Boeing 747-800 Rocking Violently at cruise level

Does anyone know why when I fly the 748 im at cruise and it violently shakes back and forth anywhere above FL340?

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Do you know if there are strong winds? Or if your flying fast enough at that altitude?

Are you fully loaded? and whats your indicated airspeed?

I just ran into this issue. I have a video, but don’t know how to upload it

Upload to YouTube, paste the link here.

You can upload it to YouTube and set it as a link-only video. Share the link here once you’re done uploading :)

It’s not only the 747-8.

It’s also happening on planes like the A321.
As soon as you arrive on the Flight Level you selected in ALT autopilot, the plane has some difficulties holding that level. It’s starting to correct it over and over again which causes the nose of the plane to move up and down and up and down and up and down. After some time it’ll stabilize on it’s own.

The problems get worse if you climb or descend with a higher V/S speed or if you’re flying through strong winds. You can prevent it by turning of ALT and switching on only V/S. Set it to 0fpm and the plane will fly stable. Sometimes it helps, sometimes it doesn’t.

I think it might be a general autopilot bug that occurs depending on different factors, like winds, altitude, V/S and airspeed.

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I’ve experienced it on the A321 I think it is a known issue for that aircraft but I do not know about the 747-8.

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You can upload the video to Google Drive or OneDrive if YT doesn’t work and post it here. PM me if you want more instructions on how exactly that is done. And I can even get you instructions on deleting the voice

Rgr. If recording on your device doesn’t work you could try videotaping it with another device

747-8 rocking side to side

^^^video

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Pilot error, Click on the heading button and the boat will stop rocking.

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Ok thank you. My apologies

You could increase your speed a bit too (Mach .80 is a tad slow). The 747 will fly fine if you treat her right.

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Your trim don’t need to be set to 80% though this should not be what causing your issue

Relax, its a saying… Planes and boats are often referred to as “she” or “her”.

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I have experienced this on the 787 during cruise and the A320 during cruise on a descend(I descend to an altitude and stay there until final). For me, just changing the altitude to a lower or higher altitude has worked.

There’s a chance you’re too heavy and a high altitude. FL340 may not seem high but consider FL300 to start out and work your way up from there. Like others have mentioned, consider increasing your speed as well. Anything in the range of M.85 - M.87 should work. I flew the 747-8 the other day and didn’t have any issues.

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To add to Mr Deer, LH748s on their way to South America frequently have an initial cruise of FL280. Nothing wrong with a low initial altitude, especially in the 747s.

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This has happened To me before, Sometimes if you accidentally hit the rudder slider or put trim up or down it will couse you to loose/gain Altitude fast so autopilot may over correct and couse an up and down rock

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