Had a weird static issue on a Garmin G1000 install in a Cessna 172 last month

We were finishing up the panel work at our shop in Daytona and the PFD screen kept showing random static lines during ground power checks. Traced it back to a bad ground strap on the new audio panel rack, which was picking up noise from the alternator field wire running too close. Has anyone else run into weird interference like that after what seemed like a clean install?

2 comments

2 Comments

cole_mitchell81mo ago

Wait, isn't the alternator field wire usually DC? That shouldn't cause that kind of screen noise on its own. Static lines on a PFD are almost always from an AC source. Are you sure it wasn't the alternator output wire, or maybe a bad splice in the aircraft's main power feed that was letting AC ripple through? A bad ground would make that worse for sure, but the field wire itself is a weird culprit.

leor371mo ago

Man, that reminds me of a buddy who had a gremlin in a Cherokee's new nav system. The heading would just skip a few degrees now and then, drove him nuts. Turned out the shielding on a bundle of antenna cables was crushed behind the panel, right where it passed by a strobe power supply. Took him a week to find that one.