(a) Each turbine engine powered rotorcraft and Category A reciprocating
engine powered rotorcraft, and each Category B reciprocating engine
powered rotorcraft with engines of more than 1,500 cubic inches must have
a fire extinguishing system for the designated fire zones. The fire
extinguishing system for a powerplant must be able to simultaneously
protect all zones of the powerplant compartment for which protection is
provided.
(b) For multiengine powered rotorcraft, the fire extinguishing system,
the quantity of extinguishing agent, and the rate of discharge must --
(1) For each auxiliary power unit and combustion equipment, provide at
least one adequate discharge; and
(2) For each other designated fire zone, provide two adequate
discharges.
(c) For single engine rotorcraft, the quantity of extinguishing agent
and the rate of discharge must provide at least one adequate discharge for
the engine compartment.
(d) It must be shown by either actual or simulated flight tests that
under critical airflow conditions in flight the discharge of the
extinguishing agent in each designated fire zone will provide an agent
concentration capable of extinguishing fires in that zone and of
minimizing the probability of reignition. (Secs. 313(a), 601, 603,
604, Federal Aviation Act of 1958 (49 U.S.C. 1354(a), 1421, 1423, 1424),
sec. 6(c), Dept. of Transportation Act (49 U.S.C. 1655(c)))