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Malaysian Airlines MH370 contact lost

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Malaysian Airlines MH370 contact lost

Old 26th Apr 2014, 11:28
  #10201 (permalink)  
 
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I wonder if it is simply not within their remit to express regret or any other sentiment regarding the success or otherwise of the exercise.


That would be for the JACC surely?
I agree completely. They were tasked. They carried out the mission. The boss was proud. Job done for that asset.
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Old 26th Apr 2014, 11:39
  #10202 (permalink)  
 
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Search similarities

Have been looking into an incident that took place 25 years ago over the Pacific (UA811), which involved search and eventual recovery of a relatively small piece of debris in similar depths, although the topography appeared to be a little easier.
Like many others I have found it difficult to comprehend, with all the resources being used and what we have been told was a much more focused search owing to the information from the ULB pings, that still nothing of importance has been identified.
UA811 lost its cargo door with a little of the fuselage, and about half a dozen seats. These relatively small pieces were found, and in the case of the door, recovered from approx 14000 feet.
The difference was that the search team had "a nominal radar accuracy of 1 nautical mile in range and 1 degree in bearing, resulting in a 90% probability search area for the debris of 5.5 nautical square miles".
It still took them the best part of 1 month to find the debris, even with the luxury of solid information so I do now understand the complexity of the search in this case.
What I do not believe for 1 minute unlike many of you (drivers as well?) is that this aircraft 'ditched'. If indeed it did come down in the general area, isn't it far more likely that it was destroyed completely on surface impact, as in SR111?
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Old 26th Apr 2014, 13:20
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UA811

From the NTSB report: "The undersea search operation was begun on July 22, 1990, using the Orion, a state-of-the-art Navy side-scanning sonar “fish.” Searching in the area selected by analysis of radar data and undersea currents, the Orion located a debris field on its first pass over the 14,200-foot-deep ocean floor. The second pass located a significant sonar target, which later analysis indicated was probably the cargo door. Since the Orion is only capable of searching, the debris field was marked with transponders for use during the subsequent recovery phase."
Advantage was that the falling debris had been seen on radar...
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Old 26th Apr 2014, 14:47
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Innaflap I agree with what you say. Always try to excuse the mistakes and then try to talk out of the bag as it were.
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Old 26th Apr 2014, 16:33
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A two year old recommendation:

To quote the BEA final report on AF447, page 207:

"On the basis of this work, the BEA recommends:

that EASA and ICAO study the possibility of making mandatory, for
aeroplanes making public transport flights with passengers over maritime
or remote areas, the activation of the emergency locator transmitter
(ELT), as soon as an emergency situation is detected on board."

Source:
http://www.bea.aero/docspa/2009/f-cp...p090601.en.pdf

Has this recommendation been implemented in any form since the release of the AF447 final report?

Seems to me that it could have simply been added to an emergency check list for aircraft fitted with an automatic fixed ELT and associated control panel in the cockpit.

Another thing I've noticed in this CNN video and related article:
Why didn't Flight 370's emergency beacon work? - CNN.com

The video only explains why an ELT would not work but does not mention how an ELT can be switched from ARMED to ON in the cockpit (provided the control panel is installed) although the accompanying article does mention this possibility.

The mods deleted my earlier post dealing with this subject and wonder why?


Without drawing any conclusions about the reason the plane was lost (mechanical or criminal intent) the question remains:
Why, with the automatic fixed ELT installed in 9M-MRO and provided that the control panel was installed, was it not switched to ON in the hours after it deviated from its original flight plan?

In case of a mechanical single point of failure regarding all the other communication systems located in the center pedestal, the ELT would have been the last option to "communicate" with the switch normally located on the overhead panel in a B777.


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Old 26th Apr 2014, 17:51
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Originally Posted by Green-dot
"On the basis of this work, the BEA recommends that EASA and ICAO study the possibility of making mandatory, for aeroplanes making public transport flights with passengers over maritime or remote areas, the activation of the emergency locator transmitter (ELT), as soon as an emergency situation is detected on board."
Think through what that means in practical terms, on a flight deck, when the distinction between a malfunction and an emergency isn't always as clear as hindsight indicates, or for cases when a malfunction becomes and emergency and the Flight Deck Crew have no idea such a change of condition has occurred? Such a trigger would be more likely to generate false positives than do much of any good.
.
Has this recommendation been implemented in any form since the release of the AF447 final report?
Seems like an extraneous requirement to me. They were called upon to look into, not implement. Perhaps, looking into it shone a little light on a few issues and unintended outcomes of such a system.

