Section 25.1391

14 CFR Ch. I (1-1-19 Edition)

the minimum intensity prescribed in
Section 25.1391 for the corresponding angles in
the horizontal plane.
(3) Intensities in overlaps between adjacent signals. No intensity in any overlap between adjacent signals may exceed the values given in Section 25.1395, except
that higher intensities in overlaps may
be used with main beam intensities
substantially greater than the minima
specified in SectionSection 25.1391 and 25.1393 if the
overlap intensities in relation to the
main beam intensities do not adversely
affect signal clarity. When the peak intensity of the forward position lights is
more than 100 candles, the maximum
overlap intensities between them may
exceed the values given in Section 25.1395 if
the overlap intensity in Area A is not
more than 10 percent of peak position
light intensity and the overlap intensity in Area B is not greater than 2.5
percent of peak position light intensity.
Section 25.1391 Minimum intensities in the
horizontal plane of forward and
rear position lights.
Each position light intensity must
equal or exceed the applicable values in
the following table:
Angle from right
or left of longitudinal axis, measured from dead
ahead

Dihedral angle (light included)

L and R (forward red and
green).
A (rear white) .....................

0Section to 10Section ..............
10Section to 20Section ............
20Section to 110Section ..........
110Section to 180Section ........

Intensity
(candles)

40
30
5
20

Section 25.1393 Minimum intensities in any
vertical plane of forward and rear
position lights.
Each position light intensity must
equal or exceed the applicable values in
the following table:

spaschal on DSK3GDR082PROD with CFR

Angle above or below the horizontal plane
0Section .........................................................................
0Section to 5Section ................................................................
5Section to 10Section ..............................................................
10Section to 15Section ............................................................
15Section to 20Section ............................................................
20Section to 30Section ............................................................
30Section to 40Section ............................................................
40Section to 90Section ............................................................

Intensity, l
1.00
0.90
0.80
0.70
0.50
0.30
0.10
0.05

Section 25.1395 Maximum intensities in overlapping beams of forward and rear
position lights.
No position light intensity may exceed the applicable values in the following table, except as provided in
Section 25.1389(b)(3).
Maximum intensity
Overlaps

Area A
(candles)

Green in dihedral angle L .............
Red in dihedral angle R ................
Green in dihedral angle A .............
Red in dihedral angle A ................
Rear white in dihedral angle L ......
Rear white in dihedral angle R .....

10
10
5
5
5
5

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Where - 
(a) Area A includes all directions in
the adjacent dihedral angle that pass
through the light source and intersect
the common boundary plane at more
than 10 degrees but less than 20 degrees; and
(b) Area B includes all directions in
the adjacent dihedral angle that pass
through the light source and intersect
the common boundary plane at more
than 20 degrees.
Section 25.1397

Color specifications.

Each position light color must have
the applicable International Commission on Illumination chromaticity coordinates as follows:
(a) Aviation red - 
y is not greater than 0.335; and
z is not greater than 0.002.

(b) Aviation green - 
x is not greater than 0.440Section0.320y ;
x is not greater than ySection0.170; and
y is not less than 0.390Section0.170x.

(c) Aviation white - 
x is not less than 0.300 and not greater than
0.540;
y is not less than xSection0.040; or y0Section0.010, whichever is the smaller; and
y is not greater than x + 0.020 nor
0.636Section0.400x;
Where y0 is the y coordinate of the Planckian
radiator for the value of x considered.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25-27, 36 FR 12972, July 10,
1971]

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