Originally Posted by
tdracer
The windmilling hydraulic pressure is small - barely enough to control the aircraft at approach speeds (particularly on the 747-400 - as the bypass ratio of the engines increase, the windmill N2 decreases everything else being equal). Slower speeds mean slower windmill mean lower hydraulic pressure. Hence anything you can do to reduce hydraulic demand during a dead stick is goodness.
I feel a little silly for not knowing this but.....how does arming the autobrake increase hydraulic demand? Locked wheel protection?