296 

14 CFR Ch. I (1–1–19 Edition) 

§ 25.812 

when the assist means is erected, the 
emergency lighting system must be de-
signed as follows. 

(1) The lights must be operable 

manually from the flight crew station 
and from a point in the passenger com-
partment that is readily accessible to a 
normal flight attendant seat. 

(2) There must be a flight crew warn-

ing light which illuminates when power 
is on in the airplane and the emergency 
lighting control device is not armed. 

(3) The cockpit control device must 

have an ‘‘on,’’ ‘‘off,’’ and ‘‘armed’’ posi-
tion so that when armed in the cockpit 
or turned on at either the cockpit or 
flight attendant station the lights will 
either light or remain lighted upon 
interruption (except an interruption 
caused by a transverse vertical separa-
tion of the fuselage during crash land-
ing) of the airplane’s normal electric 
power. There must be a means to safe-
guard against inadvertent operation of 
the control device from the ‘‘armed’’ or 
‘‘on’’ positions. 

(g) Exterior emergency lighting must 

be provided as follows: 

(1) At each overwing emergency exit 

the illumination must be— 

(i) Not less than 0.03 foot-candle 

(measured normal to the direction of 
the incident light) on a 2-square-foot 
area where an evacuee is likely to 
make his first step outside the cabin; 

(ii) Not less than 0.05 foot-candle 

(measured normal to the direction of 
the incident light) for a minimum 
width of 42 inches for a Type A 
overwing emergency exit and two feet 
for all other overwing emergency exits 
along the 30 percent of the slip-resist-
ant portion of the escape route re-
quired in § 25.810(c) that is farthest 
from the exit; and 

(iii) Not less than 0.03 foot-candle on 

the ground surface with the landing 
gear extended (measured normal to the 
direction of the incident light) where 
an evacuee using the established escape 
route would normally make first con-
tact with the ground. 

(2) At each non-overwing emergency 

exit not required by § 25.810(a) to have 
descent assist means the illumination 
must be not less than 0.03 foot-candle 
(measured normal to the direction of 
the incident light) on the ground sur-
face with the landing gear extended 

where an evacuee is likely to make 
first contact with the ground outside 
the cabin. 

(h) The means required in 

§§ 25.810(a)(1) and (d) to assist the occu-
pants in descending to the ground must 
be illuminated so that the erected as-
sist means is visible from the airplane. 

(1) If the assist means is illuminated 

by exterior emergency lighting, it 
must provide illumination of not less 
than 0.03 foot-candle (measured normal 
to the direction of the incident light) 
at the ground end of the erected assist 
means where an evacuee using the es-
tablished escape route would normally 
make first contact with the ground, 
with the airplane in each of the atti-
tudes corresponding to the collapse of 
one or more legs of the landing gear. 

(2) If the emergency lighting sub-

system illuminating the assist means 
serves no other assist means, is inde-
pendent of the airplane’s main emer-
gency lighting system, and is auto-
matically activated when the assist 
means is erected, the lighting provi-
sions— 

(i) May not be adversely affected by 

stowage; and 

(ii) Must provide illumination of not 

less than 0.03 foot-candle (measured 
normal to the direction of incident 
light) at the ground and of the erected 
assist means where an evacuee would 
normally make first contact with the 
ground, with the airplane in each of 
the attitudes corresponding to the col-
lapse of one or more legs of the landing 
gear. 

(i) The energy supply to each emer-

gency lighting unit must provide the 
required level of illumination for at 
least 10 minutes at the critical ambient 
conditions after emergency landing. 

(j) If storage batteries are used as the 

energy supply for the emergency light-
ing system, they may be recharged 
from the airplane’s main electric power 
system: 

Provided, 

That, the charging 

circuit is designed to preclude inad-
vertent battery discharge into charg-
ing circuit faults. 

(k) Components of the emergency 

lighting system, including batteries, 
wiring relays, lamps, and switches 
must be capable of normal operation 
after having been subjected to the iner-
tia forces listed in § 25.561(b). 

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