Realized I was grounding avionics gear to the airframe wrong for 2 years after a senior tech pointed out my ohm reading at a shop in Phoenix

Turns out I was using the static ground lug instead of the power return bus bar, causing intermittent comm errors on three separate installs has anyone else made this same dumb mistake?

2 comments

2 Comments

ryang653d ago

The static ground lug is meant for bleeding off static buildup, not handling return current from avionics that are actively pulling amps. If you were reading low ohms to ground, that doesn't automatically mean the circuit was wrong. A power return bus bar and a static ground lug might both show zero ohms to the airframe on a meter, but under load the voltage drop and noise characteristics are totally different. Did you actually chase down those comm errors or just assume the ground was the problem? I've seen guys redo a whole harness only to find out the intermittent issue was a bad crimp pin on the data line itself.

the_beth3d ago

@ryang65 that bit about voltage drop vs static ohm reading is exactly what I missed. Same boat here, chased comm errors for months on a King radio install. Turned out the static lug looked fine on the meter but under load it was a mess. Had to rip the panel apart and move everything to the bus bar. Classic rookie move.