The AIM-120 Advanced Medium-Range Air-to-Air Missile, or AMRAAM (pronounced ), is an American beyond-visual-range air-to-air missile capable of all-weather day-and-night operations. It is in diameter, and employs active transmit-receive radar guidance instead of semi-active receive-only radar guidance. It is a fire-and-forget weapon, unlike the previous generation Sparrow missiles which needed guidance from the firing aircraft. When an AMRAAM missile is launched, NATO pilots use the brevity code Fox Three. more than 14,000 had been produced for the United States Air Force, the United States Navy, and 33 international customers. The AMRAAM has been used in several engagements, achieving 16 air-to-air kills in conflicts over Iraq, Bosnia, Kosovo, India, and Syria. Origins AIM-7 Sparrow MRM The AIM-7 Sparrow medium range missile (MRM) was purchased by the US Navy from original developer Hughes Aircraft in the 1950s as its first operational air-to-air missile with "beyond visual range" (BVR) capability. With an effective range of about , it was introduced as a radar beam-riding missile and then it was improved to a semi-active radar guided missile which would home in on reflections from a target illuminated by the radar of the launching aircraft. It was effective at visual to beyond visual range. The early beam riding versions of the Sparrow missiles were integrated onto the McDonnell F3H Demon and Vought F7U Cutlass, but the definitive AIM-7 Sparrow was the primary weapon for the all-weather McDonnell Douglas F-4 Phantom II fighter/interceptor, which lacked an internal gun in its U.S. Navy, U.S. Marine Corps, and early U.S. Air Force versions. The F-4 carried up to four AIM-7s in built-in recesses under its belly. Designed for use against non-maneuvering targets such as bombers, the missiles initially performed poorly against fighters over North Vietnam, and were progressively improved until they proved highly effective in dogfights. Together with the short-range, infrared-guided AIM-9 Sidewinder, they replaced the AIM-4 Falcon IR and radar guided series for use in air combat by the USAF as well. A disadvantage to semi-active homing was that only one target could be illuminated by the launching fighter plane at a time. Also, the launching aircraft had to remain pointed in the direction of the target (within the azimuth and elevation of its own radar set) which could be difficult or dangerous in air-to-air combat. An active-radar variant called the Sparrow II was developed to address these drawbacks, but the U.S. Navy pulled out of the