in the FI, it suggests that Malaysia is down playing the significance of the cell phone data. We can only speculate as to why that is.
@sk999
I don’t find that your data is significantly different than the DSTG data. Your horizontal axis of “hours” vs figure 5.3 of Bayesian Methods in “days” makes direct comparison more difficult.
@sk999
Your Figure 3, BTO residuals.
Consider an FMC Position Report transfer, e.g. 03:29. The plot seems to simply depict the difference in BTO for each R-ch burst, carrying the report, from a calculated BTO that is derived from the last a/c position given in the report.
Do note the latency involved from the time of generating each FMC report, through to requesting access to the T-ch, and transmitting each T-ch burst.
@Don
“Do note the latency involved from the time of generating each FMC report, through to requesting access to the T-ch, and transmitting each T-ch burst.”
That is an interesting point. I would assume that position data generation and transmit times are asynchronous.
@DennisW,
That’s a correct assumption.
The latency from the FMC timestamp of the last position in the report, thru to the SDU’s request for access to a T-ch varies from 4 to 14 seconds.
@All
Here’s an expensive manual, if anyone’s got a purpose and the dollar to buy it.
http://m.ebay.com/itm/191529699894?_mwBanner=1
@Joseph
The manual is also listed in the Melbourne, VIC, library system. If any reader is in that locality I’d gladly provide the details (with the expectation for that individual to scan & distribute a copy).
Don Thompson,
All times are the GMT times given in the ACARS Position Reports themselves, not the timestamp of the packet transmission. I cross-checked the one MH370 Position Report against Factual Information to make sure I was decoding it properly.
However, the route defined by the ACARS positions is a little strange. It starts out following airways G212 and B458 – but off by a few miles, then heads off into left field as it approaches Hong Kong. Not clear what is going on. The MH370 ACARS track was also off a bit compared to the ADS-B data from FR24 and FAW.
DennisW – I was looking at the scatter in the outliers of the BTOs, not a detailed point-by-point comparison.
Mick Gilbert – the routes to the far South (LNAV and true track routes) all leave a systematic linear trend in the predicted v. measured post-FMT BFO values extending over 5+ hours. We now have BFO values for three flights (MH21 in the JON article, the Mumbai flight in Bayesian Methods, and MH371) and none exhibit that linear trend, although drift and other oddities are seen.
@sk999
Very good, thank you for that explanation/expansion.
@sk999 re paths to 38S. BFO drift amounts to only about 8hz residual doesn’t it – so very nearly within the original estimation of BFO error bounds and comfortably within more recently-popular, slacker confidence limits?
OK, I found one silly mistake (had to do with how I distinguish geodetic from geocentric latitudes). New versions of .par files have been uploaded (but if you assume the latitudes are geodetic, there is no need to refetch). New figures have been generated. The systematic drift in BTOs in the IOR satellite data is reduced, while the drift in BTOs in the POR satellite data are a little worse (more of a systemic offset).
Paul Smithson,
I get a drift of 12 hz from the 18:39 attempted phone call to the 00:11 ping for my most Southerly route. It’s not just the amplitude – it’s the systematic nature of the trend over that time that stands out. Bayesian Methods, Fig. 10.7, shows the same qualitative trend, albeit the details are different. What is the probability that one could randomly sample points from the known flight paths and generate a set of residuals with properties equivalent to those of a far-South route? I have no definitive answer, but the question should be answerable.
@sk999
One can predict BTO from the final entry in each Position Report but that’s not coincident with the time at which the Report hits the datalink & the first block’s BTO is measured at the GES. An additional 15sec (approx) of latency is implied for each subsequent SU & block involved transferring the report.
While the latency is inherent in the path from originating avionics function through DCMF, the SDU, and to the GES, it is quantifiable from the Log time of the received SUs.
I’d like to understand how the latency & corresponding position offset from the Report location is considered in your report.
Don Thompson,
I think you misapprehend what I am doing. I do not assume that the BTO of any particular transmission is synchronous with any particular ACARS position report. I take all the positions from each POSITION REPORT message (normally 6 total, spanning 30 minutes), calculate the BTO for each of those positions (each tagged with a GMT), and then interpolate in time to get a predicted BTO for any particular R-channel transmission that has a BTO associated with it; whether the transmission is a POSITION REPORT, a RR engine report, or an IFE logon report is of no consequence.
@sk999
Thanks for the explanation, I wasn’t 100% clear on the interpolation part. I did not differentiate adequately between a synthesized BTO for the given position reports and a prediction by interpolation.
So your plot, Figure 3, shows difference between BTO measured at the GES, and a predicted BTO, for each R-ch burst.
@sk999. I’m not sure that I have grasped what you are getting at. Your path model to 38S suggests drift/residual up to 12Hz, mine 8Hz. Bayesian Methods fig 10.7 residuals from all/any probable paths also indicates drift of similar magnitude. One-directional drift, we are told by folks like DW, should be expected and DSTG acknowledges the same but is unable to model/account for it without knowing a priori which direction drift should go. So what is not to like? Most probable path (38S hotspot) has a one-direction BFO drift and this is expected behaviour of the oscillator.
@sk999. I’ve looked at your updated figures. The amplitude of BTO drift is now more consistent with that reported by DSTG. Does it not look to you as if the BTO “drift” has a half-wave period of about 6 hours in both IOR and POR cases? If so, it suggests to me that the most likely candidate explanation is that the orbital model is a bit off (eg max difference when sat is moving at maximum speed N-S or S-N (crossing equator), and min difference when it is at “top”/”bottom” of its orbit.
sk999, Paul, Don…
There are several *potential* sources of BFO error and “drift”, but virtually none for the BTO bias values. Between a transmitted pulse from the GES and the received pulse in response (both times referenced to a rubidium or cesium clock), the only possible source of delay not attributable to propagation range is in the AES/SDU digital hardware logic, and that delay is fixed in hardware by design (design not to exceed 300 usec). I suspect something must be wrong somewhere in the calculations if there appears to be drift in the BTO bias.
@ALSM said: I suspect something must be wrong somewhere in the calculations if there appears to be drift in the BTO bias.
The BTO errors for flight MH371 drift in the opposite directions for the IOR and POR satellites, and the drift disappears once 9M-MRO was on the ground at KLIA, as if the position or time is off a bit during the flight. I don’t know how that would occur unless the GMT value in the position reports is not accurate. It is hard to imagine that the GPS-derived position is off.
@Don T
Your latency observations interested me relative to the 142Hz BFO at 18:25:27 (which is spot on for the track and speed of the aircraft at that time), and the 273 Hz BFO at 18:25:34 (which cannot be explained by any reasonable aircraft maneuver). The 7 second time difference is certainly inside your latency range. Is it possible that the SDU only updates the Doppler correction parameters at fresh position reports?
If so, it is easy to show that the 273Hz BFO can be explained by a 10 degree turn to the North from the 296 degree track if the SDU is still using the velocity parameters at 18:25:27. 10 degrees in seven seconds is reasonable.
@ALSM. If the satellite position is out (from that used in the “predicted BTO” then of course you will get a BTO error. That’s my point – the ~6/12 hour period on BTO drift suggests to me that satellite position error might be a probable cause.
@Paul
That could be. I tried to find information on how and when the orbit of 3F1 was last checked, and came up empty. I am sure Inmarsat knows, and their published position and velocity data in the ATSB report agrees virtually perfectly with sk999’s orbit model.
@DennisW
I do not expect any correlation between the SDU behaviour and the collation of the Position Reports.
Collating the Position Reports is a periodic function in the FMC: collate a report entry every 5 minutes; consolidate and forward to Ops at every 6th Report.
Delivering the Position Reports to the Ops team back in KL isn’t a priority task for the FMC, at 18:25 the aircraft had long deviated from the originally planned WMKK-ZBAA route. Unknown if the FMC would have even been generating reports after deviation.
The SDU will continuously receive ‘IRS’ data updates, sourced at the ADIRU, from the DCG Function on AIMS. I can’t be definitive, but the update rate should be in the order of 20-50Hz.
The characteristic of the BFO samples at 18:25 thru 18:29 looks like an OCXO overshoot?
@ALSM, SK999, Don, Paul, Dennis
If GPS updating had been disabled following the FMT, could it result in the observed, progressive BFO drift? A gradual drift in the INS calculated position and velocity might affect the velocity data fed to the SDU enough to show up as a progressive BFO shift away from the expected value as the flight proceeded south?
Rob:
If the INS lost the long term position accuracy it gets from GPS, then the 3 axis rate gyro drift would determine the added BFO bias error. But that drift is very small. After crossing the Atlantic, the gyros will be within ~10nm. And air data (IAS) would continue to be an input to the kalman filter. Given all that, I don’t believe the loss of GPS could contribute more than maybe 1Hz of additional BFO bias error.
@Don
Thanks. Just fishing on that one. I agree that the overshoot is a valid explanation. Still, I am troubled by the virtually perfect BFO at 18:25:27.
@VictorI
On your reply on discussing in circles. I just wanted to be complete.
An important subject gets shoved under the carpet this way.
@ALSM stated with absolute certainty the St’Johns Ambulance Building was the location of the celltower that made the FO connection.
Only after my persistent arguments and proof he decided the location was where I said it had to be but citing other arguments for that decision.
This location and low range urban celltower is directly surrounded by ~200 meter hills. So Imo this celltower could not have detected the FO cellphone at ~16km distance to the south flying through lobes of this low range celltower. And no other celltower in between detected the FO cellphone if we have to believe the RMP-report.
So Imo the south route over see around Penang can not be right. It had to be further north.
I find a bit disturbing that a before stated as 100% fact gets changed with good reasons but the obvious implications get shoved under the carpet.
@Ge Rijn if you look up the distance and elevation of those hills I think you will find that they are insufficient to provide terrain masking for an aircraft that is at x angle of elevation (about 16kms horizontal and 10kms vertical).
@Ge Rijn: Nobody is brushing anything under the carpet. First, I posted a comment suggesting that the location of the cell tower was not a settled matter, and solicited help. You believe that the hills would obstruct the line-of-sight between the now identified cell tower and the airplane. Let the readers here comment. You already have one comment from Paul.
@Paul Smithson
Yes that might be true. I find the masking angle is about 20.000ft.
But then for a low or medium range urban antenna with a max reach of ~8km in its strongest horizontal radiation field to detect a cellphone at 16km distance at 10km altitude in a lobe is hard to believe. Especially where no other celltower detected the cellphone in between.
..and a lot of celltowers in the south of Penang detected the cellphones during the flight-tests but none were detected by BBFARLIM2.
It just doesn’t fit.
Joesph Coleman said; “Here’s an expensive manual”..”
Yes, I noticed that last week. I would caution anyone contemplating purchasing that
that the revision dates on the front cover show it is quite old (1992).
@Don Thompson
Perhaps you could give the reference URL you saw that listing at – is the revision
given (later than the above sale item mentioned)?
@DennisW
If you could remind me, what magnitude of movement would the 273hz indicate (laterally)
if it were assumed that the only causal factor was (an instantaneous) lateral movement?
Cheers
I just had another look. The hills ~300meters south of BBFARLIM2 have an altitude of +340 meters and a few hundered meters more south its +400meters. That takes the masking altitude above 35.000ft at 17km distance.
@Andrew said;
“If the ADIRU is inoperative, the only lateral AFDS mode available is HDG SEL. The
pilots must steer the aircraft by selecting headings to maintain the desired track.”
Could you expand a bit on what events transpire when this happens? e.g. (given LNAV in prior operation) does the FMS ‘drop’ out of LNAV? Is this the programatic response of
the FMS?…
@buyer90
“@DennisW
If you could remind me, what magnitude of movement would the 273hz indicate (laterally)
if it were assumed that the only causal factor was (an instantaneous) lateral movement?”
