Experts from all over the world have converged in Perth, Australia, to meet Seabed Constructor, the exploration vessel tasked with finding the wreckage of MH370, after its first stint in the search area. Technical experts and government officials are having meetings and dinners, touring the ship, and doing photo ops. Everything glitters and spirits are high.
Lost in this excited hubub is the fact that the latest search effort has already invalidated the expert analysis that got it launched in the first place.
In a 2016 document entitled “MH370–First Principles Review,” the ATSB explained that, given the absence of wreckage in the orginal 120,000 sq km search, MH370 most likely wound up somewhere near the 7th arc between 33 degrees and 36 degrees south. A subsequent document by the CSIRO entitled “The search for MH370 and ocean surface drift–Part III” narrowed the target area considerably. “We think it is possible to identify a most-likely location of the aircraft, with unprecedented precision and certainty,” it stated. “This location is 35.6°S, 92.8°E. Other nearby (within about 50km essentially parallel to the 7th arc) locations east of the 7th arc are also certainly possible, as are (with lower likelihood) a range of locations on the western side of the 7th arc, near 34.7°S 92.6°E and 35.3°S 91.8°E.”
The wording is important, because as the original search area was winding down, Australia, China and Malaysia said that it would only be extended if “credible new information” came to light. The CSIRO’s language sounded like an attempt to make the case that this condition had been met. And indeed, the three specified points were all included the “Primary Search Area” that Seabed Constructor recently focused its efforts on.
However, that area has now been searched. And once again, the plane was not where it was supposed to be. The CSIRO’s “unprecedented precision and certainty” was a mirage.
How is that, time and time again, officials heading up the search for MH370 exude great confidence and then come up empty handed? How can we account for four years of relentless failure?
The answer, it seems to me, is quite simple. Investigators have resolutely failed to grapple with the single most salient clue: The fact that the Satellite Data Unit (SDU) was rebooted. This electronic component is the part of the 777’s sat com system that generated the Inmarsat data that has been the basis of the entire search. There is no known way that it could accidentally turn off and back on again.
If one has no idea how the SDU turned on, then one can have no confidence in the integrity of the data that it generated.
The ATSB has never publicly expressed a theory about what could have caused the reboot, except to say that most likely the power had been turned off and back on again. There was always the possibility that, behind the scenes, they had figured out a way that this could plausibly happen other than being deliberately tampered with.
Just today, however, I received confirmation that the ATSB is in fact befuddled. Mike Exner is a stalwart of the Independent Group who is currently visiting Perth, where he has had dinner with employees of Ocean Infinity and Fugro, as well as members of the ATSB and the DSTG. In response to my assertion that investigators “had never stopped to ask how on earth the SDU… came to be turned back on,” Exner tweeted that “Everyone is well aware of the question. We have all asked ourselves and others how it happened.” However, Mike writes, “no one has the answer.”
One might forgive the expenditure of vast wealth and manpower based on data of dubious provenance if there was other evidence that independently supported it. But the contrary is the case: debris collected in the western Indian Ocean shows no signs of having drifted from the search zone, as I wrote in my previous post. It is increasingly clear that the plane did not go where the Inmarsat data suggests it did. The fishiness of the Inmarsat data, and the fishiness of the SDU reboot that created it, are all of a piece.
Soon, Seabed Constructor will return to the search area; some weeks or months after that, it will leave again, empty handed. When it does, people all over the world will ask: How could they have failed yet again?
The answer will be simple. It is this: Investigators never established the provenance of the evidence that they based their search on.
HB,
I guess the term “neutralize” was misleading. In practice, the pilot signal goes through the exact same signal chain as the signal from MH370 (or any other aircraft) starting with the L-band receiver on board 3-F1, through the up-conversion process, any eclipse effects, the downlink C band Dopppler, and the C band down converter at Perth (which is where the software bug enters), BEFORE its frequency is digitized and recorded. The only frequency component in the pilot signal that is not present in the aircraft signal is the uplink L band Doppler from Burum to the satellite. However, that contribution can be calculated to high accuracy and removed (which is how I do the computation these days.) All other effects as described above are common to both the pilot signal and the aircraft BFO. Thus, the pilot signal (corrected for the uplink L band Doppler) can be subtracted from the measured aircraft BFO, and what is left is the contribution from the satellite motion as seen by the aircraft and the error in the aircraft Doppler compensation calculation ONLY. That is what I meant by “neutralize.”
The following document, particularly Figure 8, gives a more complete (although probably not more transparent) description:
https://nardamiteq.com/docs/20TEC.PDF
If you are still confused, remember – it took Inmarsat 3 months to straighten this out.
@Scott O:
I could continue to rebut your further comments but I won’t, because this blog is about MH370 not TWA800. There are plenty of other places where you can find out more and enter into discussions about that affidavit.
Suffice to say that if the NTSB investigators had been allowed to perform their own analyses of the forensics found (as they normally would – why the big change for this investigation?) and use the eyewitness testimonies (not every witness out of 500+ would be prone to error, and there were many professionals who saw the event) then based on the affidavit of H. Hughes, the conclusion of the investigation into TWA800 would likely be that of an external explosion, not internal.
@TBill said:
“Re:TWA800 From an engineering perspective, anytime we have a fuel vapor/air mixture in a confined space, it is a disaster waiting to happen (due to static elec, etc). The type of explosion that results from igniting a air/vapor mixture is called a detonation (high energy)…that would seem to be the most likely explanation.”
