KAP140 autopilot trim issue

[YCCA]

Just bought a 2004 and have had an KAP 140 autopilot trim issue.. it mostly occurs in climbs or descents but has happened once or twice in level flight. In a climb or descent, All of a sudden you will get the warning autopilot pitch trim and the wheel trim wheel keeps rotating. When you disconnect the plane is definitely out of trim.. In level flight we have got the warning with the trim wheel not rotating and when disconnected, the nose wants to pop up.. Any ideas? Also does the electric trim normally run really slow? Meaning it seems much better to use manual for larger corrections and fine tune with the electric trim.. Any help is greatly appreciated

[Rich]

There is a clutch between the pitch trim servo and the trim mechanism itself. From your description it’s possible this is slipping.

[Rich]

BTW, I used to have a problem with the trim control hanging up on an extraneous fold of leather beneath the copilot seat. This would cause some clutch slippage.

[Steve]

Also, check the elevator trim tab "friction damper" rod for cleanliness and proper friction setting:

viewtopic.php?f=8&t=3489&p=68596&hilit= ... tab#p68596

Steve

[YCCA]

Also, check the elevator trim tab "friction damper" rod for cleanliness and proper friction setting:

viewtopic.php?f=8&t=3489&p=68596&hilit= ... tab#p68596

Steve

This might be hard to quantify but how fast does your electric stab trim run.. This is my first DA-40 but I do own a DA-20 and this one seems to run extraordinarily slow..

[Steve]

It runs fairly slowly. I haven't timed it, but maybe 20 seconds to run from one stop to the other. If the pitch trim runs for more than 5 seconds there is an aural "Trim in Motion" annunciation.

[YCCA]

IMG_0394.mov
IMG_0396.mov

It got worse today. Manual and electric would not work in the air and was like this on the ground

[Steve]

Links don't work...

[Rich]

IMG_0394.mov
IMG_0396.mov

It got worse today. Manual and electric would not work in the air and was like this on the ground

Assuming the indicator groove doesn't move when you try to operate it, this sounds like it's a problem in the linkage between the trim control wheel and the "large gear segment" addressed in the AMM:

Text from same:

A handwheel assembly on the center console controls the elevator trim system. The assembly has
a metal mounting frame. The frame attaches to the rear of the engine control assembly and the top
of the control bulkhead.

A long bolt through the mounting frame carries the handwheel. The bolt also holds friction disks,
plain washers and spring washers against the handwheel. Two jam-nuts let you adjust the friction.

A small gear wheel attaches to the handwheel. The small gear wheel engages with a large gear
segment with internal teeth. The gear segment has a pivot bolt at the bottom of the mounting frame.

A ball-stud attaches the eye-end of a long flexible cable to the gear segment. An extension to the
mounting frame to the rear makes the anchor point for the outer sheath of the cable.
The gear segment is also the trim indicator. The top face of the segment has a white line across
it mid way between the front and back. The top face can be seen through a slot in the cover plate.
The sides of the cover plate have markings to show the trim position.

[Chromer]

I had the same issue earlier this summer. Never had this occurred before my annual. My plane had some work done on the GNS 430. I found that the GNS530 was not tighten down properly and would move around in the holder. I tightened the hold down screw and haven't seen the problem since. Don't know if this helps.