Part 135 Duty Time Limits: 135.267 Flight, Duty and Rest Rules

Part 135 duty time limits for on-demand (unscheduled) one- and two-pilot crews are set by 14 CFR 135.267. A pilot may log no more than 8 hours of flight time in any 24 consecutive hours on a one-pilot crew, or 10 hours on a two-pilot crew, counting all commercial flying. Each assignment must leave at least 10 consecutive hours of rest in the 24 hours before its planned completion. Under the alternative in paragraph (c), the same flight time caps apply within a regularly assigned duty period of no more than 14 hours with 10 hours of rest on each side. On top of that come flight time caps of 500 hours a calendar quarter, 800 in two consecutive quarters and 1,400 a calendar year and at least 13 rest periods of 24 consecutive hours in every calendar quarter.

Which Part 135 duty rule applies to you?

Section 135.261 sorts operations into the rules:

“Scheduled” is narrow: 135.261(b)(1) requires a published schedule of “at least five round trips per week on at least one route between two or more points,” openly advertised or available to the public. An on-demand charter operator doesn’t meet that, so 135.267 governs its one- and two-pilot crews. If you’re still deciding which part your flying belongs under at all, start with Part 91 vs Part 135 vs Part 91K.

The general rules in 135.263

Section 135.263 applies to everyone:

1. Flight time may be assigned and accepted “only when the applicable requirements of §§ 135.263 through 135.271 are met” (paragraph (a)). In its 2011 letter to Jimenez, the FAA said that when an operator assigns a flight it shouldn’t and the pilot accepts, neither is in compliance.
2. “No certificate holder may assign any flight crewmember to any duty with the certificate holder during any required rest period” (paragraph (b)).
3. Required transportation “not local in character,” to the airport where a crewmember will fly or home after being relieved, “is not considered part of a rest period” (paragraph (c)).
4. A crewmember isn’t over the limits if the flights “normally terminate within the limitations” but, because of circumstances beyond anyone’s control such as weather, “are not at the time of departure expected to reach their destination within the planned flight time” (paragraph (d)).

What are the flight time limits under 135.267?

Paragraph (a) sets the long-term caps. No assignment may be made or accepted if the crewmember’s “total flight time in all commercial flying will exceed”:

Paragraph (b) sets the daily cap. “During any 24 consecutive hours the total flight time of the assigned flight when added to any other commercial flying by that flight crewmember may not exceed” 8 hours for a one-pilot crew, or 10 hours for a crew of two pilots “qualified under this part for the operation being conducted.”

Flight time here is the 14 CFR 1.1 definition: pilot time that starts “when an aircraft moves under its own power for the purpose of flight and ends when the aircraft comes to rest after landing.” That’s block time, taxi included.

“Any 24 consecutive hours” is a rolling window, not a calendar day. “All commercial flying” means flight time a pilot logs for another commercial employer counts too.

Track (b) and track (c): the two ways to schedule

The FAA describes 135.267 as offering “two methods” of scheduling: the “moving 24 consecutive hour” limits of paragraph (b), or the regularly assigned duty period of paragraph (c) (letter to Jimenez, June 9, 2011).

Track (b): the moving 24 hours

Under (b), the flight time cap applies to every 24-hour window you can draw. Paragraph (d) adds the rest rule: “Each assignment under paragraph (b) of this section must provide for at least 10 consecutive hours of rest during the 24-hour period that precedes the planned completion time of the assignment.”

Track (b) has no stated duty limit, and the FAA has said so more than once. But the 10-hour look-back limits duty in practice. If 10 consecutive hours of the 24 before the planned completion must be rest, the remainder of that window, at most 14 hours, is all the duty there can be. The FAA’s answer to an operator in a letter to Kalantari (Premier Air, request dated August 5, 2018) put it this way: “While § 135.267(b) does not contain duty time limits, duty time is nonetheless limited by the requirement in § 135.267(d).”

Under (b), the Jimenez letter says, “operators may use a duty or on-call schedule that requires pilots to respond and report for duty at varying times from day to day,” as long as each schedule meets (d).

Track (c): the regularly assigned duty period

Paragraph (c) lets flight time “exceed the flight time limits of paragraph (b)” if it “occurs during a regularly assigned duty period of no more than 14 hours” and:

1. The duty period “is immediately preceded by and followed by a required rest period of at least 10 consecutive hours of rest”;
2. Flight time assigned in the period, “when added to any other commercial flying,” does not exceed 8 hours for one pilot or 10 hours for two pilots; and
3. “The combined duty and rest periods equal 24 hours.”

The caps are the same; under (c) they’re counted within the duty period instead of across any rolling 24 hours.

