Shoutout to the old head who told me to check the ground first, always

I was chasing a gremlin in a G1000 system for a solid three hours. The PFD kept blanking out at random, but only during engine run-up. I swapped the display unit, checked every connector on the bus, even re-seated the LRUs. Nothing. This retired guy who used to work the line saw me and just said, 'Kid, it's always the ground.' I was sure it wasn't, but I went back and ohmed out the main avionics ground strap to the airframe. It read fine at rest, but when I wiggled the bundle near the firewall, the reading jumped all over. A tiny crack in the braid you couldn't even see. Fixed the strap and the problem vanished. I felt like a total rookie, but it saved me another day of headache. How many other 'intermittent' problems have you guys traced back to a bad ground path?

4 comments

4 Comments

piper_kim2mo ago

How many times do we have to learn this lesson? Ground gremlins are the worst kind.

the_tyler2mo ago

Seriously, what even causes a ground gremlin? Is it just bad wiring or something they keep missing in checks?

thomas_torres1mo agoMost Upvoted

Dude, it's honestly such a weird combo of things, right? Usually it's a mix of bad connections and moisture getting into places it shouldn't, so even if the wiring looks fine it can still act up. I feel for you though, those delays are the absolute worst, especially when nobody can figure it out fast.

robin5912mo ago

My last flight got delayed 6 hours because of a ground gremlin in the cargo hold sensor. They had to bring a whole new crew in, it was a mess. Why do they always show up at the worst possible time?