Now, apply that to a situation where either the crew are incapacitated, they are under duress, or maybe even are in on the deal?

Of no use beyond what is already in place.
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Old 26th Apr 2014, 18:00
  #10207 (permalink)  
 
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Possible signature of a south trajectory in the Inmarsat's BFO ?

Hi there,
I would like to submit an idea (for falsification purpose) about a possible clue/signature in the Inmarsat's BFO to decide whether the real underlying trajectory is toward the south or north corridor. My (MonteCarlo) simulations show that while there are some trajectories toward the north able to mimick most of the BFO profile, none is able to generate a doppler peak in the BFO around 120 minutes of flight (labelled "possible turn" by Inmarsat) with the same magnitude like the one observed for the MH370 measured data:
https://docs.google.com/file/d/0B3sr...E9yck1mTWVjNEE
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Old 26th Apr 2014, 18:25
  #10208 (permalink)  
 
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@Hyperveloce

Excuse my ignorance, but are not all those theories concerning the Inmarsat Data analysis based on constant track, constant altitude and constant speed?

And the measurement only took place at one specific tenth of a second with a time gap of about 1 hour in between those plots?

Now if at that exact time of measurement (when the ping occurrred) the jet was maneuvering like turning away from the sat thus changing the doppler shift for only this specific time frame, would then your statement from before still hold ?

At the end, we only have few pings which create distance rings from the sat plotted to the earth and a specific doppler shift asociated with those rings. But what happened in between those pings concernng height changes, speed changes and track changes is not known at all.

Could you explain, with what percentage those asumptions would be true?
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Old 26th Apr 2014, 18:38
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Regarding the fixed ELT, which according to the CNN article was the same type as was fitted incorrectly to the 737 which crashed in Resolute Bay in 2011. (Honeywell RESCU 406 AF-type)


From the accident investigation report:


'1.15.2. Emergency locator transmitter


There was no record of any agency detecting an emergency locator transmitter (ELT) signal from the aircraft. The investigation determined that the ELT had been installed with the activation switch in the OFF position and therefore could not automatically transmit upon impact. The cable leading from the ELT to its antenna was severed on impact, which would have significantly reduced the transmission signal had the ELT been armed. It was also determined that the aircraft interface module (dongle) contained the identifier code from the previous aircraft on which it was installed. Having the incorrect identifier programmed in the ELT would not have prevented it from performing as designed, but it would have indicated to Search and Rescue that a different aircraft was transmitting an emergency signal.'
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Old 26th Apr 2014, 19:03
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@Hyperveloce

Thank you for your work on the BFO, I've been attempting similsr analysis but I've been stalled because of a few anomalies.

The first is the offset shift at 1:07 and the implication this shift provides,
the only explanation I can come up with is that the turnaround must have happened at 1:07. (This fits the timing for a turn south at 2:25. But these conclusions are a drastic departure from the Malaysian timeline of events so I haven't posted about this until now.)

The second is the seemingly odd times of the data points in the BFO chart, why was the handshake taking place at 1:07, 2:25 and 2:29?

Why are there no data points for the hourly pings if they happened at 2:11, 3:11, 4:11, 5:11........ as we have been told they occurred?

I was under the impression that Inmarsat had detected a shift about the time of crossing the equator, but I see nothing at that time.


What are your thoughts?
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Old 26th Apr 2014, 19:10
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Originally Posted by RetiredF4
@Hyperveloce
Excuse my ignorance, but are not all those theories concerning the Inmarsat Data analysis based on constant track, constant altitude and constant speed?
As far as I know, they are constant speed trajectories (Inmarsat's). You may also want to fit constant bearing trajectories or variable speed/bearing trajectories... The altitude variations (unless they are well beyond those of a controlled aircraft) do not seem to impact the doppler profile significantly.

