Naval aviation mishaps and fatigue

Naval aircraft mishap data were analyzed to determine if statistical relationships among variables generally associated with fatigue and mishap liability exist. Pilots in mishaps were divided into two groups: those who were causally involved and those who were not. The results demonstrated that fighter and helicopter pilots who had worked at least 10 h in the previous 24 were significantly more likely to fall in the causally involved group. Variables related to sleep, continuous duty, missions performed, and hours flown in the immediate past, however, showed no significant relationships with mishap liability. Analysis of mishap rates as a function of time of departure, however, indicated that rates tended to be lowest for flights originating between 0900 and 1800, a result that possibly supports the hypothesis that "circadian desynchronization" contributes to mishaps.