AutoPilot Issue

So recently, when my airplane has gotten to cruising altitude, it doesn’t stay there. it will go down 50 feet, then back up 100 feet, then back down 50 feet, and on and on. anyone know how to fix? the wind wasn’t the issue, either. thanks!

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What aircraft did you use?

Boeing 777-300ER.

Is it staying at roughly your desired altitude?

Speeds? Configurations? Altitudes?

What was your cruising altitude, were you heavy, how fast?

my speed was m.87, with a cruisng altitude of FL330.

i was not heavy, and i was going m.87. cruising altitude FL330.

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Cruise at Mach 0.84. Were you clean?

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yeah, within 100 feet, but it is annoying.

clean? what do you mean?

Clean configuration. No flaps, no spoilers, gears retracted.

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yeah, i was clean.

You mentioned the 77W…

It’s a known issue on the aircraft and will most likely be fixed with its rework. For now, you can turn off altitude hold and VS to 0.

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Are you sure it was not the winds?

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This is caused by heavy winds at cruise level altitude or gusts.
This is normal your flight won’t be affected.
Have a good day.

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It’s a known issue of the B777-300ER. I suggest taking out ALT button and reducing your VS to 0 to stay on your FL…

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Autopilot wont stay at exactly your desired altitude, it will go 50-100 fpm, but thats nothing to worry about, its normal

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my VS is at 0 tho. that’s what is weird.

He was too fast. Throttles must have been working hard. More power equals more lift equals more downward action from the autopilot equals more up commands to maintain altitude. What was your N1?

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