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The newspaper of The Johns Hopkins University April 30, 2007 | Vol. 36 No. 32
Changes Needed to Improve Safety of General Aviation Flights

By Kenna Lowe
School of Public Health

Private, or general aviation, flights are 82 times riskier than commercial airline trips and represent the overwhelming majority of aviation crashes and casualties in the United States. The safety of private flights can and should be addressed, according to researchers from the Johns Hopkins Bloomberg School of Public Health and Johns Hopkins School of Medicine, who identified major factors influencing crash involvement and crash survival and examined possible approaches for improving the safety of private flights. The commentary is published in the April 11 issue of the Journal of the American Medical Association.

General aviation includes all noncommercial flights, such as emergency medical services, sightseeing, flight training, traffic reporting, aerial surveys, search and rescue, crop dusting and firefighting, as well as recreational and business use. General aviation aircraft range from small private airplanes and business jets to helicopters, hot-air balloons and gliders.

"Commercial airlines are the safest mode of transportation, but general aviation is a serious safety concern. Fatal crash risk per-person-mile of travel for general aviation flights is comparable to riding motorcycles," said Guohua Li, lead author of the study and professor of emergency medicine at the Johns Hopkins School of Medicine.

In an examination of the crash risk of private flights, the researchers found that general aviation flights averaged 1,685 crashes and 583 deaths each year from 2002 to 2005, accounting for 91 percent of all aviation crashes and 94 percent of all aviation deaths. Small aircraft flying at low altitudes make general aviation flights especially vulnerable to adverse weather conditions. For general aviation pilots who have not obtained an instrument rating, flying out of "see and avoid" conditions into conditions that require them to fly using their instruments is the most perilous scenario. Additional risk factors include pilots flying while intoxicated, sudden incapacitation (heart attack or other health issue), older age, being male, having a nonconformist flying style (e.g., being a daredevil) and having a prior record of an aviation crash or violation. Physician pilots are also found to crash at a higher rate per-flight-hour than other pilots.

Most aviation crashes do not result in fatalities. However, when crashes occur, aircraft fire is the most important determinant of survival. Fire is involved in 13 percent of general aviation crashes but contributes to 40 percent of fatalities. Additional negative influences on crash survival are bad weather, landing at an off-airport location and failure to use safety restraints. Overall, about 20 percent of general aviation crashes result in one or more deaths, compared with 6 percent of commercial airline crashes. The additional deaths related to general aviation crashes may be partially explained by the inferior crashworthiness — the ability to withstand impact forces and protect occupants from injury — of general aviation aircraft.

Major airlines have improved the crashworthiness of their aircraft, but little has been changed in general aviation, partly because federal regulations that govern design changes apply only when entirely new aircraft models are certified. Installation and use of restraint systems that include airbags could greatly reduce general aviation deaths, according to the study authors.

Susan P. Baker, co-author of the study and a professor in the Bloomberg School of Public Health's Department of Health Policy and Management and Center for Injury Research and Policy, said, "General aviation crashes are a public safety problem that needs to be addressed. The Federal Aviation Administration and National Transportation Safety Board should prioritize and financially support interventions to improve safety of small aircraft."

The Johns Hopkins researchers have published extensively in the field of aviation safety. Recently, they reported that post-crash fires, darkness or bad weather greatly decrease the likelihood of surviving an emergency medical service helicopter crash. They recommended improving crashworthiness of EMS helicopters and reducing trips during hazardous conditions.

Li and Baker co-authored the study, which was supported by grants from the National Institutes of Health and the Centers for Disease Control and Prevention.


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