One of the NTSB lead investigators and several of his colleagues who investigated the event and the wreckage first hand disagree with you. Considering (guessing) you weren’t part of the TWA800 investigation and – guessing again – you don’t have years of experience as an air crash investigator, who’s opinion would you consider more likely to be accurate – yours or theirs?
@PS9
Not sure how to answer that 1. Take Larry Vance. He is apparently a world expert on air crash investigations yet he has come in for some sharp criticism over his thoughts about Mh370.
So what does qualify an Air Crash Investigator as someone with credibility?
@Michael John, Larry Vance is the perfect example of a clueless lunatic who, because he once had an impressive job title, gets a lot of attention and respect from the media. The guy is an absolute clown.
@Jeff
Vance is credentialed. You may not agree with him, but he has the pedigree which few of us have. A PhD in physics or math is much less impressive.
@PS9
Well to be honest I did have some very limited involvement in the search for solutions to the fuel/tank issue. So I do know first-hand that the effort for the aircraft design/procedure changes was based on a industry belief of fuel/tank issue. That much I do know.
@Michael John:
“…I still believe that the only way we will know what happened to Mh370 is by starting the entire investigation from the beginning but this time getting full transparency from all parties.”
Agree with you, but this is not going to happen.
From day one the whole MH370 story had the smell of a planned event, and the following ‘cover operation’ has been almost flawless. I’m still hoping that they have overlooked a tiny detail which will prove to be the smoking gun, or a whistle blower will provide the evidence of the planes fate – I’m not holding my breath!
@DennisW, It is precisely that fact that Vance is credentialed that has allowed him to do so much damage. TV producers can put him on screen with a chyron that justifies his presence, and are unable to judge for themselves whether what he’s saying has any validity. But make no mistake: Vance is completely full of shit. No actual, non-insane crash scene investigator would claim that a single piece of debris tells him how the plane entered the water, without having seen and handled the object in person.
Aye I have heard all about LVs rep & to be fair to Jeff a lot of people seem to hold the same opinion on the guy. But that was the reason I used him in my response to PS9. LV does have credentials & expertise despite the way he has allegedly disgraced himself. So if he & TBill were having an heated discussion in a blog like this about Mh370, people who don’t know about LVs dubious background would probably support his opinion over TBill’. My point being that just because a person holds qualifications & expertise it doesn’t mean they are always right. Personally if the issue is important I would look for the opinion of more than 1 qualified person.
@Susie Crowe
Thanks for those previous comments here. Notoriety, belittling and implying inferiority to others is a constant luring trap with the risk of scaring people off to comment and possibly miss important information. I admitt I’m not free of it myself at times when I feel attacked or read complete nonsence (imo).
These blogs are a hard place to be at times but as you noticed I’m not easily scared off.
I think it’s about keeping eye on the bigger picture. In between it’s not only rational but also emotional with (big) ego’s involved.
And that shows now and then.
I think in the end it will work out like it has done before. We’ll find some kind of consensus and gradually closing in to a solution to this drama.
@Ge Rijn, Nicely put! Always good to have @Susie Crowe weighing in with smart insight and emotional intelligence.
@Jeff Wise
I guess we just need women, like @Susie Crowe to remind us. Invaluable.
@Jeff
No actual, non-insane crash scene investigator would claim that a single piece of debris tells him how the plane entered the water, without having seen and handled the object in person.
That is my take on it as well…
@Scott O:
“I could continue to rebut your further comments but I won’t, because this blog is about MH370 not TWA800…”
Thanks for raising the issues surrounding the TWA800 debacle as it, along with some others, destroys several myths about how ‘air-accidents’ are conducted and show how easy it is to cover-up what actually happened, even after whistle blowers and eye witnesses come forward to reveal the truth.
Myth 1 – Air accident investigation bodies are independent and free to publish the investigation results free of influence from the security services or political bodies.
Myth 2 – The MSM are free to publish whatever they want in the interests of providing the facts to the public, irrespective of security or national interest.
Myth 3 – Politicians and security services work for the benefit of the general public and are subservient to the democratic voice of the electorate. The reality appears to be the exact opposite of this, with both groups serving their own ends.
I try to keep the above in mind when considering motive, means and opportunity regarding the MH370 conundrum.
@Ge Rijn:
Don Thompson says on February 22, 2018 at 9:44 am on VI’s blog:
” It is located with two spring-clips, the spring-clip fixings are then locked by means of the vertical bars.
I’m gradually compiling a detailed description, …”
Let’s just wait and see what he comes up with.
@Ge Rijn
Look back on page 5 of this topic, you can see I posted some pics of ‘seat back trim
panel for encasing the IFE monitor‘.
Victor noted recently that there seems to be some mix-ups in the items being discussed,
and/or the name(s) of the items.
Don Thompson mentioned “the IFE display component recovered by Blaine Gibson is the
seatback display chassis. It is firmly fixed to the seat frame”.
He seems to be making a rare mistake, as the item Blaine found is as you stated in
the first sentence above. It is not the ‘seatback display chassis‘.
Mention was made of ‘spring clips’ possibly fixing items together. Perhaps there are
‘spring clips’ somewhere amongst those items, but if we view the ‘seat back trim panel
for encasing the IFE monitor’ that Blaine is holding, we can see it appears to have
velcro strips on it.
