The F-4EJ was a version of the F-4E developed for the Nihon Koku Jieitai (Japanese Air Self Defense Force, or JASDF). Since the Japanese armed forces were at that time forbidden by treaty from having even a hint of an offensive capability, the F-4EJ was optimized for the air defense role, the AN/ASQ-9A nuclear weapon control system, the AN/ARW-77 Bullpup ASM control system, the AN/ASQ-91 weapons delivery system, and the AN/AJB-7 bombing system all being omitted. There was no provision for the carrying or delivery of air-to-ground weapons. Aerial refuelling was limited to use in ground refuelling ports only.
Like the USAF F-4E, the F-4EJ was fitted with the Westinghouse AN/APQ-120 radar fire control system, the 20-mm M61A1 cannon with 640 rounds, plus AIM-7 and AIM-9 air-to-air missile capability. For navigation, the An/ASN-63 and the AN/ASN-46A navigation computer set were retained. It differed in having many Japanese-built electronic systems being fitted, including the Japanese-built J/APR-2 tail-warning radar, plus a Japanese-designed AN/APR-670 datalink system that interfaced with the Japanese BADGE (Base Air Defense Ground Environment) system. Externally, the F-4EJ differed from the USAF F-4 in having non-slatted wings and stabilators.
The F-4EJ was ordered on November 1, 1968. Two F-4EJs (JASDF serials 17-8301 and 17-8302) were built by McDonnell in St Louis and tested beginning on January 14, 1971. The next eleven (JASDF serials 27-8303/8307, 37-8307/8310, and 47-8311/8313) were built by McDonnell in kit form and were assembled in Japan by Mitsubishi Heavy Industries, Ltd. The first Japanese-assembled aircraft (27-8303) flew on May 12, 1972. Subsequently, Mitsubishi built 127 F-4EJs under license, bringing the total to 140. The last example was delivered on May 20, 1981. This was the last Phantom built.
As built, the Mitsubishi-built Phantoms were not fitted with inflight refuelling receptacles because of the treaty restrictions that forbade Japan to acquire offensive weapons. However, the hardware needed for such a capability was delivered and stored. Eventually, the restrictions were relaxed and the standard F-4E boom receptacle was retrofitted to most F-4EJs. I don't think that the JASDF has any midair refuelling aircraft, but the refuelling capabilities of the F-4EJ were used during training exercises with USAF KC-135s.
Fourteen unarmed reconnaissance versions of the F-4EJ were built by McDonnell and delivered to the JASDF between November 1974 and June 1975. They were designated RF-4EJ. They were virtually identical to the USAF RF-4C, with the only differences being the deletion of certain equipment such as the radar homing and warning suite. Because of the limited number of RF-4EJs required, there was no licence production of this variant in Japan.
The F-4EJ first entered service with the JASDF in August of 1972. In the JASDF, six interceptor squadrons (hikotai) have operated the F-4EJ. These were the 301st, 302nd, 303rd, 304th, 305th, and 306th. The RF-4EJ was operated by the 501st Hikotai.
In later years, the restrictions against the F-4EJ carrying offensive weapons were lifted, and the aicraft could carry Mk 82 500 lb and JM117 750 lb bombs. The Phantom could also carry the Japanese-developed GCS-1 IR guidance system for precision attacks.
Throughout the 1980s, the force of 140 F-4EJs gradually dwindled by attrition and reached 125 in 1992. Conversions to the F-15J began in the late 1980s. Since 1984, a major SLEP (Service Life Extension Program) was undertaken in which most JASDF F-4EJs were upgraded to F-4EJ Kai standards. Currently, the F-4EJ Kai serves with three hikotai, and should remain serving until well after the year 2000. This version will be described later.
The JASDF serials of the F/RF-4EJs were as follows. In the Japanese system of serial numbers, the first digit is the final digit of the year of delivery, the second digit identifies the aircraft type (7 for the Phantom).
McDonnell F-4EJ-45-MC Phantom 17-8301/8302 McDonnell F-4EJ-45-MC Phantom 27-8303/8306 (last two assembled by Mitsubishi) McDonnell F-4EJ-45-MC Phantom 37-8307/8310 McDonnell F-4EJ-47-MC Phantom 37-8311/8313 Mitsubishi F-4EJ 37-8314/8323 Mitsubishi F-4EJ 47-8324/8352 (8324 to 8331 later renumbered with prefix 37 McDonnell RF-4EJ-56-MC Phantom 47-6901/6905 McDonnell RF-4EJ-57-MC Phantom 57-6906/6914 Mitsubishi F-4EJ 57-8353/8377 Mitsubishi F-4EJ 67-8378/8391 Mitsubishi F-4EJ 77-8392/8403 Mitsubishi F-4EJ 87-8404/8415 Mitsubishi F-4EJ 97-8416/8427 Mitsubishi F-4EJ 07-8428/8436 Mitsubishi F-4EJ 17-8437/8440