777-300ER ocelating at cruise


#1

Simply, i fly up to cruise and it oclates, i made sure to do the last 1000ft at 200fpm because i’ve seen the complaints before, however it is now going +1000fpm to -1000fpm… i need help!


#2

What Altitude are you at?

What is your load percentage?


#3

35,000 ft and 58%


#4

Am doing a flight on the a 777 - 300ER now and it’s crusing perfectly step climbing is your friend


#5

That shouldn’t necessarily propose any issues with your load. Could you try descending to FL330 or FL310?


#6

How fast are you flying?


#7

M0.86 is my speed


#8

Well that’s a bit too fast for the 777 (All variants) which typically cruise at M .84


#9

will do, thanks


#10

Turn off the altitude function of the AP and control the altitude using VS.

The root cause of this issue is a somewhat unbalanced setting in the AP but it’s tricky to repro, hence it haven’t been fixed.

The best ways to avoid this to begin with, it to reduce the VS before reaching cruising altitude. Most of the times this happens it is because the VS is too high and the AP have issues compensating for the sudden decrease in vertical speed when reaching desired altitude.


Bobbing at cruise
#11

Thanks, will try that now.


#12

But isn’t 1000 fpm quite exaggerated? I’ve never faced this issue myself… the issue with 100-200 ft up and down is understandable but this on a whole another level.


#13

nope, just before i tried that @schyllberg suggested it went 1200 + and -fpm


#14

It can escalate sometimes. Beginning with minor +/- 200 and end up with way worse.


#15

Did it get worse than before?


#16

Yes, however the VS trick seemed to work and it seems to be behaving like a normal plane now


#17

That’s good hear. Then you know how to handle this issue :)

Remember to tick Shyllberg’s post as the solution so others may also know how to take care this issue, for now at least.


#18

yeh, i do wonder tho how it will handle when dubai approach tells me “Decend and maintain…”


#19

I’ve noticed that on lower altitude, the plane behaves slightly better. I recently flew the 777-300ER from Doha to Atlanta and back, and didn’t have a major issues although this may vary from time to time and player as Seb said. So continue flying and report back here if the issue arises again or not :)


#20

sure thing, just gotta wait like 5 hours now though