Alertness in Airline Pilots During Night Flights: Assessment of Alertness Using EEG Measures
Alexander Gundel Jürgen Drescher Jacqueline Turowski
DLR-Institute of Aerospace Medicine, Cologne, Germany
An important issue in the operation of modern civil aircraft is the management of pilot alertness. It is expected that a future alertness management systems will be based on a mathematical model for alertness that incorporates several mechanisms for the dynamics of alertness ( Folkard & Akerstedt, 1992). This model will be built on an empirical data base. The purpose of the present study is to provide additional knowledge about alertness dynamics that will contribute to an alertness management system in civil aviation.
The operation of long-duration night flights usually conflicts with human circadian regulation, as the trough in several physiological and psychological functions including job performance occurs during flight. Pilots are used to this situation and are able to cope with increased fatigue to some extent. A special situation emerges if two extended night flights follow each other. This automatically involves a sleep deficit and the necessity for daytime sleep between flights. Possibly, a further decrement in alertness is observed during the second night flight.
Alertness or sleepiness is composed of at least three distinct components: (a) a circadian component with low alertness at night corresponding, approximately, with the time of the temperature minimum; (b) a component that depends on the preceding sleep; and (c) a sleep inertia effect with elevated fatigue immediately following sleep ( Folkard & Akerstedt, 1992: Folkard, Hume, Minors , Waterhouse, & Watson, 1985; Monk, Moline, Fooksen, & Peetz, 1989).