47 C.F.R. § 17.24-17.38

[Reserved] High Intensity White Obstruction Lighting Note: When authorized by the Commission, high intensity white obstruction lighting will be used in lieu of obstruction marking and lighting specified in §§ 17.23 through 17.37. In general, the number of levels of high intensity lighting specified is dependent upon the overall height of the skeletal frame or comparable main support structure, excluding antennas or similar appurtenances. A white capacitor discharge omnidirectional light is mounted on or adjacent to the appurtenance, if more than 6.10 meters (20 feet), to complement the lighting system. Where a dual lighting system is employed, i.e., high intensity white obstruction lighting during daylight and red obstruction lighting at night, the omnidirectional high intensity light, if equipped with an aviation red color filter for nighttime illumination, may be used in lieu of the 300 mm top beacon specified in § 17.24(a) and paragraph (a)(1) in §§ 17.25 through 17.37.