Originally Posted by RetiredF4
And the measurement only took place at one specific tenth of a second with a time gap of about 1 hour in between those plots?

Now if at that exact time of measurement (when the ping occurrred) the jet was maneuvering like turning away from the sat thus changing the doppler shift for only this specific time frame, would then your statement from before still hold ?
It is very much true that the underlying continuous doppler time serie has to be sampled at precise instants to see the doppler peak in the BFO... another way to put it: one the 3 consecutive handshakes around 18:30 in the BFO has to occur in a time frame of a few seconds (maybe not tenth of sec) centered on the moment when the speed vector is in the direction of the Inmarsat subsatellite. In my MonteCarlo simulations, this was the case for tens of simulated runs over a few thousands runs (a few percent probability)... This cannot be a coincidence, it would mean that the handshakes tended to occur when the flight conditions changed.

Originally Posted by RetiredF4
At the end, we only have few pings which create distance rings from the sat plotted to the earth and a specific doppler shift asociated with those rings. But what happened in between those pings concernng height changes, speed changes and track changes is not known at all.

Could you explain, with what percentage those asumptions would be true?
That's true again, we know nothing between the handshakes and we have to make assumptions like trying to find/fit trajectories with minimal speed or bearing variations. Back to the percentages, certainly, the lowest probability goes to the relative timing between the jet virage/manoeuver (toward the south) time sequence and the handshakes instants... either the handshakes are designed to be initiated when flight conditions change or this is a huge coincidence (which seems to happen also earlier in the flight when the plane diverted from its route to Beijing).
Jeff
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Old 26th Apr 2014, 19:24
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Originally Posted by Hyperveloce
Hi there,
I would like to submit an idea (for falsification purpose) about a possible clue/signature in the Inmarsat's BFO to decide whether the real underlying trajectory is toward the south or north corridor. My (MonteCarlo) simulations show that while there are some trajectories toward the north able to mimick most of the BFO profile, none is able to generate a doppler peak in the BFO around 120 minutes of flight (labelled "possible turn" by Inmarsat) with the same magnitude like the one observed for the MH370 measured data:
https://docs.google.com/file/d/0B3sr...E9yck1mTWVjNEE
It's a good observation. But I have two points to make:

* If you do a least mean square fit for all points except around 120 min, I think you'll find a scaling factor that is somewhere above 0.25 (not 0.15-0.2), and, at that scaling factor, you can't get the "possible turn" peak to match the data at _any_ heading.

* But if you assume that MH370 was climbing at around 18:25 UTC when the "peak" was observed, you can fit the peak nicely to the course before the turn. Put in something like ground speed 480 kts, heading 285, climb rate 4000 fpm. Recall that the Malaysian military radar picture has a "hole" in the track. It could be consistent with dropping to 5000' above the Strait of Malacca (for whatever reason) and then climbing back out.

BTW, how do you get the 17:07 data point to fit? It's been one of the problems bugging me for a long time. I can force-fit it by setting the heading to 5, but it's pretty artificial because we have the FR24 track up to 17:20 and it is showing straight and level flight at heading 25 from 17:01 to 17:20.
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Old 26th Apr 2014, 19:30
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Originally Posted by Propduffer
@Hyperveloce
Thank you for your work on the BFO, I've been attempting similsr analysis but I've been stalled because of a few anomalies.
The first is the offset shift at 1:07 and the implication this shift provides,
the only explanation I can come up with is that the turnaround must have happened at 1:07. (This fits the timing for a turn south at 2:25. But these conclusions are a drastic departure from the Malaysian timeline of events so I haven't posted about this until now.)
To me, both BFO inflexions at 1:07 and 2:25 are indicative of a turn (I don't see another phenomenon to explain such a rapid variation of the BFO), the 1st is when the plane diverted from the KL->Beijing route to turn back to Malaisia, the 2nd is the large turn toward the south.

