Shoutout to the crew that helped me with that crazy autopilot fault on a Citation last Thursday.

We got a write-up for intermittent pitch trim runaway on a Citation XLS. The book pointed to the servo, but after swapping it, the fault came back. A guy from another hangar suggested checking the wiring bundle near the elevator hinge, and sure enough, we found a single chafed wire in the harness. It took three of us about six hours total to find and splice it. Has anyone else had an autopilot issue that traced back to something simple like a single wire in a hard-to-see spot?

3 comments

3 Comments

faith_smith1mo ago

That wire bundle near the elevator hinge seems like a known trouble spot. Did you find any other wires in that section starting to show wear, or was it just that one single strand that gave up? I'm curious if a preventative inspection there is becoming a standard check on those models now.

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kellymurphy5d ago

Used to think that spot was overblown. Saw it on a preflight a few months back and wrote it off. Then my buddy’s shop had a strand fail on a 2018 model. Caused a minor flight control hiccup. Now I check that bundle every time I’m near it. That single strand you found is the warning sign.

tyler8221mo ago

Nah, that spot gets way too much attention honestly.