Investigation Summary
The fire began behind the vanity unit in the aft left lavatory. Despite the crew's efforts to fight the fire with extinguishers, the source remained inaccessible behind the wall panels. Thick, toxic smoke quickly filled the cabin, obscuring vision and making breathing difficult. The fire eventually burned through electrical conduits, causing a loss of various cockpit instruments and horizontal stabilizer trim control. The captain successfully landed the aircraft using manual control. Within 90 seconds of landing, as the emergency exits were opened, the influx of fresh oxygen caused a flashover—a near-simultaneous ignition of all combustible materials in the cabin—which proved fatal for those who had not yet evacuated.
Final Conclusions
The NTSB was unable to identify the exact ignition source but narrowed it down to either an electrical arc in the lavatory's motor/wiring or a discarded cigarette. The investigation highlighted critical delays in the crew's decision to initiate an emergency descent and criticized the lack of fire detection and suppression systems in aircraft lavatories.
Video Analysis
The Fire That Changed Aviation Forever | Air Canada Flight 797 — A detailed look at the 1983 disaster where a lavatory fire led to a deadly flashover during evacuation, resulting in major safety reforms.
Watch on YouTube ↗If playback is blocked, the owner has disabled embedding — use the link above.
Systems & Failure Modes
Circuit Breakers
The initial sign of trouble was the tripping of three breakers for the aft lavatory flush motor.
Horizontal Stabilizer Trim
Electrical failure caused by the fire forced the pilots to fly the aircraft using manual trim.
Lavatory Fire Suppression
At the time, lavatories were not equipped with smoke detectors or automatic fire extinguishers.
Interesting Facts
- 0123 of the 41 passengers died from smoke inhalation and thermal burns.
- 02The aircraft landed with only basic standby instruments due to electrical failure.
- 03The fire was so intense it burned through the fuselage skin in the aft section.
- 04Stan Rogers, a famous Canadian folk musician, was among the fatalities.
- 05The crew had to land the plane without functional flaps or spoilers.