Originally Posted by Propduffer
The second is the seemingly odd times of the data points in the BFO chart, why was the handshake taking place at 1:07, 2:25 and 2:29?
Why are there no data points for the hourly pings if they happened at 2:11, 3:11, 4:11, 5:11........ as we have been told they occurred?
The handshakes timing is very intriguing since it seems to capture/retain the exact flight sequence. See my answer to RetiredF4.
Jeff
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Old 26th Apr 2014, 19:46
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Hyperveloce
The altitude variations (unless they are well beyond those of a controlled aircraft) do not seem to impact the doppler profile significantly.
Well, altitude changes produce speed changes. Climb or descend will produce different speed delta / doppler, lower altitude cruise will produce less groundspeed and thus different speed delta / doppler.
Therefore it has quite significant effect on those computations.

Hyperveloce (bolding by me)
That's true again, we know nothing between the handshakes and we have to make assumptions like trying to find/fit trajectories with minimal speed or bearing variations.
That´s where i have the most reservations against those theories. While a southern routing by deliberate human action or by autopilot with the human factor removed would fit straight track and constant altitude, the northern routing with human input would look quite different in order to avoid continueous detection threat, and that would have to include changes in track, altitude and thus speed.

Therefore in assuming a constant track and speed the northern routing is excluded by this assumption itself.
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Old 26th Apr 2014, 20:30
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Originally Posted by hamster3null
It's a good observation. But I have two points to make:
* If you do a least mean square fit for all points except around 120 min, I think you'll find a scaling factor that is somewhere above 0.25 (not 0.15-0.2), and, at that scaling factor, you can't get the "possible turn" peak to match the data at _any_ heading.
With a scaling factor of 0.25 (instead of 0.15-0.2), the 1st plot of the 2nd page of my doc would basically be translated higher (the 120 min peak would reach approx 290 Hz instead of 250 Hz): it would still be possible to reproduce the 120 min turn but no longer the initial conditions (already out of the enveloppe) and even around 180 min (the min enveloppe would be at 125 Hz slightly higher than the BFO).


Originally Posted by hamster3null
* But if you assume that MH370 was climbing at around 18:25 UTC when the "peak" was observed, you can fit the peak nicely to the course before the turn. Put in something like ground speed 480 kts, heading 285, climb rate 4000 fpm. Recall that the Malaysian military radar picture has a "hole" in the track. It could be consistent with dropping to 5000' above the Strait of Malacca (for whatever reason) and then climbing back out.
Ok, this can kill this potential signature... 4000 fpm is ~22 m/s or ~14 m/s projected onto the LOS (@~40° of elevation)... which translates as a doppler of ~77 Hz (at 1640 MHz) hence 11.5 to 15.5 Hz after the scaling of 0.15 to 0.2... The last plot of my doc for the north trajectories shows that we need more than 50 Hz to get the BFO into the enveloppe of the tens of thousands of simulated flights. I would then need ~13000 fpm to fix the gap. But as RetirdF4 suggests, the ground speed would decline accordingly (also modifying the doppler), so I will introduce large altitude changes in the conditions you suggest to check it.

Originally Posted by hamster3null
BTW, how do you get the 17:07 data point to fit? It's been one of the problems bugging me for a long time. I can force-fit it by setting the heading to 5, but it's pretty artificial because we have the FR24 track up to 17:20 and it is showing straight and level flight at heading 25 from 17:01 to 17:20.
I got these runs fitting the 17:07 value of the BFO through the MonteCarlo simulation: among the thousands of simulated runs, some of them happens to replicate this inflexion at 17:07... this is exactly the same for the ~18:30 turn (some of the thousands of simulated runs replicate the peak), it seems to rely on a precise relative timing between the bearing changes (we need a turn around 17:07 to generate it) and the handshake instants.
Jeff
PS) a scaling factor between 0.15 and 0.2 is close to the wavelength value at 1640 MHz (0.1825 m): would it be possible that the Inmarsat BFO plot is plotted with a wrong unit (m/s instead of Hz) ?
PPS) to RetiredF4: note that these models/assumptions for the simulated trajectories does not hold at the 120 min turn, the only assumption behind the potential signature is the turn (toward the south or the north) itself... these assuptions apply more to the following hours of flight .

