Code of Federal Regulations - Title 14

492

14 CFR Ch. I (1–1–14 Edition)

§ 25.1191

through any designated fire zone, ex-
cept that shutoff means are not re-
quired for—

(1) Lines, fittings, and components

forming an integral part of an engine;
and

(2) Oil systems for turbine engine in-

stallations in which all components of
the system in a designated fire zone,
including oil tanks, are fireproof or lo-
cated in areas not subject to engine
fire conditions.

(b) The closing of any fuel shutoff

valve for any engine may not make
fuel unavailable to the remaining en-
gines.

interfere with the later emergency op-
eration of other equipment, such as the
means for feathering the propeller.

(d) Each flammable fluid shutoff

means and control must be fireproof or
must be located and protected so that
any fire in a fire zone will not affect its
operation.

(e) No hazardous quantity of flam-

mable fluid may drain into any des-
ignated fire zone after shutoff.

(f) There must be means to guard

against inadvertent operation of the
shutoff means and to make it possible
for the crew to reopen the shutoff
means in flight after it has been closed.

(g) Each tank-to-engine shutoff valve

must be located so that the operation
of the valve will not be affected by
powerplant or engine mount structural
failure.

(h) Each shutoff valve must have a

means to relieve excessive pressure ac-
cumulation unless a means for pressure
relief is otherwise provided in the sys-
tem.

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25–23, 35 FR 5677, Apr. 8,
1970; Amdt. 25–57, 49 FR 6849, Feb. 23, 1984]

§ 25.1191

Firewalls.

(a) Each engine, auxiliary power

unit, fuel-burning heater, other com-
bustion equipment intended for oper-
ation in flight, and the combustion,
turbine, and tailpipe sections of tur-
bine engines, must be isolated from the
rest of the airplane by firewalls,
shrouds, or equivalent means.

(b) Each firewall and shroud must

be—

(1) Fireproof;

(2) Constructed so that no hazardous

quantity of air, fluid, or flame can pass
from the compartment to other parts
of the airplane;

(3) Constructed so that each opening

is sealed with close fitting fireproof
grommets, bushings, or firewall fit-
tings; and

(4) Protected against corrosion.

§ 25.1192

Engine accessory section dia-

phragm.

For reciprocating engines, the engine

power section and all portions of the
exhaust system must be isolated from
the engine accessory compartment by a
diaphragm that complies with the fire-
wall requirements of § 25.1191.

[Amdt. 25–23, 35 FR 5678, Apr. 8, 1970]

§ 25.1193

Cowling and nacelle skin.

(a) Each cowling must be constructed

and supported so that it can resist any
vibration, inertia, and air load to
which it may be subjected in operation.

(b) Cowling must meet the drainage

and ventilation requirements of
§ 25.1187.

isolating the engine power section from
the engine accessory section, each part
of the accessory section cowling sub-
ject to flame in case of fire in the en-
gine power section of the powerplant
must—

(1) Be fireproof; and
(2) Meet the requirements of § 25.1191.
(d) Each part of the cowling subject

to high temperatures due to its near-
ness to exhaust system parts or ex-
haust gas impingement must be fire-
proof.

(e) Each airplane must—
(1) Be designed and constructed so

that no fire originating in any fire zone
can enter, either through openings or
by burning through external skin, any
other zone or region where it would
create additional hazards;

(2) Meet paragraph (e)(1) of this sec-

tion with the landing gear retracted (if
applicable); and

(3) Have fireproof skin in areas sub-

ject to flame if a fire starts in the en-
gine power or accessory sections.

§ 25.1195

Fire extinguishing systems.

(a) Except for combustor, turbine,

and tail pipe sections of turbine engine

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