Short takeoff and vertical landing F-35B stealth jets from the U.S. Marine Corps are poised to go aboard the Japan Maritime Self-Defense Force, or JMSDF, helicopter carrier Izumo, which has been modified for Joint Strike Fighter operations. The plan is to deploy the Marine Corps jets aboard the warship to prove the concept of fixed-wing operations before Japan begins to introduce its own F-35Bs in the next few years.
Japan’s Ministry of Defense announced yesterday that the Marine Corps F-35Bs would go aboard Izumo between October 3 and 7, to conduct shipborne operations in the Pacific. As far as we are aware, this will be the first time that fixed-wing aircraft have operated from a Japanese warship since World War II. The 24,000-ton Izumo has now arrived at Iwakuni, in Yamaguchi prefecture, home of a Marine Corps Air Station, as well as JMSDF and U.S. Navy flying units.
The F-35Bs that will go aboard the Izumo will be from MCAS Iwakuni’s 1st Marine Air Wing/Marine Aircraft Group 12, which includes two Lightning II squadrons.
Of these, Marine Fighter Attack Squadron 121 (VMFA-121), the “Green Knights,” received its first F-35Bs in November 2012 and declared initial operational capability (IOC) in July 2015, before relocating permanently to Iwakuni in January 2017. The squadron has developed considerable shipborne expertise, since it became the first Lightning II unit to deploy at sea, embarking six F-35Bs aboard the amphibious assault ship USS Wasp (LHD-1) in March 2018.
F-35Bs from VMFA-121 go aboard USS Wasp for the first time:
The “Green Knights” have since been joined at Iwakuni by VMFA-242, the “Bats,” which began their transition to the F-35B at the Japanese base in October 2020. They declared IOC on the new type in September this year.
It’s expected that aircraft from VMFA-121 will go aboard the Izumo next week, as the Marine Corps continue their close cooperation with allies that similarly operate, or are in the process of acquiring, short takeoff and vertical landing (STOVL) F-35B variants. In the past, the service has assisted in clearing the type to operate from the British Royal Navy’s aircraft carrier HMS Queen Elizabeth and, more recently, the Italian Navy carrier Cavour.
While Japan has already selected the F-35B as part of a wider Joint Strike Fighter acquisition program that also includes conventional takeoff and landing (CTOL) F-35A variants, next week’s deck trials will evaluate the type’s compatibility with the adapted Izumo.
Various images of the Izumo after its arrival at Iwakuni yesterday:
The warship, lead vessel in a two-ship class, was completed as a helicopter carrier, with provision initially only for the operation of rotary-wing types including tiltrotors. However, the possibility of operating fixed-wing aircraft was also in mind when Japan originally ordered the two vessels, the country’s largest warships since the end of World War II.
Indeed, back in 2018, the Japanese newspaper Asahi Shimbun quoted JMSDF sources stating the following:
“It is only reasonable to design (the Izumo) with the prospect of possible changes of the circumstances in the decades ahead… We viewed that whether the Izumo should be actually refitted could be decided by the government.”
This summer, modifications to the flight deck of the Izumo were completed at the Japan Marine United shipyard in Isogo, Yokohama, making the warship capable of supporting F-35Bs.
Among the changes required are a heat-resistant flight deck coating, a requirement to withstand the hot exhaust of the F-35B’s thrust-vectoring engine, as well as appropriate deck lighting.
These are just the first modifications, however, for what is a longer-term program that is needed to ensure that Joint Strike Fighters can be embarked and operated for sustained periods. Further changes will include a remodeled flight deck, with a squared-off rather than a tapering end. Below the flight deck, internal spaces will also be reconfigured to handle F-35Bs for stowage and maintenance, as well as providing storage for ammunition and aviation fuel.
Images of the Izumo following completion of the first phase of modifications for fixed-wing operations:
There has been some speculation that the Izumo class vessels may gain a ‘ski-jump’ takeoff ramp, as used on the British and Italian F-35B carriers, but this seems to have been deemed superfluous. At the same time, the existing rear elevator and hangar space are apparently already suitable for the movement of F-35Bs. As it is, however, the Izumo seems to offer limited deck length for STOVL operations, thanks to the cropped-off, trapezoidal shape of the deck, suggesting that the Marine Corps F-35Bs, as initially embarked, may have to perform lightly loaded, very short takeoffs.
