Autopilot engages by turning coupler dial



  • It took some time to understand what is happening for me.
    I usually set up NAV1/NAV2 prior departure, set OBS for the first VOR on NAV1 (HSI correctly shows the radial) and then I set the coupler to NAV.
    Then taxied for takeoff just to see that during takeoff run suddenly as soon as I get a bit lift, the Piper goes crazy with full aileron right, causing a wingstrike.
    With a lot of manual input I could override the effect. Once recovered if I try to enable the AP again with the switches, it again starts a full right roll instead of following whatever the coupler is dialed to.

    The reason seems to be that the AP auto-engages in the background (invisible) when turning the coupler - while the AP switch and HDG switch both remain in OFF, the AP is enabled!
    The weird thing is that at that point you can see the aileron deflection on the wing if you look at it, but the yoke still remains in centered position (which is why I did not notice it first).
    Also the AP will not follow the VOR neither the HDG (when switching back to HDG mode on the coupler), it seems to be broken some time. Switching around at some point seems to fix it though. I didn't find the right sequence that does that.

    I reported this to Support already, the workaround for me is to strictly not touch the AP controls/coupler prior takeoff, then first set heading bug to current heading, enable AP+HDG switches and then switch the coupler to OMNI or NAV.
    Only this sequence leaves me with a properly working AP.

    I also recorded a video from cold&dark if someone needs proof 😉
    https://www.youtube.com/watch?v=MX9VgToVXM8



  • I've experienced the same thing on takeoff. I couldn't understand it at the time, so thanks for the explanation.

    I've also noticed that the aircraft jumps when switching the coupler from NAV1 to NAV2 even when the autopilot is not switched on.



  • @Sender46 said in Autopilot engages by turning coupler dial:

    I've also noticed that the aircraft jumps when switching the coupler from NAV1 to NAV2 even when the autopilot is not switched on.

    According to the manual, you first have to set your heading bug to current HDG, then switch coupler to HDG mode, then retune or switch the NAV source and set OBS, then switch the coupler back to NAV (or rather OMNI which is recommended in most cases).
    You don't need to touch the coupler when staying on the same frequency but changing OBS (while overlying and setting the outbound radial for instance). That worked fine for me when I last tried it.

    Here's a manual for the real AutoControl IIIB:
    https://www.montereynavyflyingclub.org/Other Docs/AutoControl-IIIB.pdf
    Page 15 has a note that you should switch to HDG and then retune. It's recommended to use the same NAV radio instead of switching to another.

    That being said, I don't know if the "jump" you experience is still a bug.



  • @copper Thank you for that and the link. That all makes sense and yes it does work. I just don't understand why switching from NAV1 to NAV2 makes the plane jump when the autopilot is not switched on.


  • JF Staff

    Whilst this is not a support forum, please submit all bugs to the below link

    https://support.justflight.com/support/home



  • @Craig said in Autopilot engages by turning coupler dial:

    Whilst this is not a support forum, please submit all bugs to the below link

    I did on the first day I got the addon. And a Craig already replied to my ticket, that you're working on it 😉



  • I have experieced this rolling behaviour. I was flying on HDG mode and, although i was already on my nav radial, when i turned the coupler to NAV mode with AP still engaged the plane banked violently down and left. Afterwards any attempt to engage AP in any mode caused the violent roles and it really ruined my flight.

    Is this a user error or a bug?



  • @Bagpipe said in Autopilot engages by turning coupler dial:

    Is this a user error or a bug?

    It is a bug and according to the changelog of the upcoming update it should be fixed. Fingers crossed 🙂
    With the workaround by avoiding this situatoin as stated above I was able to use the autopilot without major issues for a few flights already and providing as much info as possible to support it helps figuring out these issues that quickly.



  • Thank you for this... I have been experiencing similar sudden right or left full wing dive without apparent reason and I was really freaking out... I somehow could relate it to the AP but was not at all certain about it...

    As far as I could tell, the issue will come up without the AP being even engaged, and it will disappear if I activated and then deactivated the AP master switch (or so I think).

    We can all agree that, even if you happen to activate the AP the wrong way or using an incorrect procedure, the plane should never end up in such dangerous flight attitudes...



  • @Craig said in Autopilot engages by turning coupler dial:

    https://support.justflight.com/support/home

    This a critical error which may impact the whole experience of flying this aircraft, however I dont see it in the v0.3.0 list yet. That´s not good.

    v0.3.0 (pending release)

    Direction Indicator (DI) bezel now illuminated by panel lighting
    Whiskey compass animation fixed
    Sun visor animation now visible from exterior
    GNS 530 display now remains visible after GPS unit toggle on EFB is used
    Landing gear auto-extension logic fixes



  • @anderson It's in the v0.2.0 update:

    • Autopilot heading mode active without autopilot engaged - fixed


  • @Sender46 that´s a bit weird for I have been facing issues with AP on v0.2.0, when taking off if I switch the HDG first then switch the AP the airplane turn right or left and I never get the AP to work properly again, usually need to restart the flight.


  • JF Staff

    This should be fixed in the next update.