My old boss told me to never trust a 'no fault found' on a G1000 autopilot without checking the harness first

I mean, I was working on a King Air last month and the pilot wrote up intermittent altitude hold drops. The log had a 'no fault found' from another shop. I spent a whole day running system checks and found nothing. Then I remembered what he said, pulled the panel, and wiggled the main harness bundle behind the MFD. Sure enough, altitude hold cut out. Found a chafed wire in the bundle that was shorting against a bracket. Fixed it in about an hour. Has anyone else had a specific piece of advice that saved you from chasing ghosts?

2 comments

2 Comments

eric_thompson7d ago

Ever hear the one about the loose cannon plug? Buddy of mine spent a week on a phantom transponder issue... turned out to be a connector behind the radio stack that wasn't fully seated from a prior install.

richard_kelly546d ago

Oh man, that's the worst kind of find. It's always the last thing you check. I've seen similar things with D-sub connectors on old GPS units, where just one pin backs out a hair and you lose a critical signal. You chase wiring diagrams for days, and it was just a bad seat from someone rushing. Makes you want to put a drop of nail polish on every connector after you snap it in.