Japan to upgrade 68 F-15J Eagles under JSI programme

An artist's impression of the JSI configuration for Japan's fleet of upgraded F-15J Eagle fighters. (Boeing)

The Japanese Ministry of Defense (MoD) plans to upgrade 68 Boeing-Mitsubishi F-15J Eagle fighter aircraft through the Japan Super Interceptor (JSI) programme, it confirmed on 4 February.

The MoD also said that the estimated life-cycle costs of the 68 Japan Air Self-Defense Force (JASDF) aircraft over 30 years – including the upgrade – will amount to JPY646.5 billion (USD5.6 billion).

An MoD document said the upgrade includes the integration of long-range stand-off missiles, radars that can lock multiple targets simultaneously, an increased munitions payload, and enhanced electronic warfare capability.

According to Japan's 2021 defence white paper, the JASDF operated, as of March 2021, a total of 201 single-seat F-15Js and twin-seat F-15DJs. The MoD has previously upgraded the combat capabilities of 102 of these aircraft: 68 F-15Js and 34 F-15DJs.

The remaining 99 aircraft are to be replaced by 147 Lockheed Martin F-35 fighter aircraft – 105 F-35As and 42 F-35Bs – during the coming decade.

An official from the MoD's Acquisition, Technology & Logistics Agency (ATLA) told Janes, “F-15DJ aircraft and non-modernised F-15Js are not included in the latest F-15 update programme because they have been deemed unsuitable for additional modifications.”

The JASDF's F-15J/DJs have been the mainstay of the JASDF's air combat capability since the early 1980s. The aircraft is regularly deployed in response to Chinese and Russian military aircraft approaching Japan's airspace.

The aircraft were manufactured by Mitsubishi Heavy Industries (MHI) under licence from McDonnell Douglas (now part of Boeing). MHI built 163 F-15Js and 36 F-15DJs, with the first 12 F-15DJ and two F-15J built by McDonnell Douglas.