“Regularly assigned” means fixed. In the Jimenez letter, the FAA said that to use (c), “the start and end time of the 14 hour duty day should not vary from day to day.” Track (c) suits shift work, such as 0700 to 2100 every day of a rotation; a trip starting at 0900 one day and 0630 the next is a track (b) trip.

What counts as rest under Part 135?

The regulation doesn’t define rest. The FAA’s Office of the Chief Counsel has, consistently. Rest “must be (1) continuous, (2) determined prospectively (i.e., known in advance), and (3) free from all restraint by the certificate holder, including freedom from work or the present responsibility for work should the occasion arise” (Kalantari letter, quoting earlier ones).

That test settles most arguments about on-call pilots:

• Standby is duty. “The FAA has long-held that on-call standby is not rest, and if the flightcrew member has an obligation to report for a flight assignment if contacted, the on-call standby is considered duty” (Kalantari). Duty starts when the standby shift starts, not when the phone rings.
• Rest can’t be found after the fact. In a letter to Orellana (October 6, 2015), a pilot rested 2200 to 0800, then sat on call until a 0200 call for a 0400 takeoff. That “rolling rest” fails 135.267: “rest must be prospective (i.e., determined in advance),” and the on-call hours weren’t rest.
• A 24-hour on-call schedule fails (d). “A 24-hour on-call schedule cannot meet the rest requirements of 135.267(d) because, in such a situation, the rest period is not known in advance nor is it free from all restraint” (letter to Kleiner, 2016).
• The one phone call. An operator “cannot require a flight crewmember to answer a phone call during a rest period,” but the FAA’s “one phone call” policy lets the operator initiate one call that the crewmember may choose to answer without breaking rest (letter to Moody, February 3, 2015, quoting its 2012 letter to Kidd). The Kleiner letter adds that an obligation to return calls is itself duty. The Moody letter also says a Chief Counsel interpretation “is binding on the FSDO.”

What happens when weather pushes a crew over?

Section 135.263(d) means a flight that was expected to finish within the limits at departure isn’t an over-assignment because weather or something else outside anyone’s control stretched it. The crew still owes extra rest. Under 135.267(e), a crewmember who exceeded the daily flight time limits “because of circumstances beyond the control of the certificate holder or flight crewmember” must have, before the next flight assignment:

The 13 rest periods per quarter

Section 135.267(f): “The certificate holder must provide each flight crewmember at least 13 rest periods of at least 24 consecutive hours each in each calendar quarter.”

The FAA’s letter to Schwarz (November 16, 2007) says these are the same kind of rest as daily rest: continuous, known in advance and free from all restraint, so a day a pilot happened not to be called doesn’t count. Quoting its 2005 letter to Summit Jet, it says the operator must show “that each flight crewmember actually receives at least 13 rest periods in every quarter,” on-demand charter included.

Count them per pilot and plan them early: a pilot who reaches mid-March with 9 can still get 13.

Scheduled operations under 135.265, in brief

If you fly scheduled passenger operations, or elected 135.265 in your operations specifications, the limits are tighter on flight time and more detailed on rest (135.265):

• Flight time: 1,200 hours in a calendar year, 120 in a calendar month, 34 in any 7 consecutive days, 8 in any 24 consecutive hours for one pilot, and 8 between required rest periods for two pilots.
• Rest scaled to flight time: in the 24 hours before the scheduled completion of any segment, 9 consecutive hours of rest for under 8 hours of scheduled flight time, 10 for 8 to under 9, and 11 for 9 or more.
• Reduced rest: down to 8, 8 and 9 hours, if a 10, 11 or 12-hour rest begins within 24 hours after the reduced rest began (paragraph (c)).
• A day off a week: each flight crewmember in scheduled air transportation is relieved of all duty for at least 24 consecutive hours in any 7 consecutive days (paragraph (d)).

Worked example: a two-day trip checked against 135.267

Everything in this trip is illustrative: the times, the legs and the company’s duty conventions. All times are in one time zone to keep the arithmetic readable. It’s a two-pilot crew, so the cap is 10 hours.

The company’s operations manual (illustrative) starts duty one hour before the first departure and ends it 30 minutes after the last block-in.

Day 1

Duty runs 0900 to 2030. The crew goes to the hotel by the airport, and rest starts at 2030.

Day 2, as first planned

Report is 0630, so rest was 2030 to 0630: 10 hours.

The start times differ on the two days, so the trip doesn’t fit track (c). Check it under (b) and (d):

1. Find the planned completion. Leg 5 blocks in at 1330 on Day 2. The look-back window is 1330 on Day 1 to 1330 on Day 2.
2. Check rest under (d). The window holds the 2030 to 0630 rest, 10 consecutive hours. That meets (d) with no margin.
3. Add up flight time under (b), looking back 24 hours from each block-in. From leg 5’s block-in: leg 2 (1330 to 1600, 2.5), leg 3 (3.0), leg 4 (2.5) and leg 5 (2.5), 10.5 hours. From leg 4’s block-in at 1000: leg 1 (1000 to 1230, 2.5), leg 2 (2.5), leg 3 (3.0) and leg 4 (2.5), also 10.5 hours. Both are over the 10-hour cap.

