The aft cyclic also loads the head a bit in opposition to the unload that lowering the collective may induce, depending upon rate of control movement. HC raised that point early on in this discussion, and given how rotor blades get their autorotational qualities, his early point on "don't unload the head!" remains sound advice ... and is consistent with various posts on energy management, Nr maintenance, and control manipulation.
I guess Pete has seen this as an instructor, but Savoia talks to what I have observed. Lowering the collective does not/should not happen in isolation. When flying a helicopter, one typically has to move the cyclic (and pedals) in compensation when the collective is moved depending upon the maneuver and probably on the amount of automatic/stabilization features that a given helicopter has, and has on at the time. For example, if you have an "altitude hold" feature engaged when the engines quit, you either have to override is with force or disengage it while lowering the collective and adjusting attitude at the same time.
Without a bit of practice at that, the reaction won't be instinctive, and one could indeed get a bit behind the aircraft. The Real Life experiences shared in the last few pages are most instructive, and I thank the gentlemen for taking the time to share with us their actual experiences. The only engine failures or rollback I ever had were on two engined machines, so a precautionary landing was done: hooray for two engines!
I am not sure why Pete made the case about a deep dark secret. What he may be reflecting is what he's seen people actually do, which means, he may be pointing out what reflexes and instincts seem to happen in aircraft, rather than what someone may or may not have been taught.
From the Australian teaching manual: LEARNING OUTCOMES:
The student will be able to follow the PFL drill and satisfactorily enter autorotation, glide towards a selected area, make a distress call and secure the aircraft for a landing. For the practice situation, the student will be able to overshoot safely by 500ft AGL.
An unpowered helicopter does not so much
glide as
plummet.
(With a nod to Monty Python and the flying sheep sketch
)