Endangered Species

Critics had warned that the V-22 Osprey, a craft combining the vertical talents of a helicopter and the horizontal speed of a normal airplane, would become "a stone in the air" if it lost power while making the change from one mode to the other. Tragically, that proved to be the case for the prototype tilt-rotor aircraft as it was landing at Quantico Marine Base in Virginia. Just as the Osprey was shifting from horizontal to vertical flight, with its propellers at a 60 degrees angle, it plunged into the Potomac River, killing all seven people on board.

The accident immediately...