Crew Schedules, Sleep Deprivation, and Aviation Performance

 

ScienceDaily (Apr. 24, 2012) — Night-time departures, early morning arrivals, and adjusting to several time zones in a matter of days can rattle circadian rhythms, compromise attention and challenge vigilance. And yet, these are the very conditions many pilots face as they contend with a technically challenging job in which potentially hundreds of lives are at stake.

In an article to be published in a forthcoming issue of Current Directions in Psychological Science, a journal of the Association for Psychological Science, John A Caldwell, a psychologist and senior scientist at Fatigue Science, a Honolulu business focusing on fatigue assessment, examines the problem of sleep deprived pilots by teasing out the complex interplay of inadequate sleep and circadian rhythms. He explains how airline industry solutions miss the point and then suggests other options.

Caldwell points out that "fatigue-related performance problems in aviation have been consistently underestimated and underappreciated, despite the fact that decades of research on pilots and other operational personnel has clearly established that fatigue from insufficient sleep significantly degrades basic cognitive performance, psychological mood, and fundamental piloting skills."

Evidence abounds. In 2004, a corporate airlines flight crashed as it approached Kirksville Regional Airport; in 2008, Honolulu based pilots of Go! Airlines overshot their destination by more than thirty miles because they fell asleep during a trip that was only fifty minutes long. A Northwest Airlines Flight overflew its destination by 150 miles because pilots had dozed off at the controls. In 2009, fifty people were killed when a Continental Connection flight en route from Newark to Buffalo crashed into a house. Pilots failed to respond properly to a stall warning and the flight went out of control.

After examining what went wrong, the NTSB concluded that, "the pilots' performance was likely impaired because of fatigue." Since 1990 the US National Transportation Safety Board has placed pilot fatigue on the Most Wanted List of safety related priorities.

Why? Because as fatigue increases, "accuracy and timing degrade, lower standards of performance are accepted, the ability to integrate information from individual flight instruments into a meaningful and overall pattern declines, and attention narrows. "

In one study, F-117 pilots were deprived of one night of sleep and then were tested on precision instruments. Not only did pilot errors on those instruments double after one night of sleep loss, pilots reported feeling depressed and confused.

Clearly fatigue is fundamentally the result of insufficient sleep, but for pilots the important issue is the consequences of that sleep loss when they are sitting at the control panel. The author suggests that "fatigue related risks increase substantially when (a) the waking period is longer than 16 hours, (b) the preduty sleep period is shorter than 6 hours, or (c) the work period occurs during the pilot's usual sleep hours."  READ MORE: Science Daily