FAA Part 117 flight duty limits explained

By Zulu Calculator · Updated 12 October 2026 · Aviation

FAA Part 117 limits how long a US airline pilot can be on duty and at the controls. Your maximum flight duty period (FDP) for a two-pilot crew comes from Table B: between 9 and 14 hours, set by your report time and the number of flight segments. Your flight time limit comes from Table A (8 or 9 hours), and augmented crews of 3 or 4 pilots use Table C (13 to 19 hours of FDP). Before every FDP you need at least 10 hours of rest.

This guide explains each table, acclimatisation, rest, the cumulative limits and extensions in plain English, with worked examples. To check a real pairing, use the FAA Part 117 calculator.

Who does Part 117 apply to?

• Flightcrew members in Part 121 passenger operations in the US (14 CFR Part 117).
• All-cargo operators may choose to use Part 117. If yours has not, ask which rules apply; this guide covers Part 117 only.
• Your airline may have an approved fatigue risk management system (117.7) or a collective agreement with stricter limits. Those win over the plain numbers here.

Flying outside the US under European rules? The EASA flight duty period calculator works out the EASA FTL limits instead.

Key words in Part 117

• 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.
• Flight segment: one takeoff and landing. Deadhead legs count as duty, not as segments.
• Theater: an area where the local times at the FDP's departure and arrival points differ by no more than 4 hours.
• Acclimated: you have been in a theater for 72 hours, or have had at least 36 consecutive hours free from duty there (117.3).
• Window of circadian low (WOCL): 0200–0559 in the time zone you are acclimated to.

Table A: how many hours can you fly? (117.11)

With 3 pilots the limit is 13 hours; with 4 pilots it is 17 hours. These are limits on scheduled flight time. If unforeseen circumstances arise after takeoff, flight time may go over to land safely at the destination or alternate, and the airline reports it to the FAA within 10 days. Logbooks often use tenths of an hour; the decimal flight time calculator converts block times so you can add them up against these limits.

Table B: what is the maximum FDP? (117.13)

Find the row for your scheduled report time (on the clock you are acclimated to), then the column for the number of flight segments. Values are in hours.

max FDP (2 pilots) = Table B value for your report-time row and number of segments
not acclimated: read the row on your last acclimated clock, then take off 30 minutes
latest end of FDP = report time + max FDP

Table C: augmented crews (117.17)

With 3 or 4 pilots, the limit depends on the report time and the class of on-board rest facility. Values are in hours.

• 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.
• An augmented FDP may have no more than 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.

These tables match the text of 14 CFR 117.11, 117.13 and 117.17 on the eCFR, checked on 12 October 2026.

Worked examples

Example 1: an early four-leg day

You report at 05:30, acclimated, with 2 pilots for 4 segments and 7:30 of planned block. The 0500–0559 row of Table B, 4-segment column, gives 12 hours, so the FDP must end by 05:30 + 12:00 = 17:30. Table A allows 9 hours of flight time for a 0500–1959 report, so you have 1:30 to spare. The first 30 minutes of the duty (05:30–05:59) fall inside the WOCL. Released at 17:30, your earliest next report after 10 hours of rest is 03:30 the next day.

Example 2: a long-haul night departure with 4 pilots

You report at 22:00 for one segment with 4 pilots and a class 1 bunk. Table C gives 17 hours (the 1700–2359 row), so the FDP can run to 15:00 the next day. Flight time for a 4-pilot crew is limited to 17 hours, so a 15-hour flight fits. The pilot flying the landing needs 2 consecutive hours in the bunk in the second half of the FDP. With a class 3 seat instead, the limit would drop to 13.5 hours.

Example 3: not acclimated after a long trip east

You flew from your home base to a city 8 hours ahead and have been there 30 hours, with no 36-hour break. You are not acclimated. You report at 14:00 local for 2 segments. On your home clock that is 14:00 − 8:00 = 06:00, so read the 0600–0659 row: 13 hours for 2 segments. Take off 30 minutes: your limit is 12:30, and the FDP must end by 02:30 local. Read on the local clock instead, 14:00 would wrongly give 12 hours.

Example 4: the cumulative limit bites

You report at 07:00 for 2 segments (Table B: 14 hours), but you have already done 52 hours of FDP in the past 168 hours. A 14-hour FDP would take you to 66 hours, over the 60-hour limit in 117.23. The longest FDP you can be scheduled for is 60 − 52 = 8 hours, and there is no room for a pre-takeoff extension either.

How much rest do pilots need under Part 117? (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.
• After travelling more than 60° of longitude on 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.

Crossing many time zones on days off? The jet lag planner builds a sleep and light plan for the new zone.

Cumulative limits (117.23)

These are rolling windows, not calendar weeks or months. Count every hour in the last 168 or 672 hours, including the FDP you are planning, not from Monday or the 1st.

Night flying (117.27): no more than 3 consecutive FDPs that infringe on the WOCL, or up to 5 if each one gives a rest of at least 2 hours in a suitable accommodation.

Extensions, split duty and reserve

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. An extension of more than 30 minutes may happen only once before the next 30-hour rest, and it can't take you over the cumulative FDP limits. After takeoff, the FDP may run as long as needed to land safely at the next destination or alternate. The airline reports to the FAA within 10 days any FDP that went more than 30 minutes over Table B or C. An extension is for the day of operation; a schedule built on it is not legal.

Split duty (117.15)

For unaugmented crews only, rest in a suitable accommodation during the FDP doesn't count as FDP if it falls between 22:00 and 05:00 local, lasts at least 3 hours, was scheduled before the FDP began, comes after the first segment, and FDP plus rest is no more than 14 hours. For example, report at 17:00 for 2 segments (Table B: 12 hours) with a 4-hour rest from 23:00: the 14-hour cap means the duty must end by 07:00, leaving 10 hours of FDP.

Reserve (117.21)

Airport or standby reserve counts in full as FDP. On short-call reserve, the reserve availability period is at most 14 hours, and reserve plus FDP may not pass the lesser of the Table B value + 4 hours or 16 hours (augmented: Table C value + 4 hours). On long-call reserve, an FDP that starts before and runs into the WOCL needs 12 hours' notice of the report time.

Common mistakes

• Reading Table B on local time when you are not acclimated. Use the clock where you were last acclimated, then take off 30 minutes.
• Counting deadhead legs as segments. They are duty but not flight segments.
• Mixing up FDP and flight time. Table B limits the whole duty from report; Table A limits time at the controls.
• Measuring rest from block-in. The 10 hours start at release from duty, after any post-flight duties.
• Using calendar weeks for the 60-hour limit. It is any 168 consecutive hours.
• Planning a 4-segment augmented day. Table C allows at most 3 segments.

What if you think a schedule breaks Part 117?

1. Check the pairing with the Part 117 calculator and note the rule section it flags.
2. Raise it with crew scheduling and your chief pilot before the duty, in writing if you can.
3. If you are too tired to fly safely, say so and follow your airline's fitness-for-duty and fatigue reporting procedure (FAA Advisory Circular 117-3 covers fitness for duty).
4. If it is not resolved, go to your union safety or scheduling committee, your airline's safety reporting system, or the FAA.

Sources: 14 CFR Part 117 (eCFR) and FAA Advisory Circular 117-3, Fitness for Duty (faa.gov). Always fly to your approved operator procedures.

This guide explains the rules in plain English for planning. It is not legal, financial or flight-operations advice; check your contract, the official source linked above, your employer or your operator.