Section 27.1391

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

specified in SectionSection 27.1391 and 27.1393, 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
greater than 100 candles, the maximum
overlap intensities between them may
exceed the values in Section 27.1395 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 more than 2.5 percent of
peak position light intensity.
Section 27.1391 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:
Dihedral angle (light included)

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

Angle from right or left
of longitudinal axis,
measured from dead
ahead

Intensity
(candles)

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

40
30
5
20

Maximum Intensity
Overlaps

Rear white in dihedral angle R .....

Intensity, l

0Section .........................................................................
0Section to 5Section ................................................................
5Section to 10Section ..............................................................
10Section to 15Section ............................................................
15Section to 20Section ............................................................
20Section to 30Section ............................................................
30Section to 40Section ............................................................
40Section to 90Section ............................................................

1.00
0.90
0.80
0.70
0.50
0.30
0.10
0.05

Section 27.1395 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 27.1389(b)(3).
Maximum Intensity

spaschal on DSK3GDR082PROD with CFR

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 ......

10
10
5
5
5

Area B
(candles)
1
1
1
1
1

5

Section 27.1397

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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 ycSection0.010,
whichever is the smaller; and
y is not greater than x + 0.020 nor
0.636Section0.400x;
Where yc is the y coordinate of the Planckian radiator for the value of x considered.
[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as
amended by Amdt. 27-6, 36 FR 12972, July 10,
1971]

Section 27.1399

Riding light.

(a) Each riding light required for
water operation must be installed so
that it can - 
(1) Show a white light for at least
two nautical miles at night under clear
atmospheric conditions; and
(2) Show a maximum practicable unbroken light with the rotorcraft on the
water.

554

VerDate Sep<11>2014

Area B
(candles)

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 27.1393 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:
Angle above or below the horizontal plane

Area A
(candles)

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