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Malaysian Airlines MH370 contact lost

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Malaysian Airlines MH370 contact lost

Old 2nd Apr 2014, 08:23
  #8981 (permalink)  
 
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Originally Posted by hamster3null

Incidentally, do you have any idea what, if anything, other than temporary loss of power / reboot, could cause the aircraft to send 3 packets in 18:27 to 18:29 as it was turning?
Without going back and checking the spec; it is possible this particular SATCOM installation was also equipped with IRS ability to compute the satellite position and therefor calculate the doppler shift. The rate of doppler change may well have triggered an AES to GES packet, if the the P channel hadn't already done so.
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Old 2nd Apr 2014, 08:26
  #8982 (permalink)  
 
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Posted by Propduffer: "Now, why did the Malaysian government let 8 nations search the South China Sea looking for an airliner they knew wasn't there for the next week??"


Perhaps because they were believing the radar returns they saw were not from MH370.


Perhaps they were right.

Last edited by DJ77; 2nd Apr 2014 at 08:40. Reason: grammar
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Old 2nd Apr 2014, 08:41
  #8983 (permalink)  
 
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Glen

Re "No-one had seen an incident like this before and the Malaysians were clearly not prepared for it."


It is not a case of an incident like this, it is how you handle disasters and emergencies full stop and they obviously do nit gave SOPS in place and rehearsed, especially the media side.
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Old 2nd Apr 2014, 09:14
  #8984 (permalink)  
 
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There is not a complete lack of radar data. There is some of the data available which can be found if you search for it - printed in Chinese media, as shown to Chinese relatives. However, not all the data is available as it seems the sensitive data of exactly how the turn around was achieved hasn't been seen by anyone in the public arena.

Vietnamese authorities advised Malaysia in real time of the westbound course but did not receive an official reply.

There was not an immediate connection between MH 370 dropping off communication and the westbound unidentified aircraft. It would be most natural to believe in the immediate aftermath that the aircraft was lost shortly after last contact and was in the South China Sea. The Malaysian Prime Minister did not want in the circumstances to make a definitive public announcement of a connection of the lost aircraft and the westbound track until other data corroborated the primary radar data. Whether this was wise in hindsight is another matter but it is unusual behaviour for a public carrier to suddenly go dark and head seemingly purposefully in another direction without a mayday.

We aren't privy to any corroborating satellite data other than what has been released by Inmarsat, nor are we privy to radar data from other countries. I think it best to leave super conspiracy theories of a Malaysian shoot down to one side - there are other more likely (but still not palatable) reasons the aircraft was diverted.
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Old 2nd Apr 2014, 09:35
  #8985 (permalink)  
 
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You do, however, get the distinct impression that there were facilities in place for whatever reason and the people manning these were in effect sleeping on the job.
…just when they were needed
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Old 2nd Apr 2014, 10:21
  #8986 (permalink)  
 
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Originally Posted by Blake777 View Post
There is not a complete lack of radar data. There is some of the data available which can be found if you search for it - printed in Chinese media, as shown to Chinese relatives. However, not all the data is available as it seems the sensitive data of exactly how the turn around was achieved hasn't been seen by anyone in the public arena.

Vietnamese authorities advised Malaysia in real time of the westbound course but did not receive an official reply.

There was not an immediate connection between MH 370 dropping off communication and the westbound unidentified aircraft. It would be most natural to believe in the immediate aftermath that the aircraft was lost shortly after last contact and was in the South China Sea. The Malaysian Prime Minister did not want in the circumstances to make a definitive public announcement of a connection of the lost aircraft and the westbound track until other data corroborated the primary radar data. Whether this was wise in hindsight is another matter but it is unusual behaviour for a public carrier to suddenly go dark and head seemingly purposefully in another direction without a mayday.

We aren't privy to any corroborating satellite data other than what has been released by Inmarsat, nor are we privy to radar data from other countries. I think it best to leave super conspiracy theories of a Malaysian shoot down to one side - there are other more likely (but still not palatable) reasons the aircraft was diverted.

