B777 autopilot at high altitudes

I’m currently cruising in the Sydney region at M 0.81 at FL360. I set my autopilot to FL360, and it climbed to this altitude, but instead of easing down the nose to the cruise pitch, the autopilot is making the nose pitch up and down ±4 degrees at or around 36,000, almost like riding a bull, and thus never reaches FL360. I don’t remember this being an issue with “older” version of the 777-300ER autopilot.

Edit: Disconnecting and re-enabling the autopilot sort-of solved the problem. But I’m still curious as to why this occurs.

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Maybe you’re too fast

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Mach 0.81 is a typical cruise speed for a 777 is it not?

At Mach 0.81 you’re going quite fast there, probably too fast.

0.81 is not too fast. What’s your weight?

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My weight is 301,821kg

Light/medium/heavy??

almost at heavy

Oh I have this issue all the time I’m not sure what the cause of it is but what I do is add another 100 feet to my altitude and it seems to stop raising the nose up and down and it maintains that altitude

I had to go at least a thousand feet up or down for it to almost stop fluctuating and to maintain altitude.

777s go mach .83 usually

I’ve climbed to FL410…Dude!100% sure it’s your weight…speaking from experience you’re too heavy for that altitude…reduce weight and you should be fine…hahaha about riding a bull LOL how did you even think of that! XD

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i have also had issues with the autopilot. The aircraft bobbles up and down after I select my desired altitude. I never encountered this issue prior to the latest update. The nose also pitches up much higher than it should when I try to trim it down, the plane shakes violently. Needless to say, I haven’t enjoyed the rework of the 777 as much as I thought I would.

What is your final vertical speed to get to altitude? If you’re overweight and rocketing at 3000fpm to FL360, it’s going to abruptly level off and begin the bounce. Try a lighter weight followed by a slower climb as you’re closer to the desired cruising altitude.

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My VS was 1200ft at FL280 climbing to FL330. The plane’s weight was slightly above normal at 415kts GS. At this point I selected the desired altitude of FL330 and it went haywire.

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Is there trim?

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