Last edited by Hyperveloce; 26th Apr 2014 at 20:55. Reason: corrections / precisions added
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Old 26th Apr 2014, 20:53
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Snoop

Originally Posted by susier
'That text applies in case of criminal action against air security'would imply that the Malaysian government is aware thatcsome sort of terrorist or criminal act was committed.
The question is (still)how they are aware of this. I don't think we are any further on in this
Originally Posted by Dr M
Even if the pilot wanted to commit suicide...
Killing yourself pulling 228 persons in the death with you is terrorist and criminal. Isn't it? In that hypothesis too Dr M. assets that it is Boeing's responsibility
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Old 26th Apr 2014, 21:10
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Some earlier posters have implied that if MH370 ditched under control then it would have broken up on contact. This is not true. FAA certification requires that an aircraft can survive a ditching.

Fact Sheet ? FAA Regulations on Ditching

Regulation 25.801(b) states "Each practical design measure must be taken to minimise the probability that in an emergency landing on water the behaviour of the airplane would cause immediate injury to the occupants or would make it impossible to escape".

25.801(c) states that the ditching behaviour must be investigated by model tests.

When I joined BOAC over 45 years ago we had to watch a film of the VC10 certification ditching trials. They were carried out in a large tank which was normally used for designing ships.

There have been several survivable airliner ditchings in the past. If MH370 was ditched then it will be intact on the seabed.
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Old 26th Apr 2014, 21:19
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Originally Posted by Hyperveloce
To me, both BFO inflexions at 1:07 and 2:25 are indicative of a turn (I don't see another phenomenon to explain such a rapid variation of the BFO), the 1st is when the plane diverted from the KL->Beijing route to turn back to Malaisia, the 2nd is the large turn toward the south.
I agreed with you wholeheartedly at first, but other posters here have pointed out (in deleted posts) that FR24 data as well as the probable location of the aircraft at 1:07 make this premise unsupportable. It would probably have still been northbound over the Malaysian penninsula at 1:07. Bloomberg News informed us that the last ACARS transmission at 1:07 included a position report: The engineers at Inmarsat were able to validate their estimates of the plane’s location by matching its position at 1:07 a.m., when it sent a burst of data through its Aircraft Communications and Reporting System, McLaughlin said. That final transmission on Acars included a GPS position that was used to calibrate the other estimates, he said. http://www.bloomberg.com/news/2014-03-21/missing-plane-flew-steady-speed-over-ocean-inmarsat-estimates.html - but we don't know what that position was. (Thank DocRohan for posting that link here)

Last edited by Propduffer; 28th Apr 2014 at 00:49.
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Old 26th Apr 2014, 21:31
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Originally Posted by Hyperveloce
With a scaling factor of 0.25 (instead of 0.15-0.2), the 1st plot of the 2nd page of my doc would basically be translated higher (the 120 min peak would reach approx 290 Hz instead of 250 Hz): it would still be possible to reproduce the 120 min turn but no longer the initial conditions (already out of the enveloppe) and even around 180 min (the min enveloppe would be at 125 Hz slightly below the BFO).
Consider this.

From the radar, I have the location of the turn roughly at 18:30 at 6.7N 95.5E, which gives me initial satellite elevation 53.2°. Final satellite elevation is 40°. We can calculate line of sight distances for these angles. I get the difference of 900 km (you can double check). To travel 900 km in 5.67 hours, we need mean line of sight speed 159 km/h and mean Doppler shift 235 Hz @ 1.6 GHz (241 Hz @ 1.64 GHz).

What we can do now is take BFO data points for 19:45..00:11, extrapolate them back to 18:30, and see what mean observed BFO we get, and what scaling and bias get us there. I get BFO 160.5 Hz. If I assume that the frequency bias is given by the BFO at 16:30 (~87 Hz), mean residual Doppler is 73.5 and scaling is 73.5/235 ~ 0.315.

In your case, you seem to be getting scaling below 0.20 because you're trying to fit scaling and bias at the same time, and you can only get low scaling together with high bias. Which is why you're getting bad fits to the first 30 minutes.
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Old 26th Apr 2014, 21:46
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Does the satcom firmware command an updated handshake with the satellite whenever there is a significant bearing change? I've seen it reported that the antenna was low gain (omnidirectional?) and perhaps didn't have beam steering. So this would seem pointless. Can anybody clear this up?
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