Uncommanded pitch down issues

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Johnwag
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Uncommanded pitch down issues

Post by Johnwag »

I'm having an issue with uncommanded nose pitch down and mixture retarding that I can't find a fix for. I did raise this issue on the P3D forum but that thread has gone cold without a resolution. I'm hoping that someone on this forum could help because the issue is preventing me from enjoying my A2A aircraft.

The issue is that, at random times during a flight, the nose will pitch down and the mixture will retard to about 80% - without any input from me. If I happen to be looking down in the virtual cockpit at the time, I can see the mixture lever suddenly retard without me making any inputs at all. How can that happen? When the issue happens, I can recover the aircraft to level flight and reset the mixture to 100%. It's like something is 'telling' the aircraft to pitch down and retard the mixture. The mixture knob retards and the mixture going into the engine retards because the engine sound changes the same as when I lean the mixture.

I'm using P3Dv4.2 on Win 10 up to date. A2A C172 and PA28 installed from the new installers. I haven't yet installed my other A2A aircraft - want to try to fix this issue first.

I can fly the Carenado Shrike and the issue is NOT there - but if I change to the A2A PA28 or C172 then the issue happens at some point soon after starting the flight. The issue will happened 3-4 times randomly on a flight of about 1 hour.

I tried all sorts of things such as checking control mapping, other controllers (I'm using Saitek yoke, 2 x quadrants, rudders and trim). Tried changing the USBs and the power settings for the USBs and tried deleting the standard.xml file. Those didn't fix the problem. I know about the importance of loading a default flight first - typically I start P3D into the Scenario window with the F22 then either change to an A2A aircraft or load my last saved flight (normally with an A2A aircraft). This latest occurrence, I flew the Shrike for about 2 hours without issue, landed and switched to A2A PA28 then took off again - about 1 minute into the flight the nose violently pitched down and the mixture level retarded to about 80%. Other than those random control inputs, the sim (and flight) works perfectly.

I didn't have this issue until after I installed the Shrike. (sorry, but I couldn't wait any longer for a twin from A2A !!!)

Earlier experiments indicated that the issue also occured with the default P3D Bonanza so I don't think this is an A2A issue. It seems that only the Shrike flies without the issue occuring. How could that be? Could there be something in the files/coding regarding control inputs that the Shrike has changed/upset so that only the Shrike works without the random control inputs???

I don't use FSUIC or SPAD and would prefer not to unless it's the only way to fix this problem.

Could it be a Simconnect issue?

I haven't tried uninstalling the Shrike - but I'm thinking any coding 'damage' would still be in the system???

I don't want to be limited to flying only the Shrike - I'd like to get back to enjoying the A2A aircraft without sudden random nose pitchdowns. So, I'd really appreciate any suggestions as to how to fix or what to try. My last resort will be to completely reformat the PC and reinstall everything from scratch - but that's a big job I'd like to avoid if I can.

Hope I've given appropriate information.

Thanks
John

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Nick - A2A
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Re: Uncommanded pitch down issues

Post by Nick - A2A »

Hi John,
Johnwag wrote:I'm having an issue with uncommanded nose pitch down and mixture retarding that I can't find a fix for. I did raise this issue on the P3D forum but that thread has gone cold without a resolution.
I don't recall seeing this thread. Was it one you raised on a different forum elsewhere?

Thanks for the detailed information anyway. The fact that this issue occurs with the default Baron is useful for a start and seems to suggest that a control conflict or other hardware issue is behind the behaviour you're reporting.

You mention deleting the standard.xml file, but have you tried systematically searching through it for any unwanted assignments? For example, I'd suggest opening it in a web browser or text editor and using the find function to identify any instances of the word "mixture" then checking that each corresponds to the appropriate input device and axis.

For the nose pitching down, have you been able to establish if this is the result of a pitch trim input, a primary control surface input, power loss, or something else? For instance, you could establish cruise flight and note the trim wheel position then check if it's been changed by this behaviour.

One final question for now: is the autopilot engaged when you experience this issue?

Thanks,
Nick

Johnwag
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Joined: 06 Sep 2013, 04:21
Location: Rangiora New Zealand

Re: Uncommanded pitch down issues

Post by Johnwag »

Thanks for your response Nick.

Sorry, I'd previously posted about this issue on the LM P3D forum in the Client Application Questions section.

I located the standard.xml file and made sure that there was only one mention of 'mixture' - this being associated with the Saitek throttle quadrant as mapped. As a further experiment, after checking that xml file, I started P3D and then loaded the PA28. Checked that the controls worked as intended and then left the sim running with the PA28 sitting on ground with everything turned off except for the mixture lever being in full rich (knob pushed in). I came back 20 minutes later to find that the mixture knob had retarded about 1 inch - the same issue I've been having. I closed P3D and checked the xml file again - still only the one, correct entry for mixture input via the Saitek controller.

I haven't experimented with the pitching down yet but will do so tomorrow and let you know. I haven't been able to see if the vc yoke pushes forward when the issue occurs because I instinctively pull back to raise the nose and I normally have the vc yoke hidden. It's normally a pretty violent pitch down - much stronger than I expect would occur with a small power reduction due to the mixture being leaned. Both erroneous inputs seem to always occur at the same time. Autopilot not engaged with master switch turned off.

