The Air Force said a “material failure” caused the Nov. 29 crash of an Osprey tiltrotor aircraft off the coast of Japan that killed all eight airmen on board.
Lt. Gen. Tony Bauernfeind, commander of Air Force Special Operations Command, convened an accident investigation board to determine why the Osprey, call sign Gundam 22, went down during a training mission near Japan’s Yakushima Island.
“The material failure that occurred is known, but the cause of the failure has not been determined,” the Air Force said Tuesday. “Engineering testing and analysis is ongoing to understand the cause of the material failure, a critical part of the investigation.”
The board will brief the families of the victims once the accident investigation has been completed. The information will then be released to the public, officials said.
The crash and the investigation triggered the grounding of all V-22 Ospreys flown by the Air Force, Marine Corps and Navy. It was the latest incident in a string of deadly mishaps involving the aviation hybrid that can take off and land like a helicopter and fly like an airplane.
The Osprey program has been plagued with problems since it first rolled off the assembly line and was shipped to the Marines, who remain its primary customers. Each aircraft has a sticker price of more than $70 million, but the greatest cost are the more than 50 service members who died since June 1991 in dozens of Osprey incidents, ranging from multiple crashes to hard landings on airstrips.
In August 2022, the Air Force ordered a “safety stand down” of its Osprey fleet as a result of clutch issues. Officials aren’t saying whether that was the reason for the most recent deadly crash.
“Any disclosure of findings prior to investigations being finalized is premature and presumptive,” the Air Force said Tuesday. “As final safety investigation findings and recommendations are received, the priority is to inform our deliberate return to fly and ensure CV-22 aircrew and maintainers have the information they need to prevent future mishaps.”