- Joined
- Mar 8, 2022
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- 41
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Looking for some assistance with troubleshooting a problem with the pitch axis autopilot in my plane. It is an older S-Tec that was installed back in the mid 90's. As I understand it, there are 3 main components, the programmer (pn 0117), the pitch computer (pn 0110-4) and the pitch servo (pn 0107 or 0108, cannot see to confirm). Here is the issue. When performing the preflight checklist, steps 8 and 9 fail. So the pitch servo engages, press/hold down the servo disengages, releasing the switch re-engages the servo, so that works fine. However, the pressing the up switch, the servo fails to disengage as it should. Conversely, continuing to steps 15-18, pressing down trim works, the yoke moves, but pressing up, I can hear the servo working, but the yoke barely moves. Performing steps 25-26 do work, this is going full aft and full fwd to test the up/down trim annunciator lights.
I suspect that the issue is with servo itself, as the programmer and computer appear to be working. I have been talking with a local avionics shop about this issue, but with the labor rate to troubleshoot this, the more I can figure out on my own, the less time they will need to repair the issue. If it is the servo, there are two options to fix it, send it out to S-TEC for overhaul, the cost will be either $600 or $1300 depending on the what needs fixing, or I can procure a used servo, for considerably less, and simply have it swapped out?
I suspect that the issue is with servo itself, as the programmer and computer appear to be working. I have been talking with a local avionics shop about this issue, but with the labor rate to troubleshoot this, the more I can figure out on my own, the less time they will need to repair the issue. If it is the servo, there are two options to fix it, send it out to S-TEC for overhaul, the cost will be either $600 or $1300 depending on the what needs fixing, or I can procure a used servo, for considerably less, and simply have it swapped out?
