Take-off trim setting

[Federico 1]

Hi everyone! For some time flying with the beautiful NGX I’ve been asking myself this question: is the calculated takeoff trim setting already corrected? In the Boeing manuals there’s a correction table for the trim setting based on the engine derate you choose and I don’t know if you have to apply this correction to the fmc calculated value or not.

Thanks in advance to everyone!

[Andrea1 6]

Ciao Federico,

The trim setting worked out by your FMC that you can read by your CDU (Takeoff reference page) is already corrected, based on your c.o.g. (center of gravity), faps setting and engine thrust .

In fact you you check it matches with FCOM trim setting tables .

Bye

Andrea Buono 

[Federico 1]

Ciao 😄 thanks!

[Andrea1 6]

HI,

naturally I meaned: "in fact IF you check it". Sorry, it was a "typo".

Ciao.

Andrea Buono.

[MarkJHarris 128]

It is indeed corrected. Not only that, but it's the master if there's any discrepancy in performance calculation software usually. You set Flap, Take off M.A.C. setting (or double click in NGX unlike the real world) and select your Derate, assumed temperature setting and it will generate a trim figure.

 

[Federico 1]

Thank you! I was always correcting the fmc figure...

[Ephedrin 418]

And don‘t take this calculation too serious. If there is a difference of 0.2 of the stab trim preset or so you can forget about it. You have a very vague analogue display anyway. The main thing about this setting is to have no forces during the initial climb out. But if there is a little pressure on the yoke you can easily move your thumb after lift off.. 

[Federico 1]

21 hours ago, Ephedrin said:

And don‘t take this calculation too serious. If there is a difference of 0.2 of the stab trim preset or so you can forget about it. You have a very vague analogue display anyway. The main thing about this setting is to have no forces during the initial climb out. But if there is a little pressure on the yoke you can easily move your thumb after lift off.. 

Yeah, thanks! I asked a few pilots and they told me that the calculated value can’t be set precisely due to how the trim setting is displayed in the 737..