Objective sleep tracking for fatigue management in cargo pilots: six months of continuous smart-ring monitoring

Aviation fatigue management estimates crew sleep from rosters and self-report. We examined how sleep duration changes around flights and with departure and landing times. In an observational cohort study, 13 cargo pilots wore an Ultrahuman smart ring for six months in 2026. We linked 1,504 sleep sessions to the flown schedule. Linear mixed-effects models compared each sleep session with the same pilot's rest nights, with 95% confidence intervals (CIs). Total sleep time was 48 min shorter on the night before a flight (95% CI 32 to 65 min) and 28 min shorter in the first sleep after one (95% CI 13 to 43 min). Later nights did not differ. Sleep duration varied with clock time. Compared with evening departures and landings, respectively, pilots slept 57 min less before a departure between 06:00h and 11:59h (95% CI 14 to 101 min) and 97 min less after a landing between 00:00h and 05:59h (95% CI 37 to 156 min). Flight direction and length showed no association. Differences between pilots explained 14.1% of the variance in total sleep time, more than six times the 2.2% explained by duty position. Fatigue risk management could plan rest around departure and landing times.