Flight Time Limitations - 11 October 09 - 13:57 “Summary of Flight Time Limitations” International Civil Aviation Organization Annex 6, Operation of aircraft prescribes the relevant definitions concerning the flight time limitations. It also gives guidance on the establishments of the limitations. In establishing limitations concerning the flight time limitations the size of the crew, whether the aircraft is equipped with a horizontal rest facility, traffic density, navigational and communication facilities, the biological rhythms, number of flight cycles, aircraft performance and weather conditions are taken into account. The European Union states that the maximum daily flight duty period is 13 hours. There are several exceptions to this rule. The minimum amount of rest at a pilot’s home base is at least 12 hours or the duration of the precious duty period, whichever is the greatest. Same rule counts outside the pilots home base only the minimum rest period is at least ten hours. The national legislation specifies the 18 ‘white spots’ remained from the European Union. The extension on the maximum daily flight duty period which is given when the aircraft is equipped with a rest facility is one of them.
By Hellen Caspers, Aviation Engineering, Amsterdam University of Applied Sciences
Human factors are the most restrictive aspect concerning the flight time limitations. Over 20% of the aviation accidents are related to fatigue. The most dangerous type of fatigue in the aviation industry is chronic fatigue. A flight exists out of different flight phases with flight phase specific workloads. During take-off and approach the workload of the airline pilots increases compared to the other flight phases. The biological rhythms of a human person are hard to adjust when traveling through several time zones. In general it takes one day per one hour time difference to adjust to the daily rhythm at destination. A good night of sleep can provide a maximum of eight sleep credits. One sleep credit is equal to two hours of activity. Meaning that a person is able to have an activity period of maximum 16 hours before he/she is creating a sleep deficit.
The opinions and experiences of the airline pilots are obtained through an online survey. The survey is divided into three subjects; general questions, human factor questions and questions about the flight time limitations. The general questions give an indication of how experienced a pilot is and some of the answers can be are linked to the results of other questions in the survey. The human factor questions give a clear view about the sleeping patterns of the pilots. The questions about the flight time limitations indicate that the rest facilities are not proper aids to extend a flight duty period on. Also almost half the pilots are having a hard time falling asleep due to the irregular working hours. Pilots rather work the whole working period early flights or late flights than a combination of those two. The minimum duration of the rest period which is taken outside the pilot’s home base is at least ten hours. Pilots find this duration too short.
There is never going to be legislation and job descriptions concerning the FTL in which both the airline companies as well as the airline pilots are 100% satisfied with. There are some improvements which should be made according to this research. The rest facilities other than the horizontal rest facility are not proper aid the extend a flight duty period. The minimum amount of ten hours rest which a pilot takes outside his home base should at least be lengthened to twelve hours. The airline companies should try to plan the airline pilots on early flights or on late flights during a weekly working period instead of combining early and late flights in one working period. A program, in which the airline pilots can give their preferences for flights and days off, should increase the percentage satisfied with the amount of requests taken into account in their flight duty schedules.