Aviation Knowledge writes that pilot fatigue is "the state of tiredness that is associated with long hours of work, prolonged periods without sleep or the requirement to work at times that are out of synch with the body's biological or circadian rhythms." A cause and effect relationship has been found to exist between pilot fatigue and vulnerability to pilot error in various studies.
In a news release on Jan. 3, 2013, the University of Leicester has reported, Pilot fatigue – a threat to safety. Research which has been published by Dr Simon Bennett of the University of Leicester’s Civil Safety and Security Unit in the Institute of Lifelong Learning has shown that pilots can find themselves flying an aircraft many hours after waking. Greater than 20% of Dr Bennett’s respondents have said that by the time they completed their shift they had been awake for 28 hours or more. Dr Bennett has commented, “Research proves that judgment is seriously impaired after eighteen hours of wakefulness. How well do you think you could drive after being awake for eighteen hours?"
It has been revealed that due to debts from training fees, many novice pilots struggle to make ends meet. And properties in airport catchments are expensive. Therefore, hard-up pilots find themselves commuting long distances. These long commutes add to the fatigue generated by flying multiple trips in congested airspace. Dr Bennett has also said, “Regulations made without reference to scientific knowledge or social context are dangerous. EASA’s proposed FTLs take little account of the latest sleep research and no account of the pilot lifestyle as described in my own research. Passenger safety is threatened. Those who work at the coal-face of aviation deserve better.”