FAA Airline Transport Pilot (ATM)Regulations (14 CFR 117/121/61)Medium
Under 14 CFR Part 117, the Window of Circadian Low (WOCL) is defined as occurring between which hours in the flightcrew member's theater of acclimatization?
- A2200–0600
- B0100–0459
- C0200–0559
- D0000–0400
Show answer & explanationAnswer & explanation
Correct answer: C. 0200–0559
Part 117.3 defines the Window of Circadian Low (WOCL) as the period between 0200 and 0559 in the theater to which a flightcrew member is acclimated. FDP limits in Table B are reduced when the flight duty period overlaps this window.
Why the other options are wrong
- A. Too broad; not the specific hours defined in the rule
- B. Close but does not match the exact defined hours (0200-0559)
- D. Not the defined WOCL window under Part 117
Window of Circadian Low (WOCL)
The period from 0200 to 0559 in a flightcrew member's acclimated theater, during which human alertness is lowest, used to reduce allowable FDP under Part 117.
- Defined in 117.3
- Overlap with WOCL reduces maximum FDP in Table B
- Based on acclimatization, not just local time at departure
Memory trick: 2 AM to 6 AM: your body wants to be dreaming, not flying.