Autopilot

Roger Holleger

Filing Flight Plan
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Mar 5, 2014
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Roger
My 1967 Piper Arrow has a Piper Autocontrol lll. When I turn it on it allows the Bank Command knob to control the ailerons, however when the HDG is activated it turns to extreme right. The bug has no effect. Does anyone have any experience with this kind of problem?
 
Sounds like a disconnect with the signal from the DG.
 
autopilot central in tulsa has a lot of experience with that type of problem and they even return phone calls
 
Piper Autocontrol III operating best practices:

  • Take off
  • Establish communications with ATC, receive clearance
  • Enter Clouds
  • Set Heading Bug and Engage Autopilot
  • Observe sudden uncommanded roll to the right or left
  • As the bank passes 30 degrees, wonder why you even expected it to work in the first place
  • Disengage autopilot and hand fly
 
Can't say for sure exactly what's wrong, but I can say for sure there's a failure in the system. Beyond sticking your head under the panel to see if something appears unplugged, take it to a competent avionics shop and let them troubleshoot and fix it.
 
The Autocontrol III is the same thing as a Century II, and that's no bad thing. If it works in roll mode, then you're halfway there. As suggested, get to a competent shop (tell us where you are, and there may be a suggestion here), and they can readily troubleshoot.

Could be in switching; could be the DG; could just be a wire.
 
Could be in switching; could be the DG; could just be a wire.

or connector, or analogue computer, or output amp, or....how many things did I have to fix before the darn thing work jus' fine (for the past 400 hrs)? 'cept for the random right turns 'cause the D-A converter on the Aspen was mis-matched by the "competent" avionics shop
 
My 1967 Piper Arrow has a Piper Autocontrol lll. When I turn it on it allows the Bank Command knob to control the ailerons, however when the HDG is activated it turns to extreme right. The bug has no effect. Does anyone have any experience with this kind of problem?

I flew on an Archer a while back that had the same autopilot and the same problem. No idea how to fix it, I just didn't use the autopilot.
 
Thanks for your input, I called AutoPilot Central and they gave me some ideas on how to trouble shoot.
 
My club recently bought an Archer with the same autopilot, and similar issues. So far, my experience is similar to Ren's. It does tend to keep the pilots awake when they turn the heading bug and suddenly find themselves in an unexpected 45 degree bank...
 
My 1967 Piper Arrow has a Piper Autocontrol lll. When I turn it on it allows the Bank Command knob to control the ailerons, however when the HDG is activated it turns to extreme right. The bug has no effect. Does anyone have any experience with this kind of problem?

I had a similar problem on my unit and it was a broken solder joint on the wire from the DG to the control unit.
 
Most likely problem is the connector in the back of the DG. Those old Century connectors have tended to loosen up over time. Amphenol no longer makes them, but they are now made by Cooper Interconnect. Mouser, Allied, or Newark have the connectors. I would have the local avionics shop check that circuit and replace the connector on general principles. If that doesn't cure it, then the DG itself may be suspect.
 
Consensus says I get to choose either the fluffy bunny or the teddy bear.
 
My club recently bought an Archer with the same autopilot, and similar issues. So far, my experience is similar to Ren's. It does tend to keep the pilots awake when they turn the heading bug and suddenly find themselves in an unexpected 45 degree bank...


On our club pipers.. we have two with the autocontrol autopilot.

I don't fly them that frequently and I allow myself a moment of thought before pressing the button to engage the autopilot. Typically I see either the kamikaze or the drunken sailor.

Kamikaze = Sudden uncommanded roll to the left or right.

Drunken Sailor = Maintains a course, but with shallow S turns
 
On our club pipers.. we have two with the autocontrol autopilot.

I don't fly them that frequently and I allow myself a moment of thought before pressing the button to engage the autopilot. Typically I see either the kamikaze or the drunken sailor.

Kamikaze = Sudden uncommanded roll to the left or right.

Drunken Sailor = Maintains a course, but with shallow S turns
I've seen that with the Century autopilots under both their own name and Piper's. However, when they do that, it's usually a sign of a reparable problem, and once fixed, it works just fine again.
 
I've seen that with the Century autopilots under both their own name and Piper's. However, when they do that, it's usually a sign of a reparable problem, and once fixed, it works just fine again.

Also it illustrates why the ground tests should be run when the pilot is unfamiliar with a particular aircraft or hasn't flown it recently.
 
Also it illustrates why the ground tests should be run when the pilot is unfamiliar with a particular aircraft or hasn't flown it recently.

Its a good idea, I do this in our Mooneys which have a written procedure.
 
Its a good idea, I do this in our Mooneys which have a written procedure.

Century has the ground test procedure available for download on their website. Not much help unless the pilot knows about and has the opportunity to download ahead of time (of course). The procedure should be in the AFM/POH supplement but we all know how that goes.
 
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