Investigation on cumulative psycho-physiological effects on flight crews

Description of the project

The Institute for Aerospace Medicine of the German Aerospace Center (DLR) has been working on questions concerning stress and workload of flight crews for several years. Until now only single schedules have been examined medically for different reasons. The effects during a longer period of time (consecutive schedules within 1-2 month) have not been considered so far. The aim of the research was to acquire long-term effects in order to establish a broader scientific database.


The aim of this research was to identify work-related environmental factors that may affect sleep-wake behaviour, fatigue, workload and stress of short-haul cockpit crew members during consecutive schedules within a period of eight weeks each. In addition, data should give information of potential current or long-term compensation in consequence of these effects.


Extend of the study 



During the entire investigation period activity data of each pilot were continuously recorded by means of an actimeter worn at their non-dominant wrist. A small hand held PC at pilot’s disposal allowed fast and efficient work in filling in questionnaires, handling the flight log and the daily sleep log. Completing a flight log, all relevant flight data of every duty day was documented (e.g. beginning and end of flight duty time; flight sectors; destinations, etc.).


Additionally during a duty cycle, pilots hourly ranked subjective fatigue and workload by standardized questionnaires (e.g. Karolinska Sleepiness Scale, Fatigue Scale of Samn and Perelli, NASA task load index).


Sleep – wake - cycles were documented by objectively recorded sleep-wake- data of the actimeter, as well as subjectively by daily filling in questionnaires of the sleep log before and after bedtime. The sleep log grasped specific aspects of sleep e.g. bedtime, time of awakening, number of awakenings, sleep period time, etc. The sleep log was also to be filled in before and after naps.

Besides of the sleep log, pilots also answered standardized questionnaires with respect to the subjective evaluation of fatigue, strain and recovery (e.g. subjective sleep quality; the degree of feeling refreshed). The participants’ objective performance was measured with the help of a computer-assisted single reaction task twice a day, after getting up in the morning and before going to bed in the evening. In addition, paper pencil questionnaires had to be answered at different time intervals scheduled before. These answers revealed information on relevant, psychosocial boundary circumstances, which had not been considered during the daily routines (e.g. job satisfaction, eating habits; relationship between crew members).


Aims of the study

The intention of the project is to record flight-physiological and psychological data over a period of two months to detect possible cumulative effects and their meanings on the stress of flight crews.


From the results might emerge recommendations how scheduling and rostering of cockpit crews on short haul operations can be improved.




Niederl, T.,: Untersuchung zu kumulativen psychischen und physiologischen Effekten des fliegenden Personals auf der Kurzstrecke, Dissertation Universität Kassel, DLR-Forschungsbericht 2007-17, 376 Seiten, (2007). (German with English Abstract)
 DLR- Forschungsbericht 2007-17 Abstract (19 kByte)   DLR-Forschungsbericht 2007-17 (3.4 MByte)





Data protection


The DLR-Institute for Aerospace Medicine is required to keep the regulations of the Federal Data Protection Act (BDSG) and those of internal codetermination as a matter of course. The data is treated and stored anonymously. The DLR observers are bound to legal requirement concerning confidential medical communication.


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