Why does nobody talk about using coax seal on D-sub connectors in wet wing areas?

I was working on a King Air out at KSDL a few months ago, chasing a weird intermittent nav issue that kept popping up after rain. Tried all the usual stuff, new connectors, different pins, even repinned a whole harness. Nothing stuck. Finally an old avionics guy from the next hangar over walked by and said, "You know those D-subs aren't sealed for moisture right?" I had no idea. He showed me how he wraps each one with a thin layer of coax seal before screwing the hoods down. It's not for RF, it's just to keep water from wicking down the wire strands into the connector. I redid all the connections in that wing with that trick and the problem cleared right up. Has anyone else run into moisture issues with those 25-pin D-subs in wet wing compartments?

2 comments

2 Comments

kimreed16d agoMost Upvoted

A buddy of mine used dielectric grease on a helicopter once and it did the same job.

tarar2716d ago

Yeah but dielectric grease is non-conductive right? That sounds like it'd just prevent corrosion, not fix any electrical issues mid-flight. Doesn't seem like the same application at all really.