No realistic amount of lateral movement or altitude rate of change can account for the 273hz. It would require an error somewhere in the BFO chain – i.e. AES oscillator offset (popular explanation).
Ge Rijn:
The following graphic overlays show that at the point when the cellphone registered with CelCom:
1. it was 17 km from BBFarlim on an az=175 degrees
2. it was inside the sector 2 AOC
3. it was LOS for any altitude above 11,000 feet at that location
4. it was LOS above 15,000 feet for 1 minute before and 1 minute after 17:52:27
green= 5000 feet
yellow=10,000 feet
orange=15,000 feet
red=20,000 feet
https://goo.gl/LCegb6
@Ge Rijn
“That takes the masking altitude above 35.000ft at 17km distance.”
I disagree, & confirmed by two methods. It’s relatively easy to code a 3D fan shaped KML polygon, centred at BBFARLIM2 with its circumference describing the flight path. That polygon does not impact the high ground even with its circumference, the flight path, at 7772m (25500ft).
The conclusion, resting on the (unknown) specification of the BBFARLIM2 site’s sector antenna, is that the LBS registration was possible.
The GE elevation plot for the line connecting BBFARLIM and MH370 at 17:52:27 indicates a high point of 1119 feet at a range of 1.12 miles. This would be LOS at 10,496 feet and above at 17 km. This is consistent with the ~11,000 foot estimate obtained using the Cambridge PIXIL tool used in the previous overlay.
https://goo.gl/uWx1N6
All,
I have updated the two BTO plots in my report once again. This time, BTOs from the R600 channel are plotted in magenta. The biggest outliers are almost always these types of transmission. The rms is definitely bigger than for the R1200 channel, but it doesn’t appear very Gaussian (although the total number of points is too small to say for sure.) In any case, it has long been noted that the 18:25:27 logon BTO was systematically low compared to the subsequent BTO’s (including the corrected anomalous BTO at 18:25:34). The present result suggests that such an offset is not unexpected.
Note that at least two R600 transmissions through the POR satellite were not logon requests but rather were vanilla transmissions. Perhaps low signal strength caused the SATCOM to downgrade.
A refinement that needs to be made for BTOs when the plane is parked at the gate is to identify which gate. I am using generic coordinates for ZBAA, and for KL I am using gate C1. Beijing airport is big, so using the coordinates of the proper gate might make a difference as well. (One should also delete points that were generated while the plane was taxiing.) Does anyone know which gates Malaysia Airlines was operating from in Beijing?
@Don Thompson, @ASLM: I think you’ve shown that a cell phone connect from BBFARLIM2 to MH370 at FL350 is possible. Thank you for your comments.
sk999: Did you get my email?
ALSM,
“sk999: Did you get my email?”
Nope. Just to be sure, I’ll have a look at Microsoft’s super-helpful spam filters.
ALSM
Yep, MS considers your contributions to solving the mystery of MH370 to be “Junk”. Such nice folks.
Victor:
I think the same cellphone analysis shows that MH370 was not flying at a very low altitude, as a few have suggested. Based on the LBS registration time, radar data, terrain and antenna patterns, all we can say for sure is that it happened, and MH370 was probably somewhere between 35k and 15k feet at the time… not lower than 10k.
@buyerninety
RE: “Could you expand a bit on what events transpire when this happens? e.g. (given LNAV in prior operation) does the FMS ‘drop’ out of LNAV? Is this the programatic response of
the FMS?…”
The normally FMC provides LNAV steering commands to the autopilot. If the ADIRU fails, the FMC no longer provides steering commands because it does not have a reliable heading reference. Consequently, the LNAV autopilot/flight director mode will fail and the crew must select another mode to steer the aircraft. The FMC, however, will continue to navigate using GPS data, if it’s available.
The SAARU will provide three minutes of backup heading information to the PFD/ND, based on the ADIRU heading immediately before the failure. The crew must periodically update that heading by inserting the standby compass magnetic heading in the FMC. Once the heading has been updated, the crew can use HDG SEL to steer the aircraft along the flight planned track.
From Aviation Week. Airbus To Fit Deployable Data and Voice Recorders On Long-Range Aircraft
Jun 21, 2017 Helen Massy-Beresford
Airbus will implement automatic deployable flight recorders and as well as lighter and more compact fixed cockpit voice data recorders on its airliners.
Airbus will fit new fixed and deployable combined flight data and voice recorders as standard on long-range aircraft starting in 2019 in a bid to make it easier to find aircraft wreckage in the event of an accident over the sea.
The Toulouse-based manufacturer has teamed up with commercial and military avionics specialist L3 Aviation Products as well as DRS Leonardo to develop the devices, which will be fitted on the A350 XWB first, beginning in late 2019, before being offered on A380s, A330s and A320LRs, too.
L3 will design and manufacture the lighter and more compact fixed, crash-protected cockpit voice and data recorder (CVDR), which will be able to record up to 25 hr. of voice and flight data, in line with new European Aviation Safety Agency and International Civil Aviation Organization requirements that require an increase from the current 2 hr. of voice recording.
L3 and Airbus will integrate the automatic deployable flight recorder (ADFR), designed and manufactured by DRS Technologies Canada, part of Leonardo DRS.
The ADFR will be fitted at the rear of the aircraft and is designed to deploy automatically via a preloaded spring system in the event of water submersion or significant structural deformation of the aircraft. It can float and is aimed at long-range aircraft that fly for extended periods over water or in remote areas.
The crash-protected ADFR can also store up to 25 hr. of recorded cockpit voice and flight data. It is fitted with an emergency locator transmitter to help rescuers locate and recover it rapidly.
The plan is the result of discussions about the difficulties of locating aircraft that have crashed into the sea, following the Air France Flight 447 crash in 2009 and the disappearance of Malaysia Airlines Flight 370 in 2014.
“We have had a few cases recently where everyone is frustrated because they just don’t know what happened,” Charles Champion, executive vice president of engineering at Airbus Commercial Aircraft, said at the Paris Air Show. “Of course, we could think about real-time transmission of data—it will come eventually—but in the meantime, especially in very remote areas, you need to think of a hard solution in order to be able to answer all the open questions.
Airbus said two of the new fixed CVDRs will be deployed on shorter-range A320 airliners.
“This is about Airbus’s wish to go beyond the regulations to improve the chances of recovering data in the event of an accident,” Airbus Product Safety Enhancement Manager Géraldine Vallée told journalists at a briefing in Paris on June 15.
She added that the company has done feasibility studies into retrofitting the deployable recorder and concluded that it was technically possible but would be very expensive because of the large-scale restructuring of the aircraft’s cables that would be needed.
@David
I don’t buy into the lack of real time position broadcasting. On my motorcycle adventures I carry a DeLorme Inreach that broadcasts my position to the Iridium satellite system at a selectable interval. My SO uses a similar SPOT device. Both devices have emergency activation capability as well as the ability to send distress messages as a text message or email or both. When SO or I travel with the devices the path is readily accessible on a WEB page with a Google map display. Coverage is Global for both devices – Iridium being preferred to the SPOT Globalstar system. Cost for the devices is low (<$300) and annual fee is cheap (~$100).
Sure, I am not sending fuel remaining, oil pressure, and temperature data from my motorcycle. What I am sending is position updates with the ability to activate a distress message any time I want to. If MH370 had a DeLorme or SPOT unit in an inaccessible (from inside the aircraft) location we would have know where it terminated within a couple of kilometers or less.
It is hard to understand why something like this has not been implemented in commercial airliners. Sure, it would be more expensive than consumer grade devices, but the cost would not be at all prohibitive.
Dennis:
The technology to track airliners has not only been available for 30 years, nearly all of them already carry the equipment onboard necessary to use it. But many do not use it because they don’t want to pay the cost.
Anyway, the thrust of the article was “Deployable Data and Voice Recorders”, not real-time communication. Deployable Data and Voice Recorders would be new (for commercial jets) and a worthwhile improvement in safety.
David and Dennis:
I should mention…many of my soaring friends have ditched their ELTs and now carry Spot Devices on their parachute (not the glider). Much better for routine tracking and ground crew support, not to mention the emergency alert capability.
@ALSM
Yes, SPOT or DeLorme is a no-brainer relative to safety.
Being the anal person that I am, I made Ami go to the garage and practice tire changing on the Subaru and 4×4 trucks we drive. The whining was almost unbearable. Still the roads between our ranch and beach places are largely without cellphone coverage, and very sparsely traveled.
Likewise I make her stay current on CPR. Response time is critical, and local skills are vital. Survival chances decrease by 10% per minute (huge statistical basis). I can’t get to a patient in 10 minutes in the rural areas where we live. I am batting 1 for 9 in bringing people back from the dead. I even rag on my riding brothers to stay current in CPR. My life might depend on it. It is such a simple thing to do.
So it goes. I cannot imagine a responsible airline CEO not implementing some form of uninterruptible tracking. Makes no sense at all to me. It is not a technology problem.
Blah, blah, blah,…
@sk999
You wrote, “Note that at least two R600 transmissions through the POR satellite were not logon requests but rather were vanilla transmissions. Perhaps low signal strength caused the SATCOM to downgrade.”
Yes, one of the POR Log Ons (or protracted, unsuccessful Log On attempts) was processed without the GES switching from the P600 to a P10500 channel.
I’d suggest using only R1200 and/or T1200 channels for the analysis you’re working on. The specification for the R1200 and T1200 burst structure (symbol rate, preamble and UW periods, and interleaver blocks) is identical, so, allowing comparison of “apples to apples”, if you will. Given the understanding to normalise the BTO associated with the R1200 Log On Acknowledge bursts, the R600 is somewhat unnecessary (or at least should be treated separately).
sk999, Don: Here is the R600 vs. R1200 vs. T1200 BTO Bias Calibration from 2014:
https://goo.gl/bTvWg1
We should review this in light of the new data.
@all
I don’t know for sure but most here seem to keep poking on all this BFO/BTO data like a fetisch. Like a distraction of other facts like the debris, debris damage, drift studies, cellphone connection(s), sim-data.
What’s the point. Is the IG getting payed for defending the ATSB/Malaysian narritive or so?
The reluctance to view a different standpoint becomes a bit suspicious to me.
Every other argumented view gets downplayed or denied with insufficient other arguments and after this silenced.
Like @ALSM still sticking with the ATSB scenario that dictates a high speed unpiloted dive and impact.
While all other information clearly shows this could not have been the case.
What are you all defending and why?
@Ge Rijn: Please stop with your accusations. First you accuse people of brushing under the carpet the probability of a cell phone connect with BBFARLIM2 (which nobody did) and now you ask whether the IG is payed for defending the ATSB/Malaysian narrative (nobody is payed). Disagreement with your opinions doesn’t mean improper actions.
The truth is, members of the IG have expressed disagreement with the ATSB about where the ATSB is proposing to search next. I have even posted an article questioning the ATSB’s and CSIRO’s interpretation of their drift model results, and another article proposing a descent at 18:40 with a later FMT. How does that reconcile with the official narrative?
You claim all the data contraindicates a high speed dive. I’d say the BFO values are the best evidence we have of an aircraft in an increasingly steep descent. And I’ve yet to see any credible structural, fracture, or impact analysis that suggests a ditching occurred. That’s not a swipe against those trying to analyze the evidence. Rather, it’s recognition that it’s almost impossible to definitively conclude anything based on the few parts we have, the limited photographs we have access to, and the crude and simplistic approaches towards modeling very complicated parts.
@David,
“Airbus To Fit Deployable Data and Voice Recorders On Long-Range Aircraft”
Sellers gotta sell!
Considering the record of avionics devices to autonomously trigger, and operate reliably as required, in accident situations (e.g. ULBs & ELTs) I remain to be convinced of the benefits of a deployable recorder. It is reassuring that the Airbus concept intends to duplicate, rather than replace, the existing fixed recorder with a second recorder in a deployable housing.
