309 

Federal Aviation Administration, DOT 

§ 25.899 

fire (e.g., equipment shutdown or actu-
ation of a fire extinguisher) quick act-
ing means must be provided to alert 
the crew. 

(d) Each area where flammable fluids 

or vapors might escape by leakage of a 
fluid system must be identified and de-
fined. 

[Amdt. 25–23, 35 FR 5676, Apr. 8, 1970, as 
amended by Amdt. 25–46, 43 FR 50597, Oct. 30, 
1978] 

§ 25.865

Fire protection of flight con-

trols, engine mounts, and other 
flight structure. 

Essential flight controls, engine 

mounts, and other flight structures lo-
cated in designated fire zones or in ad-
jacent areas which would be subjected 
to the effects of fire in the fire zone 
must be constructed of fireproof mate-
rial or shielded so that they are capa-
ble of withstanding the effects of fire. 

[Amdt. 25–23, 35 FR 5676, Apr. 8, 1970] 

§ 25.867

Fire protection: other compo-

nents. 

(a) Surfaces to the rear of the na-

celles, within one nacelle diameter of 
the nacelle centerline, must be at least 
fire-resistant. 

(b) Paragraph (a) of this section does 

not apply to tail surfaces to the rear of 
the nacelles that could not be readily 
affected by heat, flames, or sparks 
coming from a designated fire zone or 
engine compartment of any nacelle. 

[Amdt. 25–23, 35 FR 5676, Apr. 8, 1970] 

§ 25.869

Fire protection: systems. 

(a) Electrical system components: 
(1) Components of the electrical sys-

tem must meet the applicable fire and 
smoke protection requirements of 
§§ 25.831(c) and 25.863. 

(2) Equipment that is located in des-

ignated fire zones and is used during 
emergency procedures must be at least 
fire resistant. 

(3) EWIS components must meet the 

requirements of § 25.1713. 

(b) Each vacuum air system line and 

fitting on the discharge side of the 
pump that might contain flammable 
vapors or fluids must meet the require-
ments of § 25.1183 if the line or fitting is 
in a designated fire zone. Other vacuum 
air systems components in designated 

fire zones must be at least fire resist-
ant. 

(c) Oxygen equipment and lines 

must— 

(1) Not be located in any designated 

fire zone, 

(2) Be protected from heat that may 

be generated in, or escape from, any 
designated fire zone, and 

(3) Be installed so that escaping oxy-

gen cannot cause ignition of grease, 
fluid, or vapor accumulations that are 
present in normal operation or as a re-
sult of failure or malfunction of any 
system. 

[Amdt. 25–72, 55 FR 29784, July 20, 1990, as 
amended by Amdt. 25–113, 69 FR 12530, Mar. 
16, 2004; Amdt. 25–123, 72 FR 63405, Nov. 8, 
2007] 

M

ISCELLANEOUS

 

§ 25.871

Leveling means. 

There must be means for determining 

when the airplane is in a level position 
on the ground. 

[Amdt. 25–23, 35 FR 5676, Apr. 8, 1970] 

§ 25.875

Reinforcement near propel-

lers. 

(a) Each part of the airplane near the 

propeller tips must be strong and stiff 
enough to withstand the effects of the 
induced vibration and of ice thrown 
from the propeller. 

(b) No window may be near the pro-

peller tips unless it can withstand the 
most severe ice impact likely to occur. 

§ 25.899

Electrical bonding and protec-

tion against static electricity. 

(a) Electrical bonding and protection 

against static electricity must be de-
signed to minimize accumulation of 
electrostatic charge that would cause— 

(1) Human injury from electrical 

shock, 

(2) Ignition of flammable vapors, or 
(3) Interference with installed elec-

trical/electronic equipment. 

(b) Compliance with paragraph (a) of 

this section may be shown by— 

(1) Bonding the components properly 

to the airframe; or 

(2) Incorporating other acceptable 

means to dissipate the static charge so 

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