Electric trim INOP

[PT20J]

1 hour ago, whiskytango said:

Amelia,

This happened to me on my first flight with my current 231.  It has been "fixed" several times, except that the problem remains - if using electric trim it goes to full nose up trim and stays there. I gave up and just use manual trim, which always works fine.  I would be interested in learning what the known issue and fix are, because apparently my A&P hasn't heard about it.

 

Check to see if SI M20-88 has been done. 

[whiskytango]

5 minutes ago, PT20J said:

Check to see if SI M20-88 has been done. 

Thanks! I will look at the logs tomorrow

 

[Bob Weber]

For less than the price of fuel, or an erroneous guess at which box is bad, I can guide you or your local tech to the actual problem quickly.

I've spent the last 4 decades at an avionics facility, with factory training, performing component level repairs on the bench, helping people all over the world like this.

If any repairs of components are needed, I now work directly with the technician we would go to before and during the repair.

You will also learn things about your system that will help you operate it, and diagnose any issues that may crop up in the future.

webairconsulting.com

[TGreen]

I am having this issue now. M20R, STEC 55X, intermittent failure of the electric trim. Avionics shop sent a tech to look but of course it was working fine. He seemed reluctant to start troubleshooting a system that was not presently in a state of failure. Recommended having the mechanical components of the trim system cleaned and lubed and them maybe replacing the yoke mounted switch.

Thoughts? Should I wait until it is in persistent failure? Can make oneself crazy trying to fix something that is not presently broken. But wouldn't want this to fail in IMC on approach. 

[carusoam]

If it is the BK trim switch…. They are known to wear… and easy to find replacement parts… trim requires two switches to make it work…

Might want to preemptively chase it with electronics cleaner… as it would be easy to have one of the switches just get dirty…

Got a pic of the switch?

PP thoughts only, not a mechanic…

Best regards,

-a-

[TGreen]

14 minutes ago, carusoam said:

If it is the BK trim switch…. They are known to wear… and easy to find replacement parts… trim requires two switches to make it work…

Might want to preemptively chase it with electronics cleaner… as it would be easy to have one of the switches just get dirty…

Got a pic of the switch?

PP thoughts only, not a mechanic…

Best regards,

-a-

Thanks Anthony. Also fails with autopilot engaged, i.e., autotrim fails. Does that eliminate the yoke mounted trim switch as a potential cause or does autotrim also run through that switch. 

[carusoam]

Let’s see if @Bob Weber is around…

 Stec55X question… AP going off line randomly…

Best regards,

-a-

[Bob Weber]

Trim issues with any autopilot need to be dealt with, often times they point out some other issues.

I need to play a game of 20 questions to get a better feel for the issue.

I can be reached 8am-6pm Eastern Mon-Fri at 616 822 1999

Visit webairconsulting.com

[Jake@BevanAviation]

I have seen a 55x fail on auto-trim and be thermal related.  When the unit was cold everything worked,  add a little heat and it would stop driving in one direction. Sent the unit back to S-Tec and they replaced the board assembly.

[carusoam]

@TGreen Todd, 

Have you seen the responses above…

Bob and Jake both know their details really well…

Best rgeards,

-a-

[laytonl]

Don, please let us know what you find.  Lee