A full implementation of ICAO’s GADSS could deliver a faster, and more comprehensive, path to distress alerting & location tracking. GADSS phase II comes with Aireon’s satellite based ADS-B relay, while the airborne segment of phase III compliance should be retrofit-able by means of an updated ELT. Airbus considers deployable recorder units as a new-build, line fit option only.
Ge Rijn:
Re your statement: “I don’t know for sure but most here seem to keep poking on all this BFO/BTO data like a fetisch (sic). Like a distraction of other facts like the debris, debris damage, drift studies, cellphone connection(s), sim-data.”
The BTO and BFO data are among the most useful data sets we have to locate the plane. Analysis of the new BTO/BFO data is important. We are learning new things, and validating some previous theories. It is no fetish. Moreover, it is no distraction. IG members and other serious independent investigators have spent countless hours on “…debris, debris damage, drift studies, cellphone connection(s), sim-data…”. Indeed, I posted several times over the last few days to show why the your June 28, 2017 at 1:44 pm tweet was wrong, and why we can be sure that the 17:52:27 cell phone contact was indeed consistent with all the known facts.
Re your statement: “Like @ALSM still sticking with the ATSB scenario that dictates a high speed unpiloted dive and impact. While all other information clearly shows this could not have been the case.”
This statement is 100% pure rubbish. First up, I have never stuck “…with the ATSB scenario that dictates a high speed unpiloted dive and impact”. My analysis is independent, and I reached that conclusion long before ATSB came around to publically acknowledging the undeniable implications of the 00:19 BFOs, missing IFE logon, simulator trials, debris size, etc. In addition, contrary to your assertion, I have never stated that a rapid descent is necessarily tied to an unpiloted descent. So, once again, you are mangling the history and the facts. Moreover, there is zero “…other information clearly show[ing] this could not have been the case…”. All rubbish.
And your assertion that “…the IG [is] getting payed (sic) for defending the ATSB/Malaysian narritive (sic)…” is baseless crap. Knock it off…please.
Final thought: I get the impression that your IG attacks are based more on your impulse to distract the rest of us from your wrong analysis of the cellphone link analysis and geometry. Maybe you should start by acknowledging that it was indeed possible.
@Ge Rijn,
I have noted that your comments here are frequently founded solely on your opinion. Your opinion counts for zip without some critical thought and/or analysis to reinforce it.
Perhaps your opinion might be better received elsewhere.
You mentioned consideration of “debris, debris damage, drift studies, cellphone connection(s), sim-data.“. Each one of those subjects has been given considerable analysis by members of the IG. For example: my own efforts to identify debris items; Kenyon’s work on collating information relating to and analysing damage; RG’s work on drift studies; the analysis of the cellphone connection (related in this comments thread); and Victor’s substantial effort to engage an expert, and co-author an analysis of the pilot’s PC simulator data.
That all takes a lot more effort & time than casting a few opinions into a comments thread.
You decide, step up to the plate or switch to listen mode.
I think you better step up to the plate of reality and try to get a more realistic view not mainly based on confirmation-biased BFO/BTO’s and fuel-economy, downplaying any other possibility constantly.
And stop pressing people to the ‘listening mode’ if a comment does not please you.
To me it’s unreal keep defending a cellphone detection was made by a low or medium gain celltower in a dense urban area surrounded by +300 meter hills at a distance of 17km at 35.000ft altitude inside a plane.
The likelyhood of that to happen is almost insane and defending something like that is Imo pure wishfull thinking or confirmation biased.
The same with the official narritive of the high speed dive impact. Although the fast majority of debris and their kind of damage show this could not have been the case relentless efforts are made to defend it was all flutter related damage and/or high speed impact damage. Just bluntly ignoring new facts.
It’s this attitude I’m worried about.
ok @Ge Rijn. You feel that the cellphone detection is so far-fetched as to be incredible. I would like to hope that you have read the relevant portions and annexes of the RMP on this subject. Are you suggesting, then, that this whole aspect of the RMP’s investigation and supporting records were falsified from start to finish? Considering the level of very credible detail therein, that position would also strike me to be far-fetched to the point of being very-highly unlikely.
@Ge Rijn
Perfect example, you wrote “low or medium gain celltower in a dense urban area surrounded by +300 meter hills at a distance of 17km at 35.000ft altitude inside a plane.”
You have no basis to claim “low or medium gain celltower“, again, simply unsubstantiated opinion.
Perhaps the interest in BTO and BFO is too arcane for you, fine, take a break. Bluntly, we do have new data there, thousands of items. Combing through the data is worthwhile to determine whether previous findings hold-up or might be contradicted. Ultimately, the objective is to test the accuracy for the line of the 7th arc, and the resolution that may be extracted from the BTO.
That is all.
Ge Rijn:
It is clear you have no training in or understanding of electromagnetic field theory, antennas, link analysis, RF propagation, terrain maps, or any other aspect of the cell phone connection analysis. You should take Don’s advice and start listening to experts instead of throwing rocks at everybody you don’t understand.
@Ge Rijn
They’re scientists, not criminologists, and certainly not behaviorists. Rational (or irrational, depending on one’s inclination) human behavior is not a consideration for them despite overwhelming evidence that this event was purposeful and intentional. Victor seems to be the only one willing to fully engage in the deliberate, nefarious act scenario. Though his dismissal of certain radar data that doesn’t fit into the ‘continuous FL350 narrative’ is puzzling. First it was artifact, then unreliability and calibration error?
Of course there was a rapid depressurization near or at IGARI, and of course there was a subsequent descent near Penang, followed by a climb. And of course the aircraft was flown by living human hand until the bitter end.
The Search report.
Higgins in today’s (30th) Australian.
” The Australian Transport Safety Bureau has conceded it could be another three months before it releases its report on its failed search for Malaysia Airlines flight MH370, further angering families of the 239 victims.
The ATSB had indicated to family members that the report on the $200 million underwater hunt would be finished and published about now.
But ATSB spokesman Daniel O’Malley has now told The Australian, “we anticipate that the report will be released in the third quarter of this year”, meaning it could be published as late as the end of September.
The two-year search of 120,000sq km of ocean, funded by Australia, China and Malaysia but directed by the ATSB, ended in January without finding a trace of the aircraft.
The ATSB came under considerable scrutiny from scientists who had suggested relatively early on that drift modelling of debris from the aircraft found on the other side of the Indian Ocean indicated it came down further north than the area searched.
Some senior airline pilots and air crash investigators claim the ATSB’s strategy was flawed from the start because it assumed the Boeing 777 had crashed in a pilotless “death dive” rather than being flown to the end and outside the search area by a rogue pilot.
MH370 disappeared on March 8, 2014 on a scheduled flight from Kuala Lumpur to Beijing. Primary radar and automatic satellite tracking data indicate it doubled back over Malaysia 40 minutes in, before turning south on a long track to the southern Indian Ocean.
There is an expectation that the report on the search could be used by the ATSB to advance its tacit campaign to have the three governments relaunch the survey in a new 25,000sq km area north of the old one.
Queensland’s Danica Weeks, who lost her husband Paul on MH370, said the continuing delay in the ATSB’s formulation of its report was increasing the angst of the families.
“This is our lives they are playing with. We think of loved ones 24/7 and how this could happen; we hang on any, every information that surrounds MH370 and always will until the answers are forthcoming,” Ms Weeks told The Australian.
“If the ATSB had crossed their ‘t’s’ and dotted their ‘i’s’ on the search, why would it take nine months to produce a report? It’s inconceivable.”
Despite the plea from Ms Weeks, Mr O’Malley would not provide a clearer timeline for the release of the report, or explain why it had been delayed.
The delay comes amid continuing outrage among victims’ families at the refusal of the bureau’s chief commissioner, Greg Hood, to grant a Freedom of Information request from The Australian to release assessments of its “death dive” theory by a panel of international experts looking at the satellite data.
The lack of resolution on MH370 also sparked debate about the need for recorders that could be more readily found after crashes. Airbus has said it will equip its aircraft with new cockpit voice recorders and flight data recorders able to record up to 25 hours of information. One will “be deployed automatically in case of significant structural deformation or … submersion”.
@All
Re the Australian article: Too early to bet on the chances of the search being resumed, but in any case it can only serve to add even further significance to the current work on the unredacted ISAT data which is being discussed on this forum.
@David: Thank you for posting the article from The Australian.
Ean Higgins continues his confusion about the “death dive”. The BFO values indicating a progressively rapid descent at 00:19 could have occurred with or without pilot input.
It will be interesting to see whether the report includes anything new of significance.
@All, Thanks to your relentless efforts, you are inching forward in pealing the onion of this mystery. Thank you for educating us lay people on all of the details involved.
Was on a flight to JFK, Boeing 777-200 😃. As is often the case my Nokia smartphone was detected over Iceland at FL370. Got a text message from the local provider, welcoming me to Reykjavik. It does happen as this confirms.
@Irthet Turner: Thank you for the confirmation that a cell phone can be detected at cruise altitudes. Others have anecdotally reported similar occurrences.
@Irthe Turner
Yes as you say, it certainly does happen. It happened on MH370, of that there is no doubt. Will we see them find the wreckage? I hope so. God, I hope so. Can you imagine how this will hang over humanity if they never do. They must, and all of us will have done our bit to see it done. 😵🙏
It has been assumed by many that Hamid’s phone “had to be within the GSM range limit” of 32 km.
Is that a reasonable assumption ?
Possibly not ?
The timing protocol for registering a handset on a GSM network is based on establishing a “two way” link.
To do that, the phone has to be within the 32km, but that DOES NOT preclude a phone being DETECTED at a range greater than 32km.
Consider what happens if the phone is outside the 32km range limit.
The base station is continuously transmitting it’s identifier information on the control channels.
The phone is continuously searching (listening) for a base station to connect to.
Assume Hamid’s phone “hears” BBFARLIM2 and then tries to connect.
Hamid’s phone transmits to BBFARLIM2 and BBFARLIM2 detects and records it, and sends a control signal to hHamid’s phone that it has to reply to within a certain time period.
Because it is further away than the 32km it can not do so in the time alloted.
The base station, not receiving the reply from the phone within this time period, then discards the log on attempt (but it has been logged).
Meanwhile, Hamid’s phone, not getting the reply it expected in the allotted time slot, assumes it has not been heard, and repeats the process of attempting to log on again (assuming it can still hear BBFARLIM2).
So, a failed log on attempt “could possibly” be telling us that Hamid’s phone was:-
(a) outside the 32km “connected link” limit after all. but
(b) still within an anteena lobe of BBFARLIM2.
The case that Irthe Turner reports is interesting, since I don’t think the “two way” link is required for “sending” an SMS. The cell tower in Iceland could simply “hear” the phone, and then automatically (apparently) “send” the “welcome to Iceland” SMS, which the phone would receive. Hence, we have two independent transmissions, both of which are “one way”, without ever having established a “two way link”.
Thoughts anyone ?
@Ventus
you said:
The case that Irthe Turner reports is interesting, since I don’t think the “two way” link is required for “sending” an SMS. The cell tower in Iceland could simply “hear” the phone, and then automatically (apparently) “send” the “welcome to Iceland” SMS, which the phone would receive. Hence, we have two independent transmissions, both of which are “one way”, without ever having established a “two way link”.
I believe that is correct (not sure about LTE since I stopped following the protocols prior to LTE). SMS messages are sent on a control channel and the mobile and base station do not have to agree to a particular channel frequency like they would for voice or data. My understanding is that a “searching” mobile would respond to a base station SID with a registration request. The base station could then respond with an SMS to the mobile using the control channel as well as logging the registration request.
