Text in force at 23-63: from 23-11, effective 11 Aug 1971.
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 0.440-0.320 y; "x" is not greater than y -0.170; and "y" is not less than 0.390-0.170 x.
[(c) Aviation white-- "x" is not less than 0.300 and not greater than 0.540; "y" is not less than "x-0.040" or "y0-0.010", whichever is the smaller; and "y" is not greater than "x+0.020" nor "0.636-0.400 x"; Where "y0" is the "y" coordinate of the Planckian radiator for the value of "x" considered.]
36 FR 12971 · Source