Pilot In-Flight Sleep During Long-Range and Ultra-Long Range Commercial Airline Flights.

In commercial aviation, pilot fatigue is a major threat to safety. One key fatigue mitigation strategy on long-range (LR; 8-16 h) and ultra-long range (ULR; 16+ h on at least 10% of trips) routes is allotting in-flight rest breaks for the pilots. Since sleep is a strong predictor of performance, it is important to quantify total in-flight sleep (TIFS) and determine rest scheme schedules that optimize sleep opportunity and subsequent performance. Here we quantify in-flight sleep and characterize rest schemes by type and efficiency. Between 2015 and 2019, we collected data on in-flight sleep on 3 LR and 5 ULR routes totaling 231 pilots flying over 1200 flight duty periods. Data were collected using a combination of actigraphy and logbooks. Over all combinations of flight direction, crew and LR vs. ULR, average TIFS ranged from 3.4 h to 5.2 h with some ULR pilots getting over 8 h. Most crews made use of simple two- or three-break rest schemes and the complex four-break rest schemes were used almost exclusively on the three longest ULR routes. The complex schemes were less efficient than simple schemes, although this effect was small. Complex schemes resulted in no more TIFS compared to simple schemes on the same routes. Overall, we find that crews are getting more sleep on these routes than previously reported on similar routes. Most crews use simple rest schemes and these simple schemes are more efficient than complex schemes.