My multimeter gave a false reading on a Cessna 172 and I almost missed a broken wire

Last Thursday I was checking some wiring on a Cessna 172 in the hangar. The circuit was showing continuity on my Fluke meter so I figured everything was fine. But something felt off so I tugged on the wire bundle near the firewall. That's when a wire slipped right out of its terminal strip clean broken but still touching enough to fool the meter. I learned the hard way that a continuity test alone doesnt catch bad connections under load. Now I always do a wiggle test on every wire I check even if the numbers look good. Has anyone else had a false reading mess up your troubleshooting time?

3 comments

3 Comments

charles83610d ago

You ever have a buddy who felt like a genius for finding a short with a multimeter, then the plane caught fire on the ramp? Happened to a guy I knew.

theajohnson10d agoMost Upvoted

Hang on, isn't that more about the guy not knowing what he was doing than the multimeter being the problem? @charles836, I've seen that too where someone thinks they're a hotshot with a tool they barely understand. That's on the person, not the tool itself. A multimeter in the right hands is like a good pair of work gloves, it just helps you do the job right. Probably would've been a lot worse if he didn't have that meter to even find the short in the first place.

emma9610d agoTop Commenter

Oh man, that reminds me of a guy who worked at the shop down the street from me. He fixed some wiring on a little Cessna and was so proud of himself, popping the hood and showing everyone his work. Next thing you know, the owner tried starting it up and the whole panel started smoking. They had to drag a fire extinguisher over and douse the whole cockpit. My buddy still brings it up at cookouts to mess with the guy, lol.