MH370 Theories/Communication Loss
MH370 Theories: Causes for Loss of Communication
A mantra known by all pilots is Aviate, Navigate and Communicate.
So with MH370 still flying (Aviate), and a turnback across peninsula Malaysia, possibly towards a suitable landing site like Langkawi or Penang (Navigate), why did the pilots not Communicate?
In addition, a transponder was not operating. Was that all deliberate, or did MH370 suffer a total Loss of Communications?
The technologies or systems available for communication with flight MH370 were all functioning, and the last recorded radio transmission from MH370 at 1:19:30 MYT was Good Night Malaysian Three Seven Zero, spoken by the Pilot-in-Command, Captain Zaharie Shah. This voice communication used VHF radio. The aircraft was equipped with three VHF radios. The Pilot(s) could have chosen not to transmit; or could all three VHF radios have failed?
Technical messages were automatically collated by a system called ACARS and during flight were transmitted via satellite communications or SATCOM. The last ACARS message was sent at 1:07:48 MYT and the next routine message was never received. This has been commonly interpreted as the ACARS system being disabled but because in-flight ACARS messages are sent via SATCOM it would be more accurate to suggest that the Satellite Communications system either failed or was disabled.
In the event of communications failure it is standard procedure to change a Transponder code to 7600. Prior to departure, at 00:25:52 MYT air traffic controllers at Kuala Lumpur instructed MH370 to 'squawk two one five seven', which would be the transponder code 2157 used during the flight. However, instead of changing the code from 2157 to 7600 which would indicate a loss of communication, or 7500 which indicates a hijack, or 7700 which is an emergency, the Transponder ceased to respond. The loss of transponder signal was observed at 1:20:36 MYT when the 'blip' no longer appeared on Malaysian air traffic controller radar screen, confirmed by both Vietnamese and Thai air traffic controllers.
Possible Causes
Fire
Electrical Failure