Part 135 Rest Requirements and Flight Duty Time Rules

Part 135 rest requirements and flight duty time rules set how long a commuter or on-demand pilot can fly, how long they can be on duty, and how much rest they need before the next assignment. The specific numbers depend on three things: whether the operation is scheduled or unscheduled, how many pilots make up the crew, and whether the flight is a helicopter medical evacuation. The framework lives in 14 CFR Part 135, §§135.263 through 135.271.¹

How Flight Time, Duty, and Rest Are Counted

Flight time begins when the aircraft first moves under its own power for the purpose of flight and ends when it comes to rest after landing.² That’s the number every daily and cumulative cap is measured against.

A rest period is a continuous block during which the crewmember is free of all duties for the certificate holder. If the operator assigns any work during that window — training, paperwork, standby — it isn’t rest.³

Non-local transportation the operator requires and provides to get a crewmember to or from an assignment does not count as rest either.³ A two-hour van ride to a distant airport is duty time. Local commuting the pilot arranges independently is treated differently.

Scheduled Operations Under §135.265

Scheduled Part 135 service uses the tightest limits in the framework.

Daily and Cumulative Flight Time

Single-pilot crews are limited to 8 hours of flight time in any 24 consecutive hours. Two-pilot crews are also limited to 8 hours, measured between required rest periods.⁴ Scheduled operations do not get the 10-hour two-pilot allowance that on-demand operators use.

Cumulative flight time across all commercial flying cannot exceed:⁴

34 hours in any 7 consecutive days
120 hours in any calendar month
1,200 hours in any calendar year

Minimum Rest Before a Duty Period

Required rest scales with how much flight time is scheduled in the upcoming 24 hours:⁴

9 consecutive hours if less than 8 hours of flight time is scheduled
10 consecutive hours if 8 or more but less than 9 hours are scheduled
11 consecutive hours if 9 or more hours are scheduled

Each of those can be reduced, but the compensatory rest that follows must be longer than the original requirement:⁴

A 9-hour rest can drop to 8 hours, followed by at least 10 hours of compensatory rest beginning within 24 hours
A 10-hour rest can drop to 8 hours, followed by at least 11 hours of compensatory rest beginning within 24 hours
An 11-hour rest can drop to 9 hours, followed by at least 12 hours of compensatory rest beginning within 24 hours

Every scheduled crewmember also gets at least 24 consecutive hours free of all duty in any 7 consecutive days.⁴ The weekly reset cannot be waived.

Unscheduled One- and Two-Pilot Operations Under §135.267

Charter and other on-demand flights work differently. The daily numbers are a little more generous for two-pilot crews, and rest is measured with a look-back rather than a straight pre-duty count.

Daily Flight Time and the 14-Hour Duty Period

In any 24 consecutive hours, maximum flight time is 8 hours single-pilot or 10 hours two-pilot.⁵

A separate provision lets the duty period stretch to 14 hours, but only if three conditions all hold: the 14-hour duty is immediately preceded and followed by at least 10 consecutive hours of rest; the combined duty and rest equal 24 hours; and flight time within the duty period still respects the 8-hour or 10-hour cap.⁵ The 14-hour figure is a conditional exception, not a default.

Cumulative Flight Time

Across all commercial flying, unscheduled one- and two-pilot crews are capped at:⁵

500 hours in any calendar quarter
800 hours in any two consecutive calendar quarters
1,400 hours in any calendar year

The two-consecutive-quarter cap is the one most easily missed. A pilot can stay under 500 hours in each of two quarters and still break the 800-hour limit if the hours cluster at the boundary between them.

The Look-Back Rest Rule

Every unscheduled assignment must provide at least 10 consecutive hours of rest within the 24-hour period preceding the planned completion time of the assignment.⁵ The trigger is when the flight is planned to end, not when it starts. That means rest history has to be verified before every assignment, including late-notice flights.

Graduated Rest When the Limit Is Exceeded

When circumstances beyond the operator’s and the crewmember’s control push flight time past the daily cap, post-flight rest scales with the overage:⁵

30 minutes or less over: at least 11 consecutive hours of rest
More than 30 but no more than 60 minutes over: at least 12 consecutive hours
More than 60 minutes over: at least 16 consecutive hours

The extended rest has to be completed before the next assignment. The rule only applies to genuine uncontrollable overages. Accepting an assignment that was obviously going to run long doesn’t qualify.

