Won't hold altitude

[rennman 4]

With altitude hold selected, the plane rocks up and down +/- 500 fpm.

I turned off the weather and reset AP...but she won't stay put.

[FDEdev 955]

Lots of info missing for trouble shooting. Weight?  Altitude? Temperature? IAS? RPM?

Edited September 23, 2018 by J35OE

[rennman 4]

I'll take her up again and get the exact data...but basically normal cruise parameters.

I"ll be back with more precise data.

Edited September 25, 2018 by rennman

[FDEdev 955]

In most cases this problem occurs if you are trying to climb at a too low IAS (below 190kias) and/or to a too high flight level. E.g. MTOW the max level is 'only' FL350.

In a jet you can't trade energy in a climb to maximum altitude. If you are  climbing to a too high altitude by trading speed for altitude you are stuck at a too low IAS with a wallowing AP.

Time compression is also a factor in many cases, even at 'correct' FLs.

 

[rennman 4]

I made this video...She overshoots FL320, and when I hit ALT hold she erratic...Let me know what you think.  Thanks again.

 

 

[FDEdev 955]

Looks like the FMC/AP ALT interaction to me. AFAIR the Carenado FMC and the FSX/P3D AP altitude hold sometimes don't work together and then these oscillations start to happen, but I'm not 100% sure.

It's definitely not your flying which causes this problem and with the target FL set, the AP should automatically switch from FLC to ALT CAPT and ALT.

Edited September 25, 2018 by J35OE

[rennman 4]

I checked and the installer says 1.2.. which i think is the latest...