What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Trim indicator

TroyBranch

TroyBranch

Well Known Member
Friend
Today I went to go flying and all was well, even the elevator trim indicator. After run up I taxied out made one last trim position check before rolling. Trim indicator was on bottom of the x. Wow I know I never trimmed it there. To be safe I decided not to take off even though it was clearly only the indicator as the trim tabs were where they should be and moving properly.

I traced all the sensor wires connections and seen nothing out of line. By this time the plane had been in the warm hanger for about an hour and sensor started to work again. The efis was on and I watched the sensor flash back to the proper spot a couple of ties and begin to work correctly.

Out of all this, has anyone had trim sensors stop working from the cold? I took the plane back out again and by the time my run up was done, it was out again.

It did not work for the entire flight. It was -15c on the ground and -2c in the air. I have never had this trouble before and I flew in much colder weather. Maybe it is time to change the trim servo as the internal sensor could be on the way out. Not really sure of what else it could be.
 
As long as the pins into your EFIS or EMS are not retreating a bit, like the Dynon egt/cht pins do from bending stress, I would say it is a dud trim servo. The potentiometer is worn or defective.

Not knowing where your elevator trim is would be a good reason to fix it ASAP, as the out of trim forces are not fun :eek:
 
It's probably a faulty connection or a bad potentiometer. I would favor a faulty connection. Next time it happens wiggle the wires around at all the connectors/terminations and watch the display. If I am not mistaken, when the flaps are reading down all the way the sense line is low which would indicate that the 2.5 volt line is the culprit. At the trim servo, check to see that you have 2.5 volts on the white/blue wire at the trim servo.
Bill
 
I did wiggle all connections and watched the display. Nothing happened. The AFS harness comes made by them so I have my doughts its that. I will pull it out and confirm that the pins are good. Hard to believe it would only show up after 330 plus hours.:confused:

I really think it must be the potentiometer in the trim servo. Guess its a new servo, not looking forward to changing it. I just hope I have enough of a service loop to get at the splice to be able to re-solder. Not sure if I was that smart when I built it:)

Day project!:D
 
Find the pin that corresponds with the potentiometer on the AFS. Then check to see if the pins are firmly locked in the connector. Then check your splices on the servo, then replace the servo. If that doesn't fix it move to a warmer climate!
 
Bad Servo

Finally got around to changing the trim servo. Problem solved!! It was not much fun crawling way back there in the tailcone to work. Much easier with no pushrod in the way during the build:)
 
You must log in or register to reply here.
Back
Top