Malaysian Airlines MH370 contact lost
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Originally Posted by BOAC
mm - if there is 'Acars Data' floating around as you say, where is it and what does it contain?
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You have said this part over and over. Your statement is flatly contradicted by the preliminary report, this has been mentioned on every spin of the hampster wheel with a request to provide some insight as to why your assertion might be true and, on every occasion you have chosen not to provide that insight.
Last edited by mm_flynn; 24th Jul 2014 at 16:55. Reason: Removed potentially confusing final paragraph
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Search site moved March 28 - why?
Using p.5 of the ATSB's June 26 report, it is easy to replicate their working endurance model, March 17-27 (in, say, Google Earth):
Start at NW tip of Indonesia
Assume nil wind
Pick an arbitrary speed, s (say, 490 KGS)
Draw straight lines between Inmarsat arcs of length (time between arcs)/s
After 7th Inmarsat arc, keep going until you hit S1-S3 SE border
Repeat for several other speeds (say, 20kt intervals, down to 330KGS)
You have now precisely replicated the ATSB's working endurance model, March 17-27. (SE border of S1/S2/S3 has been publicly confirmed to be the ATSB's March 17-27 working endurance limit.)
The feasible range (S1/S2/S3) is the set of points bounded by the 6th Inmarsat arc, and the endurance line you've just reproduced.
Here's where it gets good:
Perform the update to this model the ATSB claims to have performed on March 27 - take away starting fuel. How do you do this? Easy: just shorten each flight path by the exact same PROPORTION. For example, make every flight path 5% shorter. Or 3%, or 7% - we don't know exactly how MUCH fuel they took away, so maybe try several different reductions. The key point is that each path is still going the same speed, and thus must still hit each arc at the exact same spot - the lack of fuel simply shortens the length. By the SAME X% FOR EACH PATH. Because that's precisely how a set reduction in available fuel would AFFECT each path's range.
You will find that, as you take fuel away, the S3 search zone becomes infeasible much faster than does S2. In fact, there is absolutely NO amount of fuel that could be taken away that could rule S2 out, yet S3 in.
So here's my question: why, then, did the ATSB move the search from S2 1,100km NE into S3, after taking AWAY fuel?
Illustrations (overview & close-up):
https://drive.google.com/file/d/0B-r...it?usp=sharing
https://drive.google.com/file/d/0B-r...it?usp=sharing
Something doesn't add up. At all.
Start at NW tip of Indonesia
Assume nil wind
Pick an arbitrary speed, s (say, 490 KGS)
Draw straight lines between Inmarsat arcs of length (time between arcs)/s
After 7th Inmarsat arc, keep going until you hit S1-S3 SE border
Repeat for several other speeds (say, 20kt intervals, down to 330KGS)
You have now precisely replicated the ATSB's working endurance model, March 17-27. (SE border of S1/S2/S3 has been publicly confirmed to be the ATSB's March 17-27 working endurance limit.)
The feasible range (S1/S2/S3) is the set of points bounded by the 6th Inmarsat arc, and the endurance line you've just reproduced.
Here's where it gets good:
Perform the update to this model the ATSB claims to have performed on March 27 - take away starting fuel. How do you do this? Easy: just shorten each flight path by the exact same PROPORTION. For example, make every flight path 5% shorter. Or 3%, or 7% - we don't know exactly how MUCH fuel they took away, so maybe try several different reductions. The key point is that each path is still going the same speed, and thus must still hit each arc at the exact same spot - the lack of fuel simply shortens the length. By the SAME X% FOR EACH PATH. Because that's precisely how a set reduction in available fuel would AFFECT each path's range.
You will find that, as you take fuel away, the S3 search zone becomes infeasible much faster than does S2. In fact, there is absolutely NO amount of fuel that could be taken away that could rule S2 out, yet S3 in.
So here's my question: why, then, did the ATSB move the search from S2 1,100km NE into S3, after taking AWAY fuel?
Illustrations (overview & close-up):
https://drive.google.com/file/d/0B-r...it?usp=sharing
https://drive.google.com/file/d/0B-r...it?usp=sharing
Something doesn't add up. At all.
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I think that to draw any sort of sensible conclusion about the track terminal, you must make an assumption about the starting point of the track since displacement of one, results in displacement of the other. Your analysis is fine if one supposes that the tip of Indonesia is in fact, the starting point of the southern track. This is far from clear from the known data.
