ABSTRACT

Aircrew fatigue associated with involuntary sleep episodes on the flight deck, procedural errors, unstable approaches, attempts to land on the wrong runway, landing without clearances; fatigue identified as co-factor in many crashes and fatalities. In the United Kingdom approximately one-third of reports to Confidential Human Factors Incident Reporting Programme blame pilot fatigue for incidents, errors or other flight-related problems. Humans evolved for 7–9 hr of night sleep, to be awake during the day and have a consistent sleep/wake routine. Fatigue complicated by sleep–wake patterns that are contrary to biological programming. In the modern work environment, fatigue-related performance decrements are common. Many body processes fluctuate on a 24-hr rhythm based on an internal timing mechanism or number of internal clocks which normally work in synchrony unless disrupted by scheduling changes. Sleep inertia is degraded vigilance, increased drowsiness and diminished performance that occurs immediately after awakening. Inter-individual differences exist in fatigue susceptibility and effectiveness of countermeasures.