5
$\begingroup$

Are there currently any ADs for Boing 777s which would indicate the potential for catastrophic electronic system failures that might explain MH370's transponder failure and other issues?

Was the aircraft used for MH370 in compliance with all ADs?

$\endgroup$
  • $\begingroup$ Yes, there are ADs. You can look them up here. $\endgroup$ – fooot Apr 4 '14 at 20:50
  • 11
    $\begingroup$ This isn't really a question we can answer for you - While (FAA issued) ADs are a matter of public record information on AD compliance for each airframe is not publicly/centrally recorded: it's part of the aircraft's maintenance records, so you would need to talk to the maintenance department for Malaysia Airlines. (This information would also be contained in an NTSB investigation report, but at this point there is not even an NTSB file showing in their database.) $\endgroup$ – voretaq7 Apr 4 '14 at 20:57
  • $\begingroup$ @voretaq7 that is assuming NTSB gets them $\endgroup$ – ratchet freak Apr 4 '14 at 20:59
  • 1
    $\begingroup$ They could have also fabricated maintenance records, which makes it more difficult to ascertain whether or not ADs were truly complied with. $\endgroup$ – Qantas 94 Heavy Apr 4 '14 at 23:35
  • 1
    $\begingroup$ @dvnrrs Generally any time the NTSB is involved in an investigation there will be an NTSB file number (with varying degrees of completeness in the information available - particularly in foreign investigations. e.g. this one says "Go ask the Australians"). Of course there generally has to be information to put into such a file... $\endgroup$ – voretaq7 Apr 5 '14 at 5:49
9
$\begingroup$

Are there currently any ADs for Boing 777s which would indicate the potential for catastrophic electronic system failures that might explain MH370's transponder failure and other issues?

No one of the ADs issued for 777s can by itself fully explain all the facts of the final flight of MH370/MAS370.

Basic facts

  • The aircraft was a 777-2H6ER with 53460 flight-hours and 7525 take-offs and landings
  • A 777 has three VHF radios, two HF radios and two transponders.
  • Modern airliners have two main generators, an auxiliary power unit(APU) and a ram-air turbine(RAT) for emergency power. I think the 777 also has backup generators and two independent main power buses.
  • The aircraft left Kuala Lumpur for Beijing on 8 March 2014 at 00:14 local time with 239 passengers and crew on board.
  • Communications were normal up to and including 01:19 when someone on board (believed to be the co-pilot) said to ATC KL "Good night, Malaysian three seven zero". This was the point at which ATC control is handed to Vietnamese ATC. After there were no further communications from the transponder, the ACARS system or from the VHF radios.
  • Malaysian military reported that their primary radar system records do contain information on an unidentified aircraft to the northwest of Malaysia. The timing, position and heading of the unidentified aircraft in this report are consistent with MH370 changing course away from its intended flight path.
  • MH370 did not arrive at Beijing at 06:30 as scheduled.
  • A satellite communications system on the aircraft continued to respond to routine hourly handshakes from an Inmarsat ground station via satellite 3-F1 located at 0.0°N (±1.59°), 64.5°E at a height of 35786 km. These normal handshakes ceased after 08:11, there was an unexplained incomplete handshake at 08:19.
  • Subsequent analysis of the handshakes is consistent with MH370 continuing into the southern Indian ocean (and somewhat inconsistent with other routes or it being stationary)
  • Countries within range of the plane's potential flight paths were asked to check their primary radar records for signs of MH370. No country reported finding anything.
  • No part of the aircraft or its contents have been located and firmly identified.

Electrical failure hypothesis

Anyone speculating about the fate of MH370 needs to fit their hypothesis to the above facts.

They would have to explain how the failure incapacitated multiple systems within a few minutes and before any of them could be used.

In particular what did NOT happen:

  • The pilots made no emergency broadcast on VHF
  • The transponder did not squawk any emergency code
  • The ACARS system ceased communication
  • The aircraft did not return to KL and follow procedures for loss of communication.
  • The aircraft did not continue on its planned route

And what DID happen

  • The aircraft remained airborne for a further 7 hours.
    • Therefore the engines continued to run
  • Electricity was available to a satellite communications system on the aircraft.
  • The aircraft most likely deviated from its planned route.
  • The aircraft has not been found at any of the airfields a pilot should divert to in emergency.

AD 2014-05-03

This AD issued Feb 18th was reported on in March in connection with MH370.

But Reuters reports that Boeing stated this AD does not apply to the aircraft used for flight MH370.

If you ignore that and look at the consequences of a fuselage crack in the vicinity of the satellite antenna, you can see that this would not turn off the transponder, would not affect the VHF aerials and, if it caused a slow decompression - does not by itself explain why the crew would have failed to respond to the resulting low-pressure alerts by donning oxygen-masks, contacting ATC and descending to a safe altitude.

Boeing 777 communication systems diagram

Occams razor

A shortage of facts always leads to speculation. Some of which can be very imaginative. The onus of proof is on those producing the hypothesis.

I'm sure there are thousands of hypotheses but, in my opinion, the simplest explanation I've read which is consistent with the known facts is deliberate action by a pilot or persons unknown. This doesn't mean it is the right explanation, just that it seems the most probable to me at the moment.


Was the aircraft used for MH370 in compliance with all ADs?

We won't know with any certainty until the investigations branch of the relevant regulatory authority publishes their report on the incident. In previous accidents over an ocean, it has, on at least one occasion, taken years before a final report could be written.

Currently, there have been no confirmed reports, that I can find, of an AD that warned of the potential for catastrophic failures and which should have been applied to 9M-MRO and wasn't.

$\endgroup$
  • $\begingroup$ @RedGrittyBrick, you do not have the ability to determine whether AD's for 9M-MRO were in compliance or not given that avionics records for MH370 were destroyed by arson on 26 March 2014... weechookeong.com/2014/03/26/… $\endgroup$ – user2357 Jul 23 '14 at 4:15
  • $\begingroup$ @user2357: and nowhere did I say that I did. $\endgroup$ – RedGrittyBrick Jul 23 '14 at 15:34
  • $\begingroup$ @user2357: please provide any evidence/reference that "records for MH370 were destroyed by arson". That's an unsubstantiated rumour only. MH370 is not even mentioned in your link. $\endgroup$ – summerrain Dec 9 '18 at 19:40

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.