FTDT Duty Period — USA (FAR Part 117)

Updated: 2026-08-08 07:02 ET · Audited: 2026-06-26

A duty period includes the duties performed by the flightcrew member on behalf of the certificate holder that occur before a flight segment or between flight segments without a required intervening rest period.

FDP Data Requirements

All FDP Types

FDP Start Time
FDP End Time
Crew member is Acclimated (yes/no)
FDP is Extended (yes/no — see §117.19)
FDP Notes (reason for extension if applicable)
Duration
Details about each Flight Segment Operated

Unaugmented Operations

Number of Flight Segments scheduled (1–7+) in FDP

Augmented Operations

Total Crew Count (3 or 4)
Crew Rest Facility Class (1, 2, or 3)

Short-Call Reserve

Reserve Availability Period (RAP) Start Time

Pre-FDP Rest (§117.25(e)/(f))

Sleep Opportunity hours within the pre-FDP rest period (crew-attested; null = not assessed, in which case rest-period length is used as the sleep-opportunity proxy) — model ALPAMobile.Domain/Data/Models/FlightTimeDutyTime/PreFDPRest_USA.cs
§117.25(f) self-declared insufficient-rest flag (forces a §117.25(e) violation regardless of attested hours)
UI: ALPAMobile.Presentation/Components/FTDT/SleepOpportunityInput.razor, captured on the FTDTAddRest.razor page

Results Requirements

Standard Results

Duration of Maximum Flight Duty Period
Time when Maximum FDP ends
Flight Time Limit

Reserve Results (Standard Results plus)

Duration of Maximum FDP + RAP
Time when Maximum FDP + RAP ends

Flight Segment Requirements

Flight Segment Start Time
Flight Segment End Time
Aircraft Equipment Used
Flight Number
Start/End Airport Code (City Pair)
Duration

Rest Opportunity (RO) Requirements

RO Start Time
RO End Time
RO Duration

§117.19 Extensions

Source: 14 CFR §117.19 — Extensions due to unforeseen operational circumstances. See also Extension and Unforeseen Operational Circumstance.

Extension Conditions

An FDP extension is only permitted when an unforeseen operational circumstance occurs — an unplanned event of insufficient duration to allow schedule adjustments (e.g., unforecast weather, equipment malfunction, ATC delay not reasonably expected). Extensions cannot be used for planned or foreseeable overruns.

Extension Cap — Unaugmented

For unaugmented operations, an extended FDP may not exceed the Table B maximum by more than 2 hours.

Example: If Table B permits 13 hours, the extended FDP maximum is 15 hours.

Extension Cap — Augmented

For augmented operations, the FDP may be extended beyond Table C limits under the same unforeseen operational circumstance condition. Verify the specific cap against §117.19 and current FAA guidance.

WOCL Restriction

An extension that would cause the FDP to encroach on or extend through the Window of Circadian Low (WOCL) — 0200 to 0559 is subject to additional restrictions. Pilots have the right to decline an extension if it would cause them to operate during the WOCL.

Notification and Recording

Certificate holder must record the unforeseen operational circumstance that caused the extension.
Pilot must be notified of the extended FDP as soon as practicable.
Flightcrew members retain the right to decline an extension if they determine they are too fatigued to safely operate.

Code Requirements (TDD)

Flag extended FDPs — When "FDP is Extended" is true, record the extension and apply the +2-hour cap (unaugmented).
Display extension cap — Show the extended maximum FDP ceiling alongside the standard Table B/C maximum.
WOCL warning — If the extended FDP would cause operation during 0200–0559, display a WOCL encroachment warning.
Extension notes field — "FDP Notes" captures the reason (maps to §117.19 recording requirement).
Decline right reminder — Surface a reminder that flightcrew members may decline an extension if fatigued.

Notes

Airport standby and Long-Call reserve use non-reserve operation types.
Date/time needs timezone support.