Fitness for duty

This regulation establishes mutual responsibility between pilots and airlines for fatigue management. Before any flight duty period, you must report rested and ready to fly. If you're too fatigued to safely perform your duties, you cannot accept the assignment, and the airline cannot assign it to you.

The regulation works both ways: if you report yourself as too fatigued during a duty period, the airline must remove you from that assignment. You cannot continue flying once you've declared yourself unfit due to fatigue.

Before each flight begins, you must affirmatively state during dispatch or flight release that you're fit for duty—this isn't assumed; it requires your active confirmation.

This creates a "safety valve" in the flight time and duty regulations. Even if a assignment is legal under the rest of Part 117's rules, fatigue is ultimately your call. The regulation protects your right to refuse or stop flying when genuinely too tired to operate safely.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*