by CFIDave » Sun Oct 28, 2018 3:42 pm
I experienced something similar on a DA40 last year, where the autopilot couldn't hold elevator trim when in "high-speed" cruise: The autopilot would add more nose-down trim, the wheel would then slip backwards to T/O trim, the autopilot would move the wheel forward again, and the cycle would repeat.
The first (and easiest) fix is to adjust (tighten) the friction block in the tail that's easily visible right under the elevator. If that doesn't work, then your mechanic/tech will need to take apart the center console to adjust the friction on the elevator trim wheel. A spring scale is used to measure the appropriate force (described in the DA40 AMM).
I experienced something similar on a DA40 last year, where the autopilot couldn't hold elevator trim when in "high-speed" cruise: The autopilot would add more nose-down trim, the wheel would then slip backwards to T/O trim, the autopilot would move the wheel forward again, and the cycle would repeat.
The first (and easiest) fix is to adjust (tighten) the friction block in the tail that's easily visible right under the elevator. If that doesn't work, then your mechanic/tech will need to take apart the center console to adjust the friction on the elevator trim wheel. A spring scale is used to measure the appropriate force (described in the DA40 AMM).