The Air Canada Fire
Stories from the survivors of the fire, which eventually killed twenty-three people, were sensational, frightening, and widely publicized. A fire broke out in the lavatory of the DC-9, and, as in the Varig fire, thick acrid smoke soon filled the plane. During its emergency descent to the Greater Cincinnati Airport, described by one passenger as "like an elevator ride," the pilot's chair was literally on fire. His vision was totally obscured by the time he landed the plane, tires exploding on impact. Flames burned through the roof of the fuselage, and scenes of firefighters combating the blaze with foam and water topped the national news.
The complete story, pieced together from separate reports by the National Transportation Safety Board and a special investigative unit of NFPA, is much less dramatic than the emergency landing and rescue effort. It all began with an electrical short in a lavatory pump. Three circuit breakers tripped in the cockpit, and a crew member tried without success to reset them. Eleven minutes later, a flight attendant detected smoke emanating from the lavatory. An attendant entered the lavatory, saw smoke coming from the wall liner, and discharged a carbon dioxide fire extinguisher in the general vicinity. Minutes later a second extinguisher was also discharged, and the smoke appeared to clear; but a flight attendant checking on the situation soon thereafter found the lavatory door so hot it was considered unsafe to open. The smoke reappeared and got worse. A master caution light in the cockpit signaled an electrical system failure. The pilot decided to make an emergency landing. It took ten minutes to land the plane. Visibility approached zero as the plane filled with smoke. Only those passengers who reached the emergency exits within about one minute of landing got out of the plane safely. The rest apparently succumbed to carbon monoxide poisoning.
Aviation accidents are almost never attributed to a single cause. Usually a combination of mechanical and human factors are involved.
With fires, the direct "cause" of any particular incident is obviously the ignition source. In that sense, a short circuit in the lavatory flushing pump caused the Air Canada fire. The consequences of ignition, however, depend on the combustibility of surrounding materials, the quality of fire detection and suppression, and various elements of the emergency response. Accordingly, the extensive damage from the Air Canada fire—the consequences of ignition—can be attributed to the delay before the crew detected and responded to the fire, the ineffective use of the fire extinguishers, the toxicity of the seat covers, and the difficulties encountered in evacuation.
Accident investigators tend to take an expansive approach when determining the "cause" of an accident. Aware that regulations are influenced by accident reports, investigators often seek to effect the greatest possible change. "It's better if you don't find the exact cause because then only one thing will get fixed," according to an NTSB investigator. Instead, for every serious accident the NTSB recommends a laundry list of changes in FAA regulations.
The Air Canada incident was no exception. Many culprits were identified. The NTSB was particularly critical of the crew for the delay between detecting the fire and deciding to land. A few independent experts consider this criticism unfair but concur that the crew was ineffective in its use of fire extinguishers. The NFPA report emphasized the problems of smoke and toxic gas, suggesting the need for more research on flammable materials, particularly seat covers. The NTSB wanted several things "fixed" as a result of the fire. It immediately recommended that the FAA inspect lavatory flushing pumps and establish a procedure for verifying whether the circuitry had been damaged over time. Three months later it recommended, among other things, the installation of smoke detectors and the use of Halon fire extinguishers.