When you learn to parachute jump, they teach you to perform a special landing technique called a PLF. This is intended to provide a more gradual and thus less jarring impact with terra all too firma.
Today’s invention is to orient a crashing helicopter in such a way that the tail rotor arm hits the ground first, absorbing a lot of the kinetic energy as gradual, gross plastic deformation of this region.
This reorientation could be achieved by eg having small wings extend explosively from the sides of the tail boom at the moment when the main rotor was sensed to have failed.
The tail could be designed to be internally like an automotive crush zone and also potentially angled much less upwards from the horizontal than normal.
This would allow the cabin to avoid auguring in by having its untimely descent slowed (a bit like a factory chimney demolished by the legendary Fred Dinbah).
See this, 5 minutes in
http://www.youtube.com/watch?v=7jrnj-7YKZE&feature=player_embedded