I'd guess only situation where you'd use it is when you'd lose the aircraft otherwise. In normal conditions escaping an aggressor would not be such situation.

I'd guess only situation where you'd use it is when you'd lose the aircraft otherwise. In normal conditions escaping an aggressor would not be such situation. Think it as redline in a car; take away the limit and the engine can rev higher and possibly get few hp more, but the engine won't be in any good shape after that.