Thanks again - hope we can find the problem.
John

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Nick - A2A
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Re: Uncommanded pitch down issues

Post by Nick - A2A »

Okay, thanks for the further info John.

The next thing that I'd recommend is that you unplug the Saitek throttle quadrant that has the mixture axis and try a similar experiment: leave the sim for half an hour or so and see if the mixture control still moves by itself. If it does, at least you'll know that a hardware issue with the quadrant isn't the culprit.

Thanks,
Nick

Johnwag
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Location: Rangiora New Zealand

Re: Uncommanded pitch down issues

Post by Johnwag »

Tried that but problem persists. Firstly, I unplugged the T/Q and the Yoke (leaving only the rudder pedals and trim plugged in). Then I turned the PC on. Then I deleted the P3D standard.xml file. Then launched P3D then selected the PA28 and loaded at default location. Using only the keyboard controls and rudder I started the PA28 and taxied around a bit then shut down and left it with the mixture lever fully rich. After about 30 minutes sitting there the vc mixture control retarded to about 1 in from full rich. I hadn't touched the PC for the previous 20 minutes. At the start I had set the elevator trim to neutral - it was still in the same position after the mixture control retarded.
Any other things to try?

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Nick - A2A
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Re: Uncommanded pitch down issues

Post by Nick - A2A »

Hmm, sounds like a tough one to nail down. :? Could you try a test with the trim wheel unplugged instead?

Thanks,
Nick

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Lewis - A2A
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Re: Uncommanded pitch down issues

Post by Lewis - A2A »

Just to double check you checked the mapping in P3D + the A2A input configurator. Also that the P3D settings itself are set correctly, for example mixture is not set to auto?

thanks,
Lewis
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Johnwag
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Posts: 22
Joined: 06 Sep 2013, 04:21
Location: Rangiora New Zealand

Re: Uncommanded pitch down issues

Post by Johnwag »

Ahhh, problem still there... I unplugged the Saitek trim and rudder pedals. Only controllers left plugged into the PC being the 'standard' Microsoft wired keyboard and Logitech wireless mouse. Started the PC, deleted the standard.xml file, launched P3D, selected and loaded the PA28. Went to the Options>General and checked that automixture NOT checked - only thing checked was 'Engine stress damages engine'. Realism set to 100% Options>Controls; only the 'mouse yoke' and 'mouse look' controllers were in the list. Checked that 'Mouse yoke' had only left/right/up/down actions assigned and nothing about mixture. Also went to the key assignments and deleted the 6 key assignments that can control mixture (I've also done this action the other times I've needed to redo the assignments). Then made some command inputs to the PA28 e.g. turn Master and fuel pump on and off, looked around a bit, moved the trim wheel to one mark down from neutral. Set the vc mixture lever to full rich - and waited.... About 30 minutes later still good, mixture lever still full rich. Started the PA28 and taxied around a bit (how do people manage to control aircraft using only the mouse and keyboard???). Stopped and shut the engine off by turning the mags off. Mixture still full rich.

Looked around the cockpit, set the view to looking down at the mixture control - and a few seconds later happened to see the vc mixture lever instantly retard about an inch. Same problem...…

Next I'll shut the PC down and try all that again except this time I'll also unplug the keyboard after I've set the P3D/PA28 up to see if it's the keyboard that's causing the issue. I replaced the mouse with a new one a couple of weeks ago. I'll report the outcome of that experiment.

I really appreciate the help and ideas you guys are giving me.
Thanks
John

Johnwag
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Location: Rangiora New Zealand

Re: Uncommanded pitch down issues

Post by Johnwag »

And still there. Shut everything down, restarted, as before set up the PA28 looking at the mixture lever, unplugged the keyboard. Within 5 minutes the mixture knob retarded by itself. The PC hadn't been touched. The trim was still in the same setting as when I set up the cockpit.

Also meant to mention last time that I also checked the A2A input configurator - no controllers plugged and the configurator reports that.

I've got no more ideas to try...…

Thanks
John

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Nick - A2A
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Re: Uncommanded pitch down issues

Post by Nick - A2A »

Hi John,

Thanks for the update. Could you do another test in the default Baron, just to establish if the same thing happens? Previously I think you mentioned you thought this was the case, but it'd be good to know for certain.

One further troubleshooting suggestion would be to move any saved flights out of the "Documents\Prepar3D v4 Files" folder which will force the sim to load the default flight.

Also, are you using any Saitek software to program/assign your hardware functions? In fact, please could you list any relevant utilities / P3D add-ons which are running when this issue occurs?

Thanks,
Nick

Johnwag
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Location: Rangiora New Zealand

Re: Uncommanded pitch down issues

Post by Johnwag »

Thanks Nick for your continuing help.
Reconnected all the controllers, re-calibrated them and redid the assignments.
Started P3D and loaded the default Bonanza (as per earlier experiments). About 10 minutes into the flight the mixture retarded to idle cut-off and nose pitched down to about the vertical.
Restarted P3D and loaded the default Baron. Changed the assignments to match a twin. 1 minute into flight both mixtures retarded to idle cut-off with mild nose pitch down.

