Japanese, US and UK forces have completed Lockheed Martin F-35B trials from the deck of the Japanese aircraft carrier JS Kaga.
The converted helicopter ship, which Tokyo calls a “multi-functional destroyer”, arrived off the coast of Southern California in September to conduct sea evaluations with the US Navy (USN) using F-35Bs.
The first sortie took place on 20 October, with flight operations ramping up over the ensuing weeks to certificate the second of the Japan Maritime Self-Defense Force’s (JMSDF’s) Izumo-class flattop ships.
Senior US and Japanese leaders appeared aboard the Kaga on 6 November to mark the conclusion of the three-week evaluations. Officials on hand included Vice Admiral John Wade, commander of the USN’s Pacific-focused 3rd Fleet, and JMSDF Fleet Escort Force commander Vice Admiral Goka Yoshihiro.
“This testing will support future training and operations by the JMSDF as they acquire [the] F-35 air system with its fifth-generation capabilities,” Wade said on 6 November. “The relationship between the US Navy and the JMSDF is as strong as ever.”
The trials involved specially instrumented F-35B short take-off and vertical landing (STOVL) fighters from the US Navy’s Air Test and Evaluation Squadron 23.
Sorties were flown by pilots from the US Marine Corps (USMC) and UK Royal Navy, both of which services already operate the stealth fighter aboard vessels similar to Kaga.
“With the support of the US Navy and the US Marine Corps, the destroyer has completed the F-35B training, taking a step forward toward acquiring F-35B onboard operation capability,” the JMSDF says.
Japanese personnel also spent time aboard the UK Royal Navy’s HMS Prince of Wales in 2023 as that ship underwent flight trials with the USMC. Those tests included an alternative rolling vertical landing technique and the ski-jump-assisted launch of a heavily-loaded F-35B configured in so-called “beast mode”, which gives the jet an expanded ordnance payload of 9,980kg (22,000lb).
Ahead of the Kaga flight trials, Japan retrofitted the ship, which had previously been equipped only to carry rotary-wing aircraft, to support the US-made F-35B jump jets. Japan has 42 examples of the STOVL variant on order.
“By acquiring F-35B operation capability as soon as possible, we will further contribute to peace and stability in the region,” the JMSDF says.
Lockheed says it will deliver Japan’s first F-35B in 2025. The Japan Air Self-Defense Force already operates the conventional take-off and landing F-35A.
Modifications made to Kaga included expanding the area of the flight deck and painting the landing surface with heat-resistant materials to withstand the F-35B’s Pratt & Whitney F135-PW-600 vector-thrust engine.
Kaga’s sister ship, JS Izumo, saw USMC F-35Bs demonstrate landing and taking off from the ship in 2021. The vessel is now undergoing modifications to prepare for F-35B operations.
In addition to test pilots, aircraft maintainers, flight-test engineers, flight-deck personnel and logisticians from the US Navy’s Integrated Test Force also helped put the Kaga through its paces. Evaluated tasks included aircraft recovery via vertical landing, refuelling and short take-off launching from the ship’s 248m (814ft)-long flight deck.
In addition to expanding the capability of the JMSDF, the USN says the testing helped improve interoperability between American and Japanese services, “strengthening the deterrence and response capabilities of the Japan-US alliance and strengthening the security environment in the Indo-Pacific region”.
Story updated to clarify status of JS Izumo
