Japan is spending nearly $500 million to equip its F-2 fighters (a slightly larger, locally made version of the F-16) with Japanese made AAM-4B air-to-air missiles. Although Japan also uses American AMRAAM air-to-air missiles, the new AAM-4B contains its own AESA radar, allowing the firing aircraft to turn away sooner. AMRAAM uses less powerful radar, requiring that the firing aircraft (or another aircraft) to track the target for a longer time before the small radar in the missile detects the target and takes over. The AAM-4B weighs 230 kg (506 pounds), is 3.67 meters (11.37 feet) long, and 200mm (8 inches) in diameter. Max range is 120 kilometers.
The AIM-120D AMRAAM entered service in 1992, more than 30 years after the first reliable radar guided air-to-air missile (the AIM-7 Sparrow). AMRAAM was meant to succeed where the AIM-7 didn’t. Vietnam, in the 1960s, provided ample evidence that AIM-7 wasn't really ready for prime time. Too many things could go wrong. Several versions later, the AIM-7 got another combat test during the 1991 Gulf War. In combat 88 AIM 7s were launched, with 28 percent scoring a hit. The AIM 9 Sidewinder did worse, with 97 fired and only 12.6 percent making contact. That said, most of these hits could not have been obtained with cannon, especially when the AIM 7 was used against a target trying to get away.
Japan developed their own successor to the AIM-7, the AAM-4, which was more like AMRAAM but did not enter service until 1999. AMRAAM was available earlier and was bought as well.
AMRAAM was designed to fix all the reliability and ease-of-use problems that cursed the AIM-7. But AMRAAM has only had a few opportunities to be used in combat, however, over half of those launched have hit something. The 120D version entered service four years ago and has longer range and greater accuracy and resistance to countermeasures. So far, AMRAAMs have spent nearly two million hours hanging from the wings of jet fighters in flight. Some 2,400 AMRAAMs have been fired, mostly in training or testing operations. That’s about a quarter of those produced.
AMRAAM weighs 172 kg (335 pounds), is 3.7 meters (12 feet) long, and 178mm (7 inches) in diameter. AMRAAM has a max range of 70 kilometers. These missiles cost about a million dollars each. The missiles are complex mechanical, electronic, and chemical systems and each of them, on average, suffers a component failure every 1,500 hours.