In the MH17 video (at time ~00:13) that I cited on page 5 (and in Kenyons pdf picture)
there are visible small studs on the surface of the fabric – so it is possible that
the small studs attach to velcro patches on the inside of the fabric.
If there are velcro patches on the inside of the fabric, those patches could mate with
the velcro strips that we seem to see on the ‘seat back trim panel for encasing the IFE
monitor’ that Blaine is holding.
In regard to the reason you had for drawing attention to the ‘seat back trim panel for
encasing the IFE monitor’ – probably this item is not a good item to use to illustrate
your point. There are of course more than a hundred of these things distributed inside
the aircraft, and regardless of whether the plane ditched, or whether the plane hit the
ocean at near mach speed, some of that item are likely going to detach and float away,
probably much as Blaine found it.
Probably it should be acknowledged that the discussion about the item is not going
to assist anyones theory, and ‘let it be’. (Ge Rijn – I mean like in the meaning of the
Beatles song).
@Susie Crowe
Thankyou
@buyerninety @Gysbreght
It’s in the details. We have to look at the details from every angle each time. All of us can be wrong at times.
Now I asked @Don Thompson and @Kenyon to explane themselves on this matter.
No big deal if they do so in a rational way.
It’s heavy stuff sometimes.
To me it’s all for the goal: finding the plane.
@Boris Tabaksplatt,
I believe you meant to write PS99, as your quoted material is attributable to him not me, and as I do not put much stock in the possibility that TWA 800 was blown out of the sky by anything other than faulty wiring that sparked a center fuel tank explosion. The preponderance of the evidence certainly supports this scenario, while claims to the contrary are no more than claims, without forensic support.
As for the three items you mention, I cannot speak to Myth 1, the independence of accident investigation bodies. And I agree with you more every day on Myth 3. Which is why I put so much faith-at times very strained faith, but still faith-in number 2 not being a myth.
Keeping to the United States, which I can address personally with more than 20 years’ experience spent across print, digital and broadcast media, I can say unequivocally that the government’s ability to stop a story from public dissemination is limited. The use for prior restraint, as defined by such court cases as Near v. Minnesota and the New York Times Company v the United States (the Pentagon Papers), has indeed confined matters of national security. But outside of war-time coverage and voluntary submission to military censorship, I don’t know of a single court case that has stopped a news outlet from publishing a story-including those that detail nuclear weapons design. Journalists may be a lot of things, including, sloppy, lazy, and incorrect, but the ones I have known tend not to be submissive to authority, and, fortunately (up until recently anyway) members of our government have been widely tolerant of such impetuousness. The Constitution requires it, after all.
Does that mean a publication might voluntarily withhold information? Sure, often when lives are at stake, but rarely if ever indefinitely. The truth has a way of coming out. This also speaks to people’s wrong presumption that the media is something monolithic, with the same beliefs and working from the same playbook. Nothing could be further from the truth. Media people fall all along the political, religious and moral spectrums and are often fierce rivals–or just individuals in the same line of business. For example, I know people who know this blog’s host, but, despite having colleagues in common, having had a career that more or less overlapped, and despite living in essentially the same few square mile patch of land, I have never met or even spoken to Jeff outside this forum.
I think the government is far less of a threat to the Press (not to mention the burgeoning corps of citizen journalists) than are wealthy individuals, who would seek to buy up media outlets and bankrupt reporters through law suits, as we have recently seen.
That said, a healthy skepticism is always well founded.
@sk999
“contribution can be calculated to high accuracy and removed”
Yes that make sense that it is possible to correct back the compensation.
If i understand figure 8 and the inmarsat paper, the monitored pilot signal after conversion was compared to the pilot signal to get the conversion ratio and as you said adjusted in the BFO model calculations, which looks like an acceptable way to go around the error.
My question of validation is driven by these:
* the process assumes that the same conversion applies to all signals (I would presume so)
* the process assumes that the signals are not additive and do not influence each other and the error margin is negligible (I would have guess otherwise though ???)
* the signal from Burum is taken at face value without other apparent 3rd party validation. Transparency and traceability is lacking here.
* The other issue is whether a similar fault could be on the onboard droppler compensation, was this validated with a southern hemisphere flight (I would presume not but not sure). I presume that any latent fault on the BFO logging system would be unrevealed.
I would appreciate your further view on this.
Jeff Wise
Nice comment
@Ge Rijn
I learned to admire your tenacity. Although not in your professional wheelhouse, it is obvious you have invested major time comprehending the complex nuances of the investigation.
@all
Shortly before the simulator data was made public, Victor Ianello predicted public opinion seguing in 2 primary “camps”, Captain Zaharie’s guilt, or innocence.
As the second search begins to nullify locations predicted by “experts”, validity of the data and an effective interpretation basis, is being challenged for accuracy.
If the search continues without results, it is likely the 2 “camps” will morph into support or opposition of the data. Is the constituton accurate and the translation sustainable.
@David: I’ve read your paper “MH370: Piloted Final Descent? Glide distance?” dated 24th January 2018 with considerable interest.
You write: “At the outset I discard a stall from this list, because from previous discussion that is unlikely”.
What are the reasons for discarding a stall?
An even bigger split is whether after FMT the plane was under pilot control or not….
I’m convinced it was at least for some time.
