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351 

Federal Aviation Administration, DOT 

§ 25.1383 

(b) Burns. The temperature of any 

part that may be handled by a crew-
member during normal operations 
must not cause dangerous inadvertent 
movement by the crewmember or in-
jury to the crewmember. 

[Amdt. 25–123, 72 FR 63406, Nov. 8, 2007] 

§ 25.1362

Electrical supplies for emer-

gency conditions. 

A suitable electrical supply must be 

provided to those services required for 
emergency procedures after an emer-
gency landing or ditching. The circuits 
for these services must be designed, 
protected, and installed so that the 
risk of the services being rendered inef-
fective under these emergency condi-
tions is minimized. 

[Amdt. 25–123, 72 FR 63406, Nov. 8, 2007] 

§ 25.1363

Electrical system tests. 

(a) When laboratory tests of the elec-

trical system are conducted— 

(1) The tests must be performed on a 

mock-up using the same generating 
equipment used in the airplane; 

(2) The equipment must simulate the 

electrical characteristics of the dis-
tribution wiring and connected loads to 
the extent necessary for valid test re-
sults; and 

(3) Laboratory generator drives must 

simulate the actual prime movers on 
the airplane with respect to their reac-
tion to generator loading, including 
loading due to faults. 

(b) For each flight condition that 

cannot be simulated adequately in the 
laboratory or by ground tests on the 
airplane, flight tests must be made. 

§ 25.1365

Electrical appliances, motors, 

and transformers. 

(a) Domestic appliances must be de-

signed and installed so that in the 
event of failures of the electrical sup-
ply or control system, the require-
ments of § 25.1309(b), (c), and (d) will be 
satisfied. Domestic appliances are 
items such as cooktops, ovens, coffee 
makers, water heaters, refrigerators, 
and toilet flush systems that are 
placed on the airplane to provide serv-
ice amenities to passengers. 

(b) Galleys and cooking appliances 

must be installed in a way that mini-
mizes risk of overheat or fire. 

(c) Domestic appliances, particularly 

those in galley areas, must be installed 
or protected so as to prevent damage or 
contamination of other equipment or 
systems from fluids or vapors which 
may be present during normal oper-
ation or as a result of spillage, if such 
damage or contamination could create 
a hazardous condition. 

(d) Unless compliance with § 25.1309(b) 

is provided by the circuit protective 
device required by § 25.1357(a), electric 
motors and transformers, including 
those installed in domestic systems, 
must have a suitable thermal protec-
tion device to prevent overheating 
under normal operation and failure 
conditions, if overheating could create 
a smoke or fire hazard. 

[Amdt. 25–123, 72 FR 63406, Nov. 8, 2007] 

L

IGHTS

 

§ 25.1381

Instrument lights. 

(a) The instrument lights must— 
(1) Provide sufficient illumination to 

make each instrument, switch and 
other device necessary for safe oper-
ation easily readable unless sufficient 
illumination is available from another 
source; and 

(2) Be installed so that— 
(i) Their direct rays are shielded from 

the pilot’s eyes; and 

(ii) No objectionable reflections are 

visible to the pilot. 

(b) Unless undimmed instrument 

lights are satisfactory under each ex-
pected flight condition, there must be a 
means to control the intensity of illu-
mination. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–72, 55 FR 29785, July 20, 
1990] 

§ 25.1383

Landing lights. 

(a) Each landing light must be ap-

proved, and must be installed so that— 

(1) No objectionable glare is visible 

to the pilot; 

(2) The pilot is not adversely affected 

by halation; and 

(3) It provides enough light for night 

landing. 

(b) Except when one switch is used 

for the lights of a multiple light instal-
lation at one location, there must be a 
separate switch for each light. 

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352 

14 CFR Ch. I (1–1–24 Edition) 

§ 25.1385 

(c) There must be a means to indicate 

to the pilots when the landing lights 
are extended. 

§ 25.1385

Position light system installa-

tion. 

(a) 

General.  Each part of each posi-

tion light system must meet the appli-
cable requirements of this section and 
each system as a whole must meet the 
requirements of §§ 25.1387 through 
25.1397. 

(b) 

Forward position lights. Forward 

position lights must consist of a red 
and a green light spaced laterally as 
far apart as practicable and installed 
forward on the airplane so that, with 
the airplane in the normal flying posi-
tion, the red light is on the left side 
and the green light is on the right side. 
Each light must be approved. 

(c) 

Rear position light. The rear posi-

tion light must be a white light mount-
ed as far aft as practicable on the tail 
or on each wing tip, and must be ap-
proved. 

(d) 

Light covers and color filters. Each 

light cover or color filter must be at 
least flame resistant and may not 
change color or shape or lose any ap-
preciable light transmission during 
normal use. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–38, 41 FR 55468, Dec. 20, 
1976] 

§ 25.1387

Position light system dihe-

dral angles. 

(a) Except as provided in paragraph 

(e) of this section, each forward and 
rear position light must, as installed, 
show unbroken light within the dihe-
dral angles described in this section. 

(b) Dihedral angle 

L  (left) is formed 

by two intersecting vertical planes, the 
first parallel to the longitudinal axis of 
the airplane, and the other at 110 de-
grees to the left of the first, as viewed 
when looking forward along the longi-
tudinal axis. 

(c) Dihedral angle 

(right) is formed 

by two intersecting vertical planes, the 
first parallel to the longitudinal axis of 
the airplane, and the other at 110 de-
grees to the right of the first, as viewed 
when looking forward along the longi-
tudinal axis. 

(d) Dihedral angle 

A  (aft) is formed 

by two intersecting vertical planes 

making angles of 70 degrees to the 
right and to the left, respectively, to a 
vertical plane passing through the lon-
gitudinal axis, as viewed when looking 
aft along the longitudinal axis. 

(e) If the rear position light, when 

mounted as far aft as practicable in ac-
cordance with § 25.1385(c), cannot show 
unbroken light within dihedral angle 

(as defined in paragraph (d) of this sec-
tion), a solid angle or angles of ob-
structed visibility totaling not more 
than 0.04 steradians is allowable within 
that dihedral angle, if such solid angle 
is within a cone whose apex is at the 
rear position light and whose elements 
make an angle of 30

° 

with a vertical 

line passing through the rear position 
light. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–30, 36 FR 21278, Nov. 5, 
1971] 

§ 25.1389

Position light distribution 

and intensities. 

(a) 

General. The intensities prescribed 

in this section must be provided by new 
equipment with light covers and color 
filters in place. Intensities must be de-
termined with the light source oper-
ating at a steady value equal to the av-
erage luminous output of the source at 
the normal operating voltage of the 
airplane. The light distribution and in-
tensity of each position light must 
meet the requirements of paragraph (b) 
of this section. 

(b) 

Forward and rear position lights. 

The light distribution and intensities 
of forward and rear position lights 
must be expressed in terms of min-
imum intensities in the horizontal 
plane, minimum intensities in any 
vertical plane, and maximum inten-
sities in overlapping beams, within di-
hedral angles 

L, R, and  A,  and must 

meet the following requirements: 

(1) 

Intensities in the horizontal plane. 

Each intensity in the horizontal plane 
(the plane containing the longitudinal 
axis of the airplane and perpendicular 
to the plane of symmetry of the air-
plane) must equal or exceed the values 
in § 25.1391. 

(2) 

Intensities in any vertical plane. 

Each intensity in any vertical plane 
(the plane perpendicular to the hori-
zontal plane) must equal or exceed the 
appropriate value in § 25.1393, where 

is 

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