Miscellaneous equipment

This regulation lists miscellaneous equipment required for Part 121 airline operations. Key requirements include:

• Spare fuses (if the airplane uses them)
• Windshield wipers for each pilot
• Redundant electrical power systems that can handle required instruments even if one source fails
• Power adequacy indicators for flight instruments
• Two independent static pressure systems with clear markings when switching between them
• A lockable door between the passenger cabin and flight deck (with exceptions for older non-transport category aircraft)
• Keys for doors separating compartments with emergency exits; flight deck door keys restricted to flight crew only
• Placards on doors used as emergency exits indicating they must remain open during takeoff and landing
• Emergency unlock capability for passenger-lockable doors
• For most passenger operations, a way to monitor the area outside the flight deck door
• For newer aircraft (manufactured after August 2025), a physical secondary barrier to the flight deck

These requirements enhance safety, security, and operational reliability in airline operations.

*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.*