A Japanese V-22 Osprey operates at Camp Kisarazu, Chiba Prefecture, Japan, October 5, 2024. (Japanese Ground Self-Defense Force)

CAMP FOSTER, Okinawa — Japan grounded its Osprey fleet over the weekend after one of the tilt-rotor planes hit the ground during a joint exercise with American forcesaccording to the Japanese Joint Chiefs of Staff.

The V-22 assigned to the Japan Ground Self-Defense Force’s 1st Helicopter Brigade was carrying a service member acting as a patient during a disaster response exercise Sunday morning, a spokesperson said by telephone Monday of the Joint Staff.

None of the 16 soldiers on board were injured in the incident, and the only damage was to the plane, the spokesperson said. He declined to say whether any U.S. personnel were on board.

The exercise was part of Keen Sword, a US-Japanese military exercise taking place across Japan until Friday, a Joint Chiefs of Staff press release said Sunday.

The Osprey was attempting to take off from Camp Yonaguni, a Japanese base on a remote island, when it became unbalanced and began “shaking left and right” at 11:38 a.m., the statement said. The bottom of the left wing “contacted the ground,” damaging part of the plane.

The Osprey took off and landed in a field inside the camp, he said without giving further description of the damage.

U.S. Forces Japan responded to questions emailed Monday by Stars and Stripes, but did not immediately provide answers.

American and Japanese pilots were expected to fly Ospreys for the first time on Yonaguni Island, southwest of Okinawa, the closest Japanese island to Taiwan, during this year’s Keen Sword, announced Joint Staff in September.

This is the first time a Japanese osprey has been damaged “by hitting the ground”, the spokesperson said. He did not say whether the Ospreys had ever been damaged in any other way.

The Self-Defense Force will ground its fleet of 17 Ospreys pending an investigation and “until the reason becomes clear and the measures are passed on to the troops”, the spokesperson said.

“I really want to apologize for causing this situation and causing concern to the affected communities,” said the commander of the 1st Helicopter Brigade, Maj. Gen. Toshihiko Hirose, in a statement relayed by the spokesperson for the Joint Chiefs of Staff. “We will continue to work hard to fly safely.”

Keen Sword is a biennial exercise that began in 1986 to increase combat readiness and improve working relations between U.S. and Japanese forces.

This year’s exercise is expected to include 12,000 U.S. and 33,000 Japanese troops, 40 ships and 370 aircraft, according to a Sept. 26 Joint Chiefs press release. It includes 900 Marines and sailors from across the III Marine Expeditionary Force, according to a press release. October 1.

Okinawa officials, including Gov. Denny Tamaki, protested the Osprey flights before the exercise.

“As a prefecture, we want them to clarify the reasons for this incident and, once again, we want to ask them to refrain from flying Ospreys for this exercise,” a spokeswoman for the Osprey said Monday by telephone. the Okinawa Military Base Affairs Division.

Some Japanese government officials are only required to speak to the media on condition of anonymity.

This incident involving a Japanese osprey occurred just as American ospreys are returning to a near-normal flight regime. This month, Air Force Ospreys flew from Yokota Air Base, west of Tokyo, to Okinawa for the first time since a fatal crash in Japan last year.

The American and Japanese Ospreys were grounded between December and March following the November 29 crash of a Special Operations Command tilt rotor just off the coast of Yakushima, an island south of Kyushu, in the southern Japan. The Marine Corps has Ospreys stationed at Marine Corps Air Station Futenma in Okinawa.

All eight crew members aboard the Osprey were killed. The accident investigation revealed a catastrophic mechanical failure, compounded by a “lack of urgency” on the part of the crew at the time, according to the accident report.

This revolutionary aircraft lands and takes off like a helicopter but flies like a fixed-wing plane.