Investigation Summary
The investigation became a point of significant international friction. The NTSB's analysis of the Flight Data Recorder (FDR) showed that the autopilot was disconnected and the nose was pitched down into a dive. During the dive, the relief first officer repeatedly stated, 'I rely on God.' When the captain returned to the cockpit, he attempted to recover the aircraft by pulling up, but the FDR indicated that the relief first officer continued to push the nose down, resulting in a 'split elevator' condition where the two control surfaces moved in opposite directions. The Egyptian authorities maintained that a failure of the Power Control Units (PCUs) in the tail caused the elevators to jam, leading to the dive, a theory the NTSB rejected based on simulation data and the lack of physical evidence of such a failure.
Final Conclusions
The NTSB determined the probable cause was the airplane's departure from normal cruise flight and subsequent impact with the Atlantic Ocean as a result of the relief first officer's flight control inputs. The reason for these inputs was not determined. The ECAA concluded the cause was a mechanical failure of the elevator control system.
Video Analysis
What Happened At The Crash Of The EgyptAir 990? | Mayday — Experts analyze the controversial crash of EgyptAir 990, exploring the conflicting theories of intentional pilot action versus mechanical failure.
Watch on YouTube ↗If playback is blocked, the owner has disabled embedding — use the link above.
Systems & Failure Modes
Elevator Control System
The system used to control the aircraft's pitch; ECAA alleged a mechanical failure here caused the dive.
Cockpit Voice Recorder (CVR)
Captured the relief first officer's repeated prayer and the captain's confusion upon returning.
Flight Data Recorder (FDR)
Recorded the 'split elevator' condition where the left and right elevators moved in opposite directions.
Interesting Facts
- 01The aircraft was a Boeing 767 named 'Thuthmosis III'.
- 02The crash resulted in the deaths of 33 Egyptian military officers returning from training.
- 03The NTSB and ECAA issued separate reports with conflicting conclusions.
- 04The aircraft's engines were shut down manually during the descent.
- 05The flight was in international waters, but Egypt requested the NTSB lead the investigation.
Safety Actions & Advisories
Pilot Psychological Screening
The accident prompted discussions regarding more rigorous psychological monitoring and support for commercial pilots.
Elevator PCU Inspection
Following the ECAA's claims, additional scrutiny was placed on Boeing 767 elevator power control units, though no systemic flaw was found to support the ECAA's theory.