The U.S. State Department in late October 2019 cleared the Japanese government to spend up to $4.5 billion upgrading 98 Boeing F-15J fighters to a new and greatly-improved standard it calls the “Japanese Super Interceptor.”
The JSIs could fly alongside the Japanese air force’s growing fleet of stealthy Lockheed Martin F-35 Joint Strike Fighters, each type complementing the other. The U.S. Air Force meanwhile is pursuing its own, mixed force of F-15s and F-35s.
Both air arms are trying to balance the strengths and weaknesses of stealthy and non-stealthy aircraft. While a new stealth fighter can cost as much as a conventional fighter does to procure -- around $100 million per copy -- the types possess different capabilities.
Stealth fighters are better at conventional planes at avoiding detection owing in part to their ability to carry their weapons internally. But weapons bays displace fuel, resulting in stealth fighters lacking range and payload compared to non-stealthy fighters.
Again owing to stealthy planes carrying their weapons internally, non-stealthy planes usually can carry larger weapons than their low-observable counterparts can do. These bigger munitions could include the latest, super-fast “hypersonic” missiles.
Governments are discovering that a balanced air arm can include both kinds of fighters. Thus the Japanese F-15 modernization effort comes as no surprise.
The JSI upgrade includes a wide array of new systems, including Raytheon's AN/APG-82(V)1 active electronically scanned array radar and BAE Systems' AN/ALQ-239 Digital Electronic Warfare System -- in essence, a powerful radar-jammer. The JSI also could carry new missiles.
“Japan already has the advanced AAM-4B, which has its own AESA seeker, but there are reports that the country might consider acquiring variants of the U.S.-made AIM-120 Advanced Medium-Range Air-to-Air Missile,” Joseph Trevithick noted at The War Zone.
The AIM-120s are smaller than the AAM-4B and reportedly have a shorter maximum engagement range, but the F-15J JSI may be able to carry substantially more missiles of the American weapons, which could compensate for that relative loss of capability.”