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Flight Time Duty Limitation

DGCA - Rule on Flight  Duty Time Limitation


  • Flying loads body and mind with stress and strain. Depending on the type of aircraft and the type of work involved, the strain to body and mind varies.

  • The primary issues governing fatigue and alertness on the flight deck are

    • The amount of sleep/rest put in before subjecting the body and mind to strain; duration of work.

    • Frequency of work.

    • Phase of the sleep/wake cycle ( i.e. circadian rhythm)

    • The nature of flying and the number of crew member involved in the function and their individual competence.

  • In a single day, a flight crew on international sectors, during the course of work may have to cross a number of time zones resulting in additional strain on the body. Moreover, modern jet aircraft flying at very high altitudes at rarified atmosphere also contributes to additional strain and consequent fatigue.

Fundamental Principles

  • The first is that the duty schedule should not prevent the aircrew from ensuring that they are fully rested at the start of each duty period. Particular problems can arise when duty periods encroach on the normal sleep time, or when the normal sleep pattern is disturbed by time zone transitions. In these circumstances the provision of adequate time for rest is essential.
  • The second principle is that the duration and timing of individual duty periods must enable the aircrew to maintain acceptable levels of alertness at all times.

What  Does ICAO Say

  • The maximum flight duty limits for any operating air crew in a period is limited to prevent the stress caused by the lack of sleep and provide the crew with maximum rest, since it is found in the recent studies that the stress has profound negative effect on the human performance, specially when they are exposed to unnatural environment such as flying.

    The ICAO has set the maximum flight timings for an Aircrew to fly in a given period of time, they are as follows-


    8 HOURS - 24 HOURS
    30 HOURS - 1 Week
    270 HOURS - 90 DAYS
    1000 HOURS - 1 Year


    These Flight Duty Time Limitations are applicable for Commanders, flight time flown as a Co-Pilot is counted as 80 % for this rule.

    The flight duty timings are relaxable upto 4 hours of flying in special cases, and not more than 8 hours in any case.

    Note- If a Pilot has operated a flight between 0000 hrs and 0500 hours local time, he cannot operate a flight the next day between 0000 hrs and 0500 hours in any capacity.

DGCA Rules

  • The Flight Time/Flight Duty Time limitations and rest period prescribed in the Civil Aviation Requirement shall be applicable to all operators and flight crew members as per the category of operation.


35 HOURS - 1 Week
1000 HOURS - 1 Year
  • Every crew member shall be given rest, which will be pro-rata twice the flight time subject to minimum of 10 hrs. in any 24 consecutive hrs.

  • A minimum of 24 hrs. rest encompassing period 2000 hrs. to 0600 hrs. shall be provided to all crew members in any 7 consecutive days. This will be in addition to the rest based upon the flying in the last 24 consecutive hours.

  • Whenever flight crew is scheduled on dead heading to operate the flight, this shall count as flight duty.

  • Dead heading done after operating the commercial flight will neither count as duty nor as rest period. In this case if flight duty time and dead heading time exceeds 18 hours, then the following rest period must include a local night.

  • Whenever a flight crew is deputed as safety pilot/observer the period of such duty shall be counted in his Flight Duty Time.

  • Simulator time shall not count towards the flight time.

  • Operator shall not roster any Flight Crew Member to undertake flight for more than two consecutive nights with duty period embracing any period between 0000 to 0500 hours local time.

  • Additional rest of two hour shall be provided for every hour or part thereof of duty period that impinges into the said period of 0000to 0500 hrs.


Preventive Countermeasures

  • A crewmember can use preventive strategies to maximize general alertness, so that when flight operations take their toll, the body can respond with its full potential.

  • By getting sufficient, good quality sleep while at home/off duty prior to a trip, understanding how to plan sleep and naps, and developing good sleep habits, a crewmember maximizes the potential for staying alert on duty.
  • Conversely, starting a trip with a sleep debt, little knowledge of how to plan sleep times, or bad sleep habits, makes a crewmember much more vulnerable to increased sleepiness and performance decrements.

