Section 25.1163

14 CFR Ch. I (1-1-19 Edition)

Section 25.1163 Powerplant accessories.
(a) Each engine mounted accessory
must - 
(1) Be approved for mounting on the
engine involved;
(2) Use the provisions on the engine
for mounting; and
(3) Be sealed to prevent contamination of the engine oil system and the
accessory system.
(b) Electrical equipment subject to
arcing or sparking must be installed to
minimize the probability of contact
with any flammable fluids or vapors
that might be present in a free state.
(c) If continued rotation of an enginedriven cabin supercharger or of any remote accessory driven by the engine is
hazardous if malfunctioning occurs,
there must be means to prevent rotation without interfering with the continued operation of the engine.

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[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25-57, 49 FR 6849, Feb. 23,
1984]

Section 25.1165 Engine ignition systems.
(a) Each battery ignition system
must be supplemented by a generator
that is automatically available as an
alternate source of electrical energy to
allow continued engine operation if
any battery becomes depleted.
(b) The capacity of batteries and generators must be large enough to meet
the simultaneous demands of the engine ignition system and the greatest
demands of any electrical system components that draw electrical energy
from the same source.
(c) The design of the engine ignition
system must account for - 
(1) The condition of an inoperative
generator;
(2) The condition of a completely depleted battery with the generator running at its normal operating speed; and
(3) The condition of a completely depleted battery with the generator operating at idling speed, if there is only
one battery.
(d) Magneto ground wiring (for separate ignition circuits) that lies on the
engine side of the fire wall, must be installed, located, or protected, to minimize the probability of simultaneous
failure of two or more wires as a result
of
mechanical
damage,
electrical
faults, or other cause.

(e) No ground wire for any engine
may be routed through a fire zone of
another engine unless each part of that
wire within that zone is fireproof.
(f) Each ignition system must be
independent of any electrical circuit,
not used for assisting, controlling, or
analyzing the operation of that system.
(g) There must be means to warn appropriate flight crewmembers if the
malfunctioning of any part of the electrical system is causing the continuous
discharge of any battery necessary for
engine ignition.
(h) Each engine ignition system of a
turbine powered airplane must be considered an essential electrical load.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25-23, 35 FR 5677, Apr. 8,
1970; Amdt. 25-72, 55 FR 29785, July 20, 1990]

Section 25.1167 Accessory gearboxes.
For airplanes equipped with an accessory gearbox that is not certificated as
part of an engine - 
(a) The engine with gearbox and connecting transmissions and shafts attached must be subjected to the tests
specified in Section 33.49 or Section 33.87 of this chapter, as applicable;
(b) The accessory gearbox must meet
the requirements of SectionSection 33.25 and 33.53 or
33.91 of this chapter, as applicable; and
(c) Possible misalignments and torsional loadings of the gearbox, transmission, and shaft system, expected to
result under normal operating conditions must be evaluated.
[Amdt. 25-38, 41 FR 55467, Dec. 20, 1976]

POWERPLANT FIRE PROTECTION
Section 25.1181 Designated fire zones; regions included.
(a) Designated fire zones are - 
(1) The engine power section;
(2) The engine accessory section;
(3) Except for reciprocating engines,
any complete powerplant compartment
in which no isolation is provided between the engine power section and the
engine accessory section;
(4) Any auxiliary power unit compartment;
(5) Any fuel-burning heater and other
combustion equipment installation described in Section 25.859;
(6) The compressor and accessory sections of turbine engines; and

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