Venanzi said autorotation tests have been conducted at altitude, and that “it doesn’t take much altitude” to achieve a power-off full flair (sic) to a sink rate of zero fpm.
SAS (and everyone else), what Pietro Venanzi was obviously talking about there was the ability of the 609 to flare (correct spelling) to zero sink rate
while already established in an auto. He's clearly trying to appease the critics who say the tilt-rotor cannot autorotate to a safe landing.
Presumably, a run-on landing in helicopter mode would be less risky than a forced-landing in King Air mode. Either way, the landing is going to be breathtaking! With regard to the former, imagine timing that flare? Hoo! But even King Air pilots don't practice dual engine failure landings in real life - probably not even in the sim. Then again, King Airs aren't often asked to hover.
However, one has to chuckle a little at Venanzi's clever use of that vague, "doesn't take much" phrase. Sooooo...how much is "not much?" And how much
more "not much" would it take for the heavier V-22 to flare to zero fpm in an auto? Ah, semantics, gotta love them.
When it comes to engine failures, we know that the transition from
hover-to-stabilized-auto or
hover-to-airplane-mode is going to take up quite a bit of altitude. But let's dismiss the idea of having a dual engine failure while hovering and then transitioning to airplane mode. When would that ever happen? When would a V-22 be hovering high enough to even consider such a procedure?
On the other hand, if both of an Osprey's engines quit when it's cruising along up high, it becomes a bank safe with little stubby wings. Look for something soft to land on (hopefully near a hospital), not Interstate-10.
If you have a dual engine failure at the end of a flight when you're on approach and transitioned back to helicopter mode, you're pretty much screwed; we understand this. But you would have to be having a REALLY bad day. (Hopefully nobody would experience a dual engine failure on take-off.)
It's a compromise aircraft. Those who fly it (and fly in it) accept those compromises that come with the increased capability. They look at the instances of dual engine failures in existing multi-engine aircraft and they consider the risk of that particular emergency to be low enough to not worry about.