No single day had more than 8 hours, but Day 1’s legs are still inside the window when Day 2’s legs end.

Two ways it could be fixed

• Start Day 2 thirty minutes later. Report at 0700, leg 4 from 0800 to 1030 and leg 5 from 1130 to 1400. Looking back from 1030, only the last 2.0 hours of leg 1 count: 2.0 + 2.5 + 3.0 + 2.5 = 10.0 hours. Looking back from 1400, only the last 2.0 hours of leg 2 count: 2.0 + 3.0 + 2.5 + 2.5 = 10.0 hours. Both are within the cap, and rest grows to 10.5 hours (2030 to 0700). Moving only leg 5 wouldn’t be enough, because the look-back from leg 4 would still hold 10.5 hours.
• Move leg 4 earlier instead. Suppose the client asks for an 0630 departure, with a 0530 report. Rest is now 2030 to 0530, 9 hours, and every Day 2 assignment fails (d), whatever the flight times add up to.

Last, add the trip’s 13.0 hours to each pilot’s quarter, two-quarter and year totals (500, 800, 1,400) and confirm neither pilot will fall short of 13 rest periods this quarter.

Every change to a leg means running steps 1 to 3 again for each pilot. On the plan for charter operators, Avion Desk runs these 135.267 checks again whenever the schedule moves.

Common misreadings of the Part 135 rest rules

• “Part 135 has no duty limit.” Track (b) states none, but (d) caps it at what fits around 10 consecutive hours of rest, and track (c) caps it at 14.
• “A calendar day is the window.” Paragraph (b) says “any 24 consecutive hours,” as the example shows.
• “Home on call is rest.” Required standby is duty (Kalantari, Orellana).
• “The pilot had 10 hours off at some point.” The 10 hours must fall in the 24 before the planned completion of the assignment, and must have been known in advance.
• “Days without a trip are rest periods.” Only if they were scheduled in advance as free from all restraint (Schwarz).
• “The airline seat home is rest.” Required transportation not local in character “is not considered part of a rest period” (135.263(c)).
• “Weather overruns are violations” or “weather overruns don’t matter.” Neither: 135.263(d) excuses the overrun, and 135.267(e) then requires 11, 12 or 16 hours of rest.
• “135.265 applies to all Part 135 flying.” It applies to scheduled passenger operations and to operators that elect it (135.261).

If some of your flying is under Part 91 or 91K, those rules are different again: see Part 91K duty and rest and Part 91 duty time limits.

Part 135 duty and rest in Avion Desk

Avion Desk checks duty and rest whenever the schedule moves. On the plan for charter operators, that check applies §135.267, on track (b) or track (c), and Part 91K’s §91.1057 to §91.1059. Every save of a trip is checked and you see the result each time; a problem is named, and an admin’s override is recorded with a note. You choose the plan your free trial runs on when you sign up, so a charter operator can try the Part 135 checks from the first day (see pricing). The crew, duty and rest page shows how it works. To try it, start a free trial on the plan for charter operators, put next week’s trips in and see each pilot’s duty checked against 135.267, or request a demo.

Frequently asked questions

What is the maximum duty day under Part 135?

Track (c) allows a regularly assigned duty period of no more than 14 hours. Track (b) states no limit, but the 10-hour rest look-back leaves at most 14 hours of duty in the window (135.267).

How many hours can a Part 135 pilot fly in a day?

On unscheduled operations, 8 hours in any 24 consecutive hours for one pilot and 10 for two, counting all commercial flying; under track (c), the same caps apply within the duty period (135.267(b) and (c)).

How much rest does a Part 135 pilot need?

At least 10 consecutive hours in the 24 hours before the planned completion of each track (b) assignment, or 10 hours immediately before and after a track (c) duty period. After a weather overrun, 11, 12 or 16 hours depending on how far over (135.267(d) and (e)).

Does on-call time count as rest under Part 135?

No. The FAA has held that required on-call standby, with an obligation to report if called, is duty, and that rest must be continuous, known in advance and free from all restraint (letter to Kalantari).

How many days off does a Part 135 pilot get?

Under 135.267(f), at least 13 rest periods of at least 24 consecutive hours each calendar quarter. In scheduled operations under 135.265(d), at least 24 consecutive hours free of all duty in any 7 consecutive days.

Can a charter operator call a pilot during rest?

It can make one call, which the pilot may choose to answer without breaking the rest period. It can’t require the pilot to answer or return the call (letter to Moody).

This article explains the rules in plain language and isn’t legal advice; the regulation text governs.

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