By Jim Wolf
WASHINGTON (Reuters) - Japan's defense minister flew from the Pentagon grounds Friday in a revolutionary hybrid aircraft at the heart of a controversy that threatens to strain strong defense ties between the United States and its Asian ally.
The minister, Satoshi Morimoto, donned a white flight helmet and goggles before taking the jump-seat, between the pilots, on the flat-gray Marine Corps MV-22 Osprey troop transport.
The Pentagon is seeking to deploy the tilt-rotor aircraft - which takes off like a helicopter but flies like a plane - as early as next month to the southern Japanese island of Okinawa despite strong public opposition, largely on safety grounds.
An initial shipment of 12 of the aircraft have arrived at Iwakuni Air Station, the only U.S. Marine Corps station in the main Japanese islands.
Activists are hoping to attract hundreds of thousands to what could be the island's largest-ever protest rally on Sunday.
The United States has agreed to refrain from flying the Osprey in Japan "in the short term," Defense Secretary Leon Panetta told a news conference with Morimoto at his side.
Morimoto's trip, to Marine Corps Base Quantico in northern Virginia and back, would let the Japanese defense chief experience first-hand the Osprey's "impressive capabilities," Panetta said.
The aircraft with the minister aboard headed low from the Pentagon over the Potomac River, crossing not far from the cherry tree plantings that originated in 1912 as a gift of friendship to the people of the United States from the people of Japan.
At Quantico, Morimoto watched a second Osprey land, evaluating its operation and noise levels in patterns meant to mimic their intended use at Futenma Marine Air Station on Okinawa island, where the Pentagon plans to base the Ospreys to replace aging CH-46 helicopters. The air base has long been a focus of local resentment over noise, safety and crime.
Panetta said the Pentagon responded in "a deeply respectful, collaborative and a constructive manner" when the Japanese government voiced safety concerns about the MV-22 deployment.
The concerns have been heightened by two Osprey crashes this year, one in Morocco in April that killed two Marines and another in Florida in June that injured five service members.
The Defense Department plans to present results of investigations into these mishaps to the Japanese government later this month "and the safety of flight operations will, hopefully, be reconfirmed," Panetta said. For now, Japan is the only place worldwide where the MV-22 has been grounded.
The Osprey's deployment to Okinawa, Panetta said, was a key part of the realignment of U.S. forces in the Asia-Pacific as troops return from the wars in Iraq and Afghanistan launched after the September 11 attacks.
The aircraft is built by Bell Helicopter Textron and Boeing Co and will let Marines fly faster and farther from Okinawa to remote islands in Japan. Panetta said it was important to Japan's defense.
Okinawa was occupied by the United States from 1945 to 1972. It accounts for less than 1 percent of Japan's soil but hosts 65 percent of total U.S. forces in Japan.
Morimoto, speaking through an interpreter, told the Pentagon news conference that the Japanese government would give "utmost consideration to ensure the safety of the local population" in weighing U.S. plans for the Osprey.
Japan and the United States are military allies under a security treaty concluded in 1951 and revised in 1960. Under the treaty, Japan grants the U.S. military base rights in return for a pledge to protect Japan's security.
Panetta did not join the flight with his Japanese counterpart, but has flown on the Osprey in Afghanistan and the United States, including to New York and back.
A combined total of 30 people, including 26 Marines, were killed in test flights or training accidents from 1991 through 2000 during the aircraft's development.
It has, however, been one of the safest rotorcraft in the U.S. military since it went into service in 2007, according to Richard Whittle, author of The Dream Machine: The Untold History of the Notorious V-22 Osprey.
(Reporting by Jim Wolf; Editing by Anthony Boadle)