Introduction
International and national air operators usually assign their crewmembers flight duty times and rest periods as per the requirements of Federal Aviation Administration (FAA), which aim at ensuring that pilots have sufficient rest to carry out their duties effectively and contribute to the improvement of aviation safety. A longer flight period with minimal rest is one of the sources of fatigue in most crewmembers. Pilot fatigue raises major concerns in the aviation industry as it increases the risk of the pilot making mistakes that could result to an accident. While it is important that the crew exercise caution in their actions, communications, and observations to promote aviation safety, sufficient rest is a necessary requirement as it reduces fatigue. Fatigue leads to physiological and performance burnouts, which increase the risk of accidents. Adequate rest of the crewmembers reduces fatigue and ensures that the pilots remain alert during flight thus contributing to flight safety. The common fatigue risk factors such as inadequate sleep due to long flight hours and sleep disorders like insomnia reduce the level of pilot alertness; a major contributing factor to pilot error leading to flight incidents and accidents.
Factors that contribute to Pilot Fatigue
A high percentage of pilot fatigue, which often results in flight accidents, is mainly attributed to inadequate sleep by the crewmembers (Caldwell & Caldwell, 2003, p. 67). Good quality sleep of up to eight hours helps to avoid the risk of fatigue in crewmembers. Decline in sleep hours accumulates sleep over time, which eventually results to pilot fatigue. Night flights affect the normal sleep cycle, which reduces the level of pilot alertness and induces fatigue. In addition, daytime sleep by pilots working in night shifts presents a major problem, as it is often shorter than night sleep. Pilots required to report early are also deprived of enough sleep and are thus prone to fatigue during daytime flights. Consecutive flight duties with little or no rest periods lead to sleep debt, which contributes to fatigue.
The workload assigned to the crewmembers also contributes to fatigue during duty hours. Aviation often involves taxing mental work and consequently pilots need sufficient rest to remain alert during subsequent flights. However, heavy workload assigned to crewmembers particularly short-distance flight pilots contributes to fatigue. Short-distance pilots have to perform many take-offs and landings compared to long-distance pilots, who engage in a single long distance flight in 24 hours. Consequently, short-distance pilots are more prone to fatigue than long-distance pilots are. However, the long-distance flight crewmembers also experience mental boredom due to the long continuous flight period and can likewise have fatigue. Long-haul flights pilots have prolonged duty periods, which imply they have to remain alert for a long period and thus easily fatigued.
Psychological and physical factors also contribute to the increased risk of fatigue among crewmembers (Green, Muir, James, Gradwell, & Green, 1996, p.56). Diagnosable sleep disorders such as insomnia and sleep apnea affect the sleeping pattern of an individual contributing to fatigue and decline in the level of alertness among the crew. Psychological factors such as stress or anxiety also impair pilot performance during flights. Medical conditions such as hypoxia characterized by oxygen deficiency affect brain functions leading to fatigue. Illnesses such as anemia and influenza also cause pilot fatigue and affect performance of the crewmembers. Nutrition factors such as low blood sugar and excessive body weight also make the crewmembers more prone to fatigue.
Physiological and behavioral processes are often interrupted by the world time zones affecting the sleep/wake cycle and eating patterns of the crewmembers contributing to fatigue among them. The different time zones disrupt the circadian rhythms by affecting sleep and eating patterns of the crewmembers. A flight crossing a time zone particularly the meridian affects the night and day shifts. Consequently, the sleeping and eating patterns of the crew also have to change affecting their activity and alertness. Flights crossing three time zones have significant effects on the eating and sleeping patterns of the crewmembers. Flights from east to west present a prolonged length of day while flights from west to east experience a shortened length of day.
Crew Duty Limits and Rest Requirements
To promote the safety of air transportation, the crewmembers are assigned specific flight hours and rest period which aims at reducing fatigue of the fight crew during flights particularly fatigue caused by night flights and flights that involve many take-offs and landings (Caldwell, 1997, p. 63). The Federal Aviation Administration (FAA) has developed a maximum flight duty period (FDP) for flight crews based on their performance during flights as recommended by the Aviation Recommendation Committee (ARC). The crew duty limits consider the flight duration, the time of take-off and landing, and the duration of rest. In addition, the FDP is based on the level of fatigue experienced by the crewmembers during flights. Flights that involve multiple legs in a single flight duty period cause more fatigue than duty periods involving a single segment. The crew duty limit spans from the time the crewmember reports for duty and ends on landing and parking of the plane.
