Augmented Flight Crew Requirements: Duty, Rest, and Part 117

Augmented flight crew requirements are the FAA rules under 14 CFR Part 117 that add a third or fourth pilot to a long-haul flight, set the class of onboard rest facility the aircraft must carry, and control how long the crew can remain on duty. The rules work as a package: crew size, rest facility quality, and report time together determine whether a nonstop route is legally flyable at all.

When a Flight Must Be Augmented

A standard commercial flight runs with two pilots, a pilot in command and a second in command. Once the planned flight duty period exceeds what Table B of Part 117 allows for a two-pilot crew, the airline has to add pilots. A third pilot lets one crew member sleep while two remain at the controls, which is typical on international routes in the eight-to-thirteen-hour range. Flights that need still more time move to a four-pilot crew, which with the best rest facility can stretch the duty period to 19 hours and make routes like New York to Singapore possible.

The choice between three and four pilots is driven by the scheduled duty length and the class of rest facility installed on the aircraft, not by airline preference.¹ Whatever the size of the crew, at least one pilot qualified to relieve the pilot in command during cruise must be at the flight controls at all times.² And no augmented flight may involve more than three flight segments, which keeps augmented operations focused on long-haul point-to-point flying rather than multi-stop routings.

Maximum Duty Period for an Augmented Crew

Table C of Part 117 is the matrix airlines use to work out how long an augmented crew can stay on duty. Three variables feed the calculation: crew size (three or four pilots), rest facility class (1, 2, or 3), and the local time the crew reports for duty.

A three-pilot crew with a Class 1 bunk facility reporting between 0700 and 1259 gets a maximum flight duty period of 17 hours. A four-pilot crew with the same facility and reporting window gets up to 19 hours. Downgrade the facility to a Class 2 seat and those numbers drop to 16.5 and 18 hours. Drop again to a Class 3 seat and the ceilings fall to 15 and 15.5 hours.¹

Report time matters because it tracks circadian rhythm. A crew reporting at midnight faces the worst fatigue window, so Table C assigns shorter duty limits for late-night and early-morning starts than for mid-morning ones. A schedule that would be legal at 0800 may not be legal at 0200 with the same crew and facility. Pre-flight preparation and taxi count toward these limits, so the clock starts well before the wheels leave the ground.

Flight Time Is a Separate Cap

Flight duty period is not the same as flight time. The duty period covers everything from reporting through release. Flight time counts only the hours the aircraft is moving under its own power. Under 14 CFR 117.11, a three-pilot augmented crew is limited to 13 hours of flight time and a four-pilot crew to 17 hours.³ On most ultra-long-haul routes the duty period is the binding limit because it includes ground time on both ends, but delays or long repositioning legs can bring the flight time cap into play instead. Airlines track both simultaneously; exceeding either is a violation.

The Three Classes of Onboard Rest Facility

The quality of sleep a pilot can get aloft directly determines how long the flight can legally last, so Part 117 defines three tiers.

Class 1 is a bunk or flat surface in a compartment separated from both the cockpit and the passenger cabin. It must be temperature-controlled, let the pilot control lighting, and provide isolation from noise. FAA guidance recommends a design target of 70 to 75 dB(A) during cruise.⁴
Class 2 is a seat in the passenger cabin that reclines to a flat or near-flat position, separated from passengers by at least a curtain to reduce light and noise. Less isolation than a bunk, but meaningful physical recovery is still possible.⁴
Class 3 is a seat in the cabin or cockpit that reclines at least 40 degrees with leg and foot support. There is no flat sleeping position, so these seats yield the shortest duty extensions.⁴

The gap between the top and bottom tiers is large in practice. A four-pilot crew with Class 1 bunks can stay on duty up to 19 hours; the same four-pilot crew with only Class 3 seats is capped at 15.5 hours. That 3.5-hour loss can make an ultra-long-haul route impossible without a fuel stop, which is why installing Class 1 crew rest compartments is often the configuration decision that makes a new nonstop route financially viable.¹

In-Flight Rest for the Landing Crew

Beyond the overall duty ceiling, 14 CFR 117.17 sets specific rest minimums for the pilots who will actually land the aircraft. The pilot flying during landing must get at least two consecutive hours of in-flight rest during the second half of the duty period. The pilot performing monitoring duties during landing must get at least 90 consecutive minutes of rest in that same window.²

The rest rotation has to be planned so the landing crew’s sleep blocks fall in the right part of the flight. Too early doesn’t count toward the requirement, and too late doesn’t leave enough time to fully wake up. Airlines build these rotations into flight planning software, and deviations during the flight — turbulence that keeps everyone up, for instance — can create real compliance problems.

Who Can Serve as a Relief Pilot

A relief pilot taking over for the pilot in command during cruise must hold an unrestricted airline transport pilot certificate and the appropriate type rating, and must be qualified as PIC or SIC and specifically qualified as PIC of that aircraft during the en route cruise portion of the flight.⁵ A second in command who is qualified to act as PIC en route does not have to have completed the PIC’s recurrent flight training, operating experience, recent takeoff and landing requirements, line check, or six-month proficiency check.

