97-53 Garmin GTR 225B COM Radio Installation (continued)
E. Antenna (continued)
Removal
1. Turn battery switch off and pull out COM radio (5 amp) circuit breaker on circuit
breaker panel.
2. Using plastic scraper, remove B270-1 sealant from around COM antenna at
corners where it attaches to tailcone.
3. Disconnect antenna cable from antenna. As required, remove B270-13 sealant from
fastener holes. Remove screws securing antenna to tailcone & remove antenna.
Installation
1. Turn battery switch off and pull out COM radio (5 amp) circuit breaker on circuit
breaker panel.
2. Remove paint & primer from antenna mating surfaces to ensure electrical ground.
3. As required, apply light coat B270-13 sealant to screw threads and install
screws securing antenna to tailcone. As required, seal around screw heads and
fill fastener holes using B270-13 sealant and allow to dry. Verify security.
4. Apply small bead B270-1 sealant (0.1 inch max in height) around antenna at
corners where it attaches to tailcone and allow to dry.
5. Connect antenna cable to antenna. Verify security.
6. Perform ground checks per Part D steps 4 and 5.
F. Scheduled Maintenance and Inspections
NOTE
All factory-installed Garmin units are “on condition” and do not
require scheduled periodic maintenance. Units feature a BIT
(Built-In Test) function during each initial power-up that will
detect internal failure(s) and alert pilot.
NOTE
Refer to § 97-60 for avionics software information.
G. Special Maintenance and Inspections
1. Turn battery & avionics switches off. Open circuit breaker panel and upper console.
2. Inspect condition of and verify no obvious damage to COM radio, radio tray,
copper bus bars, circuit breaker, and wiring. Verify no loose, chafed, or broken
wires or terminals. Verify no evidence of arcing. Verify equipment security.
3. Secure circuit breaker panel and upper console. Perform ground checks per Part
D steps 4 and 5.
APR 2019 Chapter 97 Avionics Page 97.19
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