Drug Use Trends

The NTSB looked at accident records between 1990 and 2012 for what was a retrospective review of data. No fresh data was gathered in the form of new surveys or tracking of the active pilot population. If the pilot was killed in an accident appearing in its files, the NTSB checked to see whether the FAA's Civil Aerospace Medical Institute in Oklahoma City had a toxicology report on the pilot. The toxicology results for 6,677 pilots were included in the study. The study showed that almost 23% of the pilots killed had tested positive for use of a drug that had the potential to impair. However, just because there were positive results didn't mean that the pilots were actually impaired or even close to being impaired by the drugs. In fact, the NTSB could cite drug impairment as a cause or contributing factor in an average of only about nine accidents per year (3%) during the 22 years studied.

The drugs detected ranged from over-the-counter treatments for the common cold to drugs for erectile dysfunction and high cholesterol, and illegal drugs such as cocaine or marijuana. The NTSB concluded that the FAA doesn't provide pilots with adequate information to make informed decisions about which drugs are safe or unsafe to use while flying. It noted that the FAA doesn't provide pilots with a comprehensive list of medications to avoid, and that aviation organizations such as AOPA have made efforts to provide information along those lines. The study notes, "The NTSB understands the FAA's concerns about whether it's feasible to develop and maintain a list of drugs that is comprehensive and current. However, the NTSB believes the FAA doesn't need to provide comprehensive information, only the information most relevant to the pilot community."

In its study, the Safety Board singled out records from the years 2005 through 2012 to study holders of sport-pilot certificates. Those same records often have been cited by advocates of third-class medical reform as demonstrating that sport pilots have been flying with no medical-related safety issues. However, the NTSB stated, "Study pilots with a sport-pilot certificate only were more likely than those with private, commercial or airline transport pilot certificates to have positive findings for all drugs, for potentially impairing drugs and for drugs used to treat potentially impairing conditions. The increased prevalence of positive findings for fatally injured sport pilots was notable because they aren't required to have a medical certificate and are therefore likely making decisions about using particular drugs without periodic interaction with an AME [aviation medical examiner]."

The study found that use of illegal drugs by fatally injured pilots was relatively uncommon. They were detected in only 2.9% of the cases from the 1990s and increased to about 4% by 2012. Again, the detection of drug use didn't mean that the pilot had been impaired by the drug, or that use of the medication or illegal drug use contributed to the accident. In many cases, previous use of both legal and illegal drugs can be detected long after the drug level has diminished to an inconsequential level.

The Safety Board concluded that additional research is required to assess the complex relationship between the use of drugs by pilots and accident risks. It said the FAA should develop, publicize and periodically update information to educate pilots about potentially impairing drugs and to make pilots aware of alternative drugs that are less likely to result in impairment. It also said the agency should develop and distribute a clear policy regarding any marijuana use by airmen, and conduct a study of drug use among pilots who haven't been killed in accidents, so that the safety risks of using those drugs while flying can be better assessed. The NTSB also said that the FAA should require each pilot who flies without a medical certificate to periodically report his or her status as an active pilot and provide a summary of recent flight hours to aid in tracking trends.

These are three sport pilot accidents from the time period studied in which drug use was detected, but couldn't be demonstrated to have contributed to the probable cause of the accident.

Zenith CH701
On July 17, 2011, at about 5:05 p.m., an experimental amateur-built light-sport Zenith CH701 experienced a loss of engine power and crashed at Glendale, Ore. The pilot and passenger were killed. Witnesses reported that after takeoff, the airplane reached an altitude of 500 feet, and that the engine then sputtered and lost power. The airplane then turned steeply left and descended rapidly. The left-wing root-fuel valve was found in the "off" position, and the right-wing root-fuel valve was found nearly in the "off" position. Both fuel tanks were nearly full with fuel. Examination of the fuel hoses downstream of the fuel valves revealed they were empty.

No evidence was found of a mechanical malfunction, or failure with the airframe or engine that would have precluded normal operation. The NTSB said that if the pilot had performed a preflight or run-up inspection before takeoff, which should have included checking the fuel valve positions, he might have noted that the fuel valves were in the "off" position.

The pilot was 66 years old and held a private pilot certificate. He didn't hold a medical certificate, which wasn't required to fly the Zenith CH701.

Toxicology results indicated the pilot had used an anti-anxiety medication. How­ever, the level of drug detected was very low, and the NTSB said it was unlikely that it was impairing at the time of the accident. The Safety Board said it couldn't determine whether the pilot had some underlying medical condition that caused impairment and contributed to the accident.

The NTSB determined that the probable cause of the accident was a total loss of engine power due to fuel starvation and the pilot's subsequent failure to maintain airplane control during the forced landing. Contributing to the accident was the pilot's failure to ensure that the fuel valves were in the correct position for flight during the preflight inspection.

Jabiru J250
On April 2, 2010, about 6:35 p.m., an experimental amateur-built light-sport Jabiru J250 struck trees and power lines during a forced landing following loss of engine power near Middletown, Del. The private pilot was killed, and the passenger, who was the pilot's wife, received serious injuries. The flight originated from Cambridge-Dorchester Airport (CGE), Cambridge, Md.

The wife told investigators that when the engine started to lose power, her husband remarked, "She wants to quit." Her husband tried to restore normal power, but the engine eventually quit. She said the propeller wasn't turning, and there was no smoke nor loud banging noises.

The engine was test-run after the accident, and no evidence of preexisting malfunctions or anomalies were found that would have precluded normal operation. A review of FAA data indicated temperature and dew point conditions at the time of the accident were favorable for serious carburetor icing at cruise power settings. The pilot's wife said the pilot didn't mention the possibility of carburetor ice during the event.

Toxicology testing showed a low level of diphenhydramine, an antihistamine found in over-the-counter medications, in the pilot's blood. The NTSB said it couldn't determine whether the pilot was impaired enough not to recognize evidence of carburetor icing.

The NTSB determined that the probable cause of this accident was the pilot's failure to apply carburetor heat, which resulted in the formation of carburetor icing and a total loss of engine power.

Evektor SportStar Plus
On March 5, 2010, at 8:57 a.m., a special light-sport Evektor-Aerotechnik AS SportStar Plus crashed near Marysville, Ohio. Instrument meteorological conditions existed in the area, and the Safety Board concluded that the airplane flew into them. There was no flight plan filed. Both the pilot and passenger were killed. The flight was going from Indianapolis, Ind., to New Castle, Pa. There were no records of the pilot obtaining a weather briefing from flight service or DUATS. Examination of the wreckage failed to reveal anything that would have prevented normal operation of the engine or aircraft systems.

The pilot held a sport-pilot certificate and had logged about 186 hours with one hour in instrument conditions. While no FAA medical certificate was required to fly the light-sport airplane, investigators looked into his personal medical records and found that he was taking three different medications to treat diabetes. The NTSB said this would have increased his risk for impairment due to excessively low blood sugar. He also had been using medication for respiratory symptoms combining a narcotic and an antihistamine, both of which have potentially impairing effects.

The NTSB determined that the probable cause of this accident was the pilot's improper decision to initiate and continue a flight into instrument meteorological conditions that led to spatial disorientation and a loss of control during cruise flight.

Peter Katz is editor and publisher of NTSB Reporter, an independent monthly update on aircraft accident investigations and other news concerning the National Transportation Safety Board. To subscribe, write to: NTSB Reporter, Subscription Dept., P.O. Box 831, White Plains, N.Y. 10602-0831.