A draft study of pilots killed in plane crashes over more than two decades has revealed an increase in use of both legal and illegal drugs, including some that could impair flying, the Associated Press reported.
The National Transportation Safety Board study released Tuesday examined toxicology reports for almost 6,700 pilots killed in crashes from 1990 to 2012.
In those years, 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.
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 five to 15 years older than the general population of active pilots.
Over the same period, demand for drugs increased since the U.S. population was aging and new drugs were being introduced simultaneously. The toxicology tests "reflect trends in the general population and likely indicate a significant increase in drug use" by pilots as well, the study said.
Since 1990, pilot impairment was a cause or contributing factor in about 3 percent of fatal civil aviation accidents, the NTSB said.
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, according to the AP.
Specifically, the most common drug found was an antihistamine that causes drowsiness and is a key ingredient in many over-the-counter allergy, cold and sleep medications.
Although the share of pilots testing positive for illegal drugs was small, it has grown from 2.3 percent to 3.8 percent, mostly due to an increase in marijuana use in the past 10 years.
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."
Although similarly comprehensive drug test data doesn't exist for fatal highway, rail and maritime accidents, it is highly possible that similar trends afflict those modes as well, said Dr. Mary Pat McKay, the board's chief medical officer.
Meanwhile, the board issued several recommendations to the Federal Aviation Administration and state governments to inform pilots and operators in all transportation modes of the various drug risks that might cause impairment.
