Hey folks,

this is something that occurs since couple of days and is pretty new to me after years of simming with different Boeing models, including PMDG. The problem looks as follows:
after doing all preparations, setting FMC route, weights, speeds, I taxi to the runway, engage A/T and F/D, set the throttles to T/O, rotate, set gear up and engage LNAV, FLCH and finally A/P I notice that allthought the engines are running on full the A/C is hardly ascending and acceleratin. After levelling up the angle of attack drops below zero but still the plane is not accelerating allthough engines are running on full power.
And it happens both with A/P engaged and on manual.

After some time then the plane resumes normal operation but not always permanently.

Either there is a sudden glitch in the model or I overlook something but I never had this problem before.

Please help!

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I believe it has something to do with weather generation, so if you look at your TAT you will see it's pretty hot, and therefore the aircraft cannot climb any further even at full throtlle also called Density Altitude, the higher the aircraft climbs the colder it would get and thus optimizes the engine performance, I think if you search the forum you will find the answer, it was a pretty common issue but nothing to do with the aircraft itself, as it is functioning exactly as expected.

Here is a possible solution found by searching the forums:

 

 

Hi Marius
thanks for the tip but I don't think it is the case.
I am trying to find out the problem right now and the situation looks as follows:
present altitude is 7600ft

throttle set to CLB (N1 shows 93.5 on both engines)

v/s +1000 ft/min

IAS: 176 and dropping

TAT: 8 degrees Celsius

I am pretty much confused...

 

which weather engine are you using?

 

99% of the time it is this issue. 

Also trying Google it will probably point you to various posts even here on Avsim regarding that issue! 

FSUIPC maybe?

I had exactly the same problem with the T 7.  I deleted the FSUIPC ini and let it rebuild.  No problem then with the AC climbing.  After trial and error of seeing what in the ini  was the cause and reading in the forums, it was calibration of the flap axes thru FSUIPC.  If you delete the calibration thru FSUIPC and just use the settings in FSX, that should resolve the problem.

George Nacino

5 hours ago, Wojciech Jakubowski said:

Either there is a sudden glitch in the model or I overlook something but I never had this problem before.

"Sudden" anything means something got changed, and it's rarely the aircraft.

My bet would be a configuration change you made, particularly FSUIPC-related.

Thank you guys for the tips, I will give it a try tonight.

It worked. I mean FSUIPC.ini removal. 
Thank you all very much for you help. I am no computer geek and if something does not work on the P&P basis, I get lost pretty fast.

Thanks again!