Three- and Four-Pilot Crews Under §135.269

Augmented crews get more duty and aloft time in exchange for carrying relief pilots and providing onboard sleeping facilities.⁶ The key numbers:

Flight deck duty: no more than 8 hours in any 24 consecutive hours
Duty period: up to 18 hours with three pilots, 20 hours with four
Time aloft: up to 12 hours with three pilots, 16 hours with four
Pre-assignment rest: at least 10 consecutive hours
Post-assignment rest: at least 12 consecutive hours

Cumulative limits match the one- and two-pilot on-demand caps: 500 hours per quarter, 800 hours per two consecutive quarters, 1,400 hours per year. If the daily flight deck duty limit is exceeded by more than 60 minutes due to uncontrollable circumstances, 16 hours of rest is required.⁶

Augmented crews also get a quarterly guarantee of at least 13 rest periods of 24 consecutive hours or more per calendar quarter.⁶

Helicopter EMS Assignments Under §135.271

Helicopter hospital emergency medical evacuation service (HEMES) has its own rules.⁷ A HEMES crewmember must have at least 10 consecutive hours of rest immediately before reporting to the hospital for flight availability. On assignment, the pilot cannot fly more than 8 hours in any 24-hour period and must receive at least 8 consecutive hours of rest during each 24-hour block. The full HEMES assignment at one hospital cannot exceed 72 consecutive hours, and the operator cannot assign any other duties during that time.

Post-assignment rest depends on how long the crewmember was on station:⁷

Assignment under 48 hours: at least 12 consecutive hours of rest
Assignment over 48 hours: at least 16 consecutive hours of rest

If a medical flight takes the pilot past the 8-hour daily flight cap, the crewmember must be relieved from the HEMES assignment immediately after that flight and given the applicable post-assignment rest. HEMES crewmembers share the augmented-crew guarantee: 13 rest periods of at least 24 consecutive hours per calendar quarter.⁷

Flying for More Than One Operator

The cumulative caps in §135.265 and §135.267 apply to all commercial flying, not just time logged for one certificate holder.⁴ A pilot who logs 90 hours for one scheduled Part 135 operator in a calendar month and then takes 35 hours of Part 91 commercial work is over the 120-hour cap, and both the pilot and the certificate holder are in violation.

The obligation runs both ways. A certificate holder cannot schedule a crewmember, and a crewmember cannot accept an assignment, if the combined total across all commercial flying would break any applicable limit.⁵ Pilots freelancing across operators have to report cumulative time honestly, and operators have to ask.

Emergency Deviations

In an emergency involving the safety of persons or property, the certificate holder and the pilot in command may deviate from Part 135 rules to the extent needed to handle the emergency.⁸ This is narrow. Genuine emergencies qualify; operational inconveniences do not, and the FAA can review the decision after the fact.

What Violations Cost

For pilots, certificate suspensions for flight and duty time violations run from 20 to 270 days depending on culpability:⁹

Low range (careless, first offense): 20 to 60 days
Moderate range: 60 to 120 days
High range: 90 to 150 days
Maximum range: 150 to 270 days

Revocation is generally reserved for cases where the pilot lacks the qualifications to hold the certificate at all, such as intentional falsification or drug and alcohol violations. A single flight-time overage typically will not trigger revocation on its own.⁹

For operators, the FAA can impose civil penalties. As of 2025, the maximum civil penalty for a Part 135 violation is $75,000 per violation for an operator and $1,875 per violation for an individual or small business.¹⁰ Those caps apply per violation, so a pattern of understaffed scheduling adds up fast.

What Operators Have to Keep on File

An operator has to keep an individual record for every pilot used in Part 135 operations. Each record must show the pilot’s full name, certificate type and number, ratings held, current duty assignment and its start date, and enough flight time detail to verify compliance with every applicable limit.¹¹

Pilot records must be retained for at least 12 months, held at the principal business office or another FAA-approved location, and available for inspection on request.¹¹ Clean, current records are the operator’s first line of defense if the FAA comes asking.

1
eCFR. 14 CFR Part 135 – Operating Requirements: Commuter and On Demand Operations
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eCFR. 14 CFR 1.1 – General Definitions
3
eCFR. 14 CFR 135.263 – Flight Time Limitations and Rest Requirements: All Certificate Holders
4
eCFR. 14 CFR 135.265 – Flight Time Limitations and Rest Requirements: Scheduled Operations
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eCFR. 14 CFR 135.267 – Flight Time Limitations and Rest Requirements: Unscheduled One- and Two-Pilot Crews
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eCFR. 14 CFR 135.269 – Flight Time Limitations and Rest Requirements: Unscheduled Three- and Four-Pilot Crews
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eCFR. 14 CFR 135.271 – Helicopter Hospital Emergency Medical Evacuation Service
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eCFR. 14 CFR 135.19 – Emergency Operations
9
Federal Aviation Administration. FAA Compliance and Enforcement Program (FAA Order 2150.3C)
10
Federal Register. Revisions to Civil Penalty Amounts, 2025
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eCFR. 14 CFR 135.63 – Recordkeeping Requirements