The U.S. Air Force, Navy and Marine Corps grounded their fleets of V-22 Ospreys after eight crew members were killed when one of the aircraft crashed in Japan. The Air Force’s move was announced in a news release Wednesday from Air Force Special Operations Command. Lt. Gen. Tony Bauernfeind, AFSOC commander, said he gave the order for Ospreys to be grounded while the force investigates whether any problems with the tilt-rotor aircraft could have led to the Nov. 29 crash near Yakushima Island. “The standdown will provide time and space for a thorough investigation to determine causal factors an…