Flight, flight duty, and rest times: a comparison between the regulations of different countries

Flight time, flight duty limitations, and rest requirements are compared between the regulations from nine different countries. Twelve factors are identified which played a role in formulating restrictions and criteria. Duration of flight duty and crew augmentation are the factors considered by most countries; time of day, night flight, night sleep, and time zones are the factors least considered. Conformity exists in the necessity to prescribe maximum permissible flight or duty times and minimum rest requirements on a daily basis. Agreement was also observed in grading the standards according to more or less fatiguing conditions. Six out of nine regulations define night hours, but fail to agree upon beginning, end, and duration of night. All countries but one limit flying hours on a monthly and yearly basis, although the limits diverge. A brief outline of the German provisions is presented as an example for a compact and practicable regulation.