Japan Is Slowly Preparing Its Own Stealth Fighter

X-2 demonstrator. Via ATLA.

The public document titled Defense Programs and Budget of Japan – Overview of FY2020 Budget Request (download here) is a useful guide to the country’s immediate national security goals and among its recurring programs is fifth-generation combat aircraft. The JASDF does have plans for acquiring additional F-35A’s and at least six F-35B’s–the latter variant are probably meant for the navy–but there are also new objectives regarding the “F-X” or a locally made twin engine stealth fighter. According to the budget request published by the defense ministry and detailed on page 14 the “F-X” program costs $103 million (at current exchange rates) for “Japan-led development” and another $70 million to complete its mission system integration.

What “mission system integration” entails isn’t discussed in the budget request although its scope may include pilots able to exercise limited control over nearby aircraft. Part of Japan’s fifth-generation fighter program is $93 million earmarked “to conduct research related to human-machine interface technology necessary for formation flight and remote control, which are required for future remote-control support aircraft that can assist manned aircraft.”

What the text in the budget request describes is no different from Boeing’s successful Loyal Wingman, which is a single engine AI-enabled drone capable of supersonic speeds. As its name indicates the Loyal Wingman enhances a conventional fighter aircraft’s awareness and capabilities, being fully networked with its squadron whether it’s simply loitering or engaged in actual combat. If Japan’s defense ministry secures funding throughout the 2020s to develop a comparable single engine AI-enabled drone it marks a significant breakthrough and puts the JASDF at the forefront of regional aerospace innovation. It’s doubtful if other countries with ambitions for homegrown stealth fighters (India, South Korea, and Turkey) achieve the same without external partners.

A detailed presentation of Japan’s fifth-generation fighter is excluded from the budget request aside form a thumbnail image depicting a conceptual aircraft model. While China has successfully developed its own stealth aircraft the J-20, albeit rated as “fourth-generation +” rather than a true peer to the US Air Force’s F-22 Raptor, with another twin engine model on the way, Japan’s own efforts are moving at a slower pace. In 2018 the Mitsubishi X-2 demonstrator’s flight test proved how viable a locally made fifth-generation fighter could be. But countries that have gone ahead with their own stealth fighter programs always face serious technological gaps and Japan is no exception. The engine type for a fifth-generation stealth fighter is always a hurdle and to date, the Acquisition, Technology and Logistics Agency (ATLA) is still experimenting with the XF9-1 prototype engine.

Japan’s defense ministry anticipates foreign partners helping advance its fifth-generation fighter aircraft program since there are other technologies local manufacturers will struggle to develop. Nothing indicates whether Boeing or Lockheed Martin have plans on a joint venture with Japanese partners to fulfill ATLA’s requirements. Other aspects of a true fifth-generation stealth fighter are a powerful AESA radar married to a sensor suite for harnessing battlespace data in real time. This also allows the pilot to detect and observe possible hostiles at beyond visual range (BVR) and counter them. The stealth fighter’s internal weapons storage is vital too since a twin engine model needs a large enough airframe for carrying its payload. It might take the rest of the 2020s for ATLA to roll out the F-X and in the meantime, the upgraded F-15J equipped for electronic warfare and the F-35A are the JASDF’s most potent assets for territorial defense.

The JASDF’s current strength pales in comparison to China’s PLAAF but its inventory is formidable. With 46,000 personnel and more than 500 combat aircraft it has enough resources for its ordained role as an air warfare branch equipped for securing national territory. Its fixed wing third and fourth-generation combat aircraft include 189 F-15J/DJ and 148 F-2A/B, whose appearance resembles the F-16A, with 51 F-4E Phantoms still in service. The JASDF does boast superb intelligence and surveillance capabilities.