QS, Just a comment on the H/V diagram (avoid curve);
It's a bit worrying that some on this thread have said that the H/V diagram applies to the take off phase only. Hmmmm.....
To quote from Bell training: "The height-velocity diagram defines the conditions from which a safe landing can be made on a smooth, level, firm surface following an engine failure"
The avoid curve deals with energy - kinetic (speed) & potential (height), required to regain rrpm following it's enevitable decay after an engine failure and the unsuspecting pilots' time to react. I've haven't seen or heard off an avoid curve predicated for the take off phase only (please someone advise if these charts exist on other types).
Those kind & brave test pilots went up and tested various combinations of height and airspeed from which they could safely pull off an auto & walk away. These were done from various flight regimes i.e. straight & level, climbing, descending etc.
All the H-V diagram is telling you is that if you fly in the shaded area, regardless of what phase of flight it is (and where the collective is sitting), you cannot be assured of pulling off a successful auto (EOL).
So, be aware that flying a constant angle approach could well put you inside the avoid (shaded) area with a combination of height & airspeed that falls in the grey e.g. 20kts @ 40 feet with an armful of collective/pitch as you approach the OGE hover condition, the FM says your rrpm will decay real quick in this condition and your landing will not be assured.
Cheers
J