FAA Federal Aviation Regulations (FARS, 14 CFR)

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

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Angle from right or
left of longitudinal    Intensity
Dihedral angle (light included)      axis, measured from    (candles)
dead ahead
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L and R (red and green).............  0° to 10°...          40
10° to 20°..          30
20° to 110°.           5
A (rear white)......................  110° to 180°          20
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[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as amended by Amdt. 23-43, 58 FR 18977, Apr. 9, 1993]