Investigation Summary
Approximately 53 minutes after takeoff, the flight crew detected an unusual odor in the cockpit. Initially attributed to the air conditioning system, the situation rapidly escalated as smoke became visible. The crew initially requested a diversion to Boston because it was their designated alternate and a familiar destination, but they accepted the air traffic controller's suggestion of Halifax due to its closer proximity. Following standard operating procedures for 'Smoke of Unknown Origin,' the crew began a descent profile and prepared for fuel dumping to reach a safe landing weight. These necessary procedural steps, however, extended the time the aircraft remained in the air. The fire, fueled by Metallized Polyethylene Terephthalate (MPET) insulation blankets, spread rapidly above the cockpit ceiling, destroying critical flight systems and eventually the flight data and cockpit voice recorders. The crew was blinded by smoke and lost primary flight displays, leading to a high-speed impact with the water.
Final Conclusions
The TSB concluded that the fire started due to an electrical arcing event on a wire associated with the In-Flight Entertainment (IFE) system. The fire was sustained and spread by the highly flammable MPET insulation blankets. The lack of built-in fire detection or suppression systems in the overhead area allowed the fire to grow undetected until it was too late to save the aircraft.
Video Analysis
The Tragic Story of Swissair Flight 111 — A detailed look at the investigation into the MD-11 crash off the coast of Nova Scotia and the fire that brought it down.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Systems & Failure Modes
MPET Insulation Blankets
Metallized Polyethylene Terephthalate blankets used for thermal and acoustic insulation, which were found to be highly flammable.
In-Flight Entertainment (IFE) System
A newly installed passenger video system whose wiring was the source of the initial electrical arc.
Overhead Circuit Breaker Panel
The area where the fire first breached the cockpit, causing massive electrical failure.
Interesting Facts
- 01The investigation lasted over four years and cost approximately 57 million CAD.
- 02Over 2 million pieces of debris were recovered from the ocean floor, representing approximately 98 percent of the aircraft by weight.
- 03The IFE system was powered by a bus that was not easily isolatable by the crew.
- 04The aircraft hit the water with a force of 350g.
- 05The fire was located in a 'blind spot' above the cockpit ceiling where no smoke detectors were installed.
Safety Actions & Advisories
Insulation Material Replacement
The FAA and other regulators mandated the removal of flammable MPET insulation blankets from all commercial aircraft.
Enhanced Flammability Standards
New test standards were developed to ensure that materials used in inaccessible areas of the aircraft are self-extinguishing.
Circuit Breaker Reset Policy
Revised procedures were implemented regarding the resetting of tripped circuit breakers in flight to prevent re-energizing short circuits.
Location
ACCIDENT SITE · Coordinates taken from the wikidata coordinate.