295 

Federal Aviation Administration, DOT 

§ 23.1195 

(1) The flame to which the materials 

or components are subjected must be 
2,000 

±

150 

°

F. 

(2) Sheet materials approximately 10 

inches square must be subjected to the 
flame from a suitable burner. 

(3) The flame must be large enough 

to maintain the required test tempera-
ture over an area approximately five 
inches square. 

(g) Firewall materials and fittings 

must resist flame penetration for at 
least 15 minutes. 

(h) The following materials may be 

used in firewalls or shrouds without 
being tested as required by this sec-
tion: 

(1) Stainless steel sheet, 0.015 inch 

thick. 

(2) Mild steel sheet (coated with alu-

minum or otherwise protected against 
corrosion) 0.018 inch thick. 

(3) Terne plate, 0.018 inch thick. 
(4) Monel metal, 0.018 inch thick. 
(5) Steel or copper base alloy firewall 

fittings. 

(6) Titanium sheet, 0.016 inch thick. 

[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as 
amended by Amdt. 23–43, 58 FR 18975, Apr. 9, 
1993; 58 FR 27060, May 6, 1993; Amdt. 23–51, 61 
FR 5138, Feb. 9, 1996] 

§ 23.1192

Engine accessory compart-

ment diaphragm. 

For aircooled radial engines, the en-

gine power section and all portions of 
the exhaust sytem must be isolated 
from the engine accessory compart-
ment by a diaphragm that meets the 
firewall requirements of § 23.1191. 

[Amdt. 23–14, 38 FR 31823, Nov. 19, 1973] 

§ 23.1193

Cowling and nacelle. 

(a) Each cowling must be constructed 

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

(b) There must be means for rapid 

and complete drainage of each part of 
the cowling in the normal ground and 
flight attitudes. Drain operation may 
be shown by test, analysis, or both, to 
ensure that under normal aerodynamic 
pressure distribution expected in serv-
ice each drain will operate as designed. 
No drain may discharge where it will 
cause a fire hazard. 

(c) Cowling must be at least fire re-

sistant. 

(d) Each part behind an opening in 

the engine compartment cowling must 
be at least fire resistant for a distance 
of at least 24 inches aft of the opening. 

(e) Each part of the cowling subjected 

to high temperatures due to its near-
ness to exhaust sytem ports or exhaust 
gas impingement, must be fire proof. 

(f) Each nacelle of a multiengine air-

plane with supercharged engines must 
be designed and constructed so that 
with the landing gear retracted, a fire 
in the engine compartment will not 
burn through a cowling or nacelle and 
enter a nacelle area other than the en-
gine compartment. 

(g) In addition, for all airplanes with 

engine(s) embedded in the fuselage or 
in pylons on the aft fuselage, the air-
plane must be designed so that no fire 
originating in any engine compartment 
can enter, either through openings or 
by burn-through, any other region 
where it would create additional haz-
ards. 

[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964; 30 
FR 258, Jan. 9, 1965, as amended by Amdt. 23– 
18, 42 FR 15042, Mar. 17, 1977; Amdt. 23–34, 52 
FR 1833, Jan. 15, 1987; 58 FR 18975, Apr. 9, 
1993; Amdt. 23–62, 76 FR 75759, Dec. 2, 2011] 

§ 23.1195

Fire extinguishing systems. 

(a) For all airplanes with engine(s) 

embedded in the fuselage or in pylons 
on the aft fuselage, fire extinguishing 
systems must be installed and compli-
ance shown with the following: 

(1) Except for combustor, turbine, 

and tailpipe sections of turbine-engine 
installations that contain lines or com-
ponents carrying flammable fluids or 
gases for which a fire originating in 
these sections is shown to be control-
lable, a fire extinguisher system must 
serve each engine compartment; 

(2) The fire extinguishing system, the 

quantity of the extinguishing agent, 
the rate of discharge, and the discharge 
distribution must be adequate to extin-
guish fires. An individual ‘‘one shot’’ 
system may be used, except for en-
gine(s) embedded in the fuselage, where 
a ‘‘two shot’’ system is required. 

(3) The fire extinguishing system for 

a nacelle must be able to simulta-
neously protect each compartment of 
the nacelle for which protection is pro-
vided. 

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