CHAPEL HILL – Flying after drinking alcoholic beverages remains a factor in some fatal North Carolina air crashes and likely contributes to fatal crashes in other states, a study of 10 years of aviation-related deaths across North Carolina suggests.
The study, conducted at Johns Hopkins University and the University of North Carolina at Chapel Hill, showed that 7 percent of dead pilots and 15 percent of other aircraft occupants had consumed at least some alcohol before or during flights.
No pilots killed during commercial air crashes tested positive for alcohol, but 20 percent of their passengers did test positive, researchers found. The four pilot crash victims with blood-alcohol contents greater than 0.10 percent were men ages 20 to 29 on non-commercial night flights.
A report on the investigation appeared in August in the journal Aviation, Space and Environmental Medicine. Johns Hopkins authors are Drs. Guohua Li and Susan P. Baker of the emergency medicine department and the Center for Injury Research and Policy. N.C. authors are Dr. John D. Butts, N.C. chief medical examiner and professor of pathology and laboratory medicine at the UNC-CH School of Medicine, and Elizabeth Gerken Hooten, research associate at the UNC-CH Injury Prevention Research Center.
The study involved analyzing N.C. Medical Examiner Information System data on all victims who died in civilian aircraft crashes in North Carolina from 1985 to 1994, along with crash investigation reports from the National Transportation Safety Board. Excluded were 44 pilots and military aircraft occupants.
During the decade studied, researchers identified 337 aviation-related fatalities, including 111 pilots. Ninety-one percent of the pilots and 72 percent of the non-pilot occupants were tested for alcohol.
"Results of this study indicate that alcohol in fatally injured pilots is less prevalent than reported in previous studies, but intoxicated flying is still a valid concern, particularly for general aviation," the authors wrote. "Among the alcohol-positive pilots, all except one had blood-alcohol contents of 0.04 or higher, the legal limit for both commercial and general aviation. Fifty percent had blood alcohol contents above 0.10, which would be considered prima facie evidence of driving while intoxicated in all states."
Research dating back to 1963 showed alcohol to be a significant factor in fatal crashes, with some studies indicating as many as a third of pilots killed had detectable alcohol. Subsequent work confirmed that alcohol was a problem in fatal crashes but suggested that alcohol use by pilots has declined over the past several decades, possibly due to stricter enforcement efforts.
Alcohol use by passengers can interfere with aviation safety in two ways, the authors wrote.
"First, passengers under the influence of alcohol may become abusive and violent because alcohol even at a moderate dose can trigger aggressive behavior," they said. "A case in point is the USAir Flight 292 incident of July 6, 1996, in which a 40-year-old man, who apparently had been drinking before going aboard, assaulted two flight attendants shortly after take-off because the attendants refused his request for more alcohol."
As a result, the pilot had to fly the airplane back to the departing airport immediately, the authors wrote. Also, 882 reported incidents of verbal or physical abuse against American Airlines crew members occurred in 1996, which were nearly three times as many as reported in 1994. Unclear was how many involved alcohol.
"Second, alcohol may pose a serious threat to the intoxicated passengers themselves as well as other occupants in situations that require emergency evacuation because alcohol even at a low level can impair cognitive function and performance," the authors wrote. "An intoxicated passenger is less able to perceive the need for immediate action, to follow directions and to quickly exit the aircraft."
Because such a high percentage of the pilot victims in the new study were tested for alcohol, the findings are particularly useful, they said. The work was supported in part by the National Institute on Alcohol Abuse and Alcoholism and the U.S. Public Health Service’s Centers for Disease Control and Prevention. National Transportation Safety Board staff also participated.
Note: Butts and Hooten can be reached at (919) 966-2253. Baker's number is (410) 955-2078. Li is currently unavailable to speak with reporters.