Acute and cumulative effects of scheduling on aircrew fatigue in ultra‐short‐haul operations

Abstract

Fatigue is a major cause of accidents in transport work, including aviation, according to the National Transportation Safety Board (NTSB, 1999). Because fatigue-related safety is linked to scheduling practice, authorities attempt to prevent fatigue through flight time limitations. The European Aviation Safety Agency (EASA) identifies night flying, early morning starts, long flight duty periods (>13 h during daytime) and a high level of sectors as scheduling characteristics contributing to aircrew fatigue (Commission, 2014).Several of these limitations are founded on experience and on results from circadian and sleep science (Rangan et al., 2020).There is no consensus definition of fatigue, but in aviation research it has a connotation of sleepiness (Caldwell et al., 2009;Weiland et al., 2013), which refers to a drive towards sleep (Dement & Carskadon, 1982). Fatigue in aviation shows a pronounced link with sleep loss, time awake and time of day (Dawson & McCulloch, 2005;

Early starts and late finishes both reduce alertness and performance among short‐haul airline pilots

“…Others have also demonstrated that fatigue ratings are higher during early starts compared with later morning starts (Åkerstedt et al, 2021;Bourgeois-Bougrine et al, 2003;Flynn-Evans et al, 2018;Roach et al, 2012;Sallinen et al, 2017). This likely relates to later starts affording a longer sleep opportunity and to the circadian drive for alertness promoting waking during the biological day (Roach et al, 2012).…”

“…In contrast, later morning starts would have involved providing fatigue assessments at times that were likely during habitual wake periods. Åkerstedt et al ( 2021 ) found that sleep was the strongest predictor of fatigue over a 24‐period followed by duty type (including both early and late duties) and duty time. Although we did not find a statistically significant association between prior night's sleep duration and subsequent fatigue or performance, the amount of sleep that the pilots reported prior to early starts was 6.90 h, which is considered insufficient relative to consensus recommendations (Hirshkowitz et al, 2015 ; Watson et al, 2015 ).…”

“…Fatigue remains a challenge in short‐haul aviation due to (1) irregular schedules that prevent adequate duration and timing of sleep (Borgeois‐Bougrine et al, 2003 ); (2) early and late duty times that encroach on the nightly sleep opportunity (Åkerstedt et al, 2021 ; Flynn‐Evans et al, 2018 ; Roach et al, 2012 ; Vejvoda et al, 2014 ); and (3) workload factors, such as duty length and the number of sectors (Flynn‐Evans et al, 2018 ; Goffeng et al, 2019 ; Honn et al, 2016 ; Powell et al, 2007 ). The International Civil Aviation Organization (ICAO) defines fatigue as “a physiological state of reduced mental or physical performance capability resulting from sleep loss or extended wakefulness, circadian phase, or workload (mental and/or physical activity) that can impair a crew member's alertness and ability to safely operate an aircraft or perform safety‐related duties” (International Air Transport Association (IATA; 2015 ).…”

“…As early start flights often begin before typical wake times (e.g., 05:00–07:00), it would be expected that the influence of the circadian system might cause pilots to feel sleepy and perform poorly at the beginning of their shift . In addition, early start times reduce the amount of sleep that pilots obtain the night before a flight (Åkerstedt et al, 2021 ; Flynn‐Evans et al, 2018 ; Roach et al, 2012 ). For instance, Roach et al ( 2012 ) found that for every hour of duty start before 9:00 am, pilots lose approximately 15 min of sleep.…”

Organizational Risk Factors for Aircrew Health: A Systematic Review of Observational Studies

“…The studies by Goffeng et al [ 43 ] and Åkerstedt et al [ 44 ] evaluated both pilots and flight attendants. The first of these investigations, a seven-day prospective cohort study confirmed higher number of consecutive workdays (≥days), short sleep, less rest time between flights, and high workload as risk factors for greater cardiovascular effort among pilots and flight attendants.…”