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Elevator trim servo locked up?

TJHeller

I'm New Here
My plane has been sitting for almost 2 months while an avionics upgrade was taking place. Upon arrival to pick it up it was discovered that the elevator trim wasn’t functioning. There’s power at the panel, switch, and motor, and it worked 2 months ago. An internet search revealed its not uncommon for servos to just freeze, and I’m thinking this is what happened. Anyone have similar experience?
 
That ray allen servo/motor is used in a LOT of planes and doesn't seem like they fail or stick often. I would be looking at binding in either of the two cables or possibly the aluminum transfer components being stuck. They sit on the plate near the servo and they transfer the force from the servo to the two cables. Pull the Emp cover and get eyes on the components under the turtle deck.

Larry
 
Never had an issue with the trim servo - itself. My RV14 had a nonfunctional trim one day and it turned out to be the micro molex plug supplied (since replaced). Like Walt indicated, I have had TT servo completely lock up and had to send back.
 
Never had an issue with the trim servo - itself. My RV14 had a nonfunctional trim one day and it turned out to be the micro molex plug supplied (since replaced). Like Walt indicated, I have had TT servo completely lock up and had to send back.

Don’t ever use the supplied micro molex plugs provided in the wiring kit.

Carl
 
We had an issue with the trim servo on my wife's plane. After many instances and hours of searching, it turned out to be a defective/intermittent micro switch in the stick's trim switch.
 
just me

We had an issue with the trim servo on my wife's plane. After many instances and hours of searching, it turned out to be a defective/intermittent micro switch in the stick's trim switch.

Just for kicks, I originally planned to only have the pilot stick with trim buttons, but this thought crossed my mind that if a trim switch failed, i would be up a creek without a paddle. So i added trim buttons to the copilot's stick too.
 
Just for kicks, I originally planned to only have the pilot stick with trim buttons, but this thought crossed my mind that if a trim switch failed, i would be up a creek without a paddle. So i added trim buttons to the copilot's stick too.

Hopefully you arranged the wiring so pushing trim up while the passenger is (inadvertently) pushing trim down won’t trip the CB or blow a fuse. Likewise, I have heard of serious trim excursions when the passenger rested a magazine against the trim button. Something to think about.
 
TCW Technologies

https://www.tcwtech.com/product/safety-trim-intelligent-servo-controller/?v=7516fd43adaa

This was my answer to the frequent reports of stuck trim motors.
It comes with a few additional features besides trim reverse etc.

A trim motor malfunction seems less of an issue in the spring biased aileron installation but a rather difficult problem to handle on the elevator.

A passenger trim disconnect switch is also a good idea, installed in my 10 as well
 
Hopefully you arranged the wiring so pushing trim up while the passenger is (inadvertently) pushing trim down won’t trip the CB or blow a fuse. Likewise, I have heard of serious trim excursions when the passenger rested a magazine against the trim button. Something to think about.

These were my concerns as well, so have no copilot stick trim. However, I also was worried about the stick button failing and the 10 is a bear without up trim on landing. So I put a small DPDT (Mom-off-Mom) switch on the panel as a backup. No real risk of a passenger activating it, though still can be used by someone flying right seat.

Larry
 
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Welcome to VAF

Jason, welcome to VAF.

Have you tried to apply power directly at the servo----a 9v battery will be enough to make the servo move if it will.
 
These were my concerns as well, so have no copilot stick trim. However, I also was worried about the stick button failing and the 10 is a bear without up trim on landing. So I put a small DPDT (Mom-off-Mom) switch on the panel as a backup. No real risk of a passenger activating it, though still can be used by someone flying right seat.

Larry
I installed a lever-lock trim cutout switch on the left panel with easy access in the event it “runs away”. In the event your pitch trim jams, plan a no-flap landing since the pitch forces will not be as heavy. Have never had a problem in the -10, but I have in other airplanes I’ve flown in another life. Fly safe!
 
Answer

Hopefully you arranged the wiring so pushing trim up while the passenger is (inadvertently) pushing trim down won’t trip the CB or blow a fuse. Likewise, I have heard of serious trim excursions when the passenger rested a magazine against the trim button. Something to think about.

I am using the Garmin GEA24 for trim relays. It has priority to pilot’s trim inputs. And the circuit breaker is in front of the pilot, not part of the CB “stack”
 
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Hopefully you arranged the wiring so pushing trim up while the passenger is (inadvertently) pushing trim down won’t trip the CB or blow a fuse. Likewise, I have heard of serious trim excursions when the passenger rested a magazine against the trim button. Something to think about.

This is why I installed a co-pilot switches enable/disable switch.
 
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