@Susie Crowe, I think you’re right about the splitting up of the camps, though I hope that it will play out not as a disagreement about whether the Inmarsat data is valid or not, but whether or not officials should be pressured to grapple with the question of whether the data is valid or not, and if it’s not valid, but what means it came to be invalid. For me the worst-case scenario is that the public comes to widely doubt the validity of the data, but are satisfied to leave it at that, in a giant collective shrug, thinking that the experts are simply wrong, and unreliable, and who knows what could have happened. The best case scenario is that people with some credibility left (if there are any) will step up and say, “We have this data, it is a record of a physical process, if it was somehow altered or distorted we need to use reason and logic to figure out what the options are.” However at the moment there seem to be very few people with me in this camp.
Sort of a segue here… one of the people who would fall into what I’ll call the “indeterminist” camp, meaning they’re happy to discard the Inmarsat data without further interrogation, is Ghyslain Wattrelos, who has been doing some press lately to support his book. Ghyslain thinks that the plane was shot down, most likely by the US. I’m not a big fan of this theory but otherwise I think that he’s been doing a commendable job keeping the case in the public eye and bringing a skeptical perspective to what otherwise can feel like uncritical acceptance of the ATSB/IG/OI line on the part of the media.
I just read an interview with him in Paris-Normandie.fr:
http://www.paris-normandie.fr/ouverture/ghyslain-wattrelos-en-quete-de-verite-sur-la-disparition-du-vol-mh-370-KA12308046
If you’ve been following Ghyslain there won’t be much new–except for one bit which I found somewhat shocking”
Which I translate as:
Q: You say that some people have been assigned to turn you away from the truth…
A: Yes, I’m thinking of Sarah [Bajc] for example, this American woman who presented herself as the partner of a victim and organized a crowdfunding campaign for a search. I’m sure that since March 8, 2014, she was there to control the families and prevent them from finding the truth.
Back in 2014 Bajc led an effort that raised $100,000 to hire private investigators to look into the disappearance; nothing came of it that I’m aware of, so I don’t understand how she might have led the public or family members one way or another. I used to go on CNN with her (she always appeared via remote) and was impressed by her poise and passion. I’ve been in touch with her from time to time, though lately she’s been distancing herself from MH370 and recently got married. I’ve never heard this kind of allegation levied against her before, and don’t know what evidence Ghyslain has. Which is not to say that there’s no substance to what he says.
He thinks America shot down the plane & he also thinks an American woman has played a part in covering that up. Be interesting to see what evidence he has for those claims. Does he have a place for where this alleged shoot down happened?
HB,
Here are answers, as best I can, to your questions.
“the process assumes that the same conversion applies to all signals (I would presume so)”
Yes, this is shown in Fig. 8 and explained in the text of the Miteq technical note. It is a technical advantage of the EAFC over the older AFC system, which required a separate down-converter for the pilot signal.
“the process assumes that the signals are not additive and do not influence each other and the error margin is negligible (I would have guess otherwise though ???)”
Not sure what you mean. An entire block of frequencies with many channels and aircraft signals is being converted in the process, and one uses digital filters to pull out the desired signal. Since the pilot signal is presumably unmodulated, one can use a narrow filter and pull it out with high accuracy. Figure 11 of the JON paper plots the pilot frequency error after conversion, and it is very smooth.
“the signal from Burum is taken at face value without other apparent 3rd party validation. Transparency and traceability is lacking here.”
That is correct. The same goes for the Perth – we rely on both stations having a stable frequency standard. Unlikely to be an issue, however.
“The other issue is whether a similar fault could be on the onboard droppler compensation, was this validated with a southern hemisphere flight (I would presume not but not sure). I presume that any latent fault on the BFO logging system would be unrevealed.”
Again, I am not sure what you mean. The only Southern hemisphere flights I am aware of flown by a 777 were to Sydney and Auckland, and those flights would mainly use the POR satellite.
@HB
It is of course possible for the BFO (quartz crystal frequency) to drift or shift to new calibration. Also if there is somehow a small error in heading data the BFO calc will be off.
But I favor starting with the assumption that the BFO is correct as reported, which I believe points to the current search area (assuming they get up to at least 29S).
To quote Victor if OI fails to find MH370 again, we will have a mess on our hands. There will be a lot of possibilities that we do not know how to priortize:
Possbilties:
(1) On Arc7 further north
(2) On Arc7 but search failed to see it
(3) On Arc7 with 100nm glide out of search range
(4) More complex piloted path
(5) BTO/BFO data issues
(6) Spoofing
(7) Unfindable location on Broken Ridge
(8) Did I miss any?
@Jeff, doesn’t the idea that the United States Navy shot down MH370 feels fairly unsupportable–not because it’s impossible, but because it would be seemingly impossible to cover it up?
Such an incident would not explain the turn back and flight path of the ship. It would not explain the lack of fireworks off of any populated coast. It would not explain the lack of debris field, which, if a break up originated at altitude, would be huge–the Lockerbie bombing, for example, produced 4 million pieces of debris, AF 447, which, perhaps is more applicable, well over one thousand.
Hard to imagine it would be intentional give the good state of U.S. Malaysian relations at the time. And hard to imagine an accident remaining quiet, just as it did not remain quiet in the Vincennes incident with Air Iran 655, where the commanders of other nearby ships were not silenced in their opinion. (See also the protocols put in place since then to avoid such an accidental shoot down again.)
