performance
 

Hi all

In what situation would you be able to derate/reduce thrust in order to increase takeoff weight?

Thanks

clear_right

You haven't given enough clues to what looks like a trick question.

Are you considering All Up Weight AUW.?

Use a longer runway
Fit a smaller lighter engine.
Go to the Moon !!
Wait for a stronger wind
Take off down hill.
Use JATO

Probably the point of the question relates to Vmcg considerations.

With a derated (but not a reduced thrust - as the rated thrust remains the same) takeoff, the lower rated thrust may result in a lower Vmcg permitting a lower min V1 and reduced ASDR. If the takeoff at a higher rated thrust previously was accel-stop limiting on a modest length runway, the use of a derate might permit an increase in RTOW.

This is an interesting curiosity and periodically comes up in PPRuNe discussions. For larger aircraft at light weights on shorter runways it can make for significant RTOW deltas. If you run a search on Mutt's posts you will find a few examples.

Thanks John

I did find a very good thread explaining how derated thrust can increase takeoff weight.

Appreciate your help!

In some examples of the 320 ops,we were faced with limited T/Off wts off 32 @LBA(terrain limited),but if we elected to dept' off 14 with Flaps3-we had sufficient runway available to entertain Flex thrust:O

oldebloke,

Comparing takeoff weights from RWY32 with RWY14 isnt exactly comparing apples with apples.... :):)

Mutt

Too True,but changing the runway(even with a tailwind)and increasing Flap(from1+f -3)increased the gross weight and gave you the Flex option...I know, off 14 the next highest point is the Alps!!
Cheers:ok:

oldebloke
Sorry, totally off topic Ex-SSV by any chance?