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Wind-Tunnel,
I am a bit bothered too with the data. Here are my last (Montecarlo simulation) results:
The last south legs of all the simulated trajectories are at constant speed (and altitude) and the south turn occurs randomly between 18:28 and 18:40: it is assumed that the C-channel BFO measure of 88 Hz at 18:41 is a valid one (it is included in the observed BFO profile the trajectories are trying to mimick) and suggests a south bearing at 18:41. The constant (ground) speeds span from 330 kts to 530 kts, the crash latitudes from 22°S to 41°S:
https://drive.google.com/file/d/0B3s...it?usp=sharing
https://drive.google.com/file/d/0B3s...it?usp=sharing
The first part of all the trajectories comply with the ADS-B measures (they are not randomized on this first leg), and roughtly with the Butterworth radar track above the Malacca strait (supposedly linked to the MH370 ). When the south turn is triggered, a constant speed reference trajectory is built (intersecting two kinds of small circles on the earth spheroid: the ping rings and the positions reachable from one given location at a given constant speed) from the A/C position and randomized:
https://drive.google.com/file/d/0B3s...it?usp=sharing
The trajectories best fitting to the observed BTO/BFO values are around 460 kts (true gound speed) and end near 36°S, not near 30°S (ATSB):
https://drive.google.com/file/d/0B3s...it?usp=sharing
https://drive.google.com/file/d/0B3s...it?usp=sharing
the BFO errors versus the crash latitude:
https://drive.google.com/file/d/0B3s...it?usp=sharing
the BFO errors versus handshake instants and ground speed:
https://drive.google.com/file/d/0B3s...it?usp=sharing
the BFO and the BTO enveloppes of the 50 000 flights:
https://drive.google.com/file/d/0B3s...it?usp=sharing
But we do not know clearly what was the injection/turning point toward the last south leg in the ATSB report.
Jeff
PS) Rerunning the simulation (16h run time) to confirm these results.
I am a bit bothered too with the data. Here are my last (Montecarlo simulation) results:
The last south legs of all the simulated trajectories are at constant speed (and altitude) and the south turn occurs randomly between 18:28 and 18:40: it is assumed that the C-channel BFO measure of 88 Hz at 18:41 is a valid one (it is included in the observed BFO profile the trajectories are trying to mimick) and suggests a south bearing at 18:41. The constant (ground) speeds span from 330 kts to 530 kts, the crash latitudes from 22°S to 41°S:
https://drive.google.com/file/d/0B3s...it?usp=sharing
https://drive.google.com/file/d/0B3s...it?usp=sharing
The first part of all the trajectories comply with the ADS-B measures (they are not randomized on this first leg), and roughtly with the Butterworth radar track above the Malacca strait (supposedly linked to the MH370 ). When the south turn is triggered, a constant speed reference trajectory is built (intersecting two kinds of small circles on the earth spheroid: the ping rings and the positions reachable from one given location at a given constant speed) from the A/C position and randomized:
https://drive.google.com/file/d/0B3s...it?usp=sharing
The trajectories best fitting to the observed BTO/BFO values are around 460 kts (true gound speed) and end near 36°S, not near 30°S (ATSB):
https://drive.google.com/file/d/0B3s...it?usp=sharing
https://drive.google.com/file/d/0B3s...it?usp=sharing
the BFO errors versus the crash latitude:
https://drive.google.com/file/d/0B3s...it?usp=sharing
the BFO errors versus handshake instants and ground speed:
https://drive.google.com/file/d/0B3s...it?usp=sharing
the BFO and the BTO enveloppes of the 50 000 flights:
https://drive.google.com/file/d/0B3s...it?usp=sharing
But we do not know clearly what was the injection/turning point toward the last south leg in the ATSB report.
Jeff
PS) Rerunning the simulation (16h run time) to confirm these results.
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So, are we assuming that the 19:40 ping line was traversed in an easterly or westerly direction? Assuming the plane was travelling south east initially makes sense but then forces a much more southerly heading for the timing to be right for the 20:40 ping. Assuming the 19:40 ping occurred with the plane travelling west requires "the hook to the north" between 18:28 and 19:40 referred to in the Australian report but then allows a more plausible track through the 20:40 arc and results in a constant speed track which intersects the Northern end of the proposed search areas.
In the midst of all this, there is a glaring anomaly which doesn't go away unless and until you have accurate fuel figures. They have not been released AFAIK.
When all is said and done, you cannot make a good enough prediction of the terminal position unless you have certainty about the direction of travel at 19:40 and the fuel load. Even then, you must indulge in some educated guesswork to narrow down the possible tracks.
