Wednesday, October 1, 2008
Waking Up To Fatigue
Just because you’re awake, doesn’t mean you’re alert
|The FAA is paying renewed attention to human fatigue in aviation, particularly in air transport operations. This issue has troubled the NTSB to such an extent that it has appeared on its annual “Most Wanted Transportation Safety Improvements” every year since the list was first published in 1990. |
While the NTSB’s safety recommendation made no mention of GA accidents involving fatigue, it remains just as important for general aviation as it is for the airlines. In some respects, dealing with fatigue is more difficult for GA pilots operating without any framework for duty hours, maximum flight times or required rest periods. Many GA pilots have to decide whether to fly after a long day of business meetings, a poor night’s sleep, a long period of physical activity or some combination of these and other factors. Pressures to make the flight might be self-imposed or come from passengers and business associates. [See “Managing Fatigue” in the print edition of P&P
Take, for example, a PA30 Twin Comanche that crashed while making what should have been a routine approach. The pilot may not have been able to discern that fatigue was impairing his ability to function because he had been used to dealing with a number of troubling factors for an extended period of time.
At 6:19 p.m. on January 13, 2006, the airplane was descending for a landing at Visalia Municipal Airport in Visalia, Calif. The pilot had turned about a half-mile final and had been in radio contact via the local Unicom with a King Air that was on a four-mile final. The King Air pilot had radioed the accident pilot that there was plenty of room and he should go ahead and turn final for landing. The Twin Comanche struck the ground about 400 feet short of the approach end of runway 30. The commercial pilot and the three passengers were killed. The pilot had flown from Visalia to Byron Airport in Byron, Calif., to pick up two children; this was the return flight.
The pilot held a commercial certificate with ratings for single-engine and multi-engine airplanes and instruments. His logbooks couldn’t be located, but on his application for an FAA medical about two years before the accident, he reported having 5,700 flight hours.
Investigators learned that the pilot had been traveling for work in the days preceding the accident. He took a commercial flight to Portland, Ore., and worked there before driving to Seattle, Wash., for two days of meetings. The night before the accident flight, he flew commercially from Seattle to California on a flight that was delayed an hour. He dropped off a friend in Fresno at 12:30 a.m., and arrived home at 1:30 a.m., the morning of the accident.
Toxicological testing indicated the presence of drugs usually used to control high blood pressure. Also, there was a high level of doxylamine, often used in over-the-counter sleep aids. The pilot hadn’t reported using these drugs on his medical application. Investigators subpoenaed the pilot’s personal medical records, which indicated that he had a history of lower back pain. On four different occasions, the pilot had complained to his doctor about experiencing difficulty sleeping due to the pain. The NTSB report suggested that the high level of doxylamine had likely accumulated due to daily use or use in excess of the maximum recommended dose.
The NTSB determined that the probable cause of this accident was the pilot’s failure to maintain airspeed during the landing approach, which resulted in a stall and uncontrolled descent. Contributing factors included the pilot’s impairment due to his prolonged use of a highly sedating over-the-counter sleep aid and the onset of fatigue due to lack of sleep. Peter Katz is editor and publisher of
NTSB Reporter, an independent monthly update on aircraft accident investigations and other NTSB news. To subscribe, write to: NTSB Reporter, Subscription Dept., P.O. Box 831, White Plains, NY 10602-0831.
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