Compound Fatigue Risk in Medium-Haul Pilots.

Area of Science:

• Aviation Safety
• Human Factors in Aviation
• Occupational Health

Background:

• Compound fatigue, arising from multiple sources like circadian rhythms, workload, and stress, presents a significant safety risk.
• Medium-haul (M-H) pilots may be particularly susceptible to compound fatigue, yet the specific contributing factors in M-H operations remain under-quantified.

Purpose of the Study:

• To quantify the sources of fatigue experienced by airline pilots operating medium-haul routes.
• To investigate the relationship between different fatigue domains (circadian, environmental, operational, psychosocial) and pilot-reported fatigue levels.

Main Methods:

• An anonymous survey was administered to airline pilots working M-H rosters.
• Pilots ranked fatigue from 40 factors across four domains (circadian, environmental, operational, psychosocial) on a 0-10 scale.
• Pilots also reported habitual sleep duration.

Main Results:

• A total of 223 pilots completed the survey.
• Circadian factors were rated as most fatiguing (mean 6/10), followed by psychosocial and environmental factors (both 5/10), and operational factors (4/10).
• Average sleep duration was 7 hours, with no significant correlation found between sleep duration and reported fatigue levels.

Conclusions:

• Operational fatigue factors, such as longer work hours and shorter breaks, were perceived as more fatiguing.
• Schedule features disrupting the circadian low, like early starts or late finishes, contributed to fatigue even when sleep duration was adequate.