Section 23.2440 - Powerplant fire protection(a) A powerplant, auxiliary power unit, or combustion heater that includes a flammable fluid and an ignition source for that fluid must be installed in a designated fire zone.(b) Each designated fire zone must provide a means to isolate and mitigate hazards to the airplane in the event of fire or overheat within the zone.(c) Each component, line, fitting, and control subject to fire conditions must-(1) Be designed and located to prevent hazards resulting from a fire, including any located adjacent to a designated fire zone that may be affected by fire within that zone;(2) Be fire-resistant if carrying flammable fluid, gas or air, or is required to operate in the event of a fire; and(3) Be fireproof or enclosed by a fire proof shield if storing concentrated flammable fluids.(d) The applicant must provide a means to prevent hazardous quantities of flammable fluids from flowing into, within or through each designated fire zone. This means must-(1) Not restrict flow or limit operation of any remaining powerplant or auxiliary power unit, or equipment necessary for safety;(2) Prevent inadvertent operation; and(3) Be located outside the fire zone unless an equal degree of safety is provided with a means inside the fire zone.(e) A means to ensure the prompt detection of fire must be provided for each designated fire zone-(1) On a multiengine airplane where detection will mitigate likely hazards to the airplane; or(2) That contains a fire extinguisher.(f) A means to extinguish fire within a fire zone, except a combustion heater fire zone, must be provided for-(1) Any fire zone located outside the pilot's view;(2) Any fire zone embedded within the fuselage, which must also include a redundant means to extinguish fire; and(3) Any fire zone on a level 4 airplane.Doc. No. FAA-2015-1621, Amdt. 23-64, 81 FR 96689, Dec. 30, 2016, as amended by Doc. No. FAA-2022-1355, Amdt. 23-65, 87 FR 75710, Dec. 9, 2022 81 FR 96689, 8/30/2017; as amended by Doc. No. FAA-2022-1355, Amdt. 23-65, 87 FR 75710, 12/9/2022