As for Sarah Bajc, well, she strikes me as an honest broker, though perhaps she is a simple grifter–there’s no shortage of them preying on people’s good will on crowdfunding sites. But it’s hard to imagine her being deployed as an agent of misinformation in support of a thesis only a very few people claim to be true to begin with.
@TBill
I would assign probabilities to your list as follows:
Possbilties:
80% (1) On Arc7 further north
10% (2) On Arc7 but search failed to see it
10% (3) On Arc7 with 100nm glide out of search range
@ JS
You said
———————————————————
” The red flags as I see them remain as follows:
The inability for any knowledgeable party to explain why the BTO would be logged as an “offset,” when the constant making it an offset was not known prior to logging. No data expert logs half the data value and leaves the other half to be “derived” later. You can’t log data as an offset from a yet-unknown constant.
…You are saying that the total trip length was logged. That’s new information because the reported log values were on the order of 9,000 to 22,000us, while the trip time was in the neighborhood of 500,000us. Which is it? How did it get from total trip time to a 4-5 digit value?…
…But let me try to get clarity on one point. A log value of 22,000, for example, cannot be the total trip time. How did the computer writing the log come up with this value? Let’s say we have T_1, the slot start time, and T_2, the arrival time. Is this not on the order of 517ms for a plane in the SIO? If so, how did it get measured at 517ms or so, and logged as 22,000?”
——————————————————–
Its years since I looked at this, and I may be misunderstanding your question, so if this does not help I apologise.
The total signal path is GES (Perth) to satellite to aircraft (and back again). In logging the BTO, Inmarsat assume a fixed ‘nominal’ location for the aircraft, which is used to generate an ‘expected’ delay for the signal. This delay can be accurately calculated by the system, since the GES location, the satellite location and the assumed fixed nominal aircraft location are all known. The actual delay measured will be different to this expected delay, since the aircraft is typically of course not at the ‘nominal’ location. Inmarsat write to their database a BTO which is the difference between the ‘expected’ delay and the actual measured delay, and this is a relatively small number compared to the overall delay. A useful schematic of the geometry is Figure 16 in the ATSB 30th July 2015 report on search areas.
What we ultimately want to do is to calculate the actual distance from satellite to aircraft based on this logged BTO. The simplest way to do this is to directly relate the logged BTO to the overall signal path when the aircraft location is actually known (for example when parked at KL airport). The ‘bias’ term derived to do this effectively includes the ‘expected’ delay based on the nominal aircraft location, and any other processing delays in the electronics.
To see an example, consider the data presented by Inmarsat in their Journal of Navigation paper. Table 2 on page 5 assembles the important numbers. The coordinates of the GES and the parked aircraft at KL airport are known as are the coordinates of the satellite at various times. If we take the first line of data at 16.00.00 :
Satellite to GES distance can be derived using Pythagoras from the coordinates and is 39222.7 km.
Satellite to parked aircraft distance can be derived in the same way and is 37296.0 km.
The total known trip distance is thus (2 x 39222.7) + (2 x 3726.0 km) = 153037 km. This can be seen in column 3 in Table 3 in the JON paper.
The speed of light is 299792.458 km/s, and using this, we know that the time taken for the signal to cover the total trip distance (with no processing delays) would be 510478 us (column 4 in the table). For application to the observed BTOs at the ping times when we don’t know where the aircraft is, we need to relate the logged BTO figure to the the underlying distance (153037 km) travelled at the speed of light. The shift required is 495658 us, the bias figure in column 5 in the table. Rather than using a single determination of the shift, Inmarsat have done this calculation for a number of points in time while the aircraft location was known at the airport and taken the average. Applying the average (rather than a unique bias for each point) results in the errors for each point shown in column 7.
So the concept is that the single bias figure covers all of the adjustments required to the logged BTO delay (adding a chunk for the missing ‘expected’ delay due to path length at nominal location, subtracting a bit for processing delays), based on a real observed data set. It is not necessary to know the sub components of the shift themselves. An underlying assumption in using the bias for later data points when the aircraft is moving is that the bias does not change with time, ie the calculation of the ‘expected’ delay is effectively a constant, and processing delays do not vary across the duration of the flight. There has been much discussion around this.
Ground truthing of this method comparing a calculated distance from satellite to aircraft during the early stage of the flight (using the bias) with known positional data (transponder) works well (see JON report Figure 3).
Using the bias in this way is simple: for example the BTO at 16.55.53 was reported by Inmarsat to be 15240. Adding in the bias shift makes the total delay 15240 + 495679 = 510919 us. At the speed of light the total trip distance (GES => Sat => aircraft => sat => GES) is then 153169.7 km. From the known satellite position at this time we can calculate that Perth GES to Satellite is 39246 km. Twice the distance from satellite to aircraft = 153169.7 – (2 x 39246) = 74677 km, so the range from satellite to aircraft is 37338 km, and this agrees well with transponder position.
Once again my apologies if this is obvious stuff, or if it does not address your concern.
@ScottO, I agree with you completely.
