Just had a GPS antenna fail mid-flight last Tuesday

I was flying a Cessna 172 out of a small field in Ohio and suddenly the GPS signal dropped completely. The unit was showing no satellites for about 10 minutes before I switched to the backup. Turned out the antenna cable had a corroded connector under the fairing. I ended up replacing the whole antenna assembly that afternoon. Has anyone else had a weird intermittent failure like that where the wiring looked fine at first?

3 comments

3 Comments

shane_park926d ago

Check the coax where it bends near the antenna, that's always the first thing to rot.

jana8816d ago

And that's exactly where the water gets in, works its way through the whole cable

xena_bailey186d ago

Check the coax where it bends near the antenna, that's always the first thing to rot." That's what @shane_park92 said, and they're not wrong. I read somewhere that a lot of GPS antenna failures in small planes come from moisture getting into the coax where it makes a tight bend. The water sits there and eats the shielding over time, so the signal drops out randomly. Dad had a similar thing with his old Garmin unit in his Piper - the cable looked fine on the outside but the inside was all green and crusty. Replacing the whole antenna cable fixed it for him. Probably a good idea to replace the whole thing if you already had corrosion visible, because the cable wicking moisture can be worse than the antenna itself.