A U.S. navy CV-22 Osprey takes off from Iwakuni base, Yamaguchi prefecture, western Japan, on July 4, 2018.

AP

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AP

A U.S. navy CV-22 Osprey takes off from Iwakuni base, Yamaguchi prefecture, western Japan, on July 4, 2018.

AP

WASHINGTON — The navy introduced late Wednesday it was grounding all of its Osprey V-22 helicopters, one week after eight Air Force Special Operations Command service members died in a crash off the coast of Japan.

The Air Force, Navy and Marine Corps took the extraordinary step of grounding tons of of plane after a preliminary investigation of final week’s crash indicated {that a} materiel failure — that one thing went improper with the plane — and never a mistake by the crew led to the deaths.

The crash raised new questions concerning the security of the Osprey, which has been concerned in a number of deadly accidents over its comparatively brief time in service. Japan grounded its fleet of 14 Ospreys after the crash.

Lt. Gen. Tony Bauernfeind, head of Air Force Special Operations Command, directed the standdown “to mitigate risk while the investigation continues,” the command mentioned in a press release. “Preliminary investigation information indicates a potential materiel failure caused the mishap, but the underlying cause of the failure is unknown at this time.”

In a separate discover, Naval Air Systems Command mentioned it was grounding all Ospreys. The command is answerable for the Marine Corps and Navy variants of the plane.

The Air Force mentioned it was unknown how lengthy the plane can be grounded. It mentioned the standdown was anticipated to stay in place till the investigation decided the reason for the Japan crash and made suggestions to permit the fleet to return to operations.

In Japan, the place U.S. navy Ospreys had a non-fatal crash as soon as and a variety of incidents, the most recent accident has rekindled security considerations simply because the Japanese authorities builds a brand new base for its fleet of Ospreys.

Chief Cabinet Secretary Hirokazu Matsuno advised reporters in Tokyo the federal government has already formally requested that the U.S. navy guarantee the protection of Ospreys earlier than their flights, however that Tokyo will search additional info from the U.S. facet as a result of it additionally impacts the protection of Japan’s personal Osprey fleet.

“Needless to say, ensuring flight safety is the top priority of aircraft operation,” Matsuno mentioned. “Japanese Self-Defense Force also operate Ospreys, and in order to ensure their flight safety, we will continue to ask the U.S. side to share information with us.”

The U.S.-made Osprey is a hybrid plane that takes off and lands like a helicopter however can rotate its propellers ahead and cruise a lot sooner, like an airplane, throughout flight.

Its distinctive design has been a think about a number of incidents. While the investigation into final week’s crash has solely simply begun, it renewed consideration on the plane’s security report, significantly on a mechanical downside with the clutch that has troubled this system for greater than a decade. There even have been questions as as to if all elements of the Osprey have been manufactured in line with security specs.

In August, the Marines discovered {that a} deadly 2022 Osprey crash was attributable to a clutch failure, however the root trigger was nonetheless unknown. In its report on the crash, the Marines forewarned that future incidents “are impossible to prevent” with out enhancements to flight management system software program, drivetrain element materials power, and sturdy inspection necessities.”

Air Force Special Operations Command has 51 Ospreys, the U.S. Marine Corps flies as many as 400 and U.S. Navy operates 27.

The Osprey continues to be a comparatively younger plane within the navy’s fleet — the primary Ospreys solely turned operational in 2007 after many years of testing. But greater than 50 troops have died both flight testing the Osprey or conducting coaching flights within the plane, together with 20 deaths in 4 crashes over the previous 20 months.

An Osprey accident in August in Australia killed three Marines. That accident additionally continues to be below investigation.