The Air Force, Navy, and Marine Corps grounded all V-22 Osprey variants Wednesday amid an ongoing investigation into what caused a fatal crash of an Air Force CV-22 Osprey off the coast of Japan last week.
The CV-22B assigned to the Air Force’s 353rd Special Operations Wing at Yokota Air Base, Japan, went down offshore of Yakushima Island on November 29 with eight crewmembers on board during a routine training mission. The Japan Coast Guard said it received an emergency call at the time of the incident, along with reports that the aircraft’s left engine was on fire as it fell.
On Wednesday, Lieutenant General Tony Bauernfeind, the Air Force Special Operations Command’s (AFSOC) top commander, instituted an operational stand-down of the Air Force CV-22 fleet.
“Preliminary investigation information indicates a potential materiel failure caused the mishap, but the underlying cause of the failure is unknown at this time,” AFSOC said in a statement. “The stand-down will provide time and space for a thorough investigation to determine causal factors and recommendations to ensure the Air Force CV-22 fleet returns to flight operations.”
Following the AFSOC order, Naval Air Systems Command (NAVAIR), which supports aviation in both the U.S. Navy and Marine Corps, said that “out of an abundance of caution,” it had also grounded all V-22 variants.
“While the mishap remains under investigation, we are implementing additional risk mitigation controls to ensure the safety of our service members,” NAVAIR said.
The decision to ground V-22 operations comes days after Japan’s military temporarily suspended operations of its fleet of 14 tiltrotor aircraft, calling on the U.S. military to do the same in the country.
“It goes without saying that ensuring flight safety is the highest priority in the operation of aircraft,” Hirokazu Matsuno, Japan’s chief cabinet secretary, told Reuters on Thursday. “We will continue to request information sharing with the U.S. side to ensure flight safety.”
The remains of six of the eight airmen on board the CV-22 have been recovered. Search and recovery operations focused on locating the remains of the unaccounted for two airmen are ongoing, according to AFSOC.
“Following personnel recovery operations, the force will turn its efforts toward salvaging the remaining aircraft debris,” AFSOC said Thursday.