47 CFR 17.49: Recording of antenna structure light inspections in the owner record.

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:

(a) The nature of such extinguishment or improper functioning.

(b) The date and time the extinguishment or improper operation was observed or otherwise noted.

(c) Date and time of FAA notification, if applicable.

(d) The date, time and nature of adjustments, repairs, or replacements made.