Background

Flight operations often result in fatigue, sleep loss, and circadian disruption leading to significant decrements in alertness and performance. These problems can be difficult to detect reliably and counteract effectively in constrained operational environments. Yet, left unaddressed, alertness and performance decrements reduce the margin of safety and increase the chances of an incident or accident. One serious challenge facing flight crews is the requirement to maintain vigilance during long, highly-automated, and often boring nighttime flights. There is no system currently in place to assist flight crews in managing their alertness. Furthermore, strategy choices are severely restricted on the flight deck. For example, while a 26-min nap has been demonstrated to result in significant improvements in subsequent physiological alertness and psychomotor performance,1 napping on the flight deck is not currently sanctioned by the FAA. Current Federal Aviation Regulations also mandate that flight crews remain seated: ÒÉeach required flight crewmember on flight deck duty must remain at the assigned duty station with seat belt fastened while the aircraft is taking off or landing, and while it is en routeÓ (FAR requirement). Nevertheless, surveys of flight crews reveal that many use physical activity as a fatigue countermeasure. Despite this widespread belief by flight crews in its effectiveness, there have been no controlled studies in the aviation environment. The present experiment was designed to test the hypothesis that mild physical activity, coupled with social interaction, would improve alertness and performance during a long, uneventful, overnight flight requiring extended wakefulness.

Objective

Evaluate physical activity combined with social interaction as a countermeasure to the fatiguing effects of a long nighttime flight. Approach Level D 747-400 flight simulator with 2-man crews (29-62 yrs) 6-hr, uneventful, transoceanic, nighttime flight (0200-0800), encompassing the time of the circadian trough Experimental Group (n=14) Five short (7-min) breaks with physical activity, spaced hourly during cruise Control Group (n=14) One 7-min break only, in middle of cruise portion of flight Measures Psychomotor vigilance performance task (PVT; 10-min) Karolinska Sleepiness Scale (KSS) Visual Analogue Sleepiness Scale (VAS) Continuous EEG/EOG Continuous video of the face (not reported here)