Climbing/Cruising/Descending Fluctuations With AP Engaged

[MatthewMarshall]

Hello All,

I'm having some issues, during the climb, cruise and descent phase for as long as the AP is engaged, FD on and an active vertical profile is engaged either VNAV, FLCH or VS. The AP commands abrupt unnecessary inputs in pitch, this causes a fluctuation of +- 1000ft in the cruise, changes of upton 2000fpm in the climb and descent. It's basically, constantly snaking.

 

I've tried new XPIUPC a full reinstall and I'm running 1.33 with latest Xplane.

 

Any ideas?

 

EDIT: CWS is not active and joystick is calibrated and centered.

Edited August 13, 2021 by MatthewMarshall

[Litjan]

Hi Matthew,

I would try without XPUIPC first to rule out some interference with that. The only other reasons could be noise joysticks (sending erroneous signals), turbulence (check weather settings) or performance problems (trying to fly too high for the current weight, etc.).

Cheers, Jan

 

[MatthewMarshall]

Hi Litjan,

 

thanks for the quick response, I can uninstall XPUIPC however I have a lot of addons and plug-ins which rely on the use XPUIPC so going forward how could I use those both together?

 

I disconnected the joystick however we still had the same problem, I can assume this isn’t the case as I don’t have CWS active always just CMD with active pitch and roll modes on the FMA?

 

The weather was set to match real world conditions but, I’ve been in some bad turbulence but never had fluctuations  throughout the entire flight in VS.

 

As for the level, I tried many stop altitudes on the climb and descent, the issues is more dramatic at lowers levels I assume because more thrust available etc? As for altitude I flew 2000ft below OPT and the ‘coffins corner’ was about 30 knots.

 

Any ideas going forward?

 

[Litjan]

Hi,

maybe not uninstall XPUIPIC but you can disable it (in the plugins dropdown menu)... I would just like to know if it is the problem, or something else.

Try to fly in "manually set" weather and select the CAVOK option to try.

You can also try to tape a video of it happening and post it here (maybe a youtube link?) so I can take a look, this might give me a hint.

Cheers, Jan

[MatthewMarshall]

Hi Jan,

 

Sorry for the late response, I'll try and get a video of the situation by the end of this week for you.

 

Thanks,

 

Matt