Background
The International Civil Aviation Organization (2016) defines fatigue as a physiological state of reduced mental or physical performance capability resulting from sleep loss, extended wakefulness, circadian phase, and/or workload, which can impair alertness and ability to perform safety-related duties.
Research Report
The ATSB released a research report titled "Fatigue experiences and culture in Australian commercial air transport pilots" (AR-2015-095), aiming to provide insights into industry perceptions of fatigue.
Incident Findings
A fatigue analysis conducted as part of an investigation found that a pilot was very likely acutely fatigued at the time he fell asleep. The pilot was operating the aircraft in a solo capacity and did not identify fatigue as a potential hazard because he did not recognize any signs of fatigue.
Pre-Flight Preparation
The pilot had a five-day leave period before the night shift, offering an opportunity to plan and obtain adequate sleep. However, obtaining sleep in the afternoon after sleeping at night can be challenging, as pilots are not typically tired at that time. The report notes that it is vital to ensure non-fatigued operation throughout the night.
Organizational Factors
Despite knowing the circumstances of the incident, the operator did not put in place measures to ensure the pilot was fit to continue the shift. This resulted in the pilot continuing to fly while still very likely being fatigued to a level known to affect performance. The operator lacked a consistent roster pattern across weeks; rosters were provided at relatively short notice and subject to change, making it difficult for pilots to predict future shifts and effectively plan sleep for preparation for night shift work. While this roster issue was not a factor in this occurrence because the pilot knew about the night shift in advance, the report emphasizes that rosters should be maintained in a way that provides pilots the best opportunity to plan and obtain sleep to avoid flying while fatigued.
Safety Message
The research highlights that managing fatigue risk is a shared responsibility. Individual pilots must use rest periods to obtain adequate sleep and remove themselves from duty if fatigued. Operators should implement policies to reduce fatigue-related issues through rostering practices and foster an organizational culture where crew can report fatigue in a supportive environment.