In‐flight sleep, pilot fatigue and Psychomotor Vigilance Task performance on ultra‐long range versus long range flights

Abstract

Summary This study evaluated whether pilot fatigue was greater on ultra‐long range (ULR) trips (flights >16 h on 10% of trips in a 90‐day period) than on long range (LR) trips. The within‐subjects design controlled for crew complement, pattern of in‐flight breaks, flight direction and departure time. Thirty male Captains (mean age = 54.5 years) and 40 male First officers (mean age = 48.0 years) were monitored on commercial passenger flights (Boeing 777 aircraft). Sleep was monitored (actigraphy, duty/sleep diaries) from 3 days before the first study trip to 3 days after the second study trip. Karolinska Sleepiness Scale, Samn–Perelli fatigue ratings and a 5‐min Psychomotor Vigilance Task were completed before, during and after every flight. Total sleep in the 24 h before outbound flights and before inbound flights after 2‐day layovers was comparable for ULR and LR flights. All pilots slept on all flights. For each additional hour of flight time, they obtained an estimated additional 12.3 min of sleep. Estimated mean total sleep was longer on ULR flights (3 h 53 min) than LR flights (3 h 15 min; P(F) = 0.0004). Sleepiness ratings were lower and mean reaction speed was faster at the end of ULR flights. Findings suggest that additional in‐flight sleep mitigated fatigue effectively on longer flights. Further research is needed to clarify the contributions to fatigue of in‐flight sleep versus time awake at top of descent. The study design was limited to eastward outbound flights with two Captains and two First Officers. Caution must be exercised when extrapolating to different operations.

Effects of sleep/wake history and circadian phase on proposed pilot fatigue safety performance indicators

“…Seventy Delta Air Lines B‐777 200‐ER pilots (Gander et al ., ) and 74 B‐777 200‐ER pilots from Airline 4 (Wu and Belenky, ) were monitored as part of a three‐airline study requested by the Federal Aviation Administration (FAA) to compare flight crew fatigue on LR and ULR trips (the third airline is not included in these analyses). Forty‐one Singapore Airlines A340‐500 pilots were monitored as part of the operational validation of the first commercial ULR trips (Signal et al ., ).…”

“…6014, FWA No. 11627) Applications 08/68 (Gander et al ., ) and 11/74 (Signal et al ., ); and Washington State University Institutional Review Board (IRB No. 10951; Wu and Belenky, ).…”

“…Individual field studies that monitor pilot fatigue have limited combinations of these operational factors and/or limited sample sizes. To overcome these limitations, the present analyses combined data from four field studies undertaken by four different airlines based on three continents (Gander et al ., ; Signal et al ., , ; Wu and Belenky, ), including data from 237 pilots on 730 long‐range (LR) and ultra‐long‐range (ULR) flights flown as out‐and‐back trips between 13 city pairs (eight eastward outbound and five westward outbound trips).…”

Fatigue in Air Medical Clinicians Undertaking High-acuity Patient Transports

“…19 It has also been used extensively in aviation and transport research. 6,12,14,15,21 Subjects are asked to rate their fatigue on a scale where 1 = fully alert and wide awake; 2 = very lively, responsive but not at peak; 3 = OK, somewhat fresh; 4 = a little tired, less than fresh; 5 = moderately tired, let down; 6 = extremely tired, very difficult to concentrate; 7 = completely exhausted, unable to function effectively. Ratings were also made on a 100-mm visual analog scale (VAS) with "alert" at the low end of the scale up to "drowsy" at the upper limit.…”

“…[5][6][7] Research specific to health care has linked extended shifts, lack of recovery time, and night work to increased rates of fatigue and medical error [8][9][10] and lower quality patient care. 11 In aviation the risks associated with fatigue have been well recognized and there are a number of studies examining factors related to long or successive duty periods, circadian disruption, and high mental workload, [12][13][14][15] but research has focused almost exclusively on cockpit crew. There is some work from prehospital air transport settings, which suggests that overall shift length does not impact adversely on cognitive or technical skills performance in air medical clinicians.…”