Looking at the diagram Sans provided....it appears each engine/prop rotor could mechanically operate individually without benefit of the I-Shaft system. Without both engines running and a failure of the I-Shaft system I can see the end result is not pretty....only one Prop Rotor being driven. Depending what mode of flight and Airspeed/Altitude combination it might be possible (I am assuming here....)to continue flight with the one remaining engine. If the aircraft was in the Hover Mode (Helicopter Mode) at a low forward airspeed...and less than about 1600 feet or so....it would be a very interesting proposition re surviving the Emergency Landing as we know the Height/Velocity Curve for that conditon of flight has lots of bright RED. (Hover Mode/OEI....Hover Mode/Both Engine Fail). The odds of both engines failing simultaneously/almost simultaneously are very slim. One engine failing after entry to Hover Mode and below the Minimum Safe Height for recovery to Forward flight in the Airplane Mode is the range of flight that needs explaining as well. Just how large a Red Area is there on the H/V chart for that flight condition.
Compared to the Chinook and its Synch Shaft....the Osprey would have a distinct advantage.
Now the question that is begged....how does the Crew controlled Prop Rotor Speeds, pitch settings and the like to equalize the Torque/RPM/Power output for the Engines with such a failure.....which is up to the Osprey knowledgeable folks here to answer as I have no clue. It sounds doable in theory...but in reality I wonder. Hopefully, someone will come forth and enlighten us.
Did find the post made earlier by Sultan that prompted this exchange about the I-Shaft on the Osprey as compared to the Synch Shaft on the Chinook.
Saturday Shows Crippling Flaws
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The Chinook: big, slow, noisy and with a critical flaw. If you hit the interconnect shaft game over as the rotors collide and destroys the aircraft. On the V-22 take out the interconnect shaft and you get a caution light.
The Sultan