Yeah... I'd reckon pumping the collective is probably not as efficient as having the collective in the exact right spot for any given manoeuvre.
Many years ago i did me mustering learning in a 300. The instructor got me to use the pumping technique to extricate me-self from the decaying rotor/eng situations i got into amongst the trees. I noted that when the instructor thought i'd got me-self in too deep and took over that he did not use the pumping technique.
Thinking about it, one way to look at the pumping technique is it is much like an early car brakes ABS system that doesn't know exactly where the sweet spot is - i.e., put the brakes on hard, feel the lock up, release brakes and feel the free role, put the brakes on hard again... etc.
A pilot with time on type in the relavent operation would likely just put the collective/throttle in the sweet spot for any particular manouver with out much thought of it. To the novice on the other hand, who is already jerking the collective up and down in easy flight, the pumping technique is probably the only way they will find that sweet spot - albeit briefly between strokes.
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