777-300er Altitude issue

Hi I’ve recently noticed that then 777-30er and the A320 series won’t hold a stable altitude I’ve tried sep climbing and it doesn’t seem to work. I’ve looked about for a solution and tried things that have been suggested with no luck, I was wondering if you had any more solutions or if you could fix the bug as the 777-300er and the A320 series are my favourite aircrafts in the simulator.

Thanks Blair

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To fix somewhat: once you reach your desired altitude, turn off ALT and set VS to 0. I experience the same problem, and this works for me.

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Can you describe in more detail what you mean by “will not hold a stable altitude”? Is it struggling to reach it? Bobbing up and down? If so by how much? etc.

Can you share a replay of your flight? That may help to see so we know for sure.


Hey if its bobbing up and down you are reaching cruise with too high V/S try to lower it before you reach cruise…

I never set altitude and do always play with vs. I didn’t have this problem. As @yacht has said you can just set vs.

Yes, the 777-300ER keeps bobbing up and down in mid-flight, for me too by a vertical speed of +400.

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The aircraft keeps bobbing up and down to an excess of 1000 ft per min, and wont stop. I have tried what @Yacht has suggested and this is a burden when your trying to do a 15 hour flight, and you cant hold a stable constant altitude

When i reach an altitude of 10000 ft I reduce my VS to 1800 ft per min and at 25000 ft i reduce my VS to 1200 ft per min and when I’m 2000 ft form my cruise I reduce my VS to 500 ft per min to answer @Matevz_Treven s question.


@Blair_Petrie you are correct, it’s not a permanent or perfect fix, and on long hauls sometimes my aircraft will drift -100 or +100 feet from where I want it, but it’s the best solution for our problem that I have found and I’ll take it over the aircraft bobbing for 12 hours.

I have not seen this with the 320 but have seen it with others. Sometimes it is wind/weight/speed related. Turning off and setting AP again usually solves it.

As planes get reworked the physics are improved.

Yes I realise this is the best solution for now, i just don’t get how its only the 777-300er and the A320 series

I’ve definitely noticed the altitude issue with the 777-300ER. The a320 flys perfect for me but the a320 bops up and down when you start to begin your decent

@Chris_S I’ve just tried what you suggested with the auto pilot with no success there was still bobbing

There are a number of variables at play. Without a copy of a replay to see your speed, weight, etc it is hard to give you a specific answer on a resolution.

It is normal for planes do deviate a little up and down.

Here’s some photos of the 777-300er problem my weight was 531157 lbs and there was a 0 knot head wind

@Chris_S I’ve been trying for a while now to see if I can fix my problem. With no luck. I tried the 777-200 and it works perfectly so just the 300er I guess.

I just had the same issue with the 777-300ER. I crashed on short final at KLAX from RCTP just now

I could be misunderstanding the image you have posted, but 500 knots airspeed is way to fast. The maximum you should be going is 350 knots, that’s probably the reason you’re bobbing up and down. You may have turned it off but there is supposed to be an over speed alert that’ll let you know. Same thing goes for the A320.

Airspeed is the detector that appears directly on your screen, that should be at maximum of 350 if I have understood correctly. Ground speed is at the bottom of the screen and it usually varies between 400 - 500.

When in replay mode (as you can see from the time bar at the bottom and the ATC window on the left), the airspeed indicator on the left shows groundspeed (for reasons I don’t know). And 500 kts ground speed is not too fast for 31000 ft in a 777. So the problem you can only see on the right with the altitude, where the nose is going up and down continuously and overcorrecting every time.

He’s at FL310. He’s also at M 0.84, which is the normal cruise speed for the 77W. It will decrease when you have stopped climbing. There’s also no wind, which never happens at FL310.

Nah, A320 doesn’t do it. Only the A321 does.