continous trim down indication and pitch hunt

[Mathew]

Hi all

I am flying a CTSW fitted with a Digiflight II VSGV. The control unit shows a continous trim down indication and there is a slight hunt in the pitching plane.
The unit was replace a few days ago and there is no mechnical problem. Has anyome experienced the same problems? Thanks

[TrutrakTech]

The trim indication comes from a signal from the pitch servo. It is possible that it needs to be recalibrated.

Also, on the Digiflight II, the trim sensor input and the pitch servo torque output are right next to each other on the connector. If during reinstallation those pins somehow got bent or those wires are shorting to each other, this would feed the 5v torque signal into the trim sensor input causing a constant trim annunciation.

For the slight hunting in pitch, make sure your vertical activity settings are exactly what they were in the other AP controller. If it is a slow hunt in still air, you can try increasing the static lag setting from 0 to 1. Thanks!

[PhantomPholly]

What kind of airplane are you flying?

The pitch hunting can occur for a number of reasons. Try reducing the Vertical Activity setting - on some of these light weight homebuilts it can be very low. Also, adding a static lag factor can smooth things out. Your static system needs to be working very well - one way to test for problems with the static system is to run the autopilot off of cabin air. If it gets noticeably better it is likely some issue with your static system.