Japan is currently confronted with the task of getting rid of approximately 200 Pratt & Whitney F100 turbofan engines, which are mounted on its non-updated F-15J Eagle fighter jets. The engines will need to be disposed of as these fighter jets are set to be retired.

Half of the 200 F-15s currently in service with the Japanese Air Self-Defense Force (JASDF) have not been updated to the Multi-Stage Improvement Program (MSIP) configuration. The MSIP configuration is crucial as it provides wiring support necessary for firing newer air-to-air missiles. The absence of this update renders the non-updated F-15J Eagle fighter jets obsolete. Therefore, these jets will be decommissioned from service and replaced by the F-35.

Hiroshi Ide, the President of IHI Corporation, disclosed during an earnings briefing on May 9, 2023, that discussions have taken place regarding the disposal of the engines. One potential option under consideration is exporting the engines to another country. However, Japan's Three Principles on Transfer of Defense Equipment and Technology currently prohibit the transfer of fighter jet engines to foreign nations, creating a challenging deadlock that requires resolution.

Pratt and Whitney F100-100 Turbofan Engine Pratt and Whitney F100-100 Turbofan Engine

The Pratt & Whitney F100 engine has been a reliable and trusted powerplant for the F-15 Eagle for over 50 years. With variants such as the F100-PW-200, F100-PW-220, and F100-PW-229, the F100 family has continuously improved performance and incorporated advanced technologies. It has amassed an impressive record of over 30 million engine flight hours and remains the engine of choice for F-15 and F-16 campaigns worldwide.

As Japan seeks a solution for the disposal of these engines, further discussions and negotiations will be required to navigate the restrictions and find an appropriate resolution.

F-15J Eagle

Japan’s F-15Js and F-15DJ two-seat trainers are the only models of the legendary jet built outside of the United States (though an initial few were built in McDonnell-Douglas’s St. Louis plant). In the mid-1970s, Japan arranged for Mitsubishi Heavy Industries to license-manufacture a domestic model of the F-15C air superiority fighters, along with its F100 turbofans.

The F-15J had only minor differences from the F-15C. Because the United States was unwilling to transfer certain technologies, the F-15Js came with Japanese-designed datalinks, J/APR-4 radar warning receivers and J/ALQ-8 electronic countermeasure systems. They also came with racks for unguided Mark 82 bombs.

The first F-15J flew in 1980, and the aircraft entered operational service in 1982—at the time, by far the most capable jet flown by an East Asian air force. The later half of the 213 F-15Js built were Multi-Stage Improvement Package models (F-15MJs), featuring more powerful computers and digital displays, improved air conditioning, an additional J/APQ-1 radar warning system, and compatibility with Japanese missiles. Those include the short-range heat-seeking AAM-3 missile and the radar-guided AAM-4 with a range of sixty-two to seventy-five miles.

Sources: The Aviation Geek Club, The National Interest

Евгений Ушаков
Evgenii Ushakov
15 years driving