777 Bobbing After Descent

For the past few times I’ve flown the 777 (I think specifically the 77W), there has been a dramatic bobbing up and down when slowing down for my approach. Ill be at flaps 25 at 160kn (granted, I have minimal knowledge about 777 flap speeds), and my plane will have trouble maintaining 160kn, hence why it bobs up and down. This hast happened until recently. Any explanation?

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What was your weight when you started the Decent? I think it might be related to that.

I’m not sure… usually I’m below maximum landing weight.

If you have IF checklist it will show you the correct flap settings for a specific aircraft.

That’s only for the paid version.

If it happens only in paid version, i suppose differences are winds and gusts. Maybe you are doing something wrong because you didnot calculate them. Can it be possible? For example, if there is strong wind or gust, you should approach more carefully.

The winds were calm.

I have also had issues with the 777’s A/P from time to time in various stages of flight.

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I’ve had this many times too. My conclusion is the A/P is over correcting it causing it to bob up and down…

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Yeah I’ve had it before with the 77W as well. Haven’t been able to find any explanations on here.

I’ve flown the 77W for quite some time now on infinite flight. I have also encountered the ‘bobbing’ issue but it only happens to me when i am at my cruising altitude. From my experience, this only happens when the plane is too heavy, but after you fly half your route, the excessive ‘bobbing’ will start to tone down. For your case, you were probably flying to slow for your weight, leading to the autopilot correcting itself many times, therefore the ‘bobbing’. Feel free to correct my explanation if I am wrong.

This happens to me. The AP tries to adjust its angle of attack to change the VS, but, if it can’t get the right VS over and over again, the bobbing will increasingly get worse and worse. It gets to a point where thee AP is just making it worse. I just disengage it, then engage it again once I have stabilized it myself.

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