47 C.F.R. § 17.49
The owner of each antenna structure which is registered with the Commission and has been assigned lighting specifications referenced in this part must maintain a record of any observed or otherwise known extinguishment or improper functioning of a structure light. This record shall be retained for a period of two years and provided to the FCC or its agents upon request. The record shall include the following information for each such event:
[48 FR 38477, Aug. 24, 1983, as amended at 61 FR 4364, Feb. 6, 1996; 79 FR 56987, Sept. 24, 2014]