Slow Climb

[DragonNGX 1]

I have had trouble getting to cruising altitude in a reasonable amount of time. I don't know what I am doing wrong. For example, On a flight from KATL to KIAD, I didn't reach FL330 until about 80 NM from T/D. That is a very slow rate. It seems that the T/C point is kept being pushed back. For example, when I look at the LEGS page before takeoff the FMC says it will reach a certain point at FL260. After takeoff, that point keeps decreasing at the altitude the FMC thinks it will reach it. This has happened several times.

[Ponk 51]

I have never had this problem but there have been many people who have. It usually turns out to be wrong outside air temperature. Should be seeing minus degrees as you climb, if the air is too warm, the aircraft won't climb. Check what temperature you have and disable or enable a weather programme to fix it.

[TreeTops 0]

vatsim weather?

[Boeing or not going 578]

what was the outside air temp, ac weights, and your cost index?

[rocketfs 2]

Do you use FSINN from VATSIM?Bert Van Bulck

[DragonNGX 1]

Do you use FSINN from VATSIM?Bert Van Bulck

Yes, I do.

[DragonNGX 1]

what was the outside air temp, ac weights, and your cost index?

The weight was fine. CI was 200 odd.

[Tabs 2,790]

Don't use FSInn's weather - it's bugged and the temperature goes up instead of down with altitude - reduces lift hugely.

[Rey 11]

Wow. A cost index of 200 will definitely get you a climb rate like that. You should use a number under 50.

[Fabo 213]

No it will not.Stop obsessing over all CIs higher than 30... the NG can and will take anything up to 500 no problem.

[zubart 5]

A CI of 200 will stretch out the distance to TOC because the climb IAS is higher which translate to a lower rate of climb. It will also make your VNAV descent more problematic if the winds aloft are not accurate or are not inserted in the FMC Descent page. Use a lower CI. A CI of 45 is a good compromise and more economical. A CI of 45 will be slightly higher than long range cruise speed.Higher CI's just waste fuel unless speed is a priority to the destination.Aloha,John Floyd

[mikjon 0]

Another thought... Did you check your thrust mode during the climbout?It has happened to me where I inadvertently rotate the "N1 SET" nob from AUTO to BOTH which changes thrust setting from CLB to MAN, leaving me with a N1 setting of about 91% (i.e. the last N1 the engines were operating at). The climb would take longer in that case.However, weather add-on plays a large role as well, mainly due to wrong temps.Always check that your thust mode is in the CLB mode during the climb. It might just be that u've missed it this time.M.MannettiRW-ATC

[Fabo 213]

A CI of 200 will stretch out the distance to TOC because the climb IAS is higher which translate to a lower rate of climb. It will also make your VNAV descent more problematic if the winds aloft are not accurate or are not inserted in the FMC Descent page.

If that was adressed at me, then let me refer to the point in the original post - the FMC initially calculates an altitude at a fix, that gets progressively lower with time. A high CI will lower climbrate, but FMC counts with that to start with, so this problem is not CI related.

[Boeing or not going 578]

High Ci is just not realistic. Southwest uses 20 and SAS uses 7. Cathay used 80 a few years ago but that was in their 747's.

[raknal 6]

something similar happened to me once, found out I was using metric and had dialled FL280 as metresRichard