Investigation Summary
After a routine "Good night, Malaysian three-seven-zero" transmission, the transponder was switched off and the aircraft turned back across the Malay Peninsula. Primary radar tracked it across the Andaman Sea before contact was lost. Inmarsat satellite handshakes — never designed for tracking — placed the aircraft on a southerly arc into the Southern Indian Ocean for six more hours before fuel exhaustion. Confirmed debris from a flaperon and other components has washed up on Indian Ocean coastlines, but the main wreckage remains undiscovered.
Final Conclusions
The Malaysian ICAO-compliant Safety Investigation Team published its final report in July 2018 without being able to determine the cause of the disappearance. Available evidence — primary and secondary radar, Inmarsat satellite handshake metadata (the "BFO/BTO arcs"), and 33 confirmed or likely items of debris recovered along the western Indian Ocean coastline — indicates the aircraft deviated from its planned route shortly after the last ACARS transmission, recrossed the Malay Peninsula, and then flew south for several hours before fuel exhaustion in the southern Indian Ocean. The investigators could not exclude unlawful interference by a third party, and explicitly stated the change in flight path was likely the result of manual inputs. Two large-scale seabed searches (ATSB-led 2014–17 and Ocean Infinity 2018) covering over 120 000 km² of the priority arc found no wreckage.
Video Analysis
The Search for MH370 is Back ON! What’s changed?! — A careful look at what the satellite data, recovered debris, and flight performance studies do — and do not — prove about MH370.
Watch on YouTube ↗If playback is blocked, the owner has disabled embedding — use the link above.
Systems & Failure Modes
SATCOM Handshakes
The aircraft's Honeywell SATCOM unit pings the Inmarsat satellite roughly hourly when idle. These 'handshakes' carry timing and frequency data from which an arc — not a position — can be reconstructed.
Transponder vs Primary Radar
Civil air traffic radar relies on the aircraft's transponder broadcasting identity. When the transponder is off, only military primary radar can skin-paint the aircraft — and its data is not normally shared in real time with ATC.
Interesting Facts
- 01Inmarsat used Doppler residuals from satellite pings to locate the southern arc — a technique never previously applied to a missing aircraft
- 02A flaperon recovered from Réunion in July 2015 was confirmed as part of 9M-MRO
- 03The official Malaysian safety investigation closed in 2018 without determining a cause
Safety Actions & Advisories
ICAO GADSS — autonomous distress tracking
Source ↗ICAO adopted the Global Aeronautical Distress and Safety System framework: aircraft must report position at least every 15 minutes in normal flight (from 2018) and every 1 minute when in distress (from 2021), with the aim that an aircraft in distress can be located to within 6 NM.
Extended Cockpit Voice Recorder duration
ICAO Annex 6 amended to require new-build airliners to be fitted with CVRs that record at least 25 hours — so an entire long-haul flight is preserved instead of being overwritten.
Tamper-resistant tracking & deployable recorders
EASA and FAA progressed rule-making on tamper-resistant tracking systems and on the use of deployable flight recorders for over-water operations.
Malaysian Safety Investigation Report
Source ↗Final report on MH370 by the Malaysian ICAO Annex 13 Safety Investigation Team (July 2018).