190-01007-A1 System Maintenance Manual GTN 6XX/7XX Part 23 AML STCRev. 5 Page 4-34.4 Visual InspectionConduct a visual check of the GTN unit, switches, GMA 35 (if installed), and their wiring harnesses toensure continued installation integrity.1. Inspect the GTN unit(s) and GMA 35 for security of attachment, including visual inspection ofmounting racks and other supporting structure attaching the racks to aircraft instrument panel.Verify the countersunk fastener heads are in full contact with unit mounting rack holes. Re-torqueto 8.5-9.5 in-lbs if required.2. Inspect for signs of corrosion.3. Inspect all switches, knobs, and buttons for damage.4. Inspect condition of wiring, shield terminations, routing, and attachment/clamping.5. Check the fan intake slots on the sides and bottom of the GTN unit’s bezel for dust, dirt, orobstructions. Clean as needed.6. Conduct a visual check of the GPS/WAAS antenna cable overbraid if installed.7. Conduct a visual check of the WXR cable overbraid if installed.Test LightningProtectionThe GTN #1 main power input and NAV power input will have aTVS located at the LRU, for IFR non-metallic aircraft only. TheTVS must be replaced in accordance with Section 4.6.1.Conduct a visual check of the GPS/WAAS antenna cableoverbraid in accordance with Section 4.7Conduct a visual check of the WXR cable overbraid inaccordance with Section 4.8 if installed.After asuspected oractuallightningstrikeVisual InspectionThe GTN unit, GMA 35 (if installed), switches, and wiringharnesses should be inspected to ensure continued integrity of theinstallation. These items must be inspected in accordance withSection 4.4.12 CalendarMonthsItem Description/Procedure Interval
