The Navy has grounded its V-22 Osprey fleet after eight U.S. airmen were killed in a crash in Japan last week.
According to USNI News, the order to ground all aircraft in the fleet went into effect on Dec. 6, and includes the Marine Corps MV-22B and the Navy’s CMV-22B.
“Preliminary investigation information indicates a potential materiel failure caused the mishap, but the underlying cause of the failure is unknown at this time,” NAVAIR said in a statement.
“While the mishap remains under investigation, we are implementing additional risk mitigation controls to ensure the safety of our service members,” the statement continued. “The Joint Program Office continues to communicate and collaborate with all V-22 stakeholders and customers, including allied partners.”
A Japanese Coast Guard spokesperson told NBC News that the aircraft experienced an “emergency water landing” in the ocean near Yakushima, which is located approximately 45 miles south of Japan’s main island of Kyushu.
The remains of six people who were killed in the crash have been recovered so far.
“In light of this incident, the minister of defense has asked the relevant departments to cooperate with the Japan Coast Guard to confirm whether or not there are any victims and to do their utmost to rescue them,” said Japan’s Vice Defense Minister Hiroyuki Miyazawa.
When Miyazawa was asked why he did not describe the incident as a crash, the vice defense minister said, “The U.S. side explained to us that the pilot did his best until the very end, so we’re using the term ’emergency water landing.’”
The U.S. CV-22 Osprey is capable of vertical takeoffs, similar to helicopters, and the aircraft’s rotors are capable of rotating 90 degrees in the air, allowing it to be flown similarly to a rotor-powered plane after takeoff.
Wednesday’s crash is the third incident with U.S. military members flying Osprey aircraft over the past two years. In August, three U.S. Marines were killed, with several others wounded, in an MV-22B Osprey crash in Australia.