Learned the hard way about shielding on a King Air in Wichita

Had a recurring squawk on the #2 nav receiver that drove me nuts for two days. Pulled the rack, reseated everything, swapped the unit, no luck. Finally traced it to a chafed shield wire where the bundle ran under a seat track, looked fine until you flexed it just right. Took a 10x loop and a wiggle test to find it, now I do that before I ever touch a box. Cost me about 6 hours of billable time, but I've caught two similar issues since. Anyone else had shield failures that only show up with vibration?

1 comments

1 Comment

nina1473d ago

Check the antenna coax next time, not just the rack wiring. Moisture gets in the connector and corrodes the braid from the inside, so the shield looks fine on the outside but loses continuity around the bend. A simple resistance test with the coax disconnected will show it before you waste a day on wiggle tests.