@Ventus
BTW, your post highlights why experiments conducted by “two Fred’s in shed” are meaningless. In order to establish a voice channel connection a lot more has to happen beyond the mobile sending a registration request. You really need to be able to access the base station logs to see if a registration request occurred. That is how our friendly government determines who is at a particular rally or demonstration. They bring a phony portable base station to the event and log everyone’s registration requests.
ventus45:
MH370 was 17 km from BBFARLIM at the time of the registration (17:52:27). That fact has been established by the radar track and cell phone registration time. Why are you looking at ranges beyond 32 km? What part of the facts do you dispute?
https://goo.gl/LCegb6
@ventus45
Your scepticism is understandable. For instance, it has been said that “the accuracy
is really not that important wrt the link analysis. The connection was possible from
horizontal distances between ~5 and 32 km.”
Therefore, a statement that “MH370 was 17 km from BBFARLIM at the time of the registration”
is not a statement of fact, but of considered opinion, however well or ill considered.
The ‘digitalized track’ used to support that opinion, appears to be sourced from the DSTG
graphs, which are known to be ‘Smoothed estimates of speed and heading derived from radar
data’. (Perhaps ALSM has access to radar data information he has not shared with us?).
A different opinion, no less reasonable, is that the location of the registration,
as represented in the RMP report, appendix K-2, 2nd picture, is as placed by the author by
factoring the altitude of MH370 to be at 44700 feet (& marked as such!). Ventus45, if
we take the view that the author did not just randomly place a ‘registration’ pin at any
likely distance from BBFARLIM2, but rather had the LBS application return a specific distance
magnitiude with some approximate accuracy resolution (say to 440 metres), then we may take the
view that the more likely registration location was roughtly about 5 to 10% further away
outwards> from the RMP represented location – because it is now generally accepted
that MH370 was at an altitude, not of 44700, but substantially lower (e.g., Vide one Victor
Ianello, ‘2015-08-18 Radar Data for MH370.pdf’, “geometric altitude of about 36,000 ft” ).
(A small support to this view that the RMP author had a specific distance magnitiude {with some
approximate accuracy resolution} from BBFARLIM2, is that the author placed the registration
location ‘off track, inwards ‘ from the general line of that pictures track of MH370s
represented flightpath – logic would suggest that if the author had no specific distance
magnitutde, he would instead have merely placed the registration location ‘in line’ with the
pictures represented track of MH370s flightpath.)
@Ge Rijn
Your efforts to elicit replies from Malaysian authorities are to be commended – certainly
let us know, even if, (like my efforts,) no reply is obtained.
@Buyerninety,
I think you misunderstand the purpose of the cell network Location Based Service. It is not a precise position determination service for subscriber devices, it’s a means to supplement geo based services (ie advertising, or perhaps, traffic reports) using the basic knowledge that a sub is connected to a given cell.
The correlation between the radar track & the LBS registration was a product of the investigative process using the time of the LBS event.
@Ventus45
I am almost certain I have noted this to you before, but perhaps you forgot – the
Malaysian mobile communication network does use frequencies that in other countries
would be more likely to be utilized for GSM – however, the Malaysians also utilize
some of those (usually ‘GSM’) frequencies for, instead, other mobile communication
technologies. Therefore, if you have seen a frequency that you believe is ‘GSM’,
in Malaysia, that frequency may instead be utilized for e.g. UTMS.
@Don Thompson
I understand Location Based Services. It will never be precise, particularly when
a registration from only a single cell tower is all that the LBS application
has with which to determine a (likely) location, which is why I asserted above that
the blunt assertion, made by other posters, that “MH370 was 17 km from BBFARLIM2
at the time of the registration”, is not a statement of fact, (additionally, not when
a track path location is based upon ‘smoothed estimates’).
Perhaps your uncertainty arises from my reasoned assertion that the RMP author placed his
registration position as a result of an estimated location returned by the LBS application of a
‘specific distance magnitiude with some approximate accuracy resolution (say to 440 metres)’?
(Obviously, no such magnitude was stated by the RMP author in the RMP report – but you should
allow that either the author had a distance magnitude and failed to state it, or the author
simply overlaid the LBS returned ‘estimated location’ map location upon another map showing
the MH370 represented flightpath, or combined the representation of the ‘registration location’
with the ‘representation of the MH370 flightpath’ using a program compatible with the LBS
application.)
Anyway, my assertion is based upon my understanding that (single tower circumstance) the LBS
may return ‘a specific distance magnitude with some approximate accuracy resolution (say to
440 metres)’, using, possibly, the ‘Cell ID + RTT’ method. The resolution metric I cited
(to ~440 metres resolution ) appears reasonable to me – I gave pertinent references towards
the end of this post;
http://mh370.radiantphysics.com/2017/05/14/advanced-underwater-drones-may-help-find-mh370/#comment-3680
@Don Thompson
And to clarify – if the RMP author had ‘a specific distance magnitude with some approximate
accuracy resolution’ and then placed his registration location upon the map using
the (incorrect) altitude of 44700 feet – you can understand, with some careful though, that
if his registration position were instead placed using an altitude of, around, 34000
to 36000 feet, that the effect would be to move the registration postion ‘further outwards’
from the position that you see on that RMP picture, to approximately on or slightly outside
of the ‘MH370 flightpath’ shown on that map.
There may be disagreement with my assertion, but at least you understand (I hope) the
reasoning process that brought me to it.
Cheers
EDIT; to above post , should read “careful thought” .
buyerninety:
The frequencies used in Malaysia for GSM include 900, 1800 and 2100 MHz. Celcom used all 3 bands. There is only a 7.3 dB difference in path loss between 900 and 2100 MHz. Therefor, regardless of which band was involved in the 17:52:27 LBS connection, there was more than enough link margin for a connection from any altitude between 11,000 and 45,000 feet at a range of 17 km and az=175 degrees.
If the plane was 10% further (or even 50%), it would have no material impact on the conclusion. If it was higher or lower by 10,000 feet (from 35,000 feet), it would have no material impact on the conclusion that a connection was possible.
It does not matter if you assume the “noisy” radar track depicted in RMP reports (like appendix K-2, 2nd picture) or the smoothed, digitized track contributed by sk999. They agree within ~1km at 17:52:27. So this is not an relevant.
In summary, all of the assertions and arguments you raise in an attempt to discredit the analysis are little more than distractions. We know the LBS connection happened. The analysis simply confirms that it was technically possible, given the physical facts, geometry, terrain, radar, etc.
@ALSM
The majority of your arguments seem to be generated internally.
My comment (to ventus45) merely informed him in regard to his belief the cell
registration used GSM. How you springboarded that into an argument about “enough
link margin for a connection from any altitude” is a mystery, clear only to you.
You said “If the plane was 10% further..(etc etc)…would have no material impact
on the conclusion that a connection was possible“. Given that I have not made any
assertion as to whether “a connection was possible“, you seem to have
(possibly) internally misattributed ventus45’s post to me.
You said “…the “noisy” radar track depicted in RMP reports (like appendix K-2,
nd picture) or the smoothed, digitized track contributed by sk999. They agree within
~1km at 17:52:27. So this is not (sic) an relevant.”
I have not explored whether the tracks are “within ~1 km”, so I do not automatically
accept your metric of that. Regardless, obviously it is not relevant to you,
but you may not understand that other posters (Mick Gilbert, for instance), may be
interested in any indication that the registration occured ‘inside or outside’ the
conjectured flightpath (RMP or otherwise) – for instance, when trying to form an
opinion or argue a case, as to whether MH370 was navigating towards KENDI or the TP
that I seem to remember Mick first identified at 7.7 DME ILS on the Glideslope.
May I politely suggest that in the future you actually quote the particular words
that you have issue with, (see as examples, my above), so that everyone can be certain
as to what was actually said by someone, rather than a possibly incorrect interpretation
as to what you thought they said.
Your opinion on the different persective/facets of the cell registration location that
I laid out, in reply to Don Thompson, is acknowledged.
In regard to the analysis, you have missed the point that I was less interested in
‘discrediting the analysis’, than casting doubt that the information the analysis is
based on is so exact as to prove as factthe singular figure of 17km
that you several times specified.
So there the matter rests, and Don or Dennis have a different take on the cell
registration location to ponder. I judge further back and forth with others may tend
towards the acrimonious, so I will leave this matter be. For me, once again, it seems
regarding the BBFARLIM2 registration …;
https://www.youtube.com/watch?v=UPw-3e_pzqU
@Dennis, It perhaps worth mentioning that the message popped up as we were decending into JFK. I was not able to get a text out over Iceland .Ihad a winow seat and phone was in my bag during the flight. Iflew back with an A330 from Atlanta same seating and phone stored in front of me. Ireceived an Irish text this time which again popped up at when we were decending. Also over Ireland no reception to send texts or place calls.
Apologies for the spelling errors. Am severely jet lagged.
All,
Regarding the distance of MH370 w.r.t. BBFARLIM2, it should be noted that the apparent “jog” to the N at 1:52:27 seen in Fig 2 of RMP Folder 4, Appendix K-2 is also seen in Fig 2 of the ATSB Underwater Search report from 2014. After redigitizing the “jog” seen in the latter, I get a difference in position between the two figures of approximately 5 times the length of a B-777, which is within the digitization error. Other similar “jogs” are seen in the radar track of the ATSB figure, suggesting they may be caused by noise in the radar data.
I get a horizontal range from BBFARLIM2 to the 1:52:27 position of 14.8 km. The altitude (hand written on Appendix J-2, p. 6) is 35,100 feet or 10.7 km, giving a combined slant range of 18.3 km and an elevation of 36 degrees. If one thinks the actual position was more in line with a smoothed version of the track, the horizontal range is more like 16.2 km, the slant range is 19.4 km, and the elevation is 33 degrees.
None of the above relies on the reconstruction of the DSTG track.
Raw data for 1:52:27 position
RMP position: 5.220 100.289
ATSB position: 5.219, 100.286
Smoothed track position (estimated): 5.207, 100.286
I think we have converged on the following:
Using the position and altitude suggested by the radar data and the location of the BBFARLIM2 antenna, and considering effects from the distance, elevation angle, terrain masking, cell antenna sector coverage, and Doppler blocking, we can conclude that the cell phone connect at 1:52:27 was physically possible.
Thank you sk999. I agree 100%. All your calculations are very consistent with my estimates within reasonable margins of error.
No matter which of the three position estimates is assumed, or altitude assumed between 11,000 and 45,000 feet (35,100 feet likely), or base-station antenna gain pattern assumed (+19 beam center or -20 dBi null between vertical side lobes), the the link margin for GSM at 900, 1800 or 2100 MHz would have been adequate for demodulation. That is all we need to know to say the time and position estimates are consistent with physics.
PS: “jogs” = “noise” in this context.
@sk999
As a matter of interest, have you had any more thoughts on the BFO drift noted on the southward journey? Do you think there’s a likelihood it could be attributed to oscillator drift, alone?
@Irthe turner
you said:
“@Dennis, It perhaps worth mentioning that the message popped up as we were decending into JFK. I was not able to get a text out over Iceland .Ihad a winow seat and phone was in my bag during the flight. Iflew back with an A330 from Atlanta same seating and phone stored in front of me. Ireceived an Irish text this time which again popped up at when we were decending. Also over Ireland no reception to send texts or place calls.”
Yes, that is common, and has to do with how SMS messages are routed. The network in Iceland (or wherever) does not send the “welcome” message to your phone directly. All SMS messages are routed to your home location register. Your home network then delivers it to where it thinks you are located. If delivery is unsuccessful the message stays queued for some time (the queue time is debatable) and delivery is attempted again when your phone identifies itself to a network somewhere.
@All
Sorry if this has been reported before. I hadn’t seen the connection in the threads.
With the discussion around Boeing news releases I went back to the Boeing website and found an interesting relationship with Boeing, Inmarsat and Kazakhstan. The complete statements are available on the website. I hadn’t seen this reported before so I thought I would pass it along. Note that the first three Inmarsat satellites were launched from Kazakhstan. The fourth launch took place from Kennedy Space Center. The first one launched on December, 2013 and finished testing on March 11, 2014.