I think if you let data leak out via private press conferences that way you are almost guaranteeing that people will fill the void with conspiracy theories.
I think not releasing the satellite data for four days is almost unforgiveable. In particular it takes days to reach the current search zone and a few days delay makes it much worse. Spy satellites could have been tasked to the site earlier. Perhaps debris which was floating sank in the mean time. Even if they did not want to make a public announcement and tell the press, they should have shared the Inmarsat data immediately with the Chinese, US and Australian authorities.
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Old 2nd Apr 2014, 10:37
  #8987 (permalink)  
 
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multycpl - there are only three known facts about the flight:
1 The aircraft took off.
2 The aircraft has disappeared.
3 Various communication devices failed to communicate whether by deliberate action or other failure has yet to be determined. There is a plethora of ideas on this forum for the cause of this which you can spend a happy week or two working your way through.
We who are not directly involved in the SAR efforts are not entitled to any information and any which we are given is done so as a courtesy.
No country is going to reveal details of its surveillance measures but will often find ways of conveying relevant information to those who need it.
The AAIB and INMARSAT have done a brilliant job of attempting to determine where the aircraft may have flown but until definite proof, ie identifiable wreckage, is found even this remains a theory.
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Old 2nd Apr 2014, 11:09
  #8988 (permalink)  
 
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hedge:

However if lets say one of the crew was affiliated to the opposition party and was being penalized for this to an extent where the misguided individual developed a plan to take control of the aircraft and commit an act of mass murder (lets not say pilot suicide) to turn the international spotlight on the Malaysian government.
Hedge, if you followed the news, you'd know that the spotlight has been comprehensively and internationally turned onto the Malaysian Government over the Anwar Ibrahim issue consistently and persistently for at least ten years. This is just nonsense, sorry.
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Old 2nd Apr 2014, 11:20
  #8989 (permalink)  
 
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Remember how MAS reacted when questioned over running their aircraft on fumes in LHR? Expecting accurate feed back on MH370 is something to do with leopards and spots.
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Old 2nd Apr 2014, 11:27
  #8990 (permalink)  
 
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@hedge

No group or individual has so far claimed responsibility.
This has been mentioned a few times, but I think you're remembering 1970s/80s IRA SOPs and imagining that this is how Islamic extremists act.

When did anyone claim responsibility for 9/11? Or the Bali bombings? Or 7/7? Bin Laden mentioned 9/11 in one of his taped messages, much later, but never said he was responsible. Al-Qaeda didn't claim responsibility for the July 7 bombings until September, and intelligence sources reckon that was false anyway. The men convicted of the Bali bombings went to their deathbeds denying responsibility.
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Old 2nd Apr 2014, 11:38
  #8991 (permalink)  
 
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PASSENGERS CLEARED (according to CNN)

CNN now reporting :

" All MH370 passengers cleared of any role in hijacking or sabotage of missing plane, according to Malaysian police"
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Old 2nd Apr 2014, 12:11
  #8992 (permalink)  
 
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A question for 777 engineers out there.
The wiring bundles and oxygen hoses route from lower deck to the cockpit.
Can anyone provide a description or image of how this is achieved.

The link below might give a clue to my thoughts.

http://www.google.co.uk/url?q=http:/...5QRsSY4rWZzrEg
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Old 2nd Apr 2014, 12:29
  #8993 (permalink)  
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If the debris field of MH370 is similar and if Australians are looking in the right place right now or were looking in the right place at any point in the last two weeks, it's hard to explain whey they did not find anything at all so far.
The 'Occam' explanation would be that the aircraft did not come down anywhere near where they are looking.

