Nick wrote: "A cyclic climb from 50 knots in autorotation would only lead to a dull thud."
Agreed. Isn't that what happened? It is doubtful that an autorotative state or equilibrium preserving sufficient main rotor RPM for a 'non-damage landing' could have been obtained if the maneuver were performed as written.
Inspection of the main rotor blades after the "thud" data point would have probably revealed little main rotor in-plane rotational damage as there would not have been significant rotational energy remaining in the system. This would have validated your hypothesis.
Unfortunately, the residual coning angle set to the main rotor blades would probably have rendered the blades less than airworthy and re-use on an aircraft in the next chapter would have been contraindicated.
I have come to conclude that the best responses to an emergency are simple. I am always amazed at the length of pilot reaction and recognition time following a non-training emergency. In the case of an engine failure (for whatever cause) delayed response consumes energy and a procedure or method used in training can become unrealistic or unreasonable in an actual emergency. Instructors should always carefully consider the ability and knowledge of a student before the introduction of advanced autorotational techniques. Continuous forced landing area evalution during flight, techniques to anticipate problems, problem recognition skills and response methods are far more valuable than advance autorotational techniques.
Few experienced helicopter pilots will advocate low speed, low level pop-ups as a realistic engine failure response. Where a forced landing area can be identified a straight line deceleration is the appropriate technique. Flying over a jungle where the nearest forced landing area was probably the biggest tree, a pop-up 'might' allow a pilot to see an appropriate landing area that might not otherwise be seen. There is a compromise in all autorotative techniques. A pop-up provides visibility at the expense of maneuver complexity.
High speed, low level pop-ups and/or level deceleration techniques are a valid skill set for military pilots who may be required to operate in that environment. It is hard to justify this training to pilots who have no compelling reason to expose themselves to the risk of either low or high speed low level flight. My first question to pilots who request this type of training from me is "What are the compelling operational requirements that require you to learn this maneuver?". When such a requirement exists serious consideration should be given to ammending the way the operational requirement so as to reduce the risk.