Assessing Signal Detection Performance Under Operational Fatigue in Air Traffic Controllers

Abstract

Fatigue and sleepiness are critical safety issues for air traffic controllers (ATCOs) that impair cognitive performance and vigilance (Bendak & Rashid, 2020; Wingelaar-Jagt et al., 2021). They typically result from insufficient or disrupted sleep, extended duty periods, and work schedules misaligned with circadian rhythms, common in ATCO operations (Bendak & Rashid, 2020 ; Eastman & Smith, 2012 ; Wingelaar-Jagt et al., 2021). This study quantified signal detection performance in ATCOs compared to healthy controls and examined how performance varies across day and night shifts and evolves over a shift. Seventeen licensed ATCOs working rotating shifts completed a 3-minute Behavioural Sleep Resistance Task (BSRT) before their shift, during a break, and after the shift. A laboratory reference group of 36 healthy young adults following 20 hours of wakefulness served as a fatigue benchmark. The BSRT measured processing speed, attentional lapses, neurobehavioral stability, and omission errors, completed by Karolinska Sleepiness Scale (KSS) ratings. Results showed progressive cognitive slowing, increased reaction times and reduced optimal responses. Attentional lapses accumulated over time and neurobehavioral stability declined, particularly during night shifts. Despite these effects, omission errors remained low, indicating maintained task engagement. Subjective sleepiness increased across shifts and was higher at night. Comparison with laboratory benchmarks indicated that some impairments were present pre-shift, suggesting sustained baseline fatigue from cumulative sleep restriction and incomplete recovery. Findings highlight the combined influence of time-on-task and circadian vulnerability on vigilance, with ATCOs employing compensatory strategies that trade speed for accuracy to maintain operational safety.

Keywords: Air Traffic Controllers, Shift Work, Fatigue, Sleepiness, Vigilance, Signal Detection, Behavioural Sleep Resistance Task (BSRT), Oxford Sleep Resistance Test (OSLER)

DOI: 10.54941/ahfe1007835