AP Not Holding Steady Altitude at Cruise

Hi there,

Since yesterday and the last update my planes have trouble stabilising at cruising altitudes: they reach it, then the V/S goes from -1000 to +1000 and altitude varies constantly in a 200ft range around my autopilot target. This never happened before this morning, although I have a friend that has had this problem for a while too. Could there be a known glitch or a feature to activate / deactivate?
I specify that I have the right speed and the right altitude so it’s not because of that.


Hello what aircraft did the issue take place in?

Which aircraft were you in or does it happen with all of them?

Generally speaking this may occur if you are flying at an incorrect speed (too slow or too fast), your weight is too heavy for the flight level you have initially chosen and/or your aircraft is not properly trimmed.

If you attempt to level off with a VS of like 3000, your plane reaches the altitude, pitches down at VS-3000, and then it goes too far, pitches back up at VS3000, and so on.

What was the speed you was going at, as sometimes that can affect the V/S of your aircraft?

This is a known issue.

Some other aircraft have this problem as well.

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Thank you, that maybe the cause. I usually end the ascent with VS of +1000 to +1500, and I know that my speed and altitudes are in accordance to the weight and characteristics of the plane. It is indeed with the B773, and also with the B738. A320s seem to be fine.

Yea I would try lowering the VS as you get closer to cruise. I’m usually around 500-1000 VS at maximum by that point.

I noticed it with B738 and B773, and also a little bit with the Dreamliner. As an example I was flying JFK-CUN in an American B738, M 0.78, FL340, load about 50%, and VS was +1500 before reaching cruising altitude. It was nosediving to -1000 and back up to +1000.

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I believe that you will find the cruise to be more comfortable and appealing to the eye if you lower the VS. Give it a shot :)

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I may have found a fix to that. I remembered that when I installed the update I also lowered the sensitivity of the roll and the pitch to the minima (from default setting before).
I put them back to default and my current plane (B773) stopped going up and down as soon as I changed the setting. It would then mean that it is a matter of sensitivity? Weird bug. Anyway, to anyone experiencing this up and down issue, set a higher sensitivity in the controls settings panel

Thanks anyone for your input :)

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