A relief pilot stepping in for the second in command faces a lower bar. That pilot must be qualified to act as SIC of the aircraft during en route operations and does not need to meet the recent landing experience requirements.⁵

All Part 121 pilots must stay current on proficiency checks. A pilot in command must pass a proficiency check every 12 months in the aircraft type, plus either a proficiency check or approved simulator training every 6 months. Other pilots complete either a proficiency check or line-oriented flight training every 24 months, plus a proficiency check or simulator course every 12 months.⁶ Every required crew member must also have performed at least three takeoffs and landings in the aircraft type, or an approved Level B or higher full flight simulator, within the preceding 90 days.⁷

Rest Before and After the Trip

Under 14 CFR 117.25, every pilot must receive at least 10 consecutive hours of rest immediately before starting any flight duty period, measured from release from the previous duty. That 10-hour block must include a minimum of 8 uninterrupted hours of sleep opportunity.⁸

If a pilot determines that the scheduled rest will not actually provide eight uninterrupted hours of sleep, perhaps because of hotel noise, late transport, or a compressed layover, the pilot must notify the airline and cannot report for duty until a qualifying rest period is provided. The airline can schedule the rest, but the pilot has both the right and the obligation to reject it if it will not deliver real sleep.⁸

Beyond the pre-duty rest, every pilot must receive at least 30 consecutive hours completely free from duty within any rolling 168-hour (7-day) window. That prevents tight turnarounds stacked day after day without a meaningful break.⁸

Deadheading has its own rule. If travel as a passenger to reach the assignment pushes a pilot past the applicable flight duty period limit, the pilot must be given a rest period at least as long as the deadhead travel, and in no case less than the standard 10-hour block with 8 hours of sleep opportunity, before beginning the actual flight duty period.⁸

Acclimation and Time Zone Travel

Part 117 defines “acclimated” as having been in a geographic theater for at least 72 hours, or having been given at least 36 consecutive hours free from duty. A “theater” spans no more than 60 degrees of longitude. When a pilot is not acclimated, the maximum flight duty period from Table C is reduced by 30 minutes, and the applicable limits are figured against the local time of the theater where the pilot was last acclimated rather than the local time at the departure point.²

For pilots who cross more than 60 degrees of longitude during a duty period or series of duty periods and are away from home base for more than 168 consecutive hours, the recovery requirement is substantial: at least 56 consecutive hours of rest on return to home base, and that rest must include three physiological nights based on local time.⁸ The provision effectively prevents an immediate turnaround for a crew that has been on the other side of the world for a week.

Cumulative Flight Time Limits

Single-trip limits prevent exhaustion on any one flight; cumulative caps guard against chronic fatigue over weeks and months. Under 14 CFR 117.23, no pilot may fly more than 100 hours in any 672 consecutive hours (roughly 28 days) or more than 1,000 hours in any 365 consecutive calendar days. These limits apply across all flying a pilot does for any certificate holder or Part 91K program manager, so an airline cannot get around the cap by splitting a pilot’s schedule between two operating certificates.⁹

When Part 117 Doesn’t Apply

The framework above governs scheduled Part 121 operations. On-demand charter flights under Part 135 have their own augmented crew rule at 14 CFR 135.269. A Part 135 three-pilot crew can fly up to 12 hours aloft with a maximum of 18 duty hours; a four-pilot crew can fly up to 16 hours aloft with a maximum of 20 duty hours. Part 135 augmented crews must receive at least 10 consecutive hours of rest before the assignment and at least 12 hours of rest after, and no crew member may exceed 8 hours of flight deck duty in any 24 consecutive hours. If a crew member exceeds the daily flight deck duty limit by more than 60 minutes for reasons beyond anyone’s control, post-duty rest jumps to at least 16 consecutive hours. The certificate holder must provide adequate sleeping facilities on the aircraft for the relief pilot, though Part 135 does not use the same three-class facility system as Part 117.¹⁰

Part 117 also allows a certificate holder to apply for a Fatigue Risk Management System that permits operations beyond Table B or Table C limits. The FRMS must provide at least an equivalent level of safety against fatigue-related accidents as the standard provisions.¹¹ The data collection and monitoring commitments are substantial, and most airlines instead design their schedules to stay within the standard Table C limits.

Who Is Liable When the Rules Are Broken

Both airlines and individual pilots carry legal responsibility. An airline that schedules a crew beyond the applicable limits violates its operating certificate, and a pilot who knowingly accepts an assignment that exceeds duty or flight time limits is independently liable. Under 49 U.S.C. § 46301, civil penalties for regulatory violations can reach six figures per occurrence for individuals. Pilots also face potential certificate action, up to suspension or revocation of the ATP certificate.

Airlines run scheduling software that flags potential Part 117 violations before they happen, but the system is not foolproof. Weather delays, mechanical diversions, and crew swaps can push a legal schedule into illegal territory mid-trip, and both dispatch and the pilots themselves are expected to catch the problem before it becomes a violation.

1
eCFR. 14 CFR Part 117 Table C – Flight Duty Period: Augmented Operations
2
eCFR. 14 CFR 117.17 – Flight Duty Period: Augmented Flightcrew
3
eCFR. 14 CFR 117.11 – Flight Time Limitation
4
eCFR. 14 CFR 117.3 – Definitions
5
eCFR. 14 CFR 121.543 – Flight Crewmembers at Controls
6
eCFR. 14 CFR 121.441 – Proficiency Checks
7
eCFR. 14 CFR 121.439 – Pilot Qualification: Recent Experience
8
eCFR. 14 CFR 117.25 – Rest Period
9
eCFR. 14 CFR 117.23 – Cumulative Limitations
10
eCFR. 14 CFR 135.269 – Flight Time Limitations and Rest Requirements: Unscheduled Three- and Four-Pilot Crews
11
eCFR. 14 CFR 117.7 – Fatigue Risk Management System