Closed P3D and moved the 6 or so saved flight files to the Documents folder. Restarted P3D and loaded the default Baron again. About 10 minutes into flight violent pitchdown and engines stopping. The violent pitch down was recorded as an overstress crash and this happened before I was able to move the view to check that the mixture levers had again retarded.

I'm using Win 10 fully up to date.

When this first started happening a few weeks ago I was on P3D 4.1. After some unsuccessful experiments I updated to current v4.2 but problem continues

P3D is 'standard' in that I do not make any tweeks (wouldn't know what I was doing). But I do make the personalised options/settings changes - although when I first updated to 4.2 I left all the settings unchanged for the first few flights to see if I was taxing my PC too much.

I have Orbx FTX Global Base Pack, Open LC NA, Trees HD, Vector and the libraries (I see an update is available). 4 of the NA regions, the NA airport pack, KEGE and USMV.

I have Ultimate Traffic Live which has been running throughout each experiment.

I have AS for P3D and ASCA which sometimes I have running and other times I don't.

I don't use any Saitek software, the controllers work (or had been) fine using the default drivers in Windows.

Other than 6 A2A aircraft and the default, I've had the Devon for some time (before the problems) and the PA22 Tripacer (before the problems) and the Aero Commander 500 Shrike.

The 500 worked fine and it was after flying that for awhile and I went back to A2A C172 that I started getting the problem. I can't recall the first actual flight that I had the problem but from memory that first C172 flight ended up in quite a violent thunderstorm with severe up and down drafts practically uncontrollable. Perhaps the problem was happening in this flight but I didn't notice it because of the turbulence??? I think I 'ESC' from that flight rather than tried to land. Thereafter, I realised that I was getting the random violent pitch downs and soon thereafter I realised I was also getting the mixture retarding. Been like that ever since.

I did try flying the 500 again a couple of weeks ago - the problem was not there for the two flights I did. Flights were only about 30-40 minutes so maybe I finished before the random problem presented itself??? Tomorrow I'll again fly the 500 for as long as I can to see if the problem occurs with that aircraft and let you know.

Thanks again Nick.
John

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Nick - A2A
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Re: Uncommanded pitch down issues

Post by Nick - A2A »

Thanks John - sounds like a very thorough set of tests you've done there and at least we know for sure that the issue definitely extends beyond just your A2A add-ons.

To be honest, if I was in your position I'd probably go down the route of a full clean reinstallation of Prepar3D at this point. However, it may be worth waiting until Prepar3D v4.3 has been released before you do this: I've read that it should be available before the end of this month.

Before you take this step though, it may be worth trying the "delete generated files" feature of P3Dv4. More info on this can be seen in this video.

Something else you could try before going down the route of a full reinstallation is to reinstall the P3Dv4 client making sure you follow the instructions here.

Thanks,
Nick

Johnwag
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Re: Uncommanded pitch down issues

Post by Johnwag »

OK thanks Nick.

For a bit I thought we'd found the solution - I did the 'delete generated files' thing and started and loaded the default Bonanza. Flew for about 40 minutes without the problem - but then it happened again.

I think now only option is for a complete reinstall - and I'm going to take the opportunity for a complete clean of the PC with a reformat and start completely again.
If I still get the issue after that then I'm going to take up knitting or tiddly-winks, anything but flight sim !!!

Thank you very much for all your efforts and time Nick.
Regards
John

Johnwag
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Joined: 06 Sep 2013, 04:21
Location: Rangiora New Zealand

Re: Uncommanded pitch down issues

Post by Johnwag »

Hello Nick and Lewis.
I'm making this report with my fingers crossed and my toes crossed and continually knocking on wood - I may have fixed the problem ??? I've completed about 2 hours of flight without the problem occurring - but who knows if it will happen again next time.

After the last experiment, I uninstalled the Aero Commander 500 Shrike and the PA22 and deleted them from my PC. Both those aircraft I had also set up as AI aircraft in Ultimate Traffic Live - so, having deleted them, they no longer were part of UTL. I'd also again done the 'Delete Generated Files' thingy in P3D. From then, I've not had the problem occur.

I know nothing about how all this could be happening but perhaps the random nature of the problem could have related to the random injection/use of the 500 in UTL? It might also explain why I got the problem with every aircraft I tried except when flying the 500??? Perhaps using the 'complex' 500 in UTL as an AI aircraft was causing the problem? I hope it was so that, having taken it out of UTL, the problems will have gone !!!

So, I'll continue to keep my fingers crossed for the next few flights..... My only other wish now is for an A2A twin...

Thanks again guys.
Regards
John

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Nick - A2A
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Re: Uncommanded pitch down issues

Post by Nick - A2A »

Hi John,

Thanks for the update. I don't have any firsthand experience of UTL, but what you suggest seems plausible to me. Hopefully the other aircraft will continue to behave themselves now you've made this change.

If not, I'm sure knitting can make for an extremely soothing pastime. :mrgreen:

Cheers,
Nick

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