The Relationship between Working Conditions and Commercial Pilot Fatigue Development

Fatigue is an important factor in aviation accidents, and effective fatigue management requires understanding the relationship between working conditions and fatigue. Two studies were conducted to clarify the relationship between working conditions and fatigue. In the first study, 59 airline pilots completed a workload questionnaire and the Profile of Mood States (POMS) in the morning and at the completion of their final flight of the day. In the second study, 133 pilots completed a revised questionnaire and the POMS. In both samples, fatigue increased and vigor levels decreased. Regression of fatigue increase upon working conditions indicated that the number of takeoffs and landings during the day were related to fatigue development. Correlation of incident level with both weather and airport difficulty suggest that incident level is a function of weather conditions and airport difficulty. These results argue that fatigue management should be founded upon the demands of working conditions, not merely the simplistic assessment of hours of work.