piper altimatic 3 autopilot issues with Garmin 430
I have a '79 turbo lance with the Altimatic III autopilot. Just installed a Garmin 430, MX-20 and a KCS-55A HSI. Autopilot worked awesome with my old Trimble GPS....but with the new system it's steering back and forth trying to lock on the NAV, or Heading. It doesn't make a difference if you change the dial to LOC or Omni either, just turns back and forth. I had a regular DG in the plane before the HSI so I'm not sure if the issue is the Garmin GPS information or the HSI information......any ideas
Re: piper altimatic 3 autopilot issues with Garmin 430
Hi,
I had the exact problem when I installed my 430 a few years ago. Tried everything, calls to Garmin and autopilot manufacturer. Found an old timer avionics guy who knew ust what to do. Make sure that your Garmin or whatever radio you are trying to use to NAV by is set to an active VOR frequency. If it is set to an ILS freg. or anything but an active VOR frequency it won't be getting a signal and it will try to seek one. You don't have to be using that VOR freg. but an active one must be set in.
Try it. Hopefully that will corerect your problem. Not sure why it happens with certain systems but It worked for me. Even now if I put in something other than an active VOR freg. I loose all NAV tracking.
Good Luck
Re: piper altimatic 3 autopilot issues with Garmin 430
Your setup is pretty much the same as mine was a few months ago.
It does this even in HEADING position? The Garmin 430 isn't even in the circuit in that case - just the HSI heading bug. That would imply an autopilot, HSI or interconnection problem.
If the issue is with NAV/OMNI/LOC only then:
You may want to try playing with your Course Indicator on the HSI. On an HSI equipped system, the Course Indicator is in the circuit, even when following a NAV source - for reasons that I don't really understand. I found that sometimes I had to move the course indicator 10-15 degrees one side of course or the other to get the autopilot to track.
If that doesn't solve it, I'd suggest bringing it back to the installer. One thing that I would suggest is a GPSS unit. Even when it works, the normal analog NAV/OMNI/LOC isn't the greatest. GPSS is fairly cheap and wonderful to fly with.
Re: piper altimatic 3 autopilot issues with Garmin 430
It's interesting, when you put it on heading, it tracks much better, just some slight swaying back and fourth, On LOC it's moderately turning back and forth and on OMNI and NAV is is aggressively turning which leads me to believe that it's linked to the HSI/Autopilot interface. If you turn of the heading hold and just lock on altitude on the autopilot and steer with the bank trim, it works perfectly which rules out the autopilot and takes me back to believe it might be the HSI? Also, the autopilot worked perfectly with my trimble GPS and the Sigmatek DG that was in the plane before the HSI and 430 were added. I'll try your suggestions and welcome any other suggestions. My avionics guy and I have tried a couple other fixes to no avail...
Re: piper altimatic 3 autopilot issues with Garmin 430
What's happening in your plane doesn't happen in mine. I do get some wing rocking at slow speed sometimes.
Honestly it sounds like an autopilot issue to me. The autopilot has 4 different gains associated with each of the 4 feedback channels - HDG/NAV/OMNI/LOC and the autopilot will respond differently to each.
Certainly the setup does fundamentally work - it's what I have in my plane (plus a DAC GPSS added 6 months ago).
