Fatigue in military aviation shift workers: survey results for selected occupational groups

Shift workers are particularly vulnerable to increased sleepiness, chronic fatigue, and decreased performance, which can adversely impact productivity and safety in military flight operations. This study examined the association of specific risk factors including work context and shift system details (squadron: remotely piloted aircraft [RPAI vs. manned aircraft [MA]), work/rest guidelines (career field: crewmember vs. maintainer), and participation in deployed operations (environment: home base vs. deployed) on subjective fatigue using standardized and validated fatigue questionnaires.

A cross-sectional survey of 172 U.S. Air Force (USAF) personnel was conducted from October 2004 to May 2005. The study sample was recruited from four different USAF occupational groups involved in some form of shift work to include irregular, rotational, or fixed shifts.

Participants reported a mean (SD) of 6.6 (1.8) hours of sleep per day with no differences by squadron, career field, or environment. Mean daily sleep did not correlate with scores on the fatigue questionnaires. Mean scores on the fatigue questionnaires were associated with squadron (mean fatigue score: RPA > MA), but not with career field or environment. There were no significant interaction effects, nor were there significant effects based on the covariates age, gender, and rank.

Work context, shift system details, or both appeared to best explain the observed differences in fatigue between USAF shift worker populations. Crewmember work/rest guidelines did not appear to be useful for mitigating fatigue associated with shift work. Shift work is intrinsically fatiguing, regardless of whether the shift worker is at home base or deployed.