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aggierichie
08-29-2017, 10:05 PM
Howdy all, I need some help with my AP. I just bought the plane and it has a TrueTrack Gemini AP hooked to a garmin GPS. I have called TT and they are fantastic but i wanted to put it out here on VAF before sending the AP in because they are going to be a few weeks to get it back. Unfortunately I dont have any other artificial horizon in the plane so this would mean I would be grounded.

The AP works intermittently. You can set it to GPS, or to Track hold, and it will work fine and then all of a sudden bank hard left. Sometimes it happens immediately and sometimes it will work for a while and then do it. Today I flew it for an hour just fine and then all of a sudden it banked hard left. I disengaged the AP and then reengaged it and it only worked for about 4-5 mins until it banked. The one interesting thing it does is that when it turns the stick "bumps." Its hard to describe but if you watch the stick it pulls left but bumps, very similar to what it does if you force the stick to do something while the AP is engaged. Before you ask, I do let it spool up and get the gyros set before I move the airplane.

I wanted to lay this out in case anyone has had something similar and it was an easy fix. Worse case Ill pull it and send it in but any help would be appreciated. I did some tests with TT and they thought it was in the unit however could it be in the servos? It will ONLY go left and no other direction. I cannot seem to find anything that triggers it, it just happens.

Thanks all!!

Mike Macon
08-29-2017, 10:25 PM
I have the same AP and love it but I have never experienced your problem. I had some minor issues that they talked me through and it did go back for a software upgrade which took awhile. TruTrak has been great to work with and I would think if they trouble shot it with you, and asked for it to be sent in, you probably should. I will let others weigh in and maybe you will get lucky. If you have gyros spooling up, that is from a different instrument, possibly a "turn and bank indicator".

I am curious as to why you would be grounded without an artificial horizon. I flew my 6A for years without one. Not that I am trying to talk you into something that you are not comfortable with, just curious.

Jesse
08-30-2017, 06:46 AM
This should be an abvious thing that you already checked, but are you sure you are not way out of trim and it just can't hold it after a while?

Another thing is, if this is your only attitude indicator, you are probably not flying IFR. If this is the case, then removing it should not ground the airplane. Just cap the pitot and static lines and fly without attitude until it gets back. There are a LOT of airplanes out there that have never had an attitude indicator. It is not required for VFR flight.

pa38112
08-30-2017, 09:06 AM
If you engage a TT autopilot while on the ground it will "bump" to full deflection because it is not recognizing a response. That sounds like an internal problem.
If TT wants to look at it then that is your best bet. They turned my unit around very quickly when I sent it to them for a different issue. I sent it to them overnight and asked that they return it the same way. I think I was 3 day without it total.

Larry Parham
08-30-2017, 09:13 AM
My problem was similar to yours and it was NOT the TT it ended up being a problem in my AHARS unit. I sent it in and GRT repaired and my TT is solid now.

TruTrakAndrew
09-05-2017, 09:19 AM
Did you get this issue resolved?

Jesse is actually a very knowledgeable about the TruTrak product line, and in this case what he says is exactly where I would go too. It sounds like the servo is running out of torque due to a heavy wing. Especially since it seems to do it after a little while and then does it again soon thereafter. Try switching fuel tanks and checking the fuel load balance.

If this is not resolved or it doesn't appear to be a trim / fuel load issue, please feel free to give us a call and we will help you get it squared away!

thanks!

PerfTech
09-05-2017, 04:50 PM
.....Mine did this same thing and it turned out to be the
shear pin on the aileron servo arm. It had just a little
drag so it would engage, work a little bit then do the
same thing as yours. This is a very easy check and
hopefully a fix as mine was. Good luck, Allan:D