Originally Posted by
lemme
Nice graphics and analysis as before.
From your article linked above:
Generally, pilots will advance engines to an intermediate power setting prior to releasing brakes. This spool up from low idle ensure that both engines will advance to takeoff power in concert, making asymmetric thrust less likely. Without engine readings, it is not possible to know if asymmetric thrust led to loss of control.
Actually, I think the brakes will normally be released before the initial spool up per Boeing's recommendation.
I found this, allegedly from a 737-700 FCOM:
A rolling takeoff is recommended for setting takeoff thrust. It
expedites takeoff and reduces risk of foreign object damage or
engine surge/stall due to a crosswind. The change in takeoff roll
due to the rolling takeoff procedure is negligible when compared to
a standing takeoff.
Allowing the engines to stabilize for more than approximately 2
seconds prior to advancing thrust levers to takeoff thrust may
adversely affect rolling takeoff distance.
Similar verbiage is in the manuals for the larger Boeing's I've flown.