The human body requires sleep to retain its functionality, preserve alertness, and encode memory; however, obtaining required sleep over long-term missions can be difficult. Flight crews may be aware of the risks of fatigue, but will ignore them to continue their course or reduce cost of operations. Future flight operations might increase the risk of increased fatigue of flight crews. This may result from:
• ultra long range flights with minimum crew
• harmonized European legislation allowing longer flight duty times
• increased regional operations
• increased pressure on crews to improve economics
• passenger and crew screening requirements
Sleep deficits of as little as 2 hours a night can stockpile and lead to drastically reduced awareness. While the only way to truly reverse this damage is through a prolonged period of rest, other fatigue management strategies have been proposed, including off-duty rest periods integrated into the pilot’s schedule. Businesses are opposed to the change for reasons of cost, but pilots are pushing for more stringent rules on the matter to ensure safety.
It is essential that all flight crewmembers remain alert and contribute to flight safety by their actions, observations and communications.
- Impaired performance: delayed, erroneous or chaotic responses to normal stimuli
- Reduced ability for the human pilot to process complex information and cope with the unexpected. It is when the automation fails or evidences unexpected behavior that the human needs to step in. Fatigue dramatically compromises the ability of the flight crew to perform as needed in off-nominal conditions.
- Automation mode confusion.
- Reduced alertness
- Adverse physiological consequences: stressors affecting alertness
- Adverse effects of long commutes on flight crew performance
- Reversions to “fight-or-flight,” panic or freeze instinctive self-preservation behaviors in emergency situations; reflexive response to stimulation
- Failure to report errors and omissions arising from fatigue that do not necessarily result in reportable incidents
- Poor environmental characteristics of crew rest areas in aircraft
- A recent FAA Office of Inspector General report found that pilots might not be reporting all instances of fatigue. The report noted that, of 33 air carrier pilots interviewed by OIG researchers, 26 (79 percent) said that, at some time, they had been fatigued while on duty; nevertheless, only eight pilots notified their air carrier of their condition. Among the reasons cited for not reporting fatigue was the fear of “punitive action from their employers.”