WASHINGTON (AP) — Tests of pilots killed in plane crashes over more than two decades show an increasing use of both legal and illegal drugs, including some that could impair flying, according to a study released Tuesday by the National Transportation Safety Board.
The study examined toxicology reports for almost 6,700 pilots killed in crashes from 1990 to 2012. Not only did the share of pilots testing positive for a drug increase over that period, but the share of pilots who tested positive for multiple drugs increased as well. Pilots testing positive for at least one drug increased from 9.6 percent to 39 percent, while positive tests for two drugs rose from 2 percent to 20 percent and three drugs from zero to 8.3 percent.
Over the same period, new drugs were coming into use and the U.S. population was aging, creating greater demand for drugs. The toxicology tests "reflect tends in the general population and likely indicate a significant increase in drug use" by pilots as well, the study said.
However, the share of accidents the board has investigated in which impairment from a drug was found to be a factor hasn't increased appreciably, the report said. Since 1990, the NTSB has cited pilot impairment due to drugs as a cause or a contributing factor in about 3 percent of fatal civil aviation accidents.
Acting NTSB Chairman Chris Hart said the board "is concerned about possible safety implications of increased drug use in all modes of transportation." He called the report "an important first step toward understanding those implications."
Dr. Mary Pat McKay, the board's chief medical officer, said the study was limited to aviation because similarly comprehensive drug test data doesn't exist for fatal highway, rail and maritime accidents. But it's likely there are similar trends in those modes as well, she said.
The board also voted to issue a safety alert to pilots, warning of the risk of impairment from many over-the-counter drugs. The board issued several recommendations to the Federal Aviation Administration and state governments aimed at better communication of drug risks to pilots and operators in all transportation modes.
More than 9 out of 10 of the pilots tested were private rather than commercial pilots, and 98 percent were male. The average age of pilots killed also increased markedly, from 46 years old in 1990 to 57 in 2012. The average age of pilots killed was 5 to 15 years older than the general population of active pilots.
The tests also revealed increased pilot use of all kinds of drugs, including drugs that could impair a pilot's functioning as well as drugs used to treat potentially impairing conditions such as seizure disorders and psychiatric illness.
The most common drug found in the tests was an antihistamine that causes drowsiness and is a key ingredient in many over-the-counter medications for allergies, colds and sleep. Sedating antihistamines in general were found in 9.9 percent of pilots tested during the last five years studied, up from 2.1 percent of the cases during the early years examined.
The share of pilots testing positive for illegal drugs was small, but increased from 2.3 percent to 3.8 percent. The study attributed the increase mostly to greater marijuana use in the last 10 years.
A statement by the Aircraft Owners and Pilots Association, which represents private pilots, called the NTSB study incomplete and said its results "should be regarded with caution."
"There are just far too many gaps and unknowns in the study for us to be able to draw any meaningful conclusions about aviation safety," said Mark Baker, the association's president.
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