Nose up-and-down movement problems

When attempting a circling approach or traffic pattern, with the flaps set and the airspeed VRef set, if the AP is activated to maintain altitude, the nose will repeatedly move up and down violently. Therefore altitude cannot be maintained properly. The phenomenon becomes more pronounced when turning.
How do we resolve this issue?
This phenomenon occurs in aircraft such as B777-200ER and A321-200. There may be more.

This is usually because you have the A/P Speed set too slow for your weight and the flap settings.

What speed and flaps did you have set in which aircraft when this was occurring. Also what was your weight at the time.

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For example,
aircraft B777-200ER
Total 178,750kg (approach)
Flaps 30°
VRef 135kts
Maintain altitude 1500ft

Just tested this at the parameters you gave - no bouncing at all for me - its completely stable at 1500-1600ft with Flap 30 at 135kts.

So I’m not entirely sure what’s going on with your aircraft here…

Really?! I run into that phenomenon every time. It didn’t happen with the E175.





The nose will go up and down like this image. I feel that AP’s altitude hold function is dull.

Could you share the video? So I can see exactly what’s happening?

I have exactly the same problem with the A320 and 737 family, it’s annoying because I adjust everything strictly, the IF autopilot is very strange…

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Can you watch this video?

Hey there,

I would recommend setting the speed manually on approach. I think the problem is when the engines go immediately to idle thrust when reducing the speed, which is completely unrealistic.

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I would agree with @MikaL.

Also don’t use x5 mode on approach - only use it in cruise when you are maintaining the same speed and altitude. Using it when you are constantly changing speeds and adding flaps doesn’t tend to work well.

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Come to think of it,I had the same problem with my B737-800. I want adjust everything strictly too.

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Thanks to MikaL and BennyBoy_Alpha.
I’ll try it that way.

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I always reduce manually, I believe that the problem is really in the IF autopilot… it always makes absurd and unnecessary corrections

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Until this improves, we may be best off with manual control of heading and altitude without using AP when attempting a circling approach or traffic pattern…😂

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we’ll need patience 😂… AP UPDATE NOW!

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I don’t have that problem with manually setting the thrust in any aircraft. It probably depends on how and when you retract flaps/gear etc.

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