Longer Work Shifts, Faster Forward Rotation-More Sleep and More Alert in Aircraft Inspection

Abstract

The purpose of this intervention study is to compare sleep, alertness, and work ability among aircraft inspectors working under two different shift schedules. The original schedule was forward rotating: MMM - - EEE - NNN - - - (M = morning, E = evening, N = night, - = day off). The new schedule was fast forward rotating: MEN - - with 10-h shifts. The baseline data were collected before the schedule changed, and the follow-up data 12 months (n = 10, Group A) or 5 months (n = 13, Group B) after the change. Three of subjects were women and average age was 46.6 years (range 31-58). The surveys included questions on sleep quantity, sleep quality, severe sleepiness, alertness, perceived stress, current work ability, and satisfaction with the shift schedule. The results indicated that in the new schedule, the sleeping times were longer and sleep loss was less. Moreover, shift specific severe sleepiness decreased, and alertness during shifts improved. Compared to baseline, perceived stress was lower and work ability was better. Satisfaction with the shift system had also improved. To conclude, the quickly forward rotating shift system might be beneficial in terms of increased sleep length and improved alertness and overall well-being especially among older aircraft inspectors.

Keywords: age; aviation; stress; vigilance; working hours.

Figure 1

Study design. Earlier shift schedule in yellow: M = morning shifts 5.30–14.00, E = evening shifts 13.30–22.00, N = night shifts 21.30–6.00, – = free day. New shift schedule in green: M = morning shifts 5.30–15.30, E = evening shifts 12.00–22.00, N = night shifts 20.00–6.00, – = free day. Blue arrows indicate the survey times.

Figure 2

The shift-specific retrospective severe sleepiness (% of KSS ≥ 7) in every second hour of work shifts at the baseline and at the follow-up of the schedule change with combined Groups A and B (n = 23).