Caught a bad solder joint on a nav antenna after a flight last Tuesday

I was doing a routine check on a Cessna 172 last week in Nashville and found cold solder on the coax connector for the GPS antenna. The plane had just come back from a 3 hour flight with no issues, but the signal was intermittent during taxi. If I hadn't caught it, that could've caused a missed approach in IMC conditions. Weird thing is it looked fine from the outside until I flexed the cable. Anyone else seen these cheap pre-made cables with bad solder from the factory? I'm thinking of just making all my own from now on.

2 comments

2 Comments

henrycooper10d ago

...and that's the thing nobody talks about with these factory cables. They might pass a continuity test but fail under vibration or temperature changes. I've seen it happen on brand new headsets too, where the mic stops working after a few months because the solder at the connector is brittle as hell. Making your own cables is fine if you've got the right tools and a steady hand, but what takes down a plane isn't always the joint itself, it's the stress on that joint from the cable being routed wrong or clamped too tight. That cold solder might have been fine for years if the cable wasn't pulled taut against a bulkhead every time the plane landed.

nancybailey10d ago

Man, you hit the nail RIGHT on the head. I've been doing this long enough that I always tell people to leave a little slack where the cable meets the connector, maybe a half inch loop taped down. That takes all the tension off that brittle factory solder joint. And if you're clamping a cable, use a split loom or at least some electrical tape to keep it from pinching right at the stress point. That alone can save you from a headset dying six months in.