How many hours can a four-pilot augmented crew fly with a Class 1 rest facility under 14 CFR 117?

Under 14 CFR § 117.17, a four-pilot augmented crew operating with a Class 1 rest facility (a flat bunk in a dedicated crew rest compartment) may fly up to 17 hours of flight time. However, if more than one hour of the flight falls within the Window of Circadian Low — generally 0200 to 0559 at the pilot's acclimated time — the limit is reduced by one hour to 16 hours. These are per-pilot flight time limits, and all cumulative Part 117 limits still apply.

What is the difference between Class 1, Class 2, and Class 3 rest facilities for augmented crew operations?

Class 1 is a dedicated flat bunk isolated from both the cockpit and the passenger cabin, offering the highest sleep quality. Class 2 is a seat that reclines at least 40 degrees with full leg support and a privacy partition separating it from passengers. Class 3 is a seat reclining at least 40 degrees in the main passenger cabin with minimal separation — essentially a first-class or business-class seat. The better the rest facility class, the higher the maximum permitted flight time under § 117.17.

Do the 100-hour and 1,000-hour cumulative flight time limits still apply when flying as part of an augmented crew?

Yes. Augmented crew status under 14 CFR § 117.17 only raises the ceiling for flight time within a single flight duty period; it does not waive the cumulative limits found elsewhere in Part 117. Every pilot on an augmented flight remains subject to the 100-flight-hour limit in any 672 consecutive hours and the 1,000-flight-hour limit in any 365 consecutive calendar days, regardless of how many pilots were on board.

Augmented Crew and Long-Haul Flight Time Limitations

Modern long-haul aviation routinely puts aircraft aloft for 14, 16, or even 18 hours at a stretch. No single pilot can safely operate the flight deck for that entire duration, yet the economics and practicality of non-stop ultra-long routes demand continuous crew coverage. The Federal Aviation Administration addresses this reality through the concept of the augmented crew — carrying more certificated pilots than the minimum required so that each can rest during the flight while the others maintain a legal, rested watch on the flight deck. The governing regulation is 14 CFR Part 117, specifically § 117.17, which sets the flight time limits when an augmented crew is used under a certificate holder operating under Parts 121 or 135 with applicable rest rules.

Understanding augmented crew rules is essential for any Airline Transport Pilot (ATP) candidate or new-hire first officer heading into long-haul operations. The regulations are more nuanced than a single number: permitted flight time depends on the number of pilots carried, the class of the onboard rest facility, and each pilot's acclimated time of day. An examiner expects you to understand why each of those three variables exists, not just memorize a table.

The Mechanics of Augmented Crew Operations

A minimum crew for a typical air carrier airplane is two pilots — a captain and a first officer. An augmented crew adds one or two additional certificated pilots (relief first officers, additional captains, or both) who are qualified for the duty positions they will occupy. Their role is straightforward in concept: while a portion of the crew rests in an onboard rest facility, the remaining pilots legally occupy the required flight deck positions. The crew rotates through rest breaks so that every pilot who takes a control seat has had an opportunity to sleep and is within the flight time limits.

The regulation does not simply permit unlimited flight because extra pilots are present. Instead, § 117.17 caps the maximum flight time for any individual pilot on an augmented operation at values that are higher than the basic two-pilot limits in § 117.11 but still capped — and the cap varies based on two key factors.

The Two Core Variables: Crew Size and Rest Facility Class

Number of Pilots

Part 117 recognizes two augmented configurations: a three-pilot crew and a four-pilot crew. Adding more pilots increases the maximum allowed flight time because each pilot spends a larger fraction of the flight resting. The four-pilot crew therefore receives a higher ceiling than the three-pilot crew.

Rest Facility Class

A pilot's in-flight rest is only restorative if the sleep environment is adequate. Part 117 defines three classes of onboard rest facility, and the class directly determines how much flight time is permitted:

Class 1 rest facility: A bunk or seat that allows a flat sleeping position, isolated from the flight deck and passenger cabin with noise attenuation, temperature control, and adequate ventilation. This is the best environment for quality sleep.
Class 2 rest facility: A seat that reclines at least 40 degrees from vertical and provides leg and foot support, separated from passengers by a minimum privacy partition. Sleep quality is lower than Class 1.
Class 3 rest facility: A seat that reclines at least 40 degrees but provides only the separation afforded by the seat's position — generally, a first-class or business-class seat in the main passenger cabin. This is the lowest-quality rest environment recognized by the rule.

The FAA's logic is straightforward: the better the rest, the closer to full recuperation each pilot achieves, and therefore the more flight time is defensible. Carriers operating older widebody fleets without dedicated crew rest compartments may be limited to Class 2 or Class 3 facilities, which reduces the permitted flight time ceiling compared with aircraft equipped with dedicated crew rest bunks.

