Need a help with an A350 please

Hello aviators…
I’ve just finished a flight from OTHH - EFHK with Qatar Airways A350… Everything went perfect until reaching approach…
The final approach fix for EFHK is 3000 feet which is the same altitude on the last three waypoints of the SID used for this flight which was INTOR5A… After reaching 3000 feet, and while the aircraft turning to final; it was struggling to maintain the altitude and kept bobbing up and down although my speed was 190 knots with 35% load… Flaps was 2, and gear up… Then i did lower the speed to 185 knots in order to intercept the localizer of RWY 22L while on the base leg and set flaps 3 with gear down. On turning; the aircraft pitched highly up and gained up to 400 feet at which it was supposed to maintain 3000 feet. Moreover; the aircraft didn’t intercept the localizer of RWY 22L correctly and made a steep turn which put me far from localizer although all the waypoints that allign me with the runway were included in the flight plan… I did disconnect the AP to stop this mess and hand fly the entire approach but unfortunately ended up high due to exccessive pitch up and was obliged to put a huge nose down correction. Upon disconnecting the AP, the aircraft has pitched up further with unknown reason… Trim was 19% with no pink line showing… Kindly take a look at the video below in order to understand the situation… Any help would be much appreciated… Thanks for giving your valuable time reading my topic…

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How heavy were you, if you know?

Sometimes the AP does like some fun on a bouncy castle, just doing the almost basic turning it off, stabilizing the aircraft, and turning it back on again can do the trick.

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Was just 35% total load… The AP wasn’t able to maintain the altitude and did over turns to intercept the localizer without a logical reason… In addition to that; there was no winds… Wind speed was 5 knots only

Hey! If you had activated VNAV, this happens a lot because VNAV descends very fast and levels off all of a sudden. Coupled with the final base turn, and a relatively low speed as I’m guessing you were on finals or close to them, this can cause the aircraft to bob up and down. Make sure to always monitor the descent completely regardless of if is VNAV activated or not to ensure a steady and shallow balance into the final assigned altitude.

In addition, what I’ve noticed is that VNAV will mostly take control of the aircraft all the way into finals for the runway, and APPR is really only activated for the last 3-5 (or so) nautical miles of the approach. Again, always monitor your descents to ensure a shallow leveling off.

I would get comfortable with just flying it by hand I’ve had a few of these issues when using the AP i usually just turn it off and fly it in myself its much more rewarding especially when you butter it.

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Thanks for your answer… I’m aware of this issue with the AP particularly with old aircrafts but I didn’t expect that could have happened with a new aircraft… I noticed that while the aircraft is turning and descending simultaneously; it gains more down vertical speed which is a weird behavior… The problem was that I wasn’t descending and i just wanted to maintain 3000 feet to intercept G/S…

Unfortunately this will be my protocol next time as AP always messing the approach

Not always a bad thing once you get used to i theres no better way to do it good luck!

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Thanks for your valuable participation… I like to have everything realistic but sometimes things get out of controls… I hate it when the aircraft starts to swerve aggressively and bobbing in a weird manner which ruin your flight and decrease the realism…

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How many tonnes is 35% of total load? I usually land the 359 at around 160+ tonnes so my approach speeds really will differ

I don’t remember actually… But the problem started way before reaching FAF and setting final approach speed

Did you select the runway which you would like to make the approach to?

You have your flaps fully extended (I see this because it says “gear up” and it says that when you have your flaps fully extended, but your gear not down, I believe) while you fly 190 IAS, that makes you go up. Maybe AP couldn’t handle it

Sure i did… as a part of my flight plan

The mess started before that… I did this step just to try minimizing the instability…

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