EL SEGUNDO, Calif., May 16, 2017 – The fourth Boeing Inmarsat-5 satellite, which was launched yesterday, will noticeably expand the high-speed broadband service available through Inmarsat’s Global Xpress network after the satellite becomes fully operational later this year. Inmarsat-5 F4 lifted off May 15 from Kennedy Space Center aboard a SpaceX Falcon 9 rocket.
EL SEGUNDO, Calif., Aug. 29, 2015 – When the third Boeing-built Inmarsat-5 satellite, which is now in orbit, becomes fully operational later this year it will provide the technology and coverage necessary for worldwide high-speed broadband access. The Inmarsat-5 F3 satellite launched Friday aboard a International Launch Services (ILS) Proton Breeze M rocket from Baikonur, Kazakhstan.
EL SEGUNDO, Calif., July 21, 2015 – Boeing is completing the first tests of military Ka-band service available through the Inmarsat-5 F2 commercial communications satellite, part of Inmarsat’s Global Xpress network. The demonstrations to securely transmit high-data-rate information have involved ten major U.S. Department of Defense customer groups on fast-moving platforms and with users at multiple locations.
EL SEGUNDO, Calif., Feb. 1, 2015 – The second Boeing-built Inmarsat-5 satellite has sent its first signals from orbit, an essential step toward establishing Inmarsat’s Global Xpress network, the first global, high-speed mobile broadband service. The spacecraft was launched on an International Launch Services Proton Breeze M rocket from the Baikonur Cosmodrome in Kazakhstan on Feb. 1 at 7:31 a.m. Eastern time.
EL SEGUNDO, Calif., July 29, 2014 – In a first-of-its-kind arrangement for the company, Boeing [NYSE: BA] is providing a U.S. government customer with military Ka-band satellite…
EL SEGUNDO, Calif., March 11, 2014 — Boeing and TrustComm, Inc., of Stafford, Va., are partnering to sell satellite bandwidth to government and commercial users as a way of addressing…
EL SEGUNDO Calif., March 11, 2014 — Boeing’s first of four satellites for Inmarsat’s Global Xpress network, has passed all of its on-orbit testing and has now been handed over…
EL SEGUNDO, Calif., Dec. 9, 2013 – The first Boeing Inmarsat-5 satellite has launched and sent signals from orbit, the initial step to establishing Global Xpress, the world’s first globally available high-speed mobile broadband service for government and commercial users. The spacecraft was launched on an International Launch Services Proton Breeze M rocket from the Baikonur Cosmodrome in Kazakhstan on Dec. 8 at 7:12 a.m. Eastern time.
@Trip: The fact that there is so much activity of American and British companies at Baikonur is one of the many reasons why trying to hide a B777 there would be foolish. Some other obvious problems with this theory is the distance of Baikonur from the 7th arc (about 100 km) and the fuel load would not have allowed MH370 to reach this destination.
@Trip
Inmarsat put another satellite up a couple of days ago. This time launching from French Guiana using an Ariane rocket.
http://www.bbc.com/news/science-environment-40435832
I’m not suggesting that’s where the plane went, only that I hadn’t seen this connection before. You folks know a lot more about this than I do.
@Trip: I think you’ll find a lot of collaboration among various companies and countries in the space industry.
@Victor
I would use “competition” rather than “collaboration”. It is revenue Brexit be damned.
@ buyerninety. Thanks for chewing on that particular bone. It was precisely what I was getting at in my previous posts: What is presumed accuracy of range, azimuth, both? Slant range or horizontal range?
Granted that +/- several kms will make no difference to the physical feasibility range of cell phone registration. But it does make a difference on presumed track/position/turn time past Penang. Which is why I continue to take a particular interest in this.
The questions at hand – which I believe selected contributors here are equipped to answer with some professional & definitive responses are:
What is the “position” accuracy of an LBS registration? Do we think it is range, azimuth, elevation or all of the above? Do we think the position as plotted is horizontal range corrected for presumed altitude of 44k ft? Or do we not really know the precise answer to either of the above?
@Paul
Why would you think that a registration would imply anything besides being in the piece of pie shaped sector of the antenna?
@dw – because i have only a rudimentary understanding of GSM / TDMA.
my guess – reinforced by your “pie” comment is that the registration can provide no azimuth indication whatever beyond the physical limits of that antenna (120 degrees, if I’m not mistaken). and if that is the case, then i guess it was plotted pro-rata seconds after the xx.59 radar positions proceeding/following it. is that your understanding?
now, second question. the TDMA protocol should, in principle, give a slant range +/- x from antenna – yes? if so, what is that +/- confidence limit?
and finally, if we think that a specific “range” was attributed to this detection, was it transposed directly to the horizontal (since carrier LBS, one would imagine, assumes their clients to be on the surface of the earth rather than 10kms above it) or altitude-corrected. and if the latter, at what altitude?
in short, @buyerninety’s request for clarification has merit and I’m not quite satisfied with a glib ’17kms on bearing such-and-such from tower position x,y.’ in the absence of informed confidence limits and declaration of implicit assumptions.
@Paul
Yes, on azimuth. Basestations do not routinely do anything to measure or log the distance to the mobile. This has been looked at in some detail for the 911 location mandates in the US. Nothing I know of has made the cut. Location using a single base station without handset cooperation such as GPS is non-existent.
@Victor. About the recent Higgins article you commented, “Ean Higgins continues his confusion about the “death dive”. The BFO values indicating a progressively rapid descent at 00:19 could have occurred with or without pilot input.”
True, though I do not think that undoes the Higgins assertion that the ATSB has assumed it was pilotless. It has maintained (Dec 2015) that the end of flight sequence, “favours a no active control scenario”, which in context and in shorthand could be called pilotless. The context in the article was that others believe the aircraft could have been flown clear of the search area.
Related, what troubles me is not so much the ATSB assumption as the logic behind it. The flight sequence the ATSB refers to is of course based on an APU start at fuel exhaustion, that powering the final log-on. Acceptance that this is the likely sequence and, implicitly, that the no-active-control scenario persisted, overlooks the possibility that a pilot might have taken over subsequently – or indeed might have had a hand in the log-on (as with that earlier).
The assumption that there was no pilot at the end leads to a conclusion that there is no pilot. That is somewhat circular isn’t it?
No evidence of a pilot is not evidence there was none.
You have done some simulation of height recovery from an early high speed dive. Even if the recovered wreckage is assessed as from a rapid descent, that could have been at the end of a glide after height recovery.
Were it up to me my inclination would be to advise the Minister here that a glide beyond the proposed search area even if unlikely cannot be ruled out.
Retrospectively, while the surface search was justified, had this point been included in sub-surface success probability assessment, that might have made that harder to justify, particularly as the surface search had located no MH370 flotsam.
@DW. “I know of has made the cut. Location using a single base station without handset cooperation such as GPS is non-existent.” Well that is WTF moment. How, then, do we suppose this LBS was derived and how reliable is it??!
David said: You [Victor] have done some simulation of height recovery from an early high speed dive. Even if the recovered wreckage is assessed as from a rapid descent, that could have been at the end of a glide after height recovery.
Yes, that’s true. You’d have to ask what the pilot was trying to accomplish, as the dive and the glide would be motivated by different objectives, but certainly possible.
@David
Re: “Were it up to me my inclination would be to advise the Minister here that a glide beyond the proposed search area even if unlikely cannot be ruled out.”
You might want to read (or reacquaint yourself with) the ATSB’s Definition of underwater search areas dated 3 December 2015, in particular the Search Area Width section (pp.13-15), because that’s pretty much what the ATSB did (the caption to Figure 7 Search area width priorities sums it up).
The ATSB addresses the possibility of the aircraft being glided “under active control” AND incorporates that possibility into its determination regarding the search area width; Priority Search Areas 3 and 4, each between 40 – 100 nautical miles from the 7th arc, cover the controlled glide scenario.
Had Priority Search Areas 3 and 4 been included they would have more than doubled the size of the search area; getting approval for a $0.5 billion search was probably never going to happen. The decision to limit the underwater search area to Priority Areas 1 and 2 (40 nautical miles either side of the 7th arc) was not made without any consideration of the possibility of a controlled glide; it was never ruled out, it was just considered less likely.
There being no evidence of pilot inputs over the last five hours of the flight may not be evidence that there was no active pilot but it certainly must negatively impact any reasonable assessment as to the likelihood of there being an active pilot at end-of-flight.
@Paul
“@DW. “I know of has made the cut. Location using a single base station without handset cooperation such as GPS is non-existent.” Well that is WTF moment. How, then, do we suppose this LBS was derived and how reliable is it??!”
I have no idea how it was derived or even if it was derived.
@Paul Smithson asked: How, then, do we suppose this LBS was derived and how reliable is it??!
The only cell phone geolocation that was reported in the RMP report was the sector of the cell tower antenna. The rest was radar data.
@Paul
Furthermore, as a first responder in two rural California counties (where single base station coverage is the norm) what we get is the caller’s description of where the emergency is. We never get geographic help from the network on mobile calls. On wireline 911 calls there is a database of addresses that the dispatcher has access to. We do have GPS so when the caller is found we can route helicopter resources to the scene.
@David
@Victor
Whenever the ATSB get round the table, whether by themselves or with other interested parties, there a pretty big elephant in the room with them. The elephant must take this form: if there was no pilot input after flameout, and the BFO is interpreted as a steep rate of descent, then why didn’t they find the wreckage in the 120,000sqkm search zone?
Not an easy one to answer unless you throw out the “no pilot input” scenario and instead consider a piloted descent.
@Rob: If you consider a descent at 18:40 and a late FMT, an impact along the 7th arc to the north of what was searched becomes very possible. It also better agrees with the results from CSIRO’s drift model. The main piece of conflicting evidence is the failure of the surface search to find debris. However, the extent and efficiency of this search is being called into question by some.
@Mike Gilbert
Iro whether on not there was a pilot in control during journey south: absence of evidence should not have been taken as evidence of absence. The ATSB got the DSTG to do a probability assessment on the zones 3&4, in the light of how the flight appeared to them (the ATSB) to have ended, ie in an unpiloted dive, and they concluded the probability was low. But alarm bells should have begun to ring in Canberra, as the search dragged on with no result. They didn’t reassess. A red line had been imposed by their political overseers. They were not allowed to seriously consider pilot control at the end – they weren’t to endanger the Commonwealth!
@Mick. Thanks, yes I am very conscious the ATSB did go into a glide possibility and its consequences to search area but having assessed the glide would make the search area impractical and found a rational explanation about the log-on without a pilot I think they overlooked that the pilotless bit remained an assumption. The very high estimated probabilities of success I believe did not include the effect of the assumption on the probabilities.
I think this is exemplified most recently in the First Principles Review of November last year. It said,”There is a high degree of confidence that the previously identified underwater area searched to date does not contain the missing aircraft. Given the elimination of this area, the experts identified
an area of approximately 25,000 km² as the area with the highest probability of containing the wreckage of the aircraft. The experts concluded that, if this area were to be searched, prospective areas for locating the aircraft wreckage, based on all the analysis to date, would be exhausted.”
For past and new search areas,”….would be exhausted” would apply only if certain there had been no pilot. There is no qualification along those lines or hint that allowing for that possibility while restricting the area to the practical would in fact reduce the likelihood of success somewhat.
It is likely to me that that was not imparted to government(s) by the ATSB most recently or previously.
@Mick
“There being no evidence of pilot inputs over the last five hours of the flight”
I would not say there is no evidence of that, as I feel the BTO/BFO shows possible pilot input up to at least 1941, and I feel descent can be shown as a BFO possibility after Arc5. I would say ATSB chose to favor the simplifying assumption of no pilot inputs, and that assumption is probably part of the problem finding the aircraft. Yes we are all hoping it is close to Arc7 because if not, we probably cannot find it based on current info.