Everything is being done on the basis of an estimated 'radar range' analysis of a Satcom 'handshake'. But a Satcom system is not a Transponder system. The reply delay on a transponder is very finely calibrated. The range information is extracted by subtracting the time of transmission from the time of reply, further subtracting the calibrated reply delay and dividing the result by two to get a very accurate measurement of the time the radio wave took to travel between the ground station and the transponder. From the time it took the radio wave to transit and the transit velocity (assumed as 'c') we derive the slant range. [Slant range - e.g. an aircraft directly overhead the ground station at 18,000 feet would show a slant range of 3.0 NM]

Unlike the precision of a transponder operation, Satcom reply delay during a 'handshake' is not finely calibrated to define distance from the satellite. The delay could be anything from nothing to a few hundred milliseconds, and we don't know what assumptions were used in calculating the two 'possibility arcs'. The true radial distance from the satellite position could be much different to the assumed distance currently used to direct the search. A slightly longer than assumed internal time delay could erroneously place an aircraft that was close to the satellite, as being several thousand miles away.
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Old 2nd Apr 2014, 12:35
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All MH370 passengers cleared of any role in hijacking or sabotage of missing plane, according to Malaysian police
How in the name of logic can anyone be cleared of anything when nothing is known of what actually happened to this aircraft?
This is pure and absolute nonsense!

MH370 passengers ?cleared? in four areas of probe, says top cop - The Malaysian Insider
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Old 2nd Apr 2014, 12:42
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I'd hope that the "cleared" is lost in translation. Maybe "have not found any evidence that would make them suspects" would be better?

But you'd have thought they'd have a very switched on translator prepping the multi medalled generals.
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Old 2nd Apr 2014, 12:42
  #8996 (permalink)  
 
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Good luck to the Malaysian authorities trying to sue media for false reporting when their press conferences have often announced their assumptions rather than facts. The announcement about the Thai radar detecting MH370 springs to mind as an example.

AM Monthon said further investigation is needed to find if the plane really passed the Thai skies... He said Malaysia's latest remarks were only assumptions theorising the plane's possible route. (MCOT online news)
If the Malaysians have been announcing their assumptions at press conferences, they cant then criticise the media for reporting their own or printing their own theories given the overwhelming lack of facts in this case.

The comments about Boeing, RR etc not being vocal and now this smacks of desperation to divert the criticism about the handling of this incident away from themselves by the Malaysian government.
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Old 2nd Apr 2014, 12:49
  #8997 (permalink)  
 
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I have to take issue with the comments about the Satcom system. The delays in the system are very well understood and compensated for.

The initial reply transmission will be a deliberately shortened data packet to ensure that the last symbols in this packet do not collide with the next timeslot (it will arrive later by 3.3us/km), this will be during the setup phase. It might well take only one packet to determine this time delay, the next response packet will be correctly timed because the satellite end of the link will have determined the timing delay and told the aircraft terminal what timing advance to use to ensure that the packet arrives in the correct timing window. This process is exactly analogous to how 2G GSM mobile networks operate.

The doppler shift is calculated by the modem DSP software at the point where the demodulation is done, this is a digital correction inside the modem to de-rotate the symbol constellation points to establish the symbol timing. This doppler shift will be dependent on the relative velocity of the two ends of the link, it will be very accurate provided that the signal levels are adequate.

From the data a set of equations can determine the range of position, this of course is limited by the resolution of the timing advance and the possible speed variation of the aircraft.

Of all the information that has come out, the Inmarsat data will be absolutely solid and the least likely to be open to question.

Last edited by Feathers McGraw; 2nd Apr 2014 at 12:52. Reason: Tidy up spelling and phraseology
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Old 2nd Apr 2014, 13:39
  #8998 (permalink)  
 
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Media criticism

Lynw
If the Malaysians have been announcing their assumptions at press conferences, they cant then criticise the media for reporting their own or printing their own theories given the overwhelming lack of facts in this case.
I think they can criticise as items that were clearly a supposition or a theory were announced as such, however then reported as fact by certain media outlets...
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Old 2nd Apr 2014, 13:53
  #8999 (permalink)  
 
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Circles

My Q probably wont last, or even make it to the board, but a fairly simple question if anyone can answer. Would the AC flying in anticlockwise circles of approx an hour circumference not give precisely the same Doppler shift data on the pings ? Unlikely coincidence I suspect, but would I think give precisely the same data wouldn't it ..And locate the AC in a completely different place.
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Old 2nd Apr 2014, 14:29
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duffyp99

Re your question.

A link. Not my "find" but a very interesting "paper" indeed.
Think it's credit to @ "B.A.R" this am.

Duncan Steel | Space Scientist, Author & Broadcaster
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