Citation C525B - CJ3 question

[Kagamuga]

CJ3 phase 1 recall item for a rejected take-off call for speed brakes to be deployed ... not the 'ground' flap position which automatically deploys the speed brakes.

Any informed opinion/answer/reason would be appreciated

Thanks to all ....

[JonDyer]

As a guess I'd say it's because you could be in a flap 0 configuration and very close to V1.

Deploying ground flap at that point could get you airborne or at least make you light on your gear, as you pass through 15 and 35 degrees, potentially extending your stopping distance.

[McDoo]

I'm with JD on that one...

[CL300]

answer in CS 25, but in short, you do not change the polar of the wing ( touching flaps that is ) during an RTO, Brakes, Power Off, and any other means of deceleration which are supposed reliable, the call "speed brake" is just there to confirm they are indeed deployed; reversers are there only if proved reliable ( and usually only on wet), in the C525 Thrust attenuators are no choice there are automatic.

[Kagamuga]

Thanks JD appreciated, spot on the money.....

[AZAV8R]

In addition to adding flaps potentially decreasing braking effectiveness, manipulating the flap handle quickly can cause delay if not moved precisely through the down and up gates. Extending the Speed Brakes is a simple, single motion switch flip that provides drag much more quickly than going to GRND Flaps.