Slow VNAV Climb
Hello, I'm noticing that the aircraft is exceedingly slow to climb to reach cruise alt as well as en-route altitude changes. I'm not sure if this is related to the custom flight model or the WT system version onboard. Please check it out.
I'm getting climb rates below 500 fpm, sometimes below 100 as well. Climb angle is also very shallow.
Francis @LeadDeveloper2024-05-30 14:50:29.546ZHi John,
I would like to recreate this climb. What is your weight on the plane? 99% of the pilots are climbing well, we can pinpoint together what is happening.Hey, i had a ZFW of 147.8 and a fuel load of 37.5 both KG. Simbrief gave me a CLB-2 setting for the climb. Initially it was ok but as we kept getting higher the rate kept descending. I know this supposed to happen but it was getting so slow that the plane overshot the planned T/C by almost 30 minutes. Changing back to CLB would not change much and further enroute climbs were also very sluggish.
Vance @AV8OR2024-06-02 19:31:48.685ZLet me see if some of the testers are experiencing this. I will be sure to get back to you.
- In reply toJohn92⬆:
Tyler Heard @tyl3rh3ard08Hi there! I'm one of the testers! I have yet to come across this issue. I have one idea what it could be, I believe it may be to do with your optimum flight level as it seems you are on a long haul flight with the amount of fuel. If your optimum flight level was fl340 and you were trying to go up to fl380 then this would be an issue.
Heya, flew the 789 on an ultra yesterday and still had a better climbrate all the way to cruise. I was loaded for 17 hours and had around 1500 fpm. Vs 500 and less for a 7 hour load in the 788.
It isn't unusual for the 787 to start out at very high cruises (380-400) on those shorter long hauls because of how overpowered it is.
I've noticed the plane tries to climb with almost no attitude as well, very shallow climb.
Francis @LeadDeveloper2024-06-03 13:24:18.351ZHi John
https://youtu.be/ZJF-b3voJgA this plane was only loaded for a 7 hour flight but climbed to 410.
How long does it take for a fully loaded 787-8 to climb to FL410?It feels sluggish, I can't tell you exactly how long it would take without a climb performance chart though.
I can tell you that the HS789 climbs a tad bit faster with a 15 hour load. I don't know if it's because the 789 has a better wing, but even then it's a difference between 37 to 90+ tons of fuel and 20 additional tons of payload.- Francis @LeadDeveloper2024-06-08 19:00:48.421Z
Well... the wings are the same size on all 787. Please give me a scenario so I can reproduce it.
Try this: Plan a flight with simbrief and cross check where the T/C is in the flightlog vs where the plane actually reaches T/C. The plane should overshoot the planned T/C by a rather wide margin. Hope this helps.
- Francis @LeadDeveloper2024-06-09 11:16:52.957Z
Okay, no problem. I'll record it. I was hoping to get the same weight as you had. But I'll go with Simbrief (with the new update-1 applied).
- In reply toJohn92⬆:Vance @AV8OR2024-06-08 19:12:15.969Z
A lot of factors play into this. The only thing different is the fuselage length, the wings as Francis stated remain the same.