A CV-22B Osprey arrives at Yokota Air Base, Japan, April 5, 2018.

A CV-22B Osprey arrives at Yokota Air Base, Japan, April 5, 2018. (Stars and Stripes)

YOKOTA AIR BASE, Japan — The U.S. military’s fleet of Osprey tiltrotor aircraft, grounded since December after a fatal crash off the Japanese coast, could be flying again within weeks, according to a media report citing unnamed military officials.

A CV-22B Osprey from Yokota’s 21st Special Operations Squadron went down Nov. 29 during a routine training mission off Yakushima, an island in southern Japan.

Investigators probing the crash, which killed eight airmen, are looking at a possible mishap involving the aircraft’s propeller rotor gearbox, the officials said in a Tuesday report by NBC News.

Preliminary findings determined the crash was likely the result of equipment failure, not pilot error, Stars and Stripes previously reported.

Twenty service members, including those killed the Japan crash, have died in Osprey mishaps the past two years.

Four Marines perished March 18, 2022, in a Norway accident attributed to pilot error.

Three months later, another five Marines died in Southern California crash investigators blamed on a hard clutch engagement associated with the gearbox.

Three Marines died and five were injured Aug. 27 in Australia in a crash still under investigation.

The Osprey grounding could have lasted as long as a year but the aircraft could fly again soon, possibly within weeks, according to the officials quoted by NBC.

Air Force Special Operations Command did not immediately respond to phone calls early Tuesday seeking comment.

Four hundred Air Force, Navy and Marine Corps Ospreys have been grounded since Dec. 6 in the wake of November’s crash. Japan also grounded its fleet of 14 Ospreys.

The Osprey is a fast-moving airframe that can take off like a helicopter and then tilt its engines and propellers to fly like an airplane.

The tiltrotor stand-down is one of the largest military aircraft groundings in terms of affecting three services’ flight operations, but it’s not the longest.

When the Osprey was still in development, two crashes in 2000 killed 23 Marines and led the Corps to ground the program for nearly 18 months.

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Seth Robson is a Tokyo-based reporter who has been with Stars and Stripes since 2003. He has been stationed in Japan, South Korea and Germany, with frequent assignments to Iraq, Afghanistan, Haiti, Australia and the Philippines.

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