Closing and locking of flightcrew compartment door

This regulation requires pilots in command to keep the cockpit door closed and locked whenever the aircraft is carrying passengers and has a lockable door installed per § 121.313. This applies throughout all phases of flight operations.

The door may be opened when necessary to allow authorized persons to enter or exit the cockpit, but only if the airline follows FAA-approved procedures for opening, closing, and locking the door. Section 121.547 specifies who is authorized to access the cockpit.

This rule is a key security measure implemented after 9/11 to prevent unauthorized access to the flight deck during passenger operations. The locked door requirement is continuous—not just during cruise flight—though practical procedures allow for necessary crew movement while maintaining security protocols. Airlines must have specific FAA-approved procedures detailing how crew members safely manage door access without compromising cockpit security.

*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.*