The F-15 Eagle entered service in 1976 and has maintained an unmatched air-to-air combat record, with a perfect 104-0 kill ratio and no losses in air-to-air engagements.
Remarkably, however, one of its variants—the Japan Air Self-Defense Force’s upgraded F-15J—was recently targeted by a Chinese J-15 fighter, which intermittently locked its fire-control radar on the Japanese aircraft during an encounter southeast of Okinawa on December 6, 2025.
The first lock took place between 4:32 and 4:35 p.m. local time, lasting roughly three minutes, whereas the second lock took place between 6:37 and 7:08 p.m., lasting almost thirty-one minutes. The incident occurred when the F-15Js were scrambled to monitor the Liaoning’s flight operations within its Air Defense Identification Zone (ADIZ).
While Chinese jets have conducted aggressive intercepts and near passes in the past, this is possibly the first publicly disclosed instance of a Chinese radar lock on JASDF fighter aircraft.
No shots were fired, but Japan viewed this as a “dangerous act” exceeding safe flight norms, as fire-control locks represent the final step in the targeting process before a missile launch.
Typically, a fighter jet’s radar functions in two primary modes: a wide-area search mode that can detect and track several targets, and a fire-control mode that provides the precise tracking required to direct weapons.
When operating in search mode, the radar only briefly and sporadically illuminates a single aircraft while scanning a large portion of the sky. In contrast, fire-control mode employs several waveforms that are tailored for weapon guidance and concentrates continuous tracking energy on a particular target.
However, the same radar system can also instantly switch from search to fire-control tracking when required.
Some military observers made a sweeping judgment, suggesting that the radar locks indicate a tactical sensor and situational awareness edge for the J-15 over the F-15J in this specific encounter, and surmised that a hypothetical beyond-visual-range (BVR) engagement could be tilted in China’s favor.
For now, there is no clarity on which J-15 variant locked onto the F-15J, but we know that the J-15B variant is more capable than the J-15 and J-15A variants and features 4.5th-generation capabilities, including a modern cockpit and a new active electronically scanned array (AESA) radar. However, the Liaoning is still believed to be using the older STOBAR J-15s (non-AESA).
Notably, the AESA systems can electronically guide many narrow beams and focus energy with remarkable precision while still appearing to conduct broad surveillance.
Additionally, AESA can use Low Probability of Intercept (LPI) strategies such as reduced sideline emissions, highly directional beams, and rapid frequency hopping. These techniques are specifically designed to blend radar signals into background noise, making it harder for older or less powerful Radar Warning Receivers (RWRs) to detect them.
Because of this, an AESA-equipped fighter can give radar-homing missiles mid-course guidance without producing the kind of recognizable fire-control signature that would often cause the targeted aircraft to lock on.
Some observers noted that the Japanese RWRs are tuned for legacy threats and may potentially misinterpret routine scans as locks or fail to fully suppress them. However, the EurAsian Times understands that these are mere conjectures, especially since Japan has also upgraded its F-15J over the years, bolstering its sensors and situational awareness.
Indian Air Force veteran Group Captain Johnson Chacko ruled out the theory that the Chinese J-15 has a tactical edge over the F-15J in an interview with EurAsian Times, saying that a radar lock-on alone does not prove whether one aircraft is superior to the other.
“The Japanese have stated that the J-15 had achieved a “lock on”, which is only one action away from firing an air-to-air missile. If the missile was fired, they may have lost the aircraft. Of course, there are ECM or Electronic Counter Measures that can be resorted to by the Japanese aircraft that could have deflected the missile,” Group Captain Chacko said.
He further emphasized that even though it “may have taken place over international waters, it looks like the Chinese were intimidating the Japanese that if you come here again, we will shoot you down.”
Some reports also noted that pilots cannot rely on the RWR to determine if they have been designated as a target. In fact, analysts predict that aerial confrontations could become more frequent, with fewer conventional warning indications, shorter reaction windows, and a higher risk of misinterpretation, as long-range missiles, stealth platforms, AESA radars, and electronic warfare systems continue to advance.
F-15: A Mighty Platform
Originally designed by McDonnell Douglas (now part of Boeing), the F-15 is a single-seat, twin-engine, all-weather fighter jet that was built to counter the USSR’s MiG series of fighters during the Cold War.
Interestingly, the F-15 is still among the fastest and most versatile fighter jets ever built, five decades after its debut.
In 1988, the Strike Eagle variant was introduced, focusing on deep-strike ground attacks, close air support for infantry, and sophisticated electronic warfare capabilities.
With its advanced nose-mounted radar system and cutting-edge air-to-air radar-guided missiles, the F-15 could eliminate threats before they even realized what was happening, setting a new standard in aerial warfare technology. It was frequently dispatched to intercept Soviet fighters and bombers during the Cold War era.
Ongoing “Block” upgrades, such as the F110 engine swap, have kept the F-15 at the forefront of aviation technology for decades. The latest model, the F-15EX, features an increased payload capacity, cutting-edge fly-by-wire controls, a digital cockpit, modernized sensors, improved radars, and robust electronic warfare capabilities. Boeing is pushing the aircraft for export by building on the jet’s cutting-edge combat performance.
The F-15 continues to give the USAF a flexible, multi-role platform for airspace and base protection, close air support, deep strikes, reconnaissance, and electronic warfare, even though its aging airframe and lack of stealth capabilities may not be able to compete with the newest 5th and 6th-generation fighters.
In addition to the US, the aircraft has been adopted by countries like Saudi Arabia, Israel, South Korea, and Japan, which use different variants to suit their needs.
Japan uses the F-15J variant of the aircraft, which is identical to the F-15C/D but has been upgraded over the years to keep it combat-ready and capable.
The F-15J Eagle, a licensed variant of the U.S. McDonnell Douglas F-15, became Japan’s premier air superiority fighter in the 1980s. In 1975, Japan selected the F-15 to replace aging F-104J Starfighters and complement F-4EJs amid Cold War tensions.
Mitsubishi Heavy Industries secured a license in 1978, with production starting after U.S. export restrictions were lifted on sensitive electronic warfare systems—Japan developed indigenous alternatives, such as the J/APR-4 radar warning receiver.
The first U.S.-built F-15J flew in June 1980, with deliveries beginning in 1981. Mitsubishi assembled the rest, including eight from knockdown kits (first flight August 1981) and fully domestic aircraft through 1997, totaling 203 single-seat F-15Js and 20 two-seat F-15DJs.
These aircraft have been modified with a new mission computer, an upgraded AN/APG-63(V)1 AESA radar, fly-by-wire flight controls, IRST pods, a helmet-mounted display, and the ability to carry more modern, lethal weapons.
Additionally, the F-15J is currently being upgraded under the Japan Super Interceptor (JSI) program, which includes mid-life upgrades for about 68 aircraft, integration of standoff weapons, an advanced electronic warfare suite, and upgraded engines.
It is also expected to feature an enhanced network-centric warfare capability. These F-15J will complement the F-35 Lightning II stealth fighters and the sixth-generation aircraft that is currently under development.
Japan has decided to retire older, non-upgraded F-15Js starting in the late 2020s, while keeping the upgraded fleet into the 2035+ timeframe.
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