In the report, we have some clues which I think are important. The report states the likelihood that the southerly track was flown on autopilot and therefore, I am inclined to believe that any solution which would require any heading or speed changes becomes highly unlikely. This in turn, implies (to me at least) that the 19:40 direction was west because that fits in with the 20:40 ping and a plausible speed and heading.
In the midst of all this, there is a glaring anomaly which doesn't go away unless and until you have accurate fuel figures. They have not been released AFAIK.
When all is said and done, you cannot make a good enough prediction of the terminal position unless you have certainty about the direction of travel at 19:40 and the fuel load. Even then, you must indulge in some educated guesswork to narrow down the possible tracks.
In the report, we have some clues which I think are important. The report states the likelihood that the southerly track was flown on autopilot and therefore, I am inclined to believe that any solution which would require any heading or speed changes becomes highly unlikely. This in turn, implies (to me at least) that the 19:40 direction was west because that fits in with the 20:40 ping and a plausible speed and heading.
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Ulric:
Ulric, I am not trying to build the ATSB's current model (and best estimate). I am trying to show you what the ATSB model (and best estimate) would have looked like in the March 17-27 era. Their report explicitly states (on p.5) that their working model at that time assumed a turn at the NW tip of Indonesia.
The reason replicating those (now obsolete) assumptions is important is because I go on to prove that the model update they (claim to have) made on March 27 could not possibly have supported the DECISION they made on March 28 - which was to move the search dramatically NE.
Your analysis is fine if one supposes that the tip of Indonesia is in fact,
the starting point of the southern track. This is far from clear from the known
data.
the starting point of the southern track. This is far from clear from the known
data.
The reason replicating those (now obsolete) assumptions is important is because I go on to prove that the model update they (claim to have) made on March 27 could not possibly have supported the DECISION they made on March 28 - which was to move the search dramatically NE.
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I think that is a reasonable thing to do. Any projection of course is based on some set of assumptions and I think the report is laced with clues about what those assumptions were. You will appreciate that there are possible scenarios implied by the data which do not sit very well with public statements made by officials. We all realise (at least I assume we must by now) where these anomalies lie and that the data necessary to resolve them is not yet available to us.
Patience is a virtue in this case.
Patience is a virtue in this case.
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Still think you're missing the point, Ulric. ATSB issued a release March 28 saying, "plane had less fuel, so we're moving search 1,100km NE". It is a matter of simple geometry to prove that, if the starting point doesn't change (Appendix A suggests it didn't), and the Inmarsat arcs didn't change (they have always been taken as gospel), then their statement is false - the decision is counter-indicated by what would have HAD to have been their model's reaction to less available fuel.
When the ATSB issues key statements (this fuel analysis underpinned the critical decision precipitating an 8 week waste of time and money up at s20 lat) which are provably false - and when this falsehood can be demonstrated by the ATSB's own data (which suggests they ought reasonably to have KNOWN they were false) - I for one feel that patience is one of the last things called for. On this, you and I may have to agree to disagree.
When the ATSB issues key statements (this fuel analysis underpinned the critical decision precipitating an 8 week waste of time and money up at s20 lat) which are provably false - and when this falsehood can be demonstrated by the ATSB's own data (which suggests they ought reasonably to have KNOWN they were false) - I for one feel that patience is one of the last things called for. On this, you and I may have to agree to disagree.
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I think the assumptions made by the investigating team are only provably false if you have certainty about some of the variables and in particular, the point at which the SSE course was assumed. Once you have fixed this point, speed and heading are covariant and the range of terminal points becomes constrained in exactly the way you describe. If you take away the certainty about the starting point, and I think we must, the range of available terminal points matches those assumed by the investigation team.
The message is clear - information about the starting point is not available to the investigators. I believe that should make us circumspect about accusing the investigation team of incompetence.
The message is clear - information about the starting point is not available to the investigators. I believe that should make us circumspect about accusing the investigation team of incompetence.
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Hyperveloce/Wind Tunnel
Excuse me if I am missing something but if the aircraft was on autopilot for the last southern leg (an assumption by ATSB) what effect would magnetic variation have on your calculations or is this allowed for? I am trying to get my head around the reasons the ATSB may have made that assumption other than "best fit model".
Excuse me if I am missing something but if the aircraft was on autopilot for the last southern leg (an assumption by ATSB) what effect would magnetic variation have on your calculations or is this allowed for? I am trying to get my head around the reasons the ATSB may have made that assumption other than "best fit model".
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This might help
https://upload.wikimedia.org/wikiped...ation_2010.pdf
https://upload.wikimedia.org/wikiped...ation_2010.pdf
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Fuel on board: 49,200 kg at 16:41.