M Pat,
I think there is one extra piece to the story that might clarify the answer for JS. An AES is required to align the timing of its transmissions on so-called “slot” boundaries. Slot boundary timings are defined by continuous broadcasts from the GES of “superframes” on the P channel. After a nominal round-trip time, the GES starts listening on the R channel for any packet sent from the AES. This round-trip time (which is just a time delay in the GES system) is short enough that it is just less than the earliest time that a packet from an AES directly under the satellite could be received. Someone worked out that it corresponded to a “nominal terminal” a few hundred km above the Earth at the sub-satellite position. The BTO is the offset in the actual start time of a packet being received relative to this earliest start time. The exact value has never been given by Inmarsat. If there were no delays anywhere in the system other than light travel time, then one could add it to the BTO and get the total round-trip time. However, since there are known delays in the system, Inmarsat chooses to calibrate the combined time delay in the GES plus the other delays in the AES and/or GES as a single number using the known position of 9M-MRO when it is stationary on the ground.
The MANUAL FOR AERONAUTICAL MOBILE SATELLITE (ROUTE) SERVICE, Part III gives details of the communications protocols in excruciating detail.
Michael John said:
“My point being that just because a person holds qualifications & expertise it doesn’t mean they are always right. Personally if the issue is important I would look for the opinion of more than 1 qualified person.”
Yes, very sensible approach. And did you notice that in the TWA800 case there are six investigators disagreeing with the official report conclusion, not one? And it is not solely their ‘opinion’: they are basing their analysis on the evidence they have seen, and they are claiming the final report conclusion was not based on the forensics and witness evidence that was found.
That is a lot different from a single individual with no direct involvement (Vance) expressing an opinion from a distance (based on a photograph) without sight of physical evidence or full knowledge of the details of the investigation.
“So what does qualify an Air Crash Investigator as someone with credibility?”
Who knows – that they do their work sufficiently ‘well’ that they are allowed to stay in their job year after year? And/or they do what they’re told?
Or more likely, when there are forensics and debris involved, that their analysis and conclusions stand up to reason, and can be shown to be true by re-enactment/experiment/testing?
@TBill said:
“Well to be honest I did have some very limited involvement in the search for solutions to the fuel/tank issue. So I do know first-hand that the effort for the aircraft design/procedure changes was based on a industry belief of fuel/tank issue. That much I do know.”
I’m not suggesting there wasn’t a fuel/vapour explosion danger in fuel tanks of that era: that did exist and was a real problem.
What I’m highlighting is that 6 investigators on the TWA800 investigation have put their reputations on the line to bring this to public attention – they are stating the report conclusions were not based on the forensics and witness evidence that pointed to an external explosion. It is not about their opinions.
My post was in response to yours, in which you claimed:
“TWA Flight 800 still has military missile cover-up theorists despite the fairly obvious design flaws discovered leading to fuel tank explosion, in that case. So probably there is no end to alternate theories.”
Their affidavits demonstrate that sometimes ‘alternate theories’, as you put it, can be just as valid and sometimes the real truth of what actually happened. As the majority of the 500+ ground witnesses might agree, had they been allowed to say what they’d seen.
@Boris Tabaksplatt said:
“Myth 1 – Air accident investigation bodies are independent and free to publish the investigation results free of influence from the security services or political bodies.
Myth 2 – The MSM are free to publish whatever they want in the interests of providing the facts to the public, irrespective of security or national interest.
Myth 3 – Politicians and security services work for the benefit of the general public and are subservient to the democratic voice of the electorate.”
It could be argued that in an ideal world that is how it should be, but sadly that doesn’t seem to be the case. Rather it sometimes seems:
1. The air investigation units sometimes conclude what they are told to conclude, if it’s more politically expedient.
2. The MSM are owned by a few very rich and powerful people who effectively form a monopoly and who can change and form public opinion to influence the course of world events, including Governments and elections.
3. Politicians, security services, and the armed services do what is politically and financially beneficial, or to protect themselves from impeachment, prosecution and/or criticism.
In the Air Italia fiasco in 1980, NATO had intelligence that Gadaffi was flying through that area at that time (he was the target). When they messed up and shot down the civilian aircraft by mistake, the Governments, security services and military of several NATO countries took part in the cover-up, according to the investigating Judge.
More recently, there is the refusal of the Australian ATSB to recover the FDR in the Pel Air crash investigation, even though its location was precisely known and it was in shallow water (about 40m?) not far offshore at Norfolk Island. It took a Senate inquiry to force the ATSB to finally recover it and repeat the investigation. It seems the ATSB wanted to put the blame solely on the pilot not having enough fuel/not allowing for changes in the weather and availability of diversion airports rather than on deficiencies in (the regulator) CASA’s aviation regulations which allowed the flight to take off without enough diversion fuel for bad weather in the first place. Ben Sandilands highlights some areas of the report here:
https://blogs.crikey.com.au/planetalking/2010/01/13/atsb-report-makes-pel-air-its-pilot-and-casa-look-like-fools/
https://blogs.crikey.com.au/planetalking/2013/05/23/damning-senate-report-on-atsb-casa-pel-air-failings/
The Australian ATSB did not come out well in that Senate committee inquiry report:
“[The Senate committee] said the methodology used by the ATSB to attribute risk in its investigation “appears to defy common sense by not asking whether the many issues that were presented to the committee in evidence but not included in the report it produced could help prevent such an accident in the future, offer lessons to the wider industry or enable a better understanding of the actions taken by the crew of the flight.”
“The committee found that the process by which the ATSB, at times in consultation with CASA, downgraded an identified safety issue in the Pel-Air Westwind operations from ‘critical’ to ‘minor’ lacked transparency, objectivity and due process.”
