FAQ – Daily Flight Duty Time Limitations – Split Duty.

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FAQ – Flight Duty Time Extensions FAQ – Consecutive Nighttime Operations.

One of the problems that this rule was intended to address is the performance degradation experienced by flightcrew members who conduct overnight FDPs and perform their duties during the WOCL after receiving less-restful daytime sleep.

This rule addresses this problem by incentivizing fatigue mitigation measures.

One of these fatigue mitigation measures is split duty which is based on the premise that there are times during an unaugmented nighttime FDP when a certificate holder could reasonably provide a flightcrew member with an opportunity for rest.

This rest opportunity (opportunity to sleep) would allow a flightcrew member to get some sleep during the night. The nighttime sleep could be used to mitigate the performance degradation created by working through the WOCL.

Q45) Is the usage of Split Duty Limitations required?

A45) No, 117.15 is an optional component to the regulations, however, the benefits associated with this section, may only be used only if the entire section is complied with, additionally, 117.15, may only be applied to un-augmented operations.

Q46) What conditions must be satisfied to allow for the benefits of Split Duty?

A46) The entire section 117.15 (a)(b)(c)(d)(e) and (f)

Q47) What conditions satisfy a rest opportunity?

A47) The rest opportunity must be provided between the hours 22:00 and 05:00 (local time), it must be at least 3 hours in duration in a suitable accommodation, it must have been scheduled before the crewmember reports for the FDP and it may not be reduced and must be after the first flight segment has been completed. 117.15 (a)(b)(c)(d) and (e) refer.

Q48) If a crewmember is scheduled 5 hours in a suitable accommodation, can that time be reduced to 3 hours?

A48) Yes, as long as the crewmember was notified at time of report that only 3 hours would be applied to the limitation of 117.15(f)

Q49) If the time spent in a suitable accommodation is not part of a FDP, do additional limitations exist for a Split Duty apart from those in 117.15?

A49) Yes, the FDP less the time in a suitable accommodation, must adhere the limitations of 117.13 as well as the limitations for extended FDP 117.19(a) and (b). The time in a suitable accommodation does not include the time to travel to/from the accommodation.

Q50) Is there a maximum time a crewmember may be on a Split Duty?

A50) Yes, the Combined FDP time and time spent in a suitable accommodation, must not exceed 14:00, 117.15(f) refers.

Q51) Can a Split Duty be extended before takeoff beyond the limitations in 117.15(f)?

A51) No, the Combined FDP time and time spent in a suitable accommodation, must not exceed 14:00, 117.15(f) refers. However, any extensions beyond the 14:00 limitation after takeoff must comply with 117.19(b).

117.15  Flight duty period: Split duty.

For an unaugmented operation only, if a flightcrew member is provided with a rest opportunity (an opportunity to sleep) in a suitable accommodation during his or her flight duty period, the time that the flightcrew member spends in the suitable accommodation is not part of that flightcrew member’s flight duty period if all of the following conditions are met:

(a)   The rest opportunity is provided between the hours of 22:00 and 05:00 local time.

(b)   The time spent in the suitable accommodation is at least 3 hours, measured from the time that the flightcrew member reaches the suitable accommodation.

(c)   The rest opportunity is scheduled before the beginning of the flight duty period in which that rest opportunity is taken.

(d)   The rest opportunity that the flightcrew member is actually provided may not be less than the rest opportunity that was scheduled.

(e)   The rest opportunity is not provided until the first segment of the flight duty period has been completed.

(f)    The combined time of the flight duty period and the rest opportunity provided in this section does not exceed 14 hours.

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FAQ – Flight Duty Time Extensions FAQ – Consecutive nighttime operations.

3 thoughts on “FAQ – Daily Flight Duty Time Limitations – Split Duty.

  1. When on split duty when does FDP end and begin again for the following example?

    Show Time: 1930; FDP starts
    Leg 1: 2030-2139
    Leg 2: 2204-2243
    Typically arrive at accommodations: 2315
    Scheduled Rest: 0100-0400
    Show Time: 0525
    Leg 3: 0625-0704
    Leg 4: 0729-0838; FDP ends

    Does FDP stop when we arrive on the 2nd leg, at the accommodation, or at 0100? Does it start at 0400, or the 2nd show time at 0525?

    All times are local.



    1. Looking at the situation you have presented:
      FDP starts at 19:30 and Ends at 08:38 for a Duration of 13:08 – FAR 117.3 Definitions.

      Split Duty must fulfill all the conditions in 117.15.


      Split Duty Break is 01:00 – 04:00 3:00 – the minimum break is 3:00, had the airline scheduled the break from 00:30 to 04:30 (4:00), the actual break may not be reduced below 4:00.
      The Break, must be in the Suitable Accommodation between the hours 22:00 to 05:00 local time at the location where the break is given.
      A break out of those hours is considered as FDP.

      The FDP applied to a Split Duty, is capped at 14:00, the cap may not be exceeded.
      The FDP must also be able to comply with the FDP limits in 117.11.
      Under Split FDP, the applied FDP is equal to the FDP 13:08 less the break 3:00, 10:08 this value is compared to the Table B limit (4 sectors at 19:30) 11:00

      Another way too view a split duty is FDP 1 – Break – FDP 2, so in your situation:
      FDP 1 – 19:30 to 01:00 – 05:30 – 2 Sectors
      Break – 01:00 to 04:00 – 03:00
      FDP 2 – 04:00 to 08:38 – 04:38 – 2 Sectors
      Combined FDP and Break is 13:08 with a 14:00 limit
      Total FDP 10:08 with a Table Limit 11:00.

      To ensure that the Actual Break given meets Another way to view this if we consider the travel times to from the suitable accommodation.
      If we assume that travel is 0:30, then the Actual Break starts at 23:13 and ends at 04:55, for a duration of 5:42.
      FDP 1 – 19:30 to 23:13 – 03:43 – 2 Sectors
      Actual Break – 23:13 to 04:55 – 05:42
      FDP 2 – 04:55 to 08:38 – 03:43 – 2 Sectors
      Combined FDP and Break is 13:08 with a 14:00 limit, so the latest the last flight may be expected to arrive before takeoff is 09:30.
      Total FDP 07:08 with a Table Limit 11:00. The Actual Break is greater than the 3:00 scheduled break.

      Lastly, the entire 13:08 is to be applied towards the cumulative limits in 117.23(c).



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