A V-22 Osprey aircraft that crash-landed off Japan's southern island of Okinawa in December last year was caused by weather conditions and human factors, according to the US military report.
The report refutes various media claims about sustainability of the Ospreys, and a Japanese government source told the Mainichi Shimbun on August 23 that the government is set to release the full report soon, once it formally receives the document from the U.S. military.
The Osprey in question based at U.S. Marine Corps Air Station Futenma in Ginowan, Okinawa Prefecture, was conducting a midair refueling exercise with an MC-130 tanker several dozen kilometers east of the Okinawa main island when one of the Osprey's propeller blades clipped the fuel hose, damaging the propeller. The aircraft turned back for Okinawa, but crash-landed just short of land near the city of Nago. The Osprey broke into several pieces, and two of the five U.S. personnel aboard were badly injured.
The U.S. military briefly suspended Osprey flights after the accident, but the aircraft were back in the air six days later after the U.S. stated that there was nothing wrong with the Osprey itself, and that the incident had been caused by turbulence and other factors.
In related developments, an Osprey based at Futenma crashed into the sea near Australia on Aug. 5. In that case, too, the U.S. military has determined that there was no fault with the aircraft, and the Japanese government has also approved continued Osprey operations in Japan. However, the Okinawa Prefectural Government is calling for the tilt-rotor aircraft to be grounded due to safety concerns.