Note the: ‘… presented to the committee in evidence but not included in the report [the ATSB] produced” and: ‘… lacked transparency, objectivity and due process”. How could that possibly be interpreted (by anyone, even those with a preponderance of rolls of aluminium foil in their kitchen) as an attempt to, shall we say, diminish or hide unwelcome evidence? Perish the thought.
The Australian ATSB also came out badly in a peer review of its handling of the Pel Air crash by its Canadian counterpart, the TSBC, and there were reports of internal ATSB disagreements, as there have been with the MH370 investigation:
https://blogs.crikey.com.au/planetalking/2014/12/02/damning-review-of-atsb-pel-air-investigation-released/
“The independent peer review of the ATSB by its Canadian counterpart the TSBC finds serious issues with the methodologies and processes it followed before publishing its much criticised final report into the Pel-Air crash near Norfolk Island in 2009.
This might not of course, be what the ATSB or the minister responsible for aviation, Warren Truss, might say, but the closely argued Canadian report, if read in its detail, makes it clear that the Australian safety body failed at many levels to collect and process the necessary information.
The report also casts light on internal frustrations and divisions within the ATSB investigation.”
Martin Dolan was Chief Commissioner (and therefore in charge) of the ATSB at the time of the Pel Air incident. He was also in charge of the MH370 investigation until 1st July 2016 when Greg Hood took over.
In connection with MH370 and MAS, there is also the censorship imposed by the strange agreement all parties to the MH17 investigation entered, which prevents any party disclosing any information without the agreement of all the other parties. That seems to suggest one country could veto anything it wanted, preventing it being in the final report. It might be asked what could the (legitimate) purpose of such a veto be in an air accident investigation, when the forensics and evidence should be the sole basis for the report’s conclusion?
@PS9
OK…I would want to hear from someone like Greg Feith, former NTSB, if he thought there was a mistake. I could not immediately find if he had a position on the matter.
@Brian Anderson:
@DennisW:
DennisW said:
“No one is disagreeing (Brian or anyone else) with the notion that the ISAT could be flawed in some way. What is fundamentally incorrect is believing that the data is flawed because the aircraft has not been found. The data could be perfectly correct, and still result in a “not found” situation.”
So, in the absence of a: ‘Is the aircraft actually where we predicted it would be, based on the data’ test, how then would you determine if the data was flawed?
Ask Inmarsat some pertinent questions?
Has anyone in the IG done that, or have they all simply accepted the data as complete and accurate as given to them (ie. ‘Inmarsat must not be questioned’) and proceeded to immerse themselves in seemingly endless debate about the minute details, as given and whether flawed or not, from there on?
In other words, who has done due diligence in enquiring into the provenance and reliability of the data before relying on it?
Has anyone?
@PS9
I’m not the IG but I tried:
Tuesday, 1 April, 2014 12:28
Click to view full HTML
Hello
ISAT has been appointed as advisors to the Air Accident Technical committee and is therefore unable to discuss the circumstances surrounding Air Malaysia.
Kind Regards,
Gillian Nair
Customer Service Executive, Technical Helpdesk
Customer Service & Operations
Inmarsat
99 City Road
London EC1Y 1AX
United Kingdom
@M Pat and sk999,
Thanks for the thorough responses.
Starting with M Pat’s, here is the part I struggle with:
“Inmarsat write to their database a BTO which is the difference between the ‘expected’ delay and the actual measured delay, and this is a relatively small number compared to the overall delay.”
This quote, by itself, makes complete sense. Where I struggle is with the “expected” delay and what “expected” means at the time of logging. As you put it,
BTO_Logged = Delay_expected – Delay_actual.
Delay_actual is a known quantity at the time the log was written – as you say, it was measured. BTO_Logged was obviously derived, because it was indeed written to the log.
That makes Delay_expected a known quantity as well, at the time the log was written. One could not log the difference between a known, measured quantity, and an unknown, expected quantity.
Further, logging the difference between a measured value and an expected value does not require further ground-truthing. Either the definitions are off, or the equation is off.
I’ve heard other explanations which make different variables known and unknown at the time the log was written. Beyond the possibility that I’m right or wrong, the mere fact that there are slight inconsistencies bothers me.
@sk999 – thanks as well. I am reading it now.
@sk999,
I don’t want to put words in your mouth, but it sounds like you are saying that an exact value for the nominal terminal exists. Or, there is an exact value for the difference between the ground slot time start and the earliest return time.
If so, then indeed the Delay_expected in my formula above would be known by Inmarsat and the equation and logging makes sense. (Sorry – I flipped the signs).
Except in that case, what was derived as 495,679us wasn’t really the difference between the trip time and the logged BTO. Rather, it is a combination of some known constant pre-programmed into the log and a much smaller bias.
In other words,
BTO = Delay_actual – K
Where K was set in advance.
However, the time the signal spent actually traveling is less, being that it is relayed by several circuits.
Time_travelled = BTO + K – bias
Where K – bias is what they tested using the ground times and what amounts to 495,679.
Does that make sense? Would not a K of exactly 500,000 be possible?
@Jeff Wise
IMO, family members are damaged goods and exempt from public scrutiny.
JS – Keep digging on that data issue, I’m glad someone is. My niggling unease over the data never went away either. Well back in the piece I appealed to anyone who was bold enough to “guarantee it”. No one did, and the only person to weigh in at all was Victor to say – “there are no guarantees with the data”. Instead you have many expressions of high confidence etc.
