Vent: Fuel panel shorted out on a Cessna 172 yesterday

Was doing a routine inspection on a rental 172 at our shop in Tucson, everything looked fine until I powered up the avionics and the fuel quantity gauge started jumping all over. Turned out a wire had chafed through behind the panel, took me 3 hours to trace it. Anyone else run into weird intermittent electrical gremlins on smaller GA birds?

2 comments

2 Comments

eva_lewis17d ago

Chafed wire behind the panel is a classic problem on high-time 172s. The factory wire routing uses those plastic P-clips that eventually get brittle and let the wire bundle rub against the airframe. Pull the panel off and look for any wire that crosses a sharp edge or screw tip, especially near the fuel selector valve bracket. Also check the ground wire on the sending unit, those corrode over time and cause the same jumping needle effect.

ivangrant17d ago

Did you find any chafing on the sending unit ground wire too, because I dealt with that exact issue last month.