Trim is random

[ronin5573]

This is in a Tecnam 2008 t 2018 model with dual G3X screens. When the Autopilot master switch is on the trim isn’t working on the sticks. When you turn off the autopilot master, it’s normal. Maybe an update or something changed ? I tried to turn off esp but that didn’t seem to make a difference

[Flocker]

You mention "sticks" so I assume you checked the L/R switch on the panel - yes?

[ronin5573]

I checked the L/R switches. When the autopilot master is on the trim doesn’t move. It makes the trim icon on the G3x screens turn green showing the button being
Pressed but the actual trim doesn’t move the elevator

[Cluemeister]

Which autopilot do you have?

[ronin5573]

Dec 8, 2021 20:38:25 GMT Cluemeister said:

Which autopilot do you have?

Garmin gnc 307

[Cluemeister]

So does the trim work when just the Flight Director button is on, but not the autopilot?

Are you getting any error messages on screen?

[Flocker]

My AP will autotrim - both in the climb and when we level off. Perhaps that's what's going on here, but you should be able to override it. It might be a setting in the config menu. I'd start there.

[Flocker]

There is another thread on a similar topic:  Auto pilot pitch settings

[ronin5573]

Dec 8, 2021 23:01:35 GMT Cluemeister said:

So does the trim work when just the Flight Director button is on, but not the autopilot?

Are you getting any error messages on screen?

View Attachment

No errors

[ronin5573]

I'm annoyed. The parts manual Ed. 1 Rev. 0 – Issue January 2010 page 15 shows the pitch trim controller to be a t2-10a. Which I ordered. After removing the tail cone cover a Ray Allen B6-11T is installed.
Do I have an older version of the parts manual? I understand there is a euro and a US version for the p2008t but the docs should be correct or am I nutz?

[ChiMike]

My electronic trim is disengaged when the AutoPilot is engaged.

On my aircraft, if the AutoPilot is engaged and I want to disengage the AP, touching the up or down trim stick buttons disengages the AP immediately. I confess that I’ve done that accidentally a couple of times when placing my hand on the stick to toggle the transmit button to ATC. Oops!! Lol.

As some configurations are different— I have an AP on/off switch on my instrument panel that provides power to the AP. It must be manually switched ‘on’ before I attempt any functions on the AP panel.

Turning that power switch ‘off’ or hitting the trim control button on the active trim Stick are the methods to disengage the AP. I use the trim touch method 100% of the time.

And one safety note—I always ensure the instrument panel AP switch is ‘off’ until I’m ready to potentially use the AP after take off, and it is turned ‘off’ as part of my pre-landing checklist.

[ronin5573]

Jan 7, 2022 19:19:42 GMT ChiMike said:

My electronic trim is disengaged when the AutoPilot is engaged.

On my aircraft, if the AutoPilot is engaged and I want to disengage the AP, touching the up or down trim stick buttons disengages the AP immediately. I confess that I’ve done that accidentally a couple of times when placing my hand on the stick to toggle the transmit button to ATC. Oops!! Lol.

As some configurations are different— I have an AP on/off switch on my instrument panel that provides power to the AP. It must be manually switched ‘on’ before I attempt any functions on the AP panel.

Turning that power switch ‘off’ or hitting the trim control button on the active trim Stick are the methods to disengage the AP. I use the trim touch method 100% of the time.

And one safety note—I always ensure the instrument panel AP switch is ‘off’ until I’m ready to potentially use the AP after take off, and it is turned ‘off’ as part of my pre-landing checklist.

That’s when I have the issue , when the autopilot master switch is on . Then the stick trim isn’t working.

[ChiMike]

Ok. Yes. That is a difference. My master switch can be ‘on’ and the trim function still works. The trim function only does not work if the AP is actually engaged.

But next time I’m up (which should be next week) I will validate that. Mine may work just like yours when the master switch is on and I did not notice it. I usually don’t do any trim adjustments after I get to my cruise altitude and engage the AP.

[ronin5573]

So after calling Garmin ..... not there issue and calling RayAllen .. also not there issue I had the trim servo replaced. After an hour flight, the trim servo is perfect when the autopilot master is on and working correctly. I took apart the old trim servo and the solder joint which goes into the motor it self looked weak which could have been the issue. The old servo is fit pretty tight into the tail and is a pain to remove and reinstall due to where the screws are located. I just wanted to update this incase it help others.