Air Force Special Operations Command (AFSOC) has grounded the United States' entire fleet of CV-22 Ospreys while an investigation into a Nov. 29 crash off the Japanese coast is ongoing.
So far, no timeline for the investigation and a possible end date have been revealed publicly.
"While the mishap remains under investigation, we are implementing additional risk mitigation controls to ensure the safety of our service members," the federal agency said.
"The Joint Program Office continues to communicate and collaborate with all V-22 stakeholders and customers, including allied partners."
Osprey crashes have plagued the U.S. military for years. A fatal crash that killed three in August led to the Marines ordering a safety review of the aircraft.
The fleet was also grounded earlier this year following yet another incident. Last year, AFSOC ordered a temporary stand-down of its Osprey fleet following safety incidents where the clutch slipped, causing an uneven power distribution to the rotors.