If I had the time and interest I would go back through the thread and find the information John Dixson posted that detailed the Emergency Procedures and a discussion of the H/V diagram which showed a fair old height being required for the transition from Hover Mode into a No-Engines Operating Airplane Glide. It was startling to see how high one needed to be in order to achieve a proper Glide Speed and descent rate.
As the Marines say...it is not a helicopter....it is a tilt rotor and thus cannot be expected to autorotate like a helicopter.
Also...the odds of having a dual engine failure is quite remote....but possible as we all know about "Sod's Law".
The trick will be operating in the Hover Mode at heights lower than required to make that transition....where one cannot autorotate or go gliding....not that will ever happen mind you!
The difficulty of a transition from Hover Mode to an authoritative descent and landing must rather sporty as it is only done in the Simulator....and unless I misunderstand....it was not done in much detail during testing.
The other quote I found interesting is the Civil version has a different system for controlling the prop rotors angles and uses "Detents". I wonder why the difference and which system is the better? Could it be the Military froze the design in order to get into production and decided not to use the "Detent" method as Agusta has for the 609.