Japan was one of the first countries which announced its intention to buy the highly capable new fighter of United States, the F-4 Phantom II, in order to replace its fleet of Lockheed F-104 J Starfighters.
1968, Japan signed a letter of agreement with Mc Donnell Douglas and it was also announced that it would become one of the few countries worldwide that was going to license-produce this aircraft. Over the following years, the Nihon KokuJietai (Japan Air Self-Defense Force) received a total of 154 F-4EJ and RF-4Es.The F-4EJs (the export version for Japan) were mostly similar to the F-4Es,although the Japanese aircraft had their in-flight refueling and ground-attack capabilities removed to align with Japan’s defensive posture, the F-4EJs were delivered without the AN/AJB-7 bombing computer system.
The first two F-4EJs(JASDF serials 17-8301 and 17-8302) were built by McDonnell Douglas in St Louis and first flew on January 14, 1971. The next 11 F-4EJs (JASDF serials27-8303/8307, 37-8307/8310, and 47-8311/8313) were built by McDonnell Douglas 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 all the rest 127 F-4EJ during the following nine years. The last example was delivered to the JASDF on May 20, 1981. This was the last F-4 ever built in the world.
Japan also acquired 14 RF-4Es built by McDonnell Douglas to serve in the reconnaissance role. These RF-4Es were delivered between November 1974 and June 1975. 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 the warning suite which had not been released for export to Japan.
The F-4EJs entered service with the JASDF in August 1972 with a total of six squadrons operating the aircraft: the 301st, 302nd, 303rd, 304th,305th and 306th squadrons. The RF-4Es equipped the 501stthat had previously operated one of the less-well-known Sabre models, the RF-86F.
In the early 80s, JASDF decided to upgrade its Phantom fleet with a package that would offer the ability to remain a capable opponent for years to come. The upgraded version was called F-4EJ Kai and saw the reintroduction of ground-attack capabilities in the form of anti-ship missiles, bombs and rockets. The F-4EJ Kai (the suffix Kai means “extra” or “augmented”) was fitted with the Westinghouse AN/APG-66J pulse-Doppler radar, which was much smaller and lighter than the original APQ-120 and had more operating modes with better look down – shoot down capability. Externally, the installation of the new radar could be distinguished by the presence of a new radome which had fore and aft strengthening ribs.
The F-4EJ Kai had a new central computer, a Kaiser heads-up display, a Hazeltine AN/APZ-79 IFF system,and a license-built Litton LN-39 inertial navigation unit. A new J/APR-6 radar homing and warning system was also fitted. Twin aft-facing radomes for this system were mounted on the fin tip and forward-facing antenna were mounted on the wingtips. A new, much taller UHF blade antenna was mounted on the dorsal spine, and the lower UHF antenna on the undercarriage door is larger in size.These are about the only externally-visible distinguishing points between the F-4EJ and the F-4EJ Kai. Plans to fit leading edge slats to the F-4EJ Kai were ruled out on the basis of cost, so all the Kais maintained their original leading edge flaps.
The Japanese Kai Phantoms are able to carry a 610-US gallon F-15 fuel tank on the centreline. This tank is capable to withstand higher g-loads than the original F-4 centreline tank.The F-4EJ Kai can also carry the Westinghouse AN/ALQ-131 advanced multi mode electronic countermeasures pod. This pod has a wide range of modules and has re programmable software which makes it capable of quickly countering new threats.
The F-4EJ Kai can launch the AIM-7E/F Sparrow and the AIM-9L/P Sidewinder air-to-air missiles. In addition, it can carry and launch the Mitsubishi ASM-1 anti-ship missile. This missile has a launch weight of about 1345 pounds and is powered by a Nissan Motors solid rocket engine. It has mid course guidance provided by inertial system acting in conjunction with a radar altimeter which maintains an altitude just above the tops of the waves during the final run-in to the target.Terminal guidance is provided by an active radar seeker mounted in the nose. A440-pound high-explosive warhead is carried.
The original plan was to convert 110 aircraft of the remaining 125 (after the losses), but later on it was decided to be 96. The prototype F-4EJ Kai first flew on 17 July 1984, and it was delivered to the 306th squadron on the 24th of November 1989.
In order to strengthen the original RF-4E fleet which had been reduced in size due to aircraft being lost in accidents, JASDF decided to convert 17 F-4EJs to RF-4EJ configuration.These aircraft retained the nose for the M61A1 Vulcan cannon. While mounting no internal cameras or reconnaissance equipment in their nose, they were able to carry a centreline reconnaissance equipment pod. This feature makes them easily recognizable compare to the normal RF-4E.
These aircraft can carry three different types of sensor pods, depending on the mission requirements.These comprise of the TACER (an electronic reconnaissance pod with data-link),the TAC (pod with carrying KS-135A and KS-95B cameras, plus a D-500UR IR system) and the LOROP (with KS-146B camera). The first example which was converted to these standards was the 37-6406.
Nowadays there are only three Phantom squadrons left in the inventory of the JASDF and they are all gathered in Hyakuri AB, northeast of Tokyo. Two fighter squadrons, the 301st“Hikotai” and the 302nd “Hikotai”and one reconnaissance squadron,the 501st “Hikotai”.
Japan is introducing a fleet of 42 F-35As to replace the remaining Phantoms. Pilots’ training on this fifth-generation fighter is already taking place in Misawa Air Base in the north of Japan’s main island of Honshu as deliveries of Japan’s F-35s continue apace.
The 302nd squadron will withdraw its remaining Phantoms in March 2019, the 501st reconnaissance squadron will follow in 2020 and the last remaining 301st squadron will draw the final curtain most probably the same year. Although 301 and 302 squadrons are due to permanently move to Misawa following the transition to the F-35, it’s unclear for the 501st squadron if it will then transition to a new aircraft type.
Article by George Karavantos