Finally, the Joint Precision Approach and Landing System, or JPALS, will be integrated. A GPS-based landing system, JPALS guides fixed-wing aircraft and helicopters during the approach and landing phases, and its emergence is already leading to significant changes in the way the U.S. Navy goes about training its naval aviators for carrier operations.
Work to adapt the Izumo is scheduled for completion in 2026. The second vessel in the class, Kaga, will also undergo the same modifications, providing the JMSDF with two ships capable of embarking F-35Bs. This is an important consideration to boost operational availability, bearing in mind the normal maintenance and training cycles. A major period of scheduled maintenance takes place roughly every five years.
Japan’s current Joint Strike Fighter plans call for a purchase of 157 aircraft, of which 42 will be STOVL F-35Bs. So far, eight of the STOVL jets are under contract, with deliveries to Nyutabaru Air Base in Miyazaki prefecture expected to begin in Fiscal Year 2024. Funding for another four jets has also been included under the FY2022 budget request. The 42 F-35Bs are expected to be operated by the Japan Air Self-Defense Force, or JASDF, despite their close relationship with the JMSDF and its carriers.
Ultimately, it’s possible that U.S. Marine Corps F-35Bs will become a more regular presence aboard the two modified Izumo class carriers. This would parallel the arrangement between the Marine Corps and the British Royal Navy, where U.S.-operated F-35Bs are filling in the numbers as the United Kingdom works incrementally toward a planned fleet of 24 carrier-available jets by 2023. With the total number of F-35Bs to be purchased by the United Kingdom in doubt, that arrangement may continue long term. At the same time, it ensures that the Marine Corps can share Joint Strike Fighter experience with their British counterparts.
Similar U.S.-Japan military cooperation has already brought together land-based JASDF F-35As to train alongside the U.S. Navy’s Japan-based amphibious assault ship USS America (LHA-6) in the western Pacific during “advanced combined operations” last year, drills that you can read more about here.
Japan may also seek to gain experience from the Marine Corps of the “Lightning carrier” concept, which involves amphibious assault ships operating more as light aircraft carriers with large numbers of Joint Strike Fighters embarked, something we previously discussed in depth here. That kind of arrangement could lend itself well to the adapted Izumo class, which are broadly similar in concept to the U.S. Navy’s big-deck amphibious assault ships.
As well as working alongside the U.S. armed forces, Japan may seek to establish a similar relationship with the United Kingdom, which has an increasingly strategic focus on the Asia Pacific region, and which is rapidly building up its military relationship with Tokyo. Both countries will operate F-35Bs as part of two-vessel carrier fleets and the prospect of British F-35Bs operating from Japanese carriers, and vice-versa, as part of an expanding partnership in the region should not be ruled out.
For Japan, in particular, establishing a fixed-wing carrier capability provides a counter to developments in the People’s Liberation Army Navy, which is fast establishing its own carrier fleet as well as expanding its amphibious forces. As well as providing an extended defensive umbrella around a JMSDF task force, carrier-based F-35Bs offer the ability to launch standoff anti-ship missiles against an adversary’s vessels, which would be especially relevant to blunt an amphibious assault.
Having F-35Bs operating aboard a carrier increases survivability and flexibility during a conflict, removing vulnerable land-based airfields from the equation. As The War Zone has surmised in the past, the F-35B carriers could be useful for establishing a presence near the disputed Senkaku Islands in the East China Sea and other potential flashpoints, helping project power away from the Japanese home islands.
In the past, the defensive nature of Japan’s constitution made the idea of acquiring an aircraft carrier, specifically one capable of launching fixed-wing tactical airpower with offensive capabilities, very unlikely. Indeed, the Izumo class vessels were classified as ‘helicopter destroyers’ for this very reason. However, with the growing threat posed by both China and North Korea in mind, this approach has changed, and, in the future, we can expect to see F-35Bs operating regularly from Japanese aircraft carriers as a powerful symbol of this new military reality.
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