@Victor
“@Rob: If you consider a descent at 18:40 and a late FMT, an impact along the 7th arc to the north of what was searched becomes very possible. It also better agrees with the results from CSIRO’s drift model. The main piece of conflicting evidence is the failure of the surface search to find debris. However, the extent and efficiency of this search is being called into question by some.”
Yes, I agree with what you said above.
The reality is that it is now virtually impossible for the ATSB to act on that conclusion. We (you and I and other IG members) have a long history of disagreeing on whether an underwater search should have been started based on the ISAT data alone. It was incredibly bad judgement IMO. There was no urgency. A prudent approach was to wait until debris was found to refine and support a likely terminus. Resumption of the search to the North now would be a tacit admission of a previous poor and very expensive decision. Having seen this movie a few times, I do not think that is likely to happen.
My guess is that even if the initial search was delayed and started now without the benefit of the negative search results, it is likely that the high priority search area would be about the same. That is how fixated most analysts are on the ISAT data and the “most probable” flight dynamics.
@DennisW: I am sensing a willingness from both the public and private sectors to re-start the search. I think that advanced technologies, such as the fleet of autonomous underwater vehicles now commercially offered by Ocean Infinity, could help reduce the cost of scanning large swaths of seabed and make it more politically palatable.
The official Malaysian stance has always been to refute any suggestion of the crew being responsible, and to fall back on “no conclusions can be drawn until the black boxes are recovered” while at the same time keeping their fingers crossed and hoping the wreck is never located.
If these are the conditions the ATSB have had to work under, little wonder they couldn’t find it
@Victor
I hope you are right.
@Victor
Your reply to Dennis’ last post iro the possibility of the search being resumed was “I hope you are right”. Yes, amen to that.
Unfortunately for me, the idea of a late FMT and a descent sticks in my craw. Having said, there’s obviously still a lot to be done in interpreting the BTO/BFO, and fuel analyses, and the overshoot on the first logon And Jeff Wise and his team have been busy cleaning clues from the debris – all good to them.
Hopefully, something will crystallize from these efforts.
@Paul Smithson
It is open to you form an opinion as to what, if any, ‘specific distance magnitude with some
approximate accuracy resolution’ the RMP author had when he placed the “FARIQ PHONE DETECTED”
locational pin in the the 2nd picture of appendix K-2 of the RMP report, and an opinion as to
whether the RMP author decided to (simply) locate the pin at a point nearest to the represented
MH370 flightpath.
I have cited references in the post(s) above, as to one method that is used in the UTMS system,
(Cell ID + RTT), and noted the positional accuracy discussed in those references was up to a
resolution substantially more than tens of metres (e.g. up to 440 m).
The reference illustrates that for the single tower circumstance with the Cell ID + RTT method,
a specific ‘point’ location is not obtained, but rather what is returned is an arc length and
width with which the probable location rests.
VictorI has noted the RMP report (sections publically available) make no explicit statement of
what, if any, LBS method was used in the placement of the RMP report locational pin.
The RMP report contains a diagram mentioning the Cell ID + RTT method, but the presence of that
diagram is open to interpretation as, for instance, non-relevant illustrational material, or as
applicable only to the call registration flight tests conducted by the RMP in the weeks after
MH370.
DennisW’s notes his experiences as a first responder within an area of “single base station”(s)..
(that)…”We never get geographic help from the network on mobile calls”. This is not surprizing,
as such information may take some days to obtain from the telecommunications provider.
An example of where such information was obtained days later by law enforcement personnel, is
mentioned in the following reference, wherein a Verizon technician specified (an arc at) a
distance of 10.6 miles from a single base station, CDMA2000 system, probable distance locational
method used being the CDMA RSSI method. In his later writings, the author of that reference (also
a first responder, of some fame) operates on the assumption that the (not given) arc width was in
the region of 10% (of the 10.6 mile distance).
Cheers
http://www.otherhand.org/wp-content/uploads/2012/04/Ewasko-ping-discussion.pdf
EDIT; above post,
“width within which the probable location rests.”
I seems that some here are still confused about the 17 km distance estimate. First, regarding “… LBS method was used in the placement of the RMP report locational pin….”, the RPM did not place any pin in the map related to the position of the plane based on LBS. (The only pin in the map I published was one I placed on the map, not RMP.) RMP maps only contain the radar pings and they annotated the time of those pings (which are in excellent agreement with sk999’s smoothed digital radar file). Second, the 17 km estimate has nothing to do with the LBS. It is simply the surface distance measured (using GE) between the base station antenna and the radar track position at 17:52:27. As far as we know, there was no LBS distance ever measured or reported to the RMP.
Hi all,
I don’t know if someone has already looked into that. Following up on a proposal by Don from last year:
https://www.reddit.com/r/MH370/comments/4gnjc9/atsb_online_survey_have_your_say
I had a look at the “previous satellite ID” field which is encoded in the log-on request/confirm SU contents and prepared a short write-up:
http://myonman.bplaced.net/mh370/mh370_prev_sat_id.pdf
Does that make sense? Curious to hear your opinion.
@buyerninety. Thanks for your response. I suppose that the “best guess” is that they did use RTT since the position was placed inside of the two radar positions. I they had not bothered with a distance estimate at all you would have expected them to put it nearly slap-dab-in-the-middle of those two xx.59 radar positions. Now, if we do think that somebody made a range estimate based on RTT, we don’t know if this was transposed directly to the horizontal, or – if corrected for altitude – which altitude was used. These latter qualifications could make an order of magnitude range difference above & beyond the 440m confidence limit on the RTT method. If they used 44k ft altitude, that position is too far north. If they used 0k altitude, it is much too far out.
ALSM is quite right that all of the above makes no material difference to the feasibility of a cell registration on that tower. My reason for pursuing this is that the position of that fly-by and nature of the turn towards WNW does have an important bearing on how the plane appears to have been being flown / navigated. If, for example, we allow a radar slant-range error “bulge” to have affected the trace past the south of Penang (similar to the bulge at Kota Bharu), then this suggests to me that the most parsimonious explanation of the track into-out of Penang is a single change of course from ~243T to ~290T.
@el_gato: That’s great work. I will repeat your conclusions here. The last one is particularly important:
– The AES obviously transmitted meaningful information in the „Satellite ID (previous)“ (ID) field. Its content can be interpreted as the ID of the satellite through which the AES was logged-on previous to a current log-on attempt. In that context, ID=2 would identify the POR satellite, and ID=3 equaled IOR.
– If the GES did not respond to a log-on request from the AES within approx. one second, the log-on request was repeated. In that case the value 32 was transmitted in the Satellite ID field.
– In the log-on confirm messages, the GES reproduced the Satellite ID from the first log-on request in a sequence.
– On a single occasion around 04:01 UTC the above pattern was not adhered to (yet unexplained).
– It appears that a log-off request by the AES (or the corresponding GES Log-off acknowledge, resp.) cleared the Satellite ID register which henceforth carried the value 63 (0x3F). This value used to be transmitted in subsequent log-on requests.
– At 12:50:19 UTC, the SDU has obviously been restarted after a shut-down period of several hours. No log-off request has been issued beforehand which is also corroborated by three unanswered GES Log-on interrogation messages around 09:01 UTC. After the shut-down, the Satellite ID field carried the value 63 (0x3F). This indicates that an SDU power cycle likewise caused the Satellite ID register to be cleared.
– A similar situation can be observed at 18:25:27 UTC and 00:19:31 UTC, lending further weight to the hypothesis that the SDU was without electrical power right before the AES logged on at these times.
@VictorI @AlSM @Don Thompson
While ‘getting payed’ was more meant as a figurative statement and to shake things up, I understand the effect could be as expected.
Ridiquling my views and knowledge of the case and defending yourself with delivered and presumed ‘scientific’ data that have not led to any objective result yet.
Denying all others arguments on the FO cellphone connection and the possible implications on the route MH370 took to, over and past Penang. You don’t need to have very specific ‘electro magnetic’ knowledge to see that the connection could not have been made this way and the route south around Penang over see could not have been the case according the RMP-report. But it’s no use arguing with some of you who refuse to use common sence and just stick to ‘data’ and concepts that by this time (eventualy a long time already) have proven to be invalid.
Just like the high speed nose dive impact and the flutter seperation of flaps etc.
But serve yourself and before all keep falling back on your scientific numbers and status. It’s truly important to find what not happened in this case. Ptolomaeus managed to sell his universe to the public for many centuries this way till Copernicus came around.
Hopefully the end-report will give more conclusive answers. But I’m afraid it will be all cooked up with more of the same.
Without independent forensic investigation on the debris and all the other data this case will stay closed and unresolved as it is to date.
@Ge Rijn said: You don’t need to have very specific ‘electro magnetic’ knowledge to see that the connection could not have been made this way and the route south around Penang over see could not have been the case according the RMP-report.
Most here are willing to listen to technical facts, independent of what expertise anybody might have. Analyses presented here suggest that signal-to-noise ratio, Doppler shift, and terrain masking all allow a cell phone connection with the BBFARLIM2 tower. If something has been missed, please let us know.
@Paul
“An example of where such information was obtained days later by law enforcement personnel, is
mentioned in the following reference, wherein a Verizon technician specified (an arc at) a
distance of 10.6 miles from a single base station, CDMA2000 system, probable distance locational
method used being the CDMA RSSI method. In his later writings, the author of that reference (also
a first responder, of some fame) operates on the assumption that the (not given) arc width was in
the region of 10% (of the 10.6 mile distance).”
This example actually got a bit of press. It is appropriate for MH370 discussions. The lost hiker who was the subject of your link was never found. Your information is anecdotal at best.
@el_gato
Nice work, el_gato. Serves to rule out the other competing theories iro causes of the logos, particularly the 18:25 logon.
@ALSM
You stated, “the RPM did not place any pin in the map related to the position of the plane
based on LBS“. Unless you had had discourse with the RMP author, your statement is not
fact, but your opinion. Your opinion is not the opinion of everyone.
You stated “RMP maps only contain the radar pings“. The map I specified, “the 2nd picture of
appendix K-2 of the RMP report” contains radar pins at ~1 minute intervals. The (singular) pin
not at a 1 minute interval is therefore open to interpretation as a placement, by the RMP
author, of a possible location of the plane at the time> the cell registration occured.
This is my opinion. Most readers would agree that my opinion will almost certainly never
be likely to be your opinion.
You said “the 17 km estimate has nothing to do with the LBS“. (You perhaps don’t
remember I requested you actually quote my words that you have issue with?)
I completely agree, because I never made any such assertion. Therefore readers must
contain their astonishment, that this actually is one of those unlikely times when
my opinion is your opinion.
You said “As far as we know, there was no LBS distance ever measured or reported to the
RMP. We know that the RMP report, after the 11 pages of appendix J-1, states on page
6 of 8, “Fariq Ab Hamid Detected At BBFARLIM2 LBS Only”. It is my opinion that the
LBS did return such an approximate distance, and …(I did write a more through explanation,
but..) ..my opinion is it’s just easier to read the first paragraph of Paul Smithsons post,
four posts back.
@Ge Rijn
Although I never posted about it, one of the reasons why I believe Hamids phone connected
at ~35000 feet was that I found a post by a Canadian(?) who received a message from a US
mobile company on his mobile whilst airline travelling over approximately, the Great Lakes
at something like above 20000 feet – so he was reporting an experience very similar to that
posted above by poster Irthe Turner.
@Paul Smithson
I’ll have a look at your bearings tomorrow (not clear why you specified true bearings).
Now my opinion is – time for bed!
Cheers
@ROB
Re: “Iro whether on not there was a pilot in control during journey south: absence of evidence should not have been taken as evidence of absence.”
What should it have been taken as then?
Re: “But alarm bells should have begun to ring in Canberra, as the search dragged on with no result. They didn’t reassess.”
