FAA Federal Aviation Regulations (FARS, 14 CFR)

Each position light intensity must equal or exceed the applicable values in the following table:

------------------------------------------------------------------------
Intensity,
Angle above or below the horizontal plane                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]