Inclement weather still major factors
A scientific study of aviation crashes in the United States concludes that "pilot error" is a decreasing cause of crashes involving major airlines.
Johns Hopkins researchers report that pilot error accounted for 34 percent of major airline crashes between 1990 and 1996, compared with 43 percent from 1983 to 1989. This continues a downward trend that began in the 1960s, when pilot error was a factor in an estimated 45 to 67 percent of airline crashes, the authors say.
"It's very encouraging that pilot error is decreasing as a cause of crashes of commercial flights," says Guohua Li, M.D., Dr.P.H., associate professor of emergency medicine and lead author of the study. "This decline is possibly due to increased use of advanced technologies and improved crew training."
The report, published in the January issue of Aviation, Space, and Environmental Medicine, also found that weather continues to be a significant factor in pilot error. Crashes in conditions of poor visibility that forced a pilot to rely on instrument navigation were nearly four times more likely to involve pilot error than those in which the pilot could see clearly.
"We observed a very high correlation between bad weather and pilot error," says Susan P. Baker, M.P.H., another author of the study and professor of health policy and management at Hopkins' School of Public Health. "The primary cause was the pilot's inability to deal with the weather - as the situations became more demanding, the risk of error increased. Improving our ability to predict poor weather conditions and providing better guidance to pilots in those situations warrants attention."
Li, Baker and their colleagues studied files compiled by the National Transportation Safety Board of crashes in three categories: major airlines, commuter/air taxis and general aviation (defined as personal business flights, corporate/executive flights and instructional flights, among others). They studied the sequence of events leading to the crashes and developed a mathematical model to predict the likelihood of pilot error.
Overall, 371 major airline crashes, 1,735 commuter/air taxi crashes and 29,798 general aviation crashes were reported between 1983 and 1996 (incidents resulting in only minor damage to the aircraft were excluded). Of those, pilot error was listed as a probable cause for 38 percent of major airline crashes, 74 percent of commuter/air taxi crashes and 85 percent of general aviation crashes. Other findings of the study include:
- More than half (53 percent) of fatal major airline crashes were attributed to pilot error, compared with 36 percent of nonfatal major airline crashes. The prevalence of pilot error also was significantly higher in fatal commuter/air taxi crashes and general aviation crashes.
- 45 percent of major airline crashes occurring at airports were caused by pilot error, compared with 28 percent of those occurring elsewhere.
- More than 88 percent of crashes involving student/private pilots were attributable to pilot error, compared to 80 percent for pilots with commercial or airline transport certificates.
- Female pilots involved in general aviation crashes (4 percent) recorded an average 888 total flight hours, compared with 2,411 hours among their male counterparts.
- The prevalence of pilot error was similar for daytime and nighttime crashes in each aviation category.
- Helicopters constituted 18 percent of commuter/air taxi crashes and 6 percent of general aviation crashes; pilot error was less prevalent in helicopter crashes than in airplane crashes.
Other study authors were Jurek G. Grabowski, M.P.H.; and George W. Rebok, Ph.D.
The study was supported by grants from the National Institutes of Health and the federal Centers for Disease Control and Prevention.
Related Web sites:
Johns Hopkins University Department of Emergency Medicine: http://www.
Johns Hopkins University School of Public Health: http://www.
Aerospace Medical Association: http://www.
Federal Aviation Administration: http://www.
Johns Hopkins Medical Institutions' news releases are available on an EMBARGOED basis on EurekAlert at http://www.