Japan targets T-4 replacement ahead of GCAP as pressure mounts to modernise pilot training

When issuing a request for information last October, the Japan Air Self-Defense Force (JASDF) got the ball rolling on finding a replacement platform for its aging Kawasaki T-4 intermediate jet trainers. After deadline extensions, the tender process closed on 8 May.

The JASDF possesses more than 200 domestically built T-4 jet trainers that were introduced from 1988 onwards, but the range of options for replacing them is relatively narrow.

With Japan’s air force now flying fifth-generation F-35A and F-35B fighters, and with Global Combat Air Programme (GCAP) fighters on the way a decade later, the ageing T-4 is wholly inadequate for the task of acting as an advanced jet trainer.

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Several jet vendors were present at DSEI Japan 2025, held in Chiba from May 21-23, to present their cases to the JASDF.

Boeing is offering its T-7A Red Hawk, with John Suding, executive director for defense and government services in East Asia for Boeing, emphasising its commonality with the US.

Suding told Shephard: “The training that it will do for the US Air Force is very similar to the training that Japan does for its air force, and particularly for its fighter fleet, so with F-35s and F-15s being upgraded, there’s a lot of commonality there within the training system.”

The T-7A’s chances were boosted when, at a US-Japan leaders’ summit in April 2024, the allies announced they would explore joint development of a trainer aircraft to replace the T-4. Of course, that occurred under the Joe Biden administration, so it is debatable whether the current US president would give it as much credence.

Elsewhere, Europe’s leading proponent is Leonardo’s M-346, with the company offering its upcoming Block 20 aircraft that has improved avionics and cockpit displays. The first M-346 Block 20 will be delivered to Austria in 2028.

Diego Siccardi, responsible for Leonardo’s international campaigns in the Far East and Oceania, pointed out that JASDF pilots have been training on M-346s since 2022. This is because Japan sends a small number of pilots each year to complete advanced fighter training at the International Flight Training School in Italy. Siccardi said Japan would like to expand pilot throughput there.

Leonardo’s other advantage is its involvement with Japan in the massive GCAP project. This cooperation creates synergy, and GCAP is pivotal in Japan’s new willingness to cooperate technologically with countries other than the US.

Siccardi also stressed that Leonardo was prepared to transfer technology and work with Japanese partners, something that US companies are not necessarily able to do well.

Could KAI and MHI also be among the competition?

Korea Aerospace Industries (KAI), also among the companies that attended DSEI Japan 2025, manufactures the T-50 and FA-50 aircraft that have enjoyed considerable success in Asia. The political ramifications of Tokyo opting for a Korean-built aircraft, however, likely mean KAI would not be considered a serious contender.

Finally, Mitsubishi Heavy Industries (MHI) is keen to get in on the game too, although it differs markedly from the other three players in that it is proffering a twin-engine design that currently only exists as a concept.

Known as the T-X, a scale model was displayed at DSEI Japan 2025. Because it is only a concept, MHI officials could not provide specific details, although one notable thing is its size. Because it would act as a T-4 replacement and would also supplant F-2B and F-15DJ trainer variants, the T-X is nearly the size of an F-2 fighter.

Utilising experience gained from its earlier X-2 demonstrator, MHI highlighted that the T-X would have an advanced cockpit system containing touchscreens, as well as embedded simulator functions. Mitigating against the T-X, however, is the years it would take to develop. The T-X could only eventuate if Japan’s MoD threw its weight behind this indigenous solution.

Japan moves to overhaul pilot training pipeline

After having already selected Textron’s T-6JP Texan II as its basic trainer to replace the Fuji T-7 (with a contract due to be signed before year’s end), and with a new jet trainer being sought, Japan now has the opportunity to completely overhaul its pilot training pipeline.

This is necessary, because multiple industry sources described the JASDF’s pilot training system as “quite obsolete”, siloed and conservative.

As Marc-Olivier Sabourin, division president – Defence and Security International at CAE, explained: “The current Japanese programme is relying on assets that are becoming obsolete, so their training throughput is challenged. But also the training proficiency they get with their existing training system still creates a significant gap between the cadet knowledge and F-35 operations.”

Around one and half years ago, CAE conducted a study involving 30 Japanese pilot cadets who used virtual reality-based simulators to provide independent instruction and coaching. On that occasion, CAE claimed a 20% improvement on cadets’ grade performance without an instructor.

The training company is hopeful the JASDF might make steps towards a more modern enterprise-wide solution to pilot training management.

Related Programmes in Defence Insight

Global Combat Air Programme (GCAP) [Japan]

Related Equipment in Defence Insight

T/TA-50 Golden Eagle

T-7A Red Hawk

T-4