FMC : In Flight thrust modes

[mbunjes 1]

Hi, could anyone explain when you would use the In Flight Thrust modes on the N1 limit page of the FMC ? There's a GA, Continuous, Climb and Cruise mode but isn't this taken care of by the autothrottle ? Would you ever use these buttons ?Thanks in advance

[Mats_J 2]

Martin,In some rare occasions you may want to get more thrust out of the engines than the FMC would allow. Unexpected head winds or whatever...Voil

[Guest D17S]

Like Matts said. For instance in cruise you'd assume that maximum cruise thrust would be enough. However if you were way up there at a max altitude, the AT might have thrust pushed right up against that CRZ thrust limit. If something happened and the AT needed more thrust, it wouldn't be available. In this case, what a pilot would be well advised to do would is this: Bump the thrust limit up to a "Climb" thrust limit (Again, this is not a thrust setting . . . only a thrust limit). This higher thrust limit would give the autothrottle a bit more 'room to move' if it needed to. It just lets guys get back to reading that magazine or talking real estate with a bit more comfort level.

[mbunjes 1]

Thank you very much, guys. That's cleared it up for me. The manual wasn't too explicit about this.

[Guest s_L_Y_F_a]

Just do addWhen you are executing a step climb and reach your new cruising altitude, the FMC does not switch back the N1 limit to crz so you have to do this manually after every step climb.