The epidemiology of aircraft fire in commuter and air taxi crashes

Background: Aircraft fire is recognized as an important risk factor for occupant fatality in aviation crashes, but its epidemiology has not been adequately studied. Objective: This study examines factors related to the occurrence of aircraft fire, ignition sources, and factors influencing rescue and firefighting in commuter and air taxi crashes. Methods: Commuter and air taxi crashes in 1983-88 that involved aircraft fire were analyzed using National Transportation Safety Board (NTSB) data, including NTSB supplemental forms on fire and on rescue and firefighting. Results: Aircraft fire was recorded in 17% of the 888 commuter and air taxi crashes. Factors associated with increased likelihood of fir in these crashes were non-airport location (adjusted relative risk 2.7, 95% confidence interval 1.8-4.1), twin-engine aircraft (RR 2.5 95% CI 1.6-3.9), and nighttime (RR 1.7, 95% CI 1.1-2.5). Fire was more common in Beech 18's than other twin-engine airplanes. The majority (59%) of fires occurred during impact sequence, and an additional 17% occurred after the aircraft came to rest. The engine was identified as the ignition source in 59% of the crashes. followed by hot surface (18%), short circuit (9%), and sparks (9%). Fire sensing and extinguishing systems were installed in only 19% of the aircraft. Rescue and firefighting efforts were hampered most commonly by terrain (48%), weather (47%), and darkness (38%). Conclusions: Typically induced by impact and started at the engine, aircraft fire is most likely when a crash occurs at night, in a non-airport location, and in instrument meteorological conditions. These high-risk circumstances also often thwart rescue and firefighting efforts.