Flight & Duty Time Tool

Flight Time (14 CFR § 1.1)

"Pilot time that commences when an aircraft moves under its own power for the purpose of flight and ends when the aircraft comes to rest after landing."

Simply: Block-to-block time (engine start for departure to engine shutdown at destination)

Duty Period and Rest Period (14 CFR § 135.273(a))

Duty period: "The period of elapsed time between reporting for an assignment involving flight time and release from that assignment by the certificate holder."
Rest period: "The period free of all restraint or duty for a certificate holder and free of all responsibility for work or duty should the occasion arise."

Simply: Duty runs from report to release; rest is time with no obligation to the company at all.

These definitions sit in § 135.273, the flight-attendant section. Part 135 has no pilot-specific definition of a duty period, and § 135.267 never limits duty directly — it limits flight time and prescribes rest. The calculators measure duty from report to release, which is the reading schedulers and inspectors use in practice.

§ 135.267(b) — the 24-hour flight-time limit

"Except as provided in paragraph (c) of this section, 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— (1) 8 hours for a flight crew consisting of one pilot; or (2) 10 hours for a flight crew consisting of two pilots qualified under this part for the operation being conducted."

Read it literally: the count is rolling ("any 24 consecutive hours"), it is commercial flying that counts (a Part 91 repositioning leg flown for the certificate holder counts; so does flying for anyone else for hire), and 8 hours is the single-pilot figure, 10 the two-pilot figure.

§ 135.267(c) — the regularly assigned duty period

"A flight crewmember's flight time may exceed the flight time limits of paragraph (b) of this section if the assigned flight time occurs during a regularly assigned duty period of no more than 14 hours and— (1) If this duty period is immediately preceded by and followed by a required rest period of at least 10 consecutive hours of rest; (2) If flight time is assigned during this period, that flight time is not greater than 8 hours for a flight crew consisting of one pilot or 10 hours for a flight crew consisting of two pilots; and (3) If the combined duty and rest periods equal 24 hours."

What (c) is for: it lets flight time from the previous duty period fall out of the rolling 24-hour count, provided the day is a regularly assigned duty period of no more than 14 hours, bracketed by 10 hours of rest on each side, with no more than 8 / 10 hours of flight time inside it. It is a structure for a scheduled crew day, not a licence to fly more than 10 hours in a day.

§ 135.269(a) - Cumulative Flight Time

For unscheduled three- and four-pilot crews, total flight time in all commercial flying may not exceed:

• 500 hours in any calendar quarter — § 135.269(a)(1)
• 800 hours in any two consecutive calendar quarters — § 135.269(a)(2)
• 1,400 hours in any calendar year — § 135.269(a)(3)

The 24-hour constraints live in § 135.269(b): 8 hours of flight deck duty per pilot, 12 hours aloft with three pilots or 16 with four, within an 18- or 20-hour duty window, with 10 hours of rest immediately before and 12 on completion.

§ 135.269 states no weekly or monthly cap. Neither does § 135.267. The shortest cumulative window in either section is a calendar quarter.

Single-Pilot Crews — § 135.267, not § 135.269

§ 135.269 applies only to unscheduled three- and four-pilot crews; its (b)(7) and (b)(8) define those compositions explicitly. A single-pilot crew is governed by § 135.267:

• 8 hours in any 24 consecutive hours — § 135.267(b)(1)
• 500 hours in any calendar quarter — § 135.267(a)(1)
• 800 hours in any two consecutive calendar quarters — § 135.267(a)(2)
• 1,400 hours in any calendar year — § 135.267(a)(3)

Note that the Flight & Duty calculator does not model single-pilot operations — it offers 2-, 3- and 4-pilot configurations only, and its unaugmented baseline is the two-pilot 10-hour limit of § 135.267(b)(2).

§ 135.267(d)

"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."

Ten consecutive hours of rest inside the 24 hours before planned completion leaves at most 14 hours for everything else. A two-pilot duty period planned longer than 14 hours therefore cannot satisfy (d), and (c) uses the same 14-hour ceiling for a regularly assigned duty period. That is why the Flight & Duty Time Calculator marks a two-pilot plan non-compliant above 14 hours of duty.

§ 135.269(b)(3) — three- and four-pilot crews

"No more than 18 duty hours for a three-pilot crew or 20 duty hours for a four-pilot crew in any 24 consecutive hours." The same paragraph limits each pilot to 8 hours of flight deck duty in any 24 consecutive hours, and the crew to 12 hours aloft (three pilots) or 16 hours aloft (four pilots) during the 24 duty hours. See Augmented Crew Operations below.

§ 135.267(d)

"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."

Rest means free of all duty. § 135.273(a) defines a rest period as "the period free of all restraint or duty for a certificate holder and free of all responsibility for work or duty should the occasion arise." Standby, being reachable for a call-out, a positioning leg, training, or paperwork all break a rest period; if any of them happens, the 10 hours start over.

§ 135.267(f) - Quarterly Rest Periods

The certificate holder must relieve each flight crewmember of all duty for at least 13 rest periods of at least 24 consecutive hours each in each calendar quarter.

The 11 / 12 / 16-hour figures often associated with this section are § 135.267(e)(1)–(3), and they are compensatory rest after an assignment runs long for reasons beyond the operator's control — scaled to the overrun: 11 hours if 30 minutes or less, 12 hours if 30–60 minutes, 16 hours if more than 60 minutes. They are not a general extended-operations allowance.

Not available under § 135.267

§ 135.267 runs (a) through (g) and contains no reduced-rest authority. Its (e) does the opposite — it mandates additional rest after an assignment overruns. Its (g) says only that an assignment which normally terminates within the limits, but runs over because of circumstances beyond the control of the certificate holder or crewmember (adverse weather, for example), is not an assignment in excess of the limits.

Reduced rest for flight crew exists only in § 135.265(c), which applies to scheduled operations and is therefore not available on this certificate. § 135.273 covers flight attendants separately. For unscheduled flying the rest requirement is § 135.267(d) — 10 consecutive hours within the 24 hours preceding planned completion — with no reduction pathway.

Every three- or four-pilot assignment must provide:

• At least 10 consecutive hours of rest immediately preceding the assignment — (b)(1)
• No more than 8 hours of flight deck duty per pilot in any 24 consecutive hours — (b)(2)
• No more than 18 duty hours (three pilots) or 20 duty hours (four pilots) in any 24 consecutive hours — (b)(3)
• No more than 12 hours aloft (three pilots) or 16 hours aloft (four pilots) during the 24 duty hours — (b)(4)
• Adequate sleeping facilities on the aircraft for the relief pilot — (b)(5)
• On completion of the assignment, a rest period of at least 12 hours — (b)(6)
• The crew composition in (b)(7) and (b)(8): a PIC fully qualified under subpart E, a second PIC who meets subpart E except §§ 135.244 and 135.247, and one SIC (three pilots) or two SICs (four pilots) qualified under § 135.245

Note what is not there: the regulation says "adequate sleeping facilities", not a rest-facility class. Class 1 / 2 / 3 rest facilities are Part 117 definitions and do not apply to Part 135. Nor is there a rule that each pilot receives a fixed share of the flight as rest; the binding per-pilot figure is 8 hours of flight deck duty in 24.