Section 121.313 - Miscellaneous equipmentNo person may conduct any operation unless the following equipment is installed in the airplane:
(a) If protective fuses are installed on an airplane, the number of spare fuses approved for that airplane and appropriately described in the certificate holder's manual.(b) A windshield wiper or equivalent for each pilot station.(c) A power supply and distribution system that meets the requirements of §§25.1309, 25.1331 , 25.1351 , 25.1353 , 25.1355 , and 25.1431 or that is able to produce and distribute the load for the required instruments and equipment, with use of an external power supply if any one power source or component of the power distribution system fails. The use of common elements in the system may be approved if the Administrator finds that they are designed to be reasonably protected against malfunctioning. Engine-driven sources of energy, when used, must be on separate engines.(d) A means for indicating the adequacy of the power being supplied to required flight instruments.(e) Two independent static pressure systems, vented to the outside atmospheric pressure so that they will be least affected by air flow variation or moisture or other foreign matter, and installed so as to be airtight except for the vent. When a means is provided for transferring an instrument from its primary operating system to an alternate system, the means must include a positive positioning control and must be marked to indicate clearly which system is being used.(f) A door between the passenger and pilot compartments (i.e., flightdeck door), with a locking means to prevent passengers from opening it without the pilot's permission, except that nontransport category airplanes certificated after December 31, 1964, are not required to comply with this paragraph. For airplanes equipped with a crew rest area having separate entries from the flightdeck and the passenger compartment, a door with such a locking means must be provided between the crew rest area and the passenger compartment.(g) A key for each door that separates a passenger compartment from another compartment that has emergency exit provisions. Except for flightdeck doors, a key must be readily available for each crewmember. Except as provided below, no person other than a person who is assigned to perform duty on the flightdeck may have a key to the flightdeck door. Before April 22, 2003, any crewmember may have a key to the flightdeck door but only if the flightdeck door has an internal flightdeck locking device installed, operative, and in use. Such "internal flightdeck locking device" has to be designed so that it can only be unlocked from inside the flightdeck.(h) A placard on each door that is the means of access to a required passenger emergency exit, to indicate that it must be open during takeoff and landing.(i) A means for the crew, in an emergency to unlock each door that leads to a compartment that is normally accessible to passengers and that can be locked by passengers.(j) After April 9, 2003, for airplanes required by paragraph (f) of this section to have a door between the passenger and pilot or crew rest compartments, and for transport category, all-cargo airplanes that have a door installed between the pilot compartment and any other occupied compartment on January 15, 2002; (1) After April 9, 2003, for airplanes required by paragraph (f) of this section to have a door between the passenger and pilot or crew rest compartments,(i) Each such door must meet the requirements of § 25.795 in effect on January 15, 2002; and(ii) Each operator must establish methods to enable a flight attendant to enter the pilot compartment in the event that a flightcrew member becomes incapacitated. Any associated signal or confirmation system must be operable by each flightcrew member from that flightcrew member's duty station.(2) After October 1, 2003, for transport category, all-cargo airplanes that had a door installed between the pilot compartment and any other occupied compartment on or after January 15, 2002, each such door must meet the requirements of §25.795(a)(1) and (2) in effect on January 15, 2002; or the operator must implement a security program approved by the Transportation Security Administration (TSA) for the operation of all airplanes in that operator's fleet.(k) Except for all-cargo operations as defined in § 110.2 of this chapter, for all passenger-carrying airplanes that require a lockable flightdeck door in accordance with paragraph (f) of this section, a means to monitor from the flightdeck side of the door the area outside the flightdeck door to identify persons requesting entry and to detect suspicious behavior and potential threats.(l) For airplanes required by paragraph (f) of this section to have a door between the passenger and pilot or crew rest compartments, and for passenger-carrying transport category airplanes that have a door installed between the pilot compartment and any other occupied compartment, that were manufactured after August 25, 2025, an installed physical secondary barrier (IPSB) that meets the requirements of § 25.795(a)(4) of this chapter in effect on August 25, 2023.Doc. No. 6258, 29 FR 19205, Dec. 31, 1964, as amended by Amdt. 121-5, 30 FR 6113, Apr. 30, 1965; Amdt. 121-251, 60 FR 65931, Dec. 20, 1995; Amdt. 121-288, 67 FR 2127 , Jan. 15, 2002; Amdt. 121-299, 68 FR 42881 , July 18, 2003; Amdt. 121-334, 72 FR 45635 , Aug. 15, 2007; Amdt. 121-353, 76 FR 7488 , Feb. 10, 2011