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Found a faster way to trace a 28V short in the cockpit without pulling the whole panel | Avionics Technicians - SMM Buzz

rileyp49•3mo ago

Found a faster way to trace a 28V short in the cockpit without pulling the whole panel

Was chasing a intermittent short in a King Air 200 the other day up in Bangor, Maine. Tried the standard wiggle test and continuity checks, nothing showed until I used a thermal camera on the breaker panel - spotted a hot spot on pin 12 of the master relay in like 2 minutes. Anyone else use IR tools for this kind of thing or still stick to the old multimeter method?

3 comments

3 Comments

blairtaylor3mo ago

Oh man, I had almost the exact same thing happen on a Cessna 414 last winter. Spent a whole afternoon hunting a brake light short with a multimeter and got nowhere. Broke out my phone's thermal attachment and found the bad splice in the wing root in under five minutes. Never going back to just the old way for intermittent stuff.

margaret_williams53mo ago

Actually I just read an article in Aviation Maintenance Magazine (someone left it in the break room) about a guy who used a thermal camera to find a short in a Citation's landing light circuit that had been driving the shop crazy for weeks. They had swapped relays, chased wires, even replaced the whole harness section - took him maybe 10 minutes with the IR tool. I've been using one for about two years now and it's honestly a game changer, especially for intermittent stuff that only heats up under load. The old multimeter method is fine for steady state problems but it just doesn't catch those transient hot spots (you know, where the resistance changes when things warm up). Thermal cameras are getting cheaper too, you can pick up a decent one for under $500 now which pays for itself pretty quick when you're not pulling panels all day.

the_parker3mo ago

Under load is the key part that always gets overlooked. Those intermittent shorts only show up when the current is actually flowing and things heat up, which makes the multimeter basically useless. I've always wondered though - do the cheaper thermal cameras under $500 actually have the resolution to find a hot spot in a messy bundle of wires, or do you need to spend a bit more? Would rather drop the cash on something decent than waste time on a toy that can't tell a bad splice from a warm bulkhead.