That is precisely the criticism of the conduct of the search I have made in the past. Something along the lines of the First Principles Review should have been held 12 months after the underwater search started – they had completed the high probability areas at that point and they still had nearly half their budget – and then repeated 6 monthly thereafter. By April 2016 5-7 debris items had been found across a reasonable spread of locations; that should have been used to inform the question, why haven’t we found it yet?
As Keynes said, “When my information changes, I alter my conclusions. What do you do, sir?”
Re: “ A red line had been imposed by their political overseers. They were not allowed to seriously consider pilot control at the end – they weren’t to endanger the Commonwealth!”
You can speculate till the cows come home on who said what to whom but the simple fact of the matter is that you don’t know what, if any, restrictions were placed on what was considered.
@Mick: Thank you for reminding us of the greatest failure of ATSBs management of the search — the refusal to re-evaluate after the first season, and after debris were being found. This looks to me [like the 2 US space shuttle losses] to be what you get with a bunch of scientists aiming at a consensus with political and economic constraints — weak points are often recognized, but scored as good-enough, and it’s often just too painful to go back over the same ground — even if “information changes”.
I think a big — if unspoken– constraint was always that the ATSB were talking to potato farmers — enlarging your plowed field in contiguous squares rather than picking up and moving to another area.
Victor’s judgment that the Australian government might be moving toward re-opening of the search IS heartening, and surprising to an outside observer — I presumed that the $200m failure would simply be hung around Tony Abbott’s neck, certainly by the political class — and I presumed also by CSIRO and the scientific establishment, who must have loathed him.
@Mick: One further note on how reconsiderations — particularly of debris drift — should have redirected the search as early as April 2016: It was very clear by then that the lack of debris on WA shores would greatly lower probability of the crash being on the southern end of the 7th arc.
Nevertheless, it’s heartening that the current calls for extending the search to the north seem to have made use, not only of the new drifter studies [which were a good year late!], but also detailed oceanographic current data, mostly from satellites. As depicted in the 13April17 CSIRO report, it’s interesting to see that, while most of the 7th arc south of about 32.5S would deposit debris on WA, there were windows around 35S [basically 34.5S to 36S] and again [as discussed here a couple of months ago] around 30S. So I’m more impressed than formerly about their interest in 35S — but if not there, they probably should skip a couple hundred km, to the 30S region..
And once again, if they had reconvened First Principles in early 2016, surely they could have agreed to find a college intern or two to organize debris recognition and recovery across the Indian Ocean!
lkr said: As depicted in the 13April17 CSIRO report, it’s interesting to see that, while most of the 7th arc south of about 32.5S would deposit debris on WA, there were windows around 35S [basically 34.5S to 36S] and again [as discussed here a couple of months ago] around 30S.
CSIRO’s own drift model does not show a window around 35S that results in no debris on the shores of WA, as was shown in a previous post. If you look at the first image, which shows the distribution of debris for an impact along the 7th arc at 35S, debris reaches the shores of Western Australia.
@VictorI,
I can’t find the image you are referring to regarding WA debris using the “previous post” link. That one deals with East Africa. Would you please check the link?
@Mick Gilbert
Rob said “Iro whether on not there was a pilot in control during journey south: absence of evidence should not have been taken as evidence of absence.” You replied: “What should it have been taken as then?”
You’re firing from the hip again. But I will be generous and tell what it should have been taken as. However, firstly I will tell you what it should NOT have been taken as. It should not have been used by the ATSB to invoke an unpiloted ghost flight after the final turn south, to conveniently limit the size of the search area. What they did was to take the southbound leg in isolation. The DSTG’s initial Bayesian analysis indicated a hotspot at S38. this could only be reached if the plane flew in a straight line, on autopilot and at an economical cruising altitude, after the FMT. The plane flew until fuel exhaustion, and then appeared to dive into the ocean.
But before marking out the intended search area, they should have looked carefully at the whole flight, and taken every individual event into consideration. They should have been allowed to cross the Rubicon, and state what most of the informed aviation world was thinking, that the flight looked like a deliberate, meticulously pre-planned act of murder/suicide, and that if the pre FMT part of the flight appeared to be actively piloted, then it would be unwise not to assume that the post FMT part was as well. Then they could have extended the search area south of the hotspot to make sure of encompassing the furthest theoretical unpowered glide point.
Unfortunately, the ATSB had their hands tied from the start because the accident investigation itself was specifically the responsibility of the Malaysian Authorities. The ATSB were responsible only for the search effort. This was the crux of the problem – namely, there was no one with sufficient authority at the ATSB to take proactive control of the search effort. It’s the old story, if you don’t have the right people at the top, the whole edifice will eventually crumble.
Remember, CSIRO, DSTG and ATSB all have the same political paymaster. The CSIRO drift studies have always been constrained by the need to back up the ATSB search strategy. When all the money was on the southern sector of the 7th arc, the CSIRO drift study duly supported it. When they couldn’t find the aircraft in the southern sector, hey presto, the CSIRO miraculously found S35 to be the chosen spot. I guess you can tell from this that I place no confidence in the drift studies.
@ROB
“When all the money was on the southern sector of the 7th arc, the CSIRO drift study duly supported it. When they couldn’t find the aircraft in the southern sector, hey presto, the CSIRO miraculously found S35 to be the chosen spot. I guess you can tell from this that I place no confidence in the drift studies.”
That is a generic flaw of forward based drift studies. What CSIRO concluded was that the original search area was possible i.e. toss a flaperon into the water at 38S and it could reach Reunion. That is correct, but answers the wrong question i.e. possible but not most likely.
A multi-particle reverse study generates the most likely origin, and it is not beyond 38S.
@DrB: Go to the prior post entitled Important Questions about “Most Likely” MH370 Crash Site. The first image in the post shows where debris is located on Dec 31, 2015, for a 35S impact site. Notice the label “Debris on shores of Western Australia”. If you prefer to visualize the results for yourself in Google Earth for this impact location, use this file.
@SK999: as I told @ALSM, my profession takes data verification very seriously. If I were to publicly scorn a colleague simply because she was doing her level best to independently ascertain her data’s authenticity and accuracy prior to its use, I could well end up getting summarily drummed out of the profession.
So my question to you is this: in your last comment to me, did you publicly scorn my suggestion that Step 1 should be to make every reasonable effort to get Inmarsat to publicly endorse what you seem already to think is their own data?
@VictorI
On your remark: ‘If something has been missed, please let us know.’
I’m not a ‘electro magnetic’ expert but the simple things I read about those low and medium gain urban antennas is that their detection/recieving reach is max. ~8km in their horizontal range. The lobes above this horizontal range decrease in detection/recieving range very rapidly.
The examples of messages recieved at 20.000ft or even 35.000ft(?) above the Great Lakes, Iceland etc. could be attributed to high gain rural antenna when nearing the airport/country but not to common dence urban area antennas like where BBFARLIM2 is situated.
Beside this. What is missed is that according the RMP-report BBFARLIM2 was the only station that detected the call.
No Cellcom or other antenna south (or eanywhere else) of BBFARLIM2 made a detection/ connection.
On the other hand in the flight-tests many antennas including Cellcom detected the cellphones onboard but only south of BBFARLIM2.
BBFARLIM2 detected none of those and north of BBFARLIM2 none did either.
Think about it in case I missed something.
@Andrew said;
“The SDU receives ‘raw’ ADIRU position information via the AIMS”
(and later said;)
“Navigation is handled by the Flight Management Computing Function (FMCF) within AIMS. Normally,
the FMCF uses a combination of ADIRU, GPS and radio position data to compute aircraft position.”
…”Inhibiting the GPS …only affects the FMCF’s use of the GPS data.”
If GPS updating has been inhibited does the AMM state whether;
the SDU receives the ‘inhibited’ (GPS non-corrected) ‘raw’ position from the ADIRU via the AIMS,
or
the SDU receives the ‘non-inhibited’ (GPS corrected) position from the ADIRU via the AIMS?
___________________
Andrew said;
“The AIMS cabinets receive date/time data from the multi-mode receivers (ie GPS).”
From previous comments, it seems the (navigational) aircraft present position is held by the
FMCF, (in each AIMS).
GPS data goes directly to the AIMS. Does the AMM show GPS data going directly to the ADIRU?
(for whatever reason)
@Ge Rijn
“Think about it in case I missed something.”
Missing, IMO, is your opinion of how the registration event was generated. Apparently you believe it is fraudulent. If so, for what reason? Certainly the Malays did not reveal it spontaneously.
@Andrew
I notice Oleksandr seems to have an interest in the Coriolis effect – is this mentioned in the
AMM (perhaps you have a digital searchable copy), for instance, as to whether it is the FMCF,
or the ADIRU, or both FMCF & ADIRU make the adjustment to account for it?
@Brock McEwen
It is not my wish to ‘butt in’ to your anticipated reply from SK999, but (reading any) scorn
from SK999s comments seems to be either implied, or perhaps stated somewhat obscurely –
could you quote the passage you are referring to, to minimize search time for SK999 to find
such comment (the comment is within this topic, right?)
Cheers
@DennisW
I base my opinion on what the RMP-report tells about the FO cellphone detection. They kept this important info behind for a long time. So indeed you can not know what they still keep behind and what is really true and what isn’t. For what reason I have no clue. Maybe to mystify the whole case beyond comprehension?
But just based on this reveiled information from them I see yet unexplained problems between the BBFARLIM2 cellphone detection and the route (radar track) south around Penang.
For those of you heaping scorn upon 38S because “the plane is not there”, bear in mind that the drift studies indicate that 38S (along with 35S and 30-ish) have the distinction of a) low probability of debris in australia; b) faster passage to reunion. This is due the the fact that there was a N/NNW tongue of ocean surface current around the 38S area (as there was at 35).
Some take the view that the aircraft must have terminated very close to 7th arc, therefore 38S cannot be right, and so the consensus moves on up along the arc the next best candidate area(s). The trouble is that as far as I can tell there is NO simple flight path that gets you there (I’m happy to be corrected if this is an over-simplification).
Given the choice, I would rather question the 7th arc terminus assumption (ie might, for various reasons, have gone a little further) than have to invent ever-less-probable path models.
@Ge Rijn
“For what reason I have no clue. Maybe to mystify the whole case beyond comprehension?”
I cannot think of any reason for creating a bogus registration either.
@buyerninety: feel free to “butt in” any time – I welcome the interjection.
The comment to which I refer was posted June 26, 2017 at 7:16 pm. Yes, to this thread.
I share your hope that no scorn was intended, and that we are all on the same page – that, for rigorous scientific work, data verification should precede data analysis.
@Paul Smithson
“The trouble is that as far as I can tell there is NO simple flight path that gets you there (I’m happy to be corrected if this is an over-simplification)”
I’ll send you my proposed path from ISBIX going 180S CTH, which hits Arc7 in the range of S33.5. I agree that ATSB has not provided flight path logic for their proposed search area 32-36S. My path proposal is somewhat similar to DrB’s path as well as Inmarsat’s original path in their paper, and these all end up 32-36S. Like Victor, I envision a loiter ( I prefer to call it maneuvers) until at least 19:41, and then heading due south.
I feel ATSB needs to relax the assumption of no pilot inputs from 1840. I feel 2041 to 2241 is possibly the only constant flight period if there is a pilot flying. With that assumption, I think you probably get 32-36S showing up as a good target area.
@El-gato
Thank you for picking up the ‘Prev Sat ID’ nugget.
While your conclusion is sound, I have a few points:
It appears that if the IFE system, which requires a ‘Data-3’ virtual circuit over the datalink, is not ready when the AES initiates the Log On with the GES, only one Log On Request is sent. Note the first octet of the LOR burst: 1F, the high order ‘nibble’ is a sequence ID.
If the IFE is ready, two Log On requests are sent in consecutive R/600 slots (1 sec apart). Note the first octet of each LOR burst: 2F and 3F, again the high order ‘nibble’ is the sequence ID.
