Handshake 7 — aircraft-initiated log-on

At 00:19:29 UTC the aircraft initiated a log-on request, followed at 00:19:37 by a log-on acknowledge. Unlike the hourly ground-initiated pings, an aircraft-originated log-on is what the SDU does after a power cycle. The Malaysian investigation concluded this was “most likely due to power interruption, probably due to fuel exhaustion at this time resulting in the loss of both engines and automatic start-up of the APU.” A failed ground interrogation at 01:15:56 UTC received no reply: by then the terminal was silent. Whether the aircraft was in a controlled descent, a spiral after autopilot dropout, or something else between 00:19 and impact is not recorded. No ELT signal was ever detected.