Long time ago, but…. My gallant Flt Cdr on the Puma decided to pull the rotor brake on in one fell swoop whilst both engines were powered up, but on the ground. I think it was a case of brake instead of a throttle. The brake held tight for an instant prior to self destructing with no effect on the rrpm, but in a spectacular manner. I guess the same would have happened under even higher power in flight.
I also recall there was a start procedure for windy conditions or on a ship where the brake was left on until ??% engine rpm to stop the disconcerting top heavy wobble. Good to hold a stationary rotor, but not one under power.
Me