In several studies(2 transmeridian and one north-south route), aero-medical examinations with the aim of registering changes in different bodily functions in relation to the duration of the flight were conducted. A total of 50 pilots on 100 flights took part in the examinations. Apart from subjective surveys about work strain and fatigue, objective measurements (brain waves (EEG), eye movement (EOG) und ECG ) were conducted continually.
The results show that the work strain in the cockpit is acceptable. In contrast, fatigue increases significantly - particularly during nocturnal flights (increased indication of fatigue levels, increased occurrence of micro-sleep). With all nocturnal flights of more than 10 hours of flying time and with day flights of more than 12 hours of flying time, the examinations suggest the conclusion that with a two-man cockpit crew, the limits of physical and psychical endurance are reached.
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