This entry records the installation of the Garmin GDL82 ADS-B OUT system. The system was installed using STC SA02573SE dated December 14, 2017 as the basis STC for the GDL82 ADS-B OUT transmitter and position source pairing. Removed: UAvionix SkyBeacon ADS-B out transmitter P/N UAV-1001856-002. Installed: Original Cessna left hand wingtip light assembly & Garmin GDL82 ADS-B Data Link P/N 010-01560-31. Interfaced GDL82 with existing Garmin GTX-327 transponder. Optional annunciator and anonymous switch NOT installed. The ADS-B out transmitter is compliant with FAA TSO-C154c. The internal GDL82 WAAS GPS receiver was used as the position source and is compliant with FAA TSO-C146a. The system electrical interface was completed IAW Garmin GDL82 installation manual 190-01810-00 Rev. 3 dated December 2017. A satisfactory ground test of the GDL82 system was completed using an Aeroflex IFR6000. The ground test checked for proper configuration and equipment performance requirements. The installed GDL82 system has shown to meet the equipment requirements of 14 CFR 91.227. The FAA approved Flight Manual Supplement, Garmin document # 190-01810-13 Rev. 1 dated December 2017, covering the operation limitations of the installed Garmin GDL82 has been added to the Cessna 172M Basic Airplane Flight Manual. The instructions for continued airworthiness for the GDL82 (Garmin Document # 190-01810-11 Sec. 4) has been provided to the aircraft owner for incorporation into the aircraft maintenance program. An electrical load analysis was computed and found that this installation and the existing aircraft electrical load does not exceed 80% of the aircraft alternator rated output. Weight and Balance has been revised. Equipment list has been updated. See FAA Form 337 Dated 3/25/25. Bay Avionics, CRS# K56R207Y W.O. 2781.