What to do

  •  Crewmembers should get the best possible sleep before trips and start trips fully refreshed and alert to lessen the negative impact of the sleep loss and circadian disruption that may occur during trips.
  • On trips, crewmembers should try to get as least as much sleep during each 24-hour period as they normally do at home.

  • They can schedule off-duty sleep according to personal physiology: feelings of sleepiness indeed indicate the need for sleep, while feelings of alertness or an inability to sleep suggest getting out of bed and resuming normal activity.

  • Scheduled naps can also play an important role in obtaining the sleep necessary to maintain performance.

  • When large blocks of time are unavailable, naps can be used to augment sleep periods at home or on layover.

  • When circumstances permit, naps should be taken when a person feels sleepy. The length of the nap depends on the time available. Short naps should be limited to 45 minutes or less, in order to avoid the sleep inertia associated with awakening out of deep sleep. Longer naps should be at least 2 hours to allow for the completion of a full NREM/REM cycle. It seems that no nap is too short; some sleep is generally better than no sleep.


  • Good sleep habits are beneficial in two ways:
    • one, they foster good sleep at home, which best prepares a pilot for a trip;
    • two, good sleep habits can be used on trips to maximize rest period sleep opportunities.


  • The following recommendations are suggestions based on physiological principles and scientific findings.
    • Develop and follow a pre-sleep routine to promote sleep at bedtime; a warm bath, reading calming material, or just making a ritual of pre-bed preparation can provide the routine.
    • Keep the sleep space and time sacred. Specifically, reserve the bedroom for sleeping and other pleasant activities, and avoid using it for arguments, work, or exercise; also, protect the time set aside for sleep, so that all of that time is actually available for sleep.
    • Make the sleep environment conducive to sleep: maintain dark, quiet, a comfortable temperature, and a comfortable sleep surface.
    • If hungry or thirsty before bed, eat or drink lightly to avoid being kept awake by digestive activity.
    • Avoid alcohol and caffeine prior to sleep. Alcohol can distort sleep architecture, and caffeine can disrupt or preclude sleep.
    • Determine how long before bedtime you need to avoid alcohol and caffeine, and keep in mind that colas, chocolate, and medications (including cold remedies) can contain caffeine.
    • Use physical and/or mental relaxation techniques to promote sleep as necessary. When choosing a technique, remember the following:
      • 1) the technique may require practice before it becomes significantly useful;
      • 2) there are many unsubstantiated claims concerning relaxation techniques, so judge each for yourself.
    • If you can't fall asleep, don't lie awake in bed for longer than 30 minutes; get out of bed and do something that will promote sleep (e.g., read a calming book).
    • On a larger scale, generally healthy diet and exercise habits may also promote good sleep. However, exercise should be avoided too close to bedtime, as it can take time for the body's systems to wind down.

Preventive countermeasures can prepare crewmembers for trips and improve their ability to maximize sleep opportunities on trips. However, preventive strategies alone are not necessarily sufficient to overcome the sleep loss and circadian disruption from long duty periods, time-zone changes, and irregular duty hours.

Operational Countermeasures

Operational countermeasures offer crewmembers in-flight strategies for combating fatigue.

  • Operational countermeasures must allow crewmembers to remain in their cockpit seats.

  • Sleep deprivation studies have shown that physical activity is the best way to combat fatigue.

  • Therefore, stretching and other physical activity (while limited by the seat restriction) can be used to battle sleepiness.

  • Social interaction can also help mask sleepiness; however, the interaction must be active to have an effect. In other words, while a lively conversation may help the situation, listening and nodding will not.

  • Caffeine can be another useful tool when used properly. Strategic caffeine use calls for avoiding caffeine when already alert (e.g., at the start of duty) and, instead, using it when sleepy or 10-15 minutes before a period of predicted vulnerability (e.g., before the 3-5 AM sleepiness window).

  • As reducing unnecessary physical stresses can help, crewmembers should try to maintain good nutrition and hydration.