The Flight Time Limits Under § 117.17

Section 117.17 establishes a matrix of maximum flight times for augmented operations. Rather than quoting a static table that could become outdated, the key principle to internalize is the interaction between crew size and rest facility class:

For a three-pilot crew with a Class 1 rest facility, the maximum flight time is 13 hours when the entire flight falls within the window of circadian low (WOCL), and up to 13 hours maximum in all cases (WOCL-based reduction applies).
For a three-pilot crew with a Class 2 rest facility, the ceiling drops to a maximum of 12 hours.
For a three-pilot crew with a Class 3 rest facility, the ceiling is 11 hours.
For a four-pilot crew with a Class 1 rest facility, the maximum rises to 17 hours.
For a four-pilot crew with a Class 2 rest facility, the ceiling is 16 hours.
For a four-pilot crew with a Class 3 rest facility, the ceiling is 15 hours.

These figures represent the maximum flight time for any individual pilot on that segment, not just the block time of the aircraft. The aircraft may depart and arrive within the stated limit, but each crew member's individual flight time accrued in the flight deck — the time during which they are on duty at a flight deck position — must also comply with the cumulative limits in §§ 117.23 and 117.25 (the 100-hour/672-hour/1,000-hour annual limits and the rest requirements between duty periods).

Why the WOCL Matters for Augmented Crews

Part 117 is built on fatigue science, and the Window of Circadian Low (WOCL) — generally the hours between 0200 and 0559 local time at the pilot's acclimated location — represents when human alertness is at its lowest point. Flights that overlap significantly with the WOCL impose a greater fatigue burden than daytime operations. Under § 117.17, if more than one hour of the flight falls within the WOCL (as determined by the pilot's acclimated time), the certificate holder must reduce the maximum flight time by one hour from the applicable Class/crew-size limit. This WOCL reduction acknowledges that even a rested pilot emerging from a Class 1 bunk is fighting circadian physiology at 0300.

Cumulative Limits Still Apply

Augmented crew status does not create a carve-out from the cumulative flight time limits. Every pilot — regardless of crew size — remains subject to the rolling limits in Part 117:

No more than 100 flight hours in any 672 consecutive hours (28 days).
No more than 1,000 flight hours in any 365 consecutive calendar days.

A pilot who has been flying a heavy long-haul schedule may reach the 672-hour rolling cap well before the annual 1,000-hour limit becomes the binding constraint. Schedulers at airlines must track both windows simultaneously for each crew member.

Rest Requirement Before and After Augmented Flights

The increased flight time permitted by augmented operations is predicated on a qualified pre-duty rest. Under Part 117, a pilot must receive a minimum rest period before a flight duty period — at least 10 consecutive hours of rest before any FDP, with an opportunity for at least 8 hours of uninterrupted sleep. For augmented operations that push to the maximum flight time ceiling, carriers typically find that a robust pre-departure rest — and planning for recovery time at the destination — is essential to keep pilots within cumulative limits and avoid fatigue-related performance decrements on subsequent duty periods.

Practical Operational Angle

From an airline operations standpoint, choosing the right rest facility class is a planning decision with regulatory consequences. A carrier that bids a 16-hour non-stop route must verify that its aircraft have Class 1 bunk facilities and that the operation will be staffed with a four-pilot crew. If the aircraft only offers Class 2 rest, the maximum permitted flight time for a four-pilot crew drops to 16 hours — potentially still workable — but the WOCL reduction could push that ceiling below what the city-pair actually requires, forcing either a tech stop or an aircraft change. These considerations drive fleet acquisition decisions and route planning at major carriers.

Key Numbers and Rules

Three-pilot / Class 1: max 13 hours (minus 1 hr if >1 hr in WOCL)
Three-pilot / Class 2: max 12 hours
Three-pilot / Class 3: max 11 hours
Four-pilot / Class 1: max 17 hours
Four-pilot / Class 2: max 16 hours
Four-pilot / Class 3: max 15 hours
WOCL overlap (>1 hour): subtract 1 hour from applicable limit
Cumulative: 100 hours / 672 hours and 1,000 hours / 365 days
Minimum rest before any FDP: 10 hours (8 hours uninterrupted sleep opportunity)

Common Test Traps

Confusing aircraft block time with individual pilot flight time. The regulation caps the flight time of each individual crew member, not just the trip's elapsed time. A pilot who operates two segments in the same FDP must count both in their personal total.
Ignoring the WOCL reduction. Many students memorize the base limits but forget that a flight departing in the evening and arriving in the early morning hours may trigger the one-hour WOCL deduction, changing the answer on a scenario question.
Assuming augmented crew eliminates cumulative limits. The 100-hour/672-hour and 1,000-hour/year caps apply universally; augmented status only raises the single-FDP flight time ceiling.
Mixing up rest facility classes. Class 1 is a flat bunk in a dedicated compartment — not a first-class seat. Class 3 is a first-class or business seat in the main cabin. Examiners write distractors that reverse these.
Applying Part 117 to Part 91 operations. Part 117 applies to Part 121 certificate holders (and some Part 135 operators as required). Private or corporate Part 91 flights are not subject to Part 117's augmented crew rules.