The safety investigation has raised concerns with the overall approach taken by the aviation community in addressing the ways that are available for aircraft crews to systematically detect, locate, assess, control, and suppress an in-flight fire within some areas of the fuselage of transport category aircraft. Although the origin of the fire has not been determined, the Board believes that shortcomings in design and equipment, and crew training, awareness, procedures, and checklists may have deterred prompt detection and suppression of this in-flight fire. In the course of this investigation, investigators assessed fire-fighting measures within the aviation industry, including procedures and equipment intended to prevent, control, or eliminate fires in aircraft. The TSB has identified safety deficiencies in several aspects of the current government requirements and industry standards involving in-flight firefighting. Each of these deficiencies has the potential to increase the time it takes for an aircraft crew to gain control of what could be a rapidly deteriorating situation.
Time is a prime consideration in the successful identification and control of an in-flight fire.
In the case of SR 111, approximately 20 minutes elapsed from the time the crew detected an unusual odour until the aircraft crashed, and about 11 minutes elapsed between the time the presence of smoke was confirmed by the crew and the time that the fire is known to have begun to adversely affect aircraft systems. The TSB reviewed a number of databases to look for fire events that had similarities to the scenario of SR 111. Fifteen such events were identified, the earliest of which occurred in 1967. For these events, the time from when fire was first detected until the aircraft crashed ranged from 5 to 35 minutes. The Board believes that the five Safety Recommendations released today describe initiatives that can be taken to reduce the risks that have been identified.