FLIGHT CREW FATIGUE IV - OVERNIGHT CARGO OPERATIONS

We monitored 34 B-727 crewmembers before, during, and after 8-d commer cial overnight cargo trips crossing no more than one lime zone per 24 h. Daytime sleep episodes were 41% shorter and were rated as poorer th an nighttime sleep episodes. When the layover was long enough, crewmem bers usually slept again in the evening before going back on night dut y. Nevertheless, the total sleep per 24 h on duty days averaged 1.2 h less than pretrip. The circadian temperature rhythm did not adapt comp letely to night duty, delaying by about 3 h. Self-rated fatigue was hi ghest around the time of the temperature minimum, which occurred near the end of the nighttime duty period. On trip days, crewmembers ate mo re snacks and there was a marked increase in reports of headaches, con gested noses, and burning eyes. Comparisons with daytime short-haul op erations confirm that a daytime rest period does not represent the sam e sleep opportunity as a nighttime rest period of the same duration. W e examine regulatory and scheduling options, and personal countermeasu re strategies, that could help to reduce sleep loss during overnight c argo operations.