Got stuck on a weird autopilot trim runaway for three days straight

Last month on a King Air 200, the autopilot kept commanding nose-down trim right after engagement. We swapped the servo, checked the wiring, and even pulled the flight computer. Nothing showed up on the box. Finally, on day three, we found a tiny crack in the pitch trim sensor bracket letting it shift just enough under load. The whole hangar smelled like coffee and frustration. Has anyone else had a trim fault that hid like that? What was your 'aha' moment?

3 comments

3 Comments

milaw1420d ago

Man, I read a story once about a similar gremlin on a Citation. They had a roll trim issue that only showed up in a right turn. Tore their hair out for a week. Turned out the wiring harness for the aileron trim switch was routed too tight behind the panel. When you turned the yoke hard right, it pulled just enough to make a bad connection. Those hidden mechanical things are the worst to find.

logan_young2920d ago

Totally! It's wild how often the real problem is some tiny physical thing hiding in plain sight.

the_xena20d ago

Ugh, that sounds like a special kind of torture. Three days of chasing a ghost in the machine because of a hairline crack. My "aha" moment is usually just admitting I need more coffee.

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