MELBOURNE, Australia – Japan-based U.S. Marine Corps F-35 jets will conduct flying operations from a Japan Maritime Self-Defense Force helicopter carrier that is being converted to operate the fifth-generation fighter jet.

Japan’s Ministry of Defense said in a Sept. 30 news release that the F-35Bs, which are capable of Short Take Off and Vertical Landings, or STOVL, will conduct landing and take-off tests on the JS Izumo between the 3rd and 7th of October.

The flight operations will be conducted somewhere in the Pacific Ocean off Japan, and will be used to verify modifications to the flight deck that will allow the ship to operate the Lockheed Martin-made aircraft.

The U.S. ally has a requirement for 42 F-35Bs out of a total of 157 F-35s it is acquiring. It already has eight STOVL jets on contract for delivery beginning in 2024, with the latest Japanese defense budget allocating funding for a further four aircraft in the 2022 fiscal year.

The Marine Corps F-35Bs that will conduct the operations will be drawn from the aircraft currently forward-deployed at Marine Combat Air Station Iwakuni in Yamaguchi Prefecture. According to the base, the Izumo docked at the facility earlier today “in support of regional security and stability operations.”

It is not clear which Marine squadron will support the flight operations on the Izumo, although it is likely to be the aircraft and crew from Marine Fighter Attack Squadron (VMFA) 121, which has operated the F-35B since 2012 and has been based in Japan since 2017.

The second Iwakuni squadron, VMFA-242, has only recently achieved initial operating capability on the F-35B, having only begun its transition to the type in late 2020.

The first stage of work to convert the ship, whose flight deck previously only operated helicopters, has already been completed, as the ship emerged in June with newly painted lines on its flight deck for fixed-wing air operations.

The scope of work already completed by Japan Marine United shipyard in Isogo, Yokohama, also included the application of a heat resistant coating to the flight deck to cope with temperatures from the F-35B’s exhaust and the installation of landing and other lighting to enable fixed wing aircraft operations.

Japan’s government has already allocated $60 million for additional work to convert the Izumo in the defense budget for the 2022 fiscal year. According to a report in Yahoo Japan’s news portal, this will include $32.2 million to acquire Raytheon’s Joint Precision Approach and Landing System, or JPALS, and $10.7 million to the U.S. military for unspecified technical support.

The next stage of the conversion will include rebuilding the front of the flight deck from a trapezoidal to a rectangular shape, along with changes to the ship’s internal spaces to accommodate F-35B operations.

These changes will likely create an increase in aviation fuel capacity onboard and provision for armored magazines to store air-launched weapons, and is scheduled for completion in 2026. Japan will also convert the Izumo’s sister ship, Kaga, into an F-35B carrier.

Mike Yeo is the Asia correspondent for Defense News.

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