Japan to Develop Successor to Kawasaki T-4 Trainer

Japan’s Ministry of Defense has announced plans to develop a domestic training aircraft to replace the Kawasaki T-4 fleet.

This follows an official document issued by the Defense Ministry.

As part of the effort to find a replacement, the ministry has signed three contracts with leading Japanese aerospace companies: Mitsubishi Heavy Industries, Subaru, and Kawasaki.

The contract with Mitsubishi Heavy Industries for preparatory research materials is worth about $1 million. Subaru and Kawasaki received contracts valued at $477,063 and $197,024, respectively.

Mitsubishi Heavy Industries’ existing groundwork explains the significant difference in contract values. At the DSEI Japan 2025 defense exhibition, the company presented its own conceptual model of a prospective trainer aircraft.

The higher level of funding for Mitsubishi may indicate a more advanced stage of work.

At this stage, the three companies are expected to submit their research results and initial design concepts to the Ministry of Defense. The Ministry will assess the proposals for compliance with GCAP requirements, particularly regarding digital compatibility and flight performance.

Only after a detailed review of all submissions will the government decide whether to fund the construction of a full prototype and a flying test aircraft.

Successor to the Kawasaki T-4

The Japanese Ministry of Defense is currently considering around six proposals to replace the Kawasaki T-4. Major Japanese manufacturers have submitted three, while the remainder come from foreign companies.

Italy’s Leonardo SpA is actively promoting its M-346 aircraft as a candidate. At the DSEI Japan 2025 international defense exhibition in May, the company showcased a full-scale flight simulator and a model of a Japan-specific variant designated the M-346J.

The M-346 is already familiar to Japanese pilots. Since 2022, the Japan Air Self-Defense Force has been sending pilots to the International Flight Training School (IFTS) in Italy, where they complete the fourth phase of training, known as Lead-In Fighter Training, on the aircraft in preparation for flying fifth-generation F-35 fighter jets.

In addition to the Italian proposal, the US-made Boeing T-7A Red Hawk is also among the candidates.

Japan’s key priority in developing or selecting a trainer is deep integration of training systems with its future sixth-generation fighter. That aircraft is being developed under the international Global Combat Air Programme (GCAP) in cooperation with the United Kingdom and Italy.