A "1641 492" fuel on board update (49,200 kg at 16:41) was included in the 16:41:58 ACARS OOOI off event:
The above may also be of interest for "Ian W", as it provides an example of an ACARS message, being forwarded via Satcom.
- www.paul.sladen.org/download/aaib/sladen-20140703-briefing-note.pdf (4MB, 3 July 2014)
The above may also be of interest for "Ian W", as it provides an example of an ACARS message, being forwarded via Satcom.
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Ulric,
Your last post claimed to rebut mine by pointing out that the turn point was not known. Good grief - where do I claim that it is? All I'm trying to do is accurately build the ATSB's first two performance models - for this project, then, "correct" means "what they were using as an assumption", not "where the plane actually turned". Please stay with me on that concept.
Why do I have confidence that my starting point - NW tip of Indonesia - is an accurate depiction of what the ATSB was assuming in late March?
1) That's what they said they used. On page 5 of their report. That was their assumed turn point for both March 17-27 (per p.5) and March 28-April 1 (per Appendix A) performance limits.
2) I have independently replicated their endurance line using a systematic endurance vs speed study from a paper by Delgado/Prats. When I calibrate one point of their model to the ATSB's endurance line, I find the Delgado/Prats model matches the ATSB line almost perfectly. The green line in my illustration is, in fact, the Delgado/Prats result. If I had a materially wrong starting turn point, the two curves (ATSB, Delgado/Prats) would have diverged. They match.
Your last post claimed to rebut mine by pointing out that the turn point was not known. Good grief - where do I claim that it is? All I'm trying to do is accurately build the ATSB's first two performance models - for this project, then, "correct" means "what they were using as an assumption", not "where the plane actually turned". Please stay with me on that concept.
Why do I have confidence that my starting point - NW tip of Indonesia - is an accurate depiction of what the ATSB was assuming in late March?
1) That's what they said they used. On page 5 of their report. That was their assumed turn point for both March 17-27 (per p.5) and March 28-April 1 (per Appendix A) performance limits.
2) I have independently replicated their endurance line using a systematic endurance vs speed study from a paper by Delgado/Prats. When I calibrate one point of their model to the ATSB's endurance line, I find the Delgado/Prats model matches the ATSB line almost perfectly. The green line in my illustration is, in fact, the Delgado/Prats result. If I had a materially wrong starting turn point, the two curves (ATSB, Delgado/Prats) would have diverged. They match.
Last edited by Wind_Tunnel; 25th Jul 2014 at 20:32. Reason: concision
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All I'm saying is that if the start point is not known, the end point is not known because one is dependent on the other. The investigation team presumably have access to more information than we do and at some point they changed their minds about what they thought happened.
I don't have a problem with that but when you come along and start to claim that their working hypothesis back in March was "provably false", those are strong words and I have to respond by saying that it is probably irrelevant at this point in time.
I don't have a problem with that but when you come along and start to claim that their working hypothesis back in March was "provably false", those are strong words and I have to respond by saying that it is probably irrelevant at this point in time.
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Ulric: your first two statements are completely true, and completely irrelevant to my point, for reasons already explained. They CERTAINLY have changed their mind about where the turn occurred - but not by March 28th.
Yes, "provably false" are strong words. Which is why I presented strong proof. If you don't understand it, just ask: I'm here to help; if you refuse to TRY to understand it, that's not my problem.
I have proven the ATSB went against (what they have described as) their own analysis in sending the search NE on March 28. They either...
1) stink at performance analysis,
2) lied (in release AND report) about why they REALLY moved NE, or
3) intentionally misdirected the search
I HOPE it's "only" 2) - and that the March 28 shift was for LEGITIMATE reasons. But if so, they should have told us what those legitimate reasons WERE; teams of spectacularly astute independent experts are working very hard trying to help find the plane; but they are working blind because of 2).
HIGHLY relevant, I'm afraid.
Yes, "provably false" are strong words. Which is why I presented strong proof. If you don't understand it, just ask: I'm here to help; if you refuse to TRY to understand it, that's not my problem.
I have proven the ATSB went against (what they have described as) their own analysis in sending the search NE on March 28. They either...
1) stink at performance analysis,
2) lied (in release AND report) about why they REALLY moved NE, or
3) intentionally misdirected the search
I HOPE it's "only" 2) - and that the March 28 shift was for LEGITIMATE reasons. But if so, they should have told us what those legitimate reasons WERE; teams of spectacularly astute independent experts are working very hard trying to help find the plane; but they are working blind because of 2).
HIGHLY relevant, I'm afraid.