The crew duty limits as recommended by the FAA provides that a crewmember should fly a maximum of a thousand hours per year by the airline operator excluding any possible extensions. In a month, a crewmember is allowed a maximum of a hundred hours and a maximum of thirty hours within a week. In addition, the flight crew is allowed a maximum of eight hours flight period in between recommended rest periods. The FAA also has a set of rest rules for crewmembers after the completion of a flight segment and before the next scheduled flight. The crewmembers are allowed a rest period of nine consecutive hours for eight-hour flights and a rest period of ten hours for flights taking more than eight hours but less than nine hours in the 24 hour flight segment. An eleven-hour rest is allowed after a scheduled flight of nine or more hours. In scheduling the rest periods of the crewmembers, the cumulative duty time and the type of tasks are considered. The time of waking up of the crew and the duration between preflight and actual flight are also involved in the determination of maximum limit of the flight period. Extension of the normal duration of duty can occur due to delayed flights
The FAA regulations further restrict an airline operator from assigning a flight crewmember a flight duty time of more than fourteen hours within a twenty-four hour flight segment. The regulations calls for the airline operator to consider the other factors such as the time of travel back and forth the hotel and time for meals and hygiene, in addition to the eight hours sleep period, when awarding the rest periods to the crew. Additionally, the FAA allows the crewmembers suffering from insomnia and other sleep disorders to use dietary supplements to induce sleep so long as the drugs produce no side effect. The FAA provides limits for nighttime operations by the crewmembers. A crewmember is allowed 24 consecutive hours rest period from a seven-day duty period. In addition, the FAA provides for a reduction in the duration of flight duty after many consecutive nighttime duties.
Under the FAA regulations concerning the rest period, flight crewmembers should be given a minimum rest period of thirty consecutive hours in the 168 duty period. In addition, the FAA regulations deter airline operators from assigning crewmembers three consecutive nighttime shifts without giving a rest period to the crewmembers. The FAA regulations also limit the cumulative duty of the crewmembers. The maximum cumulative FDP hours for crewmembers is set at 60 consecutive hours in a 168-hour period and 190 FDP hours for 672-hour flight period. The flight crewmembers are also assigned 75 flight rest hours in the aircraft cabin as deadhead transportation and a 215 period of rest in the aircraft cabin in 672-duty period.
Pilot Fatigue Risk Factors
Long flight periods with reduced rest periods contribute to pilot fatigue, which makes the crewmembers vulnerable to error during flights (Stokes, & Kite, 1994, p. 112). Pilot fatigue affects his/her performance in various ways exposing the passengers to risks during flight or landing. Fatigue reduces the level of alertness and awareness of the flight environment by the pilot hence more prone to error than when not fatigued. In addition, fatigue affects the ability of the pilot to multi-task during flights leading to loss of situational awareness as the pilot becomes preoccupied with one task while neglecting the other tasks. Fatigue also contributes to feelings of carelessness and indifference, which lowers the performance of the pilots during the flights.
Fatigue also affects communication and coordination between the crewmembers. Fatigue leads to reduced communication among the crew, which affects coordination in the performance tasks during flights. The reduced communication affects the crew’s ability to carry out duties effectively. In addition, the reduced communication impairs the crew’s ability to recognize danger and take appropriate preventative measures. Fatigue also leads to the loss of initiative and effort as the tasks overwhelm the crewmembers during flights. It impairs the pilot’s effective judgment and decision-making, which increases the crew’s response time in case of flight difficulties. Fatigued crewmembers often face difficulties in synthesizing important information and making accurate decisions during a flight. Fatigue reduces the visual perception of the crewmembers making bodily coordination difficult.
Conclusion
Pilot fatigue is a common problem affecting the security of flights in the aviation industry. Many factors contribute to increased incidences of fatigue among the crewmembers. Prolonged crew duty coupled with inadequate rest contributes to fatigue that increases the risk of pilot error. Inadequate sleep also contributes to pilot fatigue that impairs the performance of the crewmembers. The FAA regulations aim at promoting rest among crewmembers to improve safety of flights. The regulations provide the maximum flight duty period (FDP) and rest periods for crewmembers, which ensures that the crew get enough rest to prevent fatigue. Thus, crew rest is important in reducing fatigue and increasing aviation safety.
Reference List
Caldwell, J. (1997). Fatigue in the Aviation Environment: An Overview of the Causes And Effects As Well As Recommended Countermeasures. Aviat Space and Environ Med, 68, 630-8.
Caldwell, L., & Caldwell, A. (2003). Fatigue in aviation: A guide to staying awake at the Stick. London: Ashgate Publishing Ltd.
Green, R., Muir, H., James, M., Gradwell, D., & Green, R.L. (1996). Human factors for Pilots. London: Ashgate Publishing Ltd.
Stokes, A., & Kite, K. (1994). Flight stress: Stress, fatigue and performance in aviation. London: Ashgate Publishing Ltd.