Boeing 777 series altitude holding issue

Hello infinite flight support team😄

Currently I have experienced an issue with all boeing 777 series aircraft, which is all those aircraft does not hold its altitude stabily during cruise when enable the altitude holding key (unlike 787 that hold its altitude very very nicely) And during my almost 5 Year’s of infinite flight experience I have seen this issues 777 aircraft, since previously it hold its altitude very very nicely. Can you guys give me a hand?
Thanks a lot!

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Your speed on climb is cruitial to establishing a good altitude hold. I usually speed up to 280-290 knots after 10000ft. And your VS also needs reducing. Usually my cruise is 0.85M. It’s much harder to gain that speed once really high, so just make sure to use an appropriate climb

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Completely agree with above, I climb to 10kft at 240kts and 2500ftpm VS. Reducing by 500ft past 15kft and again past 20 and 25kft while building my speed upto around 300-320kts depending on my intended height.

It also depends on your weight, you may need to stop your climb at 29-32kft until you have burnt off enough weight. It sounds like you’re trying to climb to FL350+ at too high a weight. You’ll need to do what is called a step climb and hold a lower alt for an hour or 2 before establishing your actual intended cruise.

Ensure you step climbing very long flights .Even IRL if you track most 777 flights they usually step climb. An appropriate V/S of around 1500fpm above FL250 is advisable.
Remember the aircraft’a service ceiling reduces with more weight. On a flight from Dubai to LAX on a 777-300ER, I would start cruising from FL280 Cohen step climbing as the aircraft burns more fuel while getting lighter.

777 cruise speed is from Mach 0.84 to 0.89.
Climb with airspeed of around 280-320Kts

Always consider the plane’s weight when deciding cruising altitude.

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In addition to step climbing, on a fully loaded plane heading for long haul its unrealistic to go to cruise altitudes like FL390 right away. IRL fully loaded 777’s initial cruise altitude is about FL300. Then as it burns fuel it slowly transitions to FL320, couple hours away it climbs to FL350 etc.

If you read carefully, he is not talking about how fast he is climbing but rather how the 777 stays at that altitude during cruise. I’ve had this issue too but to work around this, manually level off to your desired FL and use the V/S button instead of altitude hold. There are many old posts regarding this issue but in the mean time this is an alternative. I’ve tried several methods to get that proper altitude hold, even climbing at 800ft/min after FL100, but the problem still persists.

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I’ve been noticing the same issue and doing what @Donny_Ng is doing. Manually setting the vs to 0 once at the desired altitude

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Thanks you guys for the tips. They are great 👍

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Yeah, same happens to me, even if airplane load is below 30%. I tried all the other planes and only happens to 777-300ER. I tried to maintain altitude only with VS set to 0 but didnt work neither. I just stopped using that plane for now. It´s probably going to be fixed soon. In the 777-200F there is absolutely no problem cruising with 65% load at FL310.

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