Investigation Summary
The fire broke out at approximately 07:11 UTC while Flight 667 was at Gate F7 of Terminal 3. The first officer heard a pop and a hissing sound from the right-hand console, followed immediately by smoke and flames. Investigation revealed that the fire was centered around the first officer's oxygen mask supply tubing. A critical finding was that the wiring in the oxygen light plate on EgyptAir's 777-200 fleet did not match Boeing's original design, lacking protective sleeving and proper wire clamps. This discrepancy created a risk where aircraft wiring could contact oxygen system components. The investigation explored the possibility that the flexible oxygen hoses, which contained anti-kink springs, could ignite if the springs were exposed to an electric current from faulty or incorrectly installed wiring. While testing confirmed that 28V DC current at 5 amps could cause a hose rupture and ignition in an oxygen-rich environment, the investigation could not definitively prove whether an electrical fault caused the initial breach or if the fire started elsewhere and subsequently caused the oxygen system to fail.
Final Conclusions
The Egyptian Ministry of Civil Aviation concluded that the fire originated near the first officer's oxygen mask supply tubing. The intensity and speed of the fire were attributed to the involvement of the flight crew oxygen system. The report identified two probable causes: an electrical fault or short circuit that resulted in the electrical heating of flexible hoses in the oxygen system, or contact between aircraft wiring and oxygen components due to missing or fractured wire clamps and incorrect installation.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Crew Experience
Captain
49 years old at the time of the accident.
First Officer
25 years old at the time of the accident.
Systems & Failure Modes
Crew Emergency Oxygen System
A system providing high-pressure oxygen to the flight crew. The flexible supply hoses contained internal anti-kink springs that were found to be potentially conductive.
Oxygen Light Plate Wiring
Electrical wiring located near the oxygen mask storage. Investigators found that missing clamps and lack of sleeving could allow these wires to contact the oxygen hoses.
Interesting Facts
- 01The aircraft was named 'Nefertiti' and was the second Boeing 777 hull loss in history.
- 02Seven people were injured: five occupants (passengers and crew) and two ground firefighters were treated for smoke inhalation.
- 03Post-accident inspections of EgyptAir's 777-200 fleet found missing wire clamps and unsleeved wiring in the oxygen light plates.
- 04The fire occurred approximately 30 minutes after the first officer performed a standard pre-flight oxygen mask test.
- 05The aircraft was 14 years old at the time of the accident.
Safety Actions & Advisories
Boeing Service Bulletin
In October 2011, Boeing issued a service bulletin recommending inspection of oxygen light plate wiring and the installation of sleeving or replacement of damaged wires.