FAA Part 117 Duty Calculator

14 CFR Part 117 sets the flight and duty limits and rest rules for flightcrew members in US Part 121 passenger operations (all-cargo operators may choose to use it). A flight duty period (FDP) starts when you report for duty that includes a flight, positioning or training, and ends when the aircraft is parked after the last flight with no plan to move it again. Its limit depends on when it starts (on the clock you are acclimated to), how many flight segments you fly and how many pilots are on board.

The formula

max FDP = Table B value for the report-time row and segments (2 pilots)
or Table C value for the report-time row, 3 or 4 pilots and rest class
not acclimated: use the last acclimated clock, then − 30 min
max flight time = Table A by report time (2 pilots), 13 h (3 pilots), 17 h (4 pilots)
latest end = report time + max FDP (+ any split duty rest, total ≤ 14 h)
earliest next report = release from duty + 10 h rest

Worked example

You report at 07:00, acclimated, with 2 pilots for 3 segments and 6:00 of planned block. 07:00 is in the 0700–1159 row of Table B, and the 3-segment column gives 13:00. The FDP must end by 07:00 + 13:00 = 20:00. Table A allows 9:00 of flight time for a report between 0500 and 1959, so 6:00 leaves 9:00 − 6:00 = 3:00 to spare. If you are released at 20:00, you need 10:00 of rest, so the earliest next report is 20:00 + 10:00 = 06:00 the next day. If something unforeseen happens before takeoff, the captain and the airline could extend the FDP by up to 2 hours, to 15:00 (ending 22:00).

Table A: max flight time, 2 pilots (117.11)

With 3 pilots the limit is 13:00, with 4 pilots 17:00. If unforeseen circumstances arise after takeoff, flight time may go over to land safely at the destination or alternate; the airline reports it to the FAA within 10 days.

Table B: max FDP, unaugmented (117.13)

Columns are flight segments. Not acclimated: read the row for the local time where you were last acclimated, then take off 30 minutes.

Table C: max FDP, augmented (117.17)

• At most 3 flight segments (117.17(d)).
• The pilot flying the landing needs 2 consecutive hours of in-flight rest in the second half of the FDP; the pilot monitoring needs 90 consecutive minutes (117.17(c)).
• Not acclimated: 30 minutes less, read on the last acclimated clock (117.17(b)).
• Rest facility classes (117.3): Class 1 is a bunk or other flat surface separate from the flight deck and cabin, with control of temperature and light, isolated from noise. Class 2 is a flat or near-flat seat in the cabin, separated from passengers by at least a curtain. Class 3 is a seat in the cabin or flight deck that reclines at least 40 degrees with leg and foot support.

Acclimation (117.3)

A theater is an area where the local times at the FDP’s departure and arrival points differ by no more than 4 hours. You are acclimated once you have been in a theater for 72 hours, or have had at least 36 consecutive hours free from duty there. The window of circadian low (WOCL) is 0200–0559 in the time zone you are acclimated to.

Extensions (117.19)

• Before takeoff, for unforeseen operational circumstances, the pilot in command and the certificate holder may extend the Table B or C limit by up to 2 hours. The same applies to the reserve-plus-FDP limit.
• An extension of more than 30 minutes may happen only once before the next 30-hour rest (117.25(b)).
• A pre-takeoff extension can’t take you over the cumulative FDP limits in 117.23(c). After takeoff, the FDP may run as long as needed to land safely at the next destination or alternate, and that may go over the cumulative limits.
• The airline reports to the FAA within 10 days any FDP that went more than 30 minutes over Table B or C.

Split duty (117.15)

For unaugmented operations only, time spent resting in a suitable accommodation during the FDP doesn’t count as FDP if: the rest is between 22:00 and 05:00 local; it is at least 3 hours from when you reach the accommodation; it was scheduled before the FDP began and you get at least what was scheduled; it isn’t given until the first segment is done; and FDP plus rest is no more than 14 hours. Example: report 17:00 for 2 segments (Table B 12:00) with a 4-hour rest from 23:00. FDP plus rest is capped at 14:00, so the duty must end by 07:00 and you have 10:00 of FDP time.

Reserve (117.21), in short

• Airport or standby reserve: all of it counts as FDP, and the Table B or C limit is based on when you reported for reserve.
• Short-call reserve: the reserve availability period (RAP) is at most 14 hours. Unaugmented, RAP plus FDP may not pass the lesser of the Table B value + 4 hours or 16 hours, counted from the start of the RAP. Augmented, it is the Table C value + 4 hours. You need the 10-hour rest between reserve periods.
• Long-call reserve: if you are called for an FDP that starts before and runs into the WOCL, you must get 12 hours’ notice of the report time. Your operator’s procedures give the details.

Rest (117.25)

• 10 consecutive hours of rest immediately before an FDP or reserve, measured from release from duty, including 8 uninterrupted hours of sleep opportunity. If you can’t get the 8 hours, tell the airline; you can’t report until you have had them.
• 30 consecutive hours free from all duty within the past 168 consecutive hours before any FDP or reserve. This calculator treats a rest that ended more than 138 hours (168 − 30) before report as outside the window.
• After travelling more than 60° of longitude during a trip that keeps you away from home base for more than 168 hours: 56 consecutive hours of rest on return home, including 3 physiological nights’ rest on local time.
• Deadheading that takes you past the Table B FDP needs a rest at least as long as the deadhead, and not less than 10 hours.

Cumulative limits (117.23) and night flying (117.27)

• FDP: 60 hours in any 168 consecutive hours, 190 hours in any 672 consecutive hours.
• Flight time: 100 hours in any 672 consecutive hours, 1,000 hours in any 365 consecutive calendar days.
• No more than 3 consecutive FDPs that infringe on the WOCL, or up to 5 if each gives a rest of at least 2 hours in a suitable accommodation.

Planning and training aid only. Always use your approved flight manual, operator procedures and official charts. Your airline may have an approved fatigue risk management system (117.7) or a collective agreement with stricter limits. Sources: 14 CFR Part 117 (eCFR) and FAA Advisory Circular 117-3, Fitness for Duty (faa.gov).