Layover start timing predicts layover sleep quantity and timing on long-range and ultra-long-range trips

Area of Science:

• Aviation Physiology
• Sleep Science
• Human Factors in Aviation

Background:

• Pilot sleep during layover is critical for maintaining alertness on subsequent flights.
• Assessing layover sleep is essential for optimizing pilot rest and performance.
• Understanding factors influencing layover sleep is key to mitigating fatigue in air transport operations.

Purpose of the Study:

• To investigate the quantity and timing of sleep obtained by airline pilots during layovers.
• To identify predictors of layover sleep quantity and timing.
• To inform strategies for improving recuperative sleep opportunities for pilots.

Main Methods:

• Actigraphy was used to assess sleep in 256 pilots across 473 long-range (LR) and ultra-long-range (ULR) flights.
• Linear mixed-effects models were employed to analyze layover sleep characteristics.
• Predictor variables included operational factors (e.g., layover start time) and pilot sleep history.

Main Results:

• Pilots averaged 7.2 hours of sleep per 24-hour layover, which was significantly less than their sleep duration before or after trips.
• Layover start time was the most significant predictor of sleep timing and quantity for both shorter and longer layovers.
• Crew type influenced sleep quantity during the latter part of extended layovers.

Conclusions:

• While average layover sleep duration was within recommended ranges, it suggests a modest overall sleep loss for pilots.
• Layover start timing emerged as the strongest predictor of sleep quantity and timing, highlighting its potential as a modifiable factor.
• Optimizing layover start times may be crucial for protecting circadian-aligned sleep opportunities and enhancing pilot rest.