What happened
On the morning of November 28, 1993, Northwest Airlines flight 434, a Boeing 727-200, was preparing for departure from Montreal International (Dorval) Airport to Detroit. During the push-back process at approximately 0650 EST, a flight attendant noticed smoke emanating from an overhead stowage bin in the rear of the cabin.
As the crew attempted to manage the situation, flames became visible at the top of the bin door. The crew utilized Halon and CO2 fire extinguishers to suppress the flames, but smoke continued to intensify and spread through the cabin. The captain subsequently ordered an evacuation. The crew utilized the front left main door escape slide to egress the aircraft. During the evacuation, some passengers landed heavily on the concrete ramp, resulting in 6 minor injuries related to smoke inhalation and physical impact.
The investigation
The investigation focused on the origin of the fire and the materials involved. Investigators examined the overhead bin, a flight attendant's bag, and several 100 per cent polyester blankets found in the bin. While the aircraft's electrical systems were cleared of involvement, the investigation found that the blankets served as the primary fuel source.
Testing by the TSB Engineering Branch revealed that although the blankets met existing FAA flammability standards for cabin interiors, the material could readily support fire when folded flat. Additionally, investigators discovered used, lit matches in handtowel dispensers in the aft lavatories of the aircraft following the incident.
Findings
- The fire originated in an overhead stowage bin but was not caused by any aircraft system or failure.
- All evidence indicates that the fire was not accidental.
- The 100 per cent polyester blankets located in the bin acted as the fuel for the fire.
- The crew successfully extinguished the flames, preventing further damage to the aircraft structure.
- The evacuation was complicated by the lack of bilingual instructions for French-speaking passengers and the absence of personnel to steady the escape slide at the base.