311
Federal Aviation Administration, DOT
§ 23.1395
be determined with the light source op-
erating at a steady value equal to the
average 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)
Position lights. The light distribu-
tion and intensities of 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 § 23.1391.
(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 § 23.1393, where
I is
the minimum intensity prescribed in
§ 23.1391 for the corresponding angles in
the horizontal plane.
(3)
Intensities in overlaps between adja-
cent signals. No intensity in any over-
lap between adjacent signals may ex-
ceed the values in § 23.1395, except that
higher intensities in overlaps may be
used with main beam intensities sub-
stantially greater than the minima
specified in §§ 23.1391 and 23.1393, if the
overlap intensities in relation to the
main beam intensities do not adversely
affect signal clarity. When the peak in-
tensity of the left and right position
lights is more than 100 candles, the
maximum overlap intensities between
them may exceed the values in § 23.1395
if the overlap intensity in Area A is
not more than 10 percent of peak posi-
tion light intensity and the overlap in-
tensity in Area B is not more than 2.5
percent of peak position light inten-
sity.
(c)
Rear position light installation. A
single rear position light may be in-
stalled in a position displaced laterally
from the plane of symmetry of an air-
plane if—
(1) The axis of the maximum cone of
illumination is parallel to the flight
path in level flight; and
(2) There is no obstruction aft of the
light and between planes 70 degrees to
the right and left of the axis of max-
imum illumination.
[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as
amended by Amdt. 23–43, 58 FR 18977, Apr. 9,
1993]
§ 23.1391
Minimum intensities in the
horizontal plane of position lights.
Each position light intensity must
equal or exceed the applicable values in
the following table:
Dihedral angle (light in-
cluded)
Angle from right
or left of longitu-
dinal axis, meas-
ured from dead
ahead
Intensity
(candles)
L and R (red and green) ....
0
°
to 10
°
..............
10
°
to 20
°
............
20
°
to 110
°
..........
40
30
5
A (rear white) .....................
110
°
to 180
°
........
20
[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as
amended by Amdt. 23–43, 58 FR 18977, Apr. 9,
1993]
§ 23.1393
Minimum intensities in any
vertical plane of position lights.
Each position light intensity must
equal or exceed the applicable values in
the following table:
Angle above or below the horizontal plane
Intensity, l
0
°
.........................................................................
1.00
0
°
to 5
°
................................................................
0.90
5
°
to 10
°
..............................................................
0.80
10
°
to 15
°
............................................................
0.70
15
°
to 20
°
............................................................
0.50
20
°
to 30
°
............................................................
0.30
30
°
to 40
°
............................................................
0.10
40
°
to 90
°
............................................................
0.05
[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as
amended by Amdt. 23–43, 58 FR 18977, Apr. 9,
1993]
§ 23.1395
Maximum intensities in over-
lapping beams of position lights.
No position light intensity may ex-
ceed the applicable values in the fol-
lowing equal or exceed the applicable
values in § 23.1389(b)(3):
Overlaps
Maximum intensity
Area A
(candles)
Area B
(candles)
Green in dihedral angle L .............
10 1
Red in dihedral angle R ................
10 1
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