At 04:00:58, an LOR burst with seq ID 2F was not received by the GES (quite possibly an R-ch ‘collision’). The AES received no Log On Confirm from the GES, timed out after 10sec, and re-transmitted the two part LOR at 04:01:10.
The format of the second LOR concerned with a Data-3 connection is not consistent with the basic GES Log On Request, as set out in Figure A2-2 which you presented. Octets 1-8 are good; 9 & on, not equivalent.
@Victor @Paul: My comments last night were on re-examination of the CSIRO [Griffin et al.] drift reports from Dec16 and Apr17, and the authors’ claim of higher-res ocean surface current data — basically satellite ocean surface height as a surrogate for current direction and speed. Most sites on the 7th arc would imply rapid transport of drift toward Australia, but according to fig. 3.3.1 in the original reports, there seem to be narrow ‘fingers’ near 35S and 30S [and for argument, I’ll accept that Paul is correct about 38S as well], where the initial drift would be to the NW. From the summary in Part II [Apr17]: Figure 3.1 and 3.2 also show that a crash location near 35S is one that results in the flaperon being unlikely to have reached Australia. This cannot be said for other potential crash sites south of 32S but can be said of the 32-30S segment. This narrows the location of the crash site down a little but remains a weak argument compared with consideration of the many other debris items.”
I have no pretension to doing more myself than tracing the various heat maps, but they seem to reasonably support the Griffon et al. summary. I do personally think some other premises of the drift studies are questionable, eg, reasoning that lack of early debris finds north of Madagascar is telling [I think no one looked!]. But the absence from W Australia is absolutely telling. It does seem to me that the conemporaneous satellite sea-surface data would tell us much more than averaged drifter data over many years.
If I were a politico holding the purse strings for re-opening the search, I’d love to see this pitch. But only after serious First Principle review.
@all:
(all times UTC – even within direct quotes, which I’ve converted for consistency)
My understanding (please correct me if I’m wrong) is that, on March 8, 2014, at 23:24 UTC, MAS issued a media statement which included the following claim:
“Malaysia Airlines confirms that flight MH370 has lost contact with Subang Air Traffic Control at 18:40 today (8 March 2014).”
I’m not suggesting this is when contact was actually lost – I’m well aware of the breadth and depth of heated “correction” subsequent to this original report – none of which I dispute here.
All I seek here is to gain a fuller understanding on one key point: if MAS erred originally, what led them to MAKE this error?
The 18:40 time corresponds to precisely nothing I’ve seen since which could explain why MAS would give that time. Even the radar data is supposed to have petered out (implausibly, but I digress) by 18:22, 18 minutes earlier.
And the “Actions taken between 17:38 and 22:14 UTC on Saturday 8 March” report sheds no light either, despite appearances. Yes, the report claims MAS OPS told* KL ATCC…
a) at 18:35 that MH370 was still on track at 18:33, but
b) that this was found to have been based on projected, not actual data
(* there is, apparently, an audio recording of a, but, sadly, not of b)
But this doesn’t explain MAS’ original “lost at 18:40” claim; it…
1) is too many minutes removed from 18:40 for comfort,
2) refers to a time at which MH370 was seemingly FOUND, not lost, and
3) had ostensibly already been corrected by MAS OPS by 19:30
Needless to say, it would be concerning if the original 23:24 media statement turned out to be correct, with the subsequent “corrections” being the fib. It might even drag our search for culprits a bay or two to the East in the SCS. So I think we need to understand precisely how and why the original MAS media statement could get it so fundamentally wrong. Any thoughts from the group?
Here’s what seems to me to be the original MAS FB post, including the sentence I cite (please correct me if I’m using an improper source):
https://m.facebook.com/my.malaysiaairlines/posts/514299315349933?from=message&isappinstalled=0
Brock,
Sorry if you feel offended. Getting Inmarsat to public endorse the data is not high on my list. In fact, it can’t be done – there is no proper chain of custody, and the metadata say that the file was modified a month ago. It is no longer Inmarsat’s file.
Fortunately I have no professional qualifications for air accident investigation, so I can’t be “drummed out”.
We are all frustrated with how the whole investigation has been an opaque process. It seems to be the nature of the beast. We are not alone. Tom Mahood (previously cited here indirectly in a completely different context), put it succinctly whe he encountered investigative agencies:
“They do not like to share.”
http://www.otherhand.org/home-page/search-and-rescue/so-whats-the-attraction-of-cold-cases/
@lkr: The KMZ files supplied by CSIRO that I used to examine the results use the BRAN2105 ocean model. To quote: The data assimilated comprises satellite estimates of the sea surface elevation (by altimetry) and temperature (by radiometry), and subsurface estimates (predominately by Argo robotic profiling floats) of temperature and salinity. CSIRO did not use two different models to generate results.
I recommend that you drag the KMZ files into Google Earth, and using the time slider, examine the time history of the debris (non-flaperon debris of both low and high windage) for an impact at 35S. Based on your comments, I suspect you have not done this. You will find that just after impact, the debris drifts generally to the west away from Australia, as you note. However, by May 2014, most of the debris has changed course and is drifting towards WA, resulting in landfalls starting in August 2014 and ending in December 2014. You can also see this effect in Figure 3.2.1 of the first CSIRO report, and Figure 4.1 of the second, where the probabilities are significant at 35S for the indicated time period for landing in WA.
@Brock McEwen said: The 18:40 time corresponds to precisely nothing I’ve seen since which could explain why MAS would give that time.
That time corresponds to the first unanswered satellite call from MAS. Perhaps it is related.
@buyerninety
RE: “If GPS updating has been inhibited does the AMM state whether;
the SDU receives the ‘inhibited’ (GPS non-corrected) ‘raw’ position from the ADIRU via the AIMS, or
the SDU receives the ‘non-inhibited’ (GPS corrected) position from the ADIRU via the AIMS?”
It doesn’t matter if GPS updating is inhibited or not. The SDU alway receives ‘raw’ (ie uncorrected) data from the ADIRU.
RE: “From previous comments, it seems the (navigational) aircraft present position is held by the
FMCF, (in each AIMS). GPS data goes directly to the AIMS. Does the AMM show GPS data going directly to the ADIRU? (for whatever reason)”
No, but GPS data is sent to the ADIRU from the AIMS cabinets. The GPS data is used by the ADIRU to calibrate its internal sensors to reduce inertial reference drift. It is NOT used by the ADIRU to correct its position output.
RE: “I notice Oleksandr seems to have an interest in the Coriolis effect – is this mentioned in the AMM (perhaps you have a digital searchable copy), for instance, as to whether it is the FMCF, or the ADIRU, or both FMCF & ADIRU make the adjustment to account for it?”
It’s not mentioned in the AMM, but Coriolis correction is a function that is normally performed by an inertial navigation system before its data is output to other systems. I think it’s reasonable to assume the ADIRU applies the Coriolis correction before sending data to the FMCF. If you’re really keen, try the following book:
Titterton, D. & Weston, J. (2004). Strapdown Inertial Navigation Technology – 2nd Edition, Stevenage: The Institution of Electrical Engineers.
Andrew: Re: “The GPS data is used by the ADIRU to calibrate its internal sensors to reduce inertial reference drift. It is NOT used by the ADIRU to correct its position output.”
Actually, both are true. “[I]nertial reference drift” is continuously zeroed out using GPS position data and a Kalman filter (typically), thereby keeping the ADIRU position accurate (free of long term drift). Loss of GPS data will not cause significant ADIRU position error unless the outage lasts for a long time (hours).
@ALSM
Thanks, I didn’t word that very well. The point I was trying to make is that the ADIRU only uses GPS data to correct the inertial drift. It doesn’t use GPS data to update its position to match the GPS position.
Yes. Exactly.
@ROB
If the ATSB had assigned a high probability of a flight crew murder-suicide on what logical basis would they assume that that entailed a lengthy controlled glide? In half a century of modern air travel, no act of murder-suicide by a flight crew member on a commercial flight has ever ended with a controlled glide; never ever. In all six cases (Germanwings flight 9525, LAM Mozambique Airlines flight 470, SilkAir flight 185, Royal Air Maroc flight 630, EgyptAir flight 990 and Japan Airlines flight 350) the flight ended with a steep descent (or an attempted steep descent) into terrain or water; no controlled glides.
Moreover, the only stick of evidence that even vaguely suggests any planning, pre- or otherwise, on the Captain’s behalf – the 10N, 45S1 and 45S2 data points from his flight simulation program – show a southbound leg that ends on fuel exhaustion with a steep descent (something like 65° nose down); no controlled glide.
Add to that the fact that the last BFO data also supports a steep descent after fuel exhaustion; no controlled glide.
So, given the historical, circumstantial and actual evidence that was available to the ATSB, why would they assign anything other than a low priority to the possibility of a theoretical unpowered glide?
The notion that three separate departments of the Australian federal government colluded to produce mutually supportive findings ostensibly at the behest of a foreign government is interesting but utterly unsupported by any evidence. Two Australian Prime Ministers and nine different federal ministers have had carriage of the various activities associated with the Australian contribution to the search for MH370; the notion that all of those people together with their respective staffs would toe the line without one hint of dissention making its way to the media stretches credibility.
@TBill
Re: “I would not say there is no evidence of that, as I feel the BTO/BFO shows possible pilot input up to at least 1941, and I feel descent can be shown as a BFO possibility after Arc5.”
Can you expand on that please?
@Brock
My understanding (please correct me if I’m wrong) is that, on March 8, 2014, at 23:24 UTC, MAS issued a media statement which included the following claim: […]
The statement was authored at 23:24 UTC on March 7th/b>, it was then posted to Facebook 48min later.
Notably, the time of authoring was 10 minutes after the second SATVOICE call attempt, the first call being 18:40.
@Victor. Are you sure that altimetry and sea surface temp are used together in a single ocean surface current model? I have seen previous work by CSIRO that produces two OSC models of the same area – one using SST and the other using altimetry.
@Mick Gilbert
All the flight events up to the FMT point to a carefully pre-planned hijacking by the Captain, no one else. The individual events have been discussed at great length – there can be no reasonable doubt that the Captain’s intention was to hide the plane in a remote area of the SIO. Now, put yourself in the Captain’s shoes and say to yourself “what would I plan for the end of flight, to ensure the aircraft is never found. Would I just let it fall out of the sky and scatter debris far and wide for the searchers to spot, or would I make sure it sank as intact as possible, at the same time making sure the fuselage mounted ELT didn’t get a chance to signal my position (50 secs delay after activation). The best way to achieve this goal is in my humble opinion, to control the impact conditions after gliding well downrange of theflameout point, and have a once and final joyride with a MAS B777, explore the uttermost limits of the unpowered flight envelope. He “lived” for flying, so we are told.
@Paul Smithson: I am quoting from the paper.
@Don: thanks. I was keenly aware the entire world was aware of the disappearance by “shortly after Arc 5” – I just forgot to convert the date whilst converting the time. Appreciated. Would also welcome your thoughts on the question I asked.
@Victor: thanks. When an airline says “we lost contact with plane x from station y at time z”, I don’t think any of us would have as a natural first reaction, “well, that must have been the time long AFTER it disappeared from all ATCC screens, when they tried a sat phone call”. By the time the media statement was issued (23:24 UTC), I’d thought the entire ATCC community had been fully canvassed, and the wheels of the SAR operation had already begun grinding toward the “coast of Vietnam”. This leaves two possibilities: the time given was eighty minutes off without rational explanation, or the ORIGINAL coast of Vietnam was the one several hundred miles to the NE.
@SK999: no personal offense is ever taken; if you wish to deride me personally, then a) good choice of target, and b) get in line (behind my family, friends, colleagues, and passers-by). All I ask is that you consider wording your posts a bit more carefully in future, so that the PRINCIPLE that data verification matters is never derided.
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