Found a weird fix for a stubborn autopilot pitch trim fault on a King Air 200

The fault kept coming back after normal checks, so I tried cycling the circuit breaker five times fast, which cleared it for good. A retired guy at the FBO in Boise said it can reset a sticky relay in the old system. Has anyone else had to use this kind of odd reset on similar vintage gear?

2 comments

2 Comments

skyler_mitchell1mo ago

Oh man, that trick is gospel for some of the older stuff. I had a similar relay issue on a Navajo's autopilot where the trim would just run to the stop. The book said to check the usual suspects, but a mechanic showed me the "percussive maintenance" method, which was just whacking the relay box with the heel of your hand. Worked every single time until we finally swapped the unit. Those old systems have their own kind of logic.

tylerr391mo ago

Gotta love the official troubleshooting guide for 30 year old avionics. Step one is check the circuit breakers, step two is consult the maintenance manual, and step three is basically a secret handshake involving rhythmic breaker flipping or controlled violence against the panel. It's like the plane only works if you perform the correct ritual dance first. My personal favorite is the "turn everything off and count to ten" fix for a glitchy Garmin, which feels suspiciously like dealing with a toddler.