FAA Part 117 Explained: Flight Time, Duty Period and Rest

Part 117 of Title 14 of the US Code of Federal Regulations limits how long airline flightcrew members can fly and work, and sets the rest they must get. This guide covers the main ideas. The regulation itself is the authority.

Flight time

Flight time is the time from the moment the aircraft first moves under its own power for flight until it comes to rest at the next point of landing. In everyday terms it is block off to block on. For a two-pilot crew the limit is 8 or 9 hours depending on when the duty period starts. With three pilots it is 13 hours, and with four pilots it is 17 hours.

Flight duty period (FDP)

The FDP starts when the crew member must report for duty and ends when the aircraft is parked after the last flight. Its maximum depends on the report time (in local time for an acclimated crew) and the number of flight segments. For a two-pilot crew reporting between 0700 and 1159 with one or two segments, the limit is 14 hours. A 30 minute reduction applies if the crew is not acclimated.

Augmented crews

Adding pilots lets the FDP be longer, because crew members can rest in flight. The limit then depends on the number of pilots (three or four) and the class of rest facility: Class 1 is the best (a bunk), Class 3 the simplest (a reclining seat). The longest possible FDP is 19 hours, with four pilots and a Class 1 facility. Augmented flights are limited to three flight segments.

Rest

• At least 10 consecutive hours of rest before a flight duty period, with an 8 hour uninterrupted sleep opportunity.
• At least 30 consecutive hours free from duty in any 168 hours.
• Deadhead travel counts as duty, and before a flight it counts toward the FDP, though it is not a flight segment.

What this guide leaves out

Extensions of the FDP, split duty, reserve duty and the cumulative weekly, monthly and yearly limits all have their own rules. Other countries, such as those under EASA, use different tables.

Open the crew duty limits calculator

FAQ

Is block time the same as flight time?

Under Part 117, flight time runs from the first movement under the aircraft's own power until it comes to rest after landing, which in practice is block off to block on.

Do these limits apply outside the United States?

No. They apply to US air carriers. EASA, ICAO member States and others set their own limits.

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For training and reference only. Check official sources before any real flight.