777-300ER Bobbing at cruise

It starts around 5 feet, then gradually increases. 38 kts right quartering tailwind.

Ok thank you.

Thank you, that was helpful!

Not really.

@Pilot_B
This is generally triggered on the A321 and the 777-300ER when slightly too “aggressive” vertical maneuvers, incorrect trim or speed is being used.

When i say aggressive, I don’t mean you’re treating it like a fighter. It usually means the V/S during climb might have been too much and when leveling off the AP overcompensates and are having troubles finding it’s way back.

Usually, adjusting the VS for the AP without altitude engaged does the trick.

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Thank you!

Can you help me? I have tried all of this and it worked for a little bit. It is now getting pretty severe and I do not want to end my flight as I am already 4h+ in.

Good timing on your problem, take a look at this:

What trim setting do you recommend? I’m at Mach .8 at FL310

Trim it so the purple bar is not visible. The triple 7 performs better at Mach .83-85, so increasing your speed might also help.

Ok. I was at .83, but the other comments suggested slowing down.

How many degrees is the nose of your aircraft pitched up?

about 2 degrees

What about the weight of the plane, and any turbulence?

Load is 68%, 644,000 lbs. Slight turbulence, and a 45 kt crosswind

The only idea I have left is to increase your cruise altitude to FL330 or 350, you should be light enough to maintain that.

Ok, I’m planned to climb to FL330 soon, so I’ll do that. Thanks for the help.

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Out of curiosity, how would this help me?

My theory is that it would fix the autopilot trying to overcompensate, and the pitch of your nose relative to the horizon will be greater, which could be causing the problem considering how light you are and your altitude is only FL310.

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You were misled. I suggest you maintain at least Mach 0.84 and take the advice given above regarding VS, step climbs and trim. I’ve logged over 60% of my flights in Infinite Flight on 777-300ERs and I have never experienced this issue since Global was released last year. At a load of 64%, your initial cruise altitude should be in the region of FL310-340, trimming at around 15-25% and as you climb to cruise reduce your VS steadily to at most 1900fpm above FL280. I hope you enjoy your future 777 flights.

For cases of turbulence, it would be normal for your plane to bob but it shouldn’t be much.

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