If you were testing SDU’s in real conditions and someone pulled the plug out you would either:
A – start again
B – not worry about it
We didn’t have option A and no one seemed to care about that. Both data sets might be wrong either incidentally or deliberate.
Separately, the Argentinians recently lost a sub in an underwater incident that unsurprisingly was detected by other players. Yet the split second destruction of a 200 ton object went unnoticed despite the presence of Garden Island naval base and the likely presence of other subs in that ball park.
The spectre of dodgy BTO’s gets me thinking about the timely Curtin boom. That trajectory sits a lot better with the bio-fouling and the drift issues – last time I was here anyway.
@Gysbreght. Thank you for your interest in the post.
“What are the reasons for discarding a stall?”
Unpiloted, my distant recall is that the flight dynamics would not support an unassisted stall and also the aircraft most likely would bank on the way to that.
Piloted, if he retained a professional pilot’s outlook there were approaching two minutes with him apparently inattentive. If instead that was deliberate, why would he allow that to precede either of a steep dive or recovery rather than nosing over?
There are other possibilities if not following a ‘formal’ flying habit but anything casual would suppose his frame of mind was not anger and despair. That seems unlikely, to me.
BTW concentration hitherto on the consequences of there being an active pilot has focused on search width. There is another though. If the terminus was a deliberate aim, as many believe, he would allow reserve fuel against vagaries in conditions, if not other, on the way. Hence he would have planned to arrive at that site with excess fuel. Supposing that proved to be the outcome he could orbit to burn it, jettison or crash with fuel, the last having shut down manually (that also leading to the final log-on). Thus in a piloted possibility, the terminus would be on the 7th arc still but could be to the NE of where fuel exhaustion would occur, not near-coincident as currently.
I will be away a couple of days.
Correction towards the bottom, “..the terminus would be BASED on the 7th arc still….”
@David: Thanks for your reply.
How about the following reasoning:
The final BFO’s can only be explained by someone acting on the controls.
That someone was unlikely to be a professional and qualified pilot, because a professional pilot would have wanted to retain full control and would not have allowed the airplane to run out of fuel.
@JS
Or, there is an exact value for the difference between the ground slot time start and the earliest return time.
If so, then indeed the Delay_expected in my formula above would be known by Inmarsat and the equation and logging makes sense.
Yes you have it now. The ‘Delay_expected’ is a big constant generated by Inmarsat based on a fixed satellite location and a fixed nominal aircraft location, and used for frame timing. All distances involved are known.
As Holland et al put it in Ch5 of the Bayesian Methods book :
“The Inmarsat Classic Aero system allocates a time slot for communications based on a nominal propagation delay that assumes a nominal satellite position and a nominal aircraft position. The nominal aircraft position is at zero altitude directly below the satellite’s nominal orbital position of 64.5◦E longitude, zero latitude and an altitude of 35788.122km. The round trip delay is proportional to the distance from the ground station to the actual aircraft location via the actual satellite location. The actual satellite position is different from the nominal satellite position because Inmarsat-3F1 is not exactly motionless, but rather moves in a known way in a region about its nominal location. The Burst Timing Offset is the additional delay after the start of the allocated time slot at which the message is received. The BTO is thus the difference between the round trip message delay and the nominal delay used for scheduling. In addition to the propagation delay the message delay includes the latency of the satellite data processing unit.”
Credit to you by the way for bothering to try to understand it.
@sk999 thanks for input.
@ Matty I am continually surprised by the vehemence with which some contributors push their particular pet theories based on the flimsiest of qualitative or circumstantial evidence. In the sea of uncertainty however the BTO looks very solid, as I’m sure you are tired of hearing.
@PS9
In other words, who has done due diligence in enquiring into the provenance and reliability of the data before relying on it?
Has anyone?
Both Inmarsat and the DSTG used data logged from previous flights of 9M-MRO and compared it to ACARS logs which were available for those flights. As I recall some 20 flights were looked at, and the Inmarsat data compared well against the ACARS data. So this tells us that the methodology of using the data is sound, and that the data itself is reliable, if it is not tampered with.
Since we have no ACARS data for MH370 there is nothing to compare the Inmarsat data against. I have no idea how someone looking at just the Inmarsat data could determine if it is perfectly valid and unaltered.
@Matty – thanks. Good to see you again.
@M Pat – unless I’m reading that wrong, there was indeed a known constant, used for scheduling purposes, defining when a signal would first be expected to arrive. It represents the beginning of the slot, at least from the perspective of receiving the signal.
I had tried to get this in the past, only to have the distinction between slot start and bias be repeatedly commingled by folks with much less patience than yourself. Thank you for that.
I stand by my earlier contention – that the constant was known and also that it was very likely 500,000us, or in the alternative it was simply the next frame boundary.
Generally I think that changes nothing about the actual calculated distances. But the fact that there remains an undisclosed constant bothers me. Was there another code bug nobody wants to talk about? Was the BTO subject to other variations, such as a delay in the pilot? Or such as a variation between different circuits on the satellite as the plane moved south? As others have pointed out, it was not validated below the equator.
Further, the fact that the initial distance rings were presented as elevation angles instead of distances also continues to bother me. What was the purpose of the elevation angle rings?
@JS
What was the purpose of the elevation angle rings?
The elevation angle to the satellite is constant anywhere on a range ring. The “radius” of the ring, say from the sub-satellite point changes due to ellipsoidal shape of the earth. Specify the rings in terms of a radius is not technically correct.