A321- auto pilot

[GoldFly]

Hi all hope you had a merry Christmas
Not sure where this topic belongs so sorry if it’s in the wrong one
I’ve been having trouble with the a321 auto pilot recently.
Last night I was flying at FL-300 at Mach .84 with 68% load, about 15 minutes after I hit cruise altitude it started jerking up and down, which I know had been a problem in the past but haven’t flown this plane for serveral months
So I dropped it back to Mach .82 and it settled down for about 10 minutes and started doing the same thing, so I dropped it back to Mach .80 and descended to FL.280
It was fine for 30 minutes until I fell asleep and woke up to saying it crashed 6 hours later
The whole flight was over ocean and tanks full when I departed, 7.5 hour flight and had 11 hours flight time so unsure as to what could have caused it to crash
Any info would be appreciated
Thanks

[Mats]

Mach .84 is way too fast. Try .78-.79, this will help. On longer routes take steep climbing into account. Hope it helps. :)

[2003iggy]

Heya, this is a known issue with the A321, please refer to this post by Deercrusher:

Autopilot problem

First: Slow down to a speed no faster than 320kts. There’s no need to fly as fast as you’re flying. This should help get the oscillations under control. Second: While you’re in flight, pause the flight and at the top left of your screen click on the gear icon. This will open up the settings page. At the bottom left hand corner there is a tab that says controls. Click on this. There will be 3 more buttons at the bottom that will say “Restore Defaults”. Click on this and return back to your…

Have a good day!

[N1RG]

A321 Autopilot Bug Multiple reports on this

[Jose_gil]

This is a known glitch with the A320 family. The best thing you could do to make the jerking stop during cruise is unselect the altitude hold button and just keep the vertical speed at 0 so you don’t experience the jerking/unusual movements.

[GoldFly]

Thanks for the replies