Following reports of a Japanese F-15DJ Eagle fighter jet going missing on January 31, it was determined that the fighter jet had crashed into the Sea of Japan shortly after taking off from the Komatsu Air Base located in the Ishikawa Prefecture.

The Japanese Air Self-Defense Forces (JASDF) stated that it had disappeared from radar after flying 3 miles from the base, with a crew of two Japanese airmen. Parts of the F-15 and lifesaving equipment were also found 3 miles west-northwest of the Komatsu Air Base, leaving the fate of the two Japanese pilots unknown. Shortly after the disappearance, the JASDF deployed a rescue team of four aircraft and a rescue helicopter to find the two pilots.

“As part of the fuselage of the fighter jet was discovered in the area, the fighter jet is believed to have crashed,” said Japanese Spokesman Hirokazu Matsuno.

A Japanese F-15 at Hyakuri Air Base, 2004 ( Source:
A Japanese F-15 at Hyakuri Air Base, 2004 (

This is not the first time the Japanese Air Self-Defense Forces have experienced fighter jet losses. In fact, it has become a worrisome sign that Japan’s fleet of F-15s is beginning to show its age. How old are they?  Well, in 2018 Japan announced that it was considering selling its F-15J to the United States to purchase F-35s, in order for the U.S. to then resell them to countries with weak airforces that could not afford new planes.  That tells you how old they are.

Their fleet is mostly built by Mitsubishi Heavy Industries (MHI) under a license from McDonnell Douglas. The JASDF considers the F-15 their top aircraft to intercept any enemies in its airspace. The 200 F-15 under its arsenal has been in use since the 1980s, usually being deployed when Chinese and Russian fighter jets are found wandering in their airspace. Apart from 12 units of the F-15DJ, it also has 163 F-15Js, 36 F-15DJs,  and 2 F-15J built by McDonnell Douglas, which is now part of Boeing. As of 2021, the JASDF uses over 201 F-15J/DJs, which means that majority of their fighter jets are severely aging and need constant repairs and upgrades.

The first signs of aging were seen in July 2008, when an F-15J launched from the Tsuiki Air Base in Fukuoka crashed into the Sea of Japan. Another incident in 2011 saw an F-15J crash into the East China Sea during a training flight. Another crash that was not a mechanical issue was the Japanese F-35 stealth fighter crash due to spatial disorientation, losing one of Japan’s most updated and sophisticated aircraft. This most recent crash was reported to be an F-15DJ fighter that had been operating since 1993 with over 5,960 hours of service.

Upgrading Their Aircraft

In response to the aging aircraft, the Japanese Ministry of Defense (MoD) has undertaken the Multistage Improvement Program (MSIP), which aims to improve the reliability and operating life of 94 of its F-15J and F-15DJs through upgrading their central computers and armament controls. Around 98 F-15s will reportedly be upgraded through the F-15 Japan Super Interceptor (JSI) program, many of which also came from the MSIP.

The program reportedly is gaining US support through the Foreign Military Sale (FMS) awarded to Japan by the US Department of Defense last December 2021. The remaining F-15J and F-15DJs are now to be replaced by the more modern F-35A and F-35B, of which they procured 105 and 42 units, respectively.

The upgrading of Japanese fighter planes is vital for Japan to be considered a useful ally in checking Chinese and Russian aggression in the region. Note that the US and the Japanese military are highly cooperative with one another. The United States is the top weapon seller to the Japanese government, with 97% of its defense equipment imported from the US. The United States also considers Japan one of its strongest missile defense partners in 2019, working together to develop ballistic missile technology. While Japanese Air Force and Navy pilots are considered well trained, there are very severe limits on what they could do in combat with aging equipment and lagging technology in sensors and weapons. Perhaps they could defend their airspace from attack, but they would be unable to bring the fight to an aggressor like China or Russia without the United States protecting them as soon as they left their territorial waters or airspace.