The AIM-120 AMRAAM (Advanced Medium-Range Air-to-Air Missile) is a fire-and-forget air-to-air missile manufactured by Raytheon, and has replaced the AIM-7 Sparrow as the U.S. military's standard BVR (Beyond Visual Range) intercept missile. It has an all-weather, beyond-visual-range capability and is scheduled to be operational beyond 2000. AMRAAM is a supersonic, air launched, aerial intercept, guided missile employing active radar target tracking, proportional navigation guidance, and active Radio Frequency (RF) target detection.
It employs active, semi-active, and inertial navigational methods of guidance to provide an autonomous launch and leave capability against single and multiple targets in all environments. When an AMRAAM missile is being launched, NATO pilots use the brevity code Fox Three.
The AMRAAM has been delivered to 36 countries tol date. The missile has completed over 1.8 million captive-carry hours and 2,900 live firings. It is integrated with combat aircraft such as the F-15, F-16, F/A-18, F-22, Typhoon, Gripen, Tornado, Harrier, F-4, and the F-35 Joint Strike Fighter. It is also used by the Surface-Launched AMRAAM of the US Army and NASAMS (Norwegian Advanced Surface to Air Missile System).
Development
In the late 1970s, the U.S. military services decided that they needed a medium-range air-to-air missile with a true fire-and-forget capability. The SARH (Semi-Active Radar Homing) guidance of the AIM-7 Sparrow required the launching aircraft's radar to illuminate the target until impact, which made the aircraft a target itself and also limited its ability to engage several targets simultaneously. In February 1979, Hughes and Raytheon were selected as finalists for the YAIM-120A AMRAAM (Advanced Medium-Range Air-to-Air Missile) competition, and in December 1981 Hughes was declared winner. A year before, a joint U.S./European agreement for development of a new family of air-to-air weapons had been signed. This agreement put the responsibility for the BVR AMRAAM to the United States, while the complementary ASRAAM (Advanced Short-Range Air-to-Air Missile) (later AIM-132) would be developed in Europe. In February 1984 the first production-representative AIM-120A missile was launched from an F-16 aircraft, but it was not before September 1987 that the first supersonic launch succeeded. The AMRAAM program was troubled by all sorts of technical and political problems, not the least of which was severe cost overrun because of the protracted development period. The first LRIP (Low-Rate Initial Production) AIM-120A was delivered in October 1988, but it took until September 1991 that IOC (Initial Operational Capability) was finally achieved. Navy IOC was completed in September 1993.
In April 1998, US Air Force officials announced the twelfth award to Raytheon Systems Company for the production of 813 additional Advanced Medium Range Air-to-Air Missiles. The total contract value is $243 million. The Lot 12 purchase includes 173 missiles for the Air Force, 120 for the Navy and an additional 520 for foreign customers. Historically, AMRAAM production awards were accomplished under a competitive, dual-source strategy with Hughes Missile Systems Company, Tucson, Ariz., and Raytheon Electronic Systems, Bedford, Mass., as the prime contractors. When Raytheon and Hughes Missile Company merged, forming the current Raytheon Systems Company, a single prime contractor, the government implemented a new strategy called AMRAAM Vision 2000. With Vision 2000, the government shifted toward a more commercial business arrangement with the contractor. Capitalizing on the efficiencies of a single prime contractor, the Air Force and the Navy recognized savings in excess of $150 million, resulting from a drop in unit price from $340,000 in Lot 11 to $299,000 in Lot 12.
Design features of AIM-120 AMRAAM
Derived from the Sparrow range of missiles, the AMRAAM was designed to be quicker, smaller and lighter than the Sparrow. The missile's layout is divided into guidance, armament, propulsion and control sections. The missile has beyond-visual-range and home-on-jamming capabilities.
The AMRAAM has a length of 3.6m, diameter of 17.7cm and wingspan of 52.5cm. The launch weight of the missile is 150.7kg. It is capable of carrying an 18.1kg high-explosive blast fragmentation warhead to a maximum range of between 20 to 30 nautical miles (nm).
Guidance Section, Weapons Guidance Unit
The Weapons Guidance Unit (WGU) consists of the radome, seeker, servo, transmitter-receiver, electronics unit, Inertial Reference Unit, Target Detection Device (TDD), the harnesses, and frame structure. All units except the TDD are contained within a sealed structure composed of the pyroceramic radome, titanium skin sections, and aluminum aft bulkhead. The TDD, RF and video processor, and the antennas are attached to the aft skin section as a complete testable assembly. Electronics group functions include radar signal processing, seeker servo control, and all of the computations performed in the central data processor. The WGU-16B is used on AIM-120A missiles, the WGU-41/B is used on AIM-120B missiles, and the WGU-44/B is used on AIM-120C missiles. Guidance sections on AIM-120B and AIM-120C missiles contain Electronic Erasable Programmable Read Only Memory which allow reprogramming of the missile software. Missile software versions are denoted by Tape and Revision Numbers, e.g., Tape 4 Revision 16.
Armament Section, Weapons Detonation Unit
The Weapons Detonation Unit (WDU)-33/B forms an integral part of the tactical missile airframe and includes the warhead, the FZU-49/B (modified Mk 3 Mod 5) safe-arm fuze device, and the Mk 44 Mod 1 booster. The armament section also includes the forward missile hook and hanger. The WDU-33/ B warhead meets the Insensitive Munitions (IM) program requirements.
Propulsion Section, Weapons Propulsion Unit
The Weapons Propulsion Unit (WPU)-6/B consists of an airframe, integral rocket motor, a blast tube and exit cone, and an Arm/Fire Device (AFD) with a visible safe-arm indicator. The high performance rocket motor utilizes a reduced smoke, hydroxyl terminated, polybutadiene propellant in a boost sustain configuration, an asbestos-free insulated case (an integral part of the airframe), and an integral aft closure, blast tube, and nozzle assembly with a removable exit cone to facilitate control section installation/removal. Wings are attached in wing sockets at the forward end of the propulsion section. Provisions are included within this section for mounting the filter rectifier assembly.
Control Section, Weapons Control Unit
The Weapons Control Unit (WCU)-11/B consists of four independently controlled electro-mechanical servo actuators, four lithium-aluminum batteries connected in parallel, and a steel fuselage section that is bolted to the propulsion section aft skirt. Each actuator consists of a brushless DC motor ballscrew, an infinite resolution potentiometer directly coupled to the output shaft, and pulse width modulated control electronics. The output shaft is engaged directly to a squib actuated lock so that it does not interfere with the fin (control surface) installation and removal. (5) Wiring Harness, Harness Cover, and Thermally Initiated Venting System. The wiring harness cover extends from the aft end of the guidance section to the forward end of the control section. Its primary purpose is to provide protection for the wiring harness. The main wiring harness electrically connects the umbilical connector, guidance section, and control section. The wiring harness cover also houses the TIVS. The TIVS is designed to vent rocket motor pressure in the event the missile is exposed to a fuel fire. The TIVS consists of an external thermal cord which, when ignited, triggers an Out-Of-Line Device (OOLD) that ignites a Linear Shape Charge that weakens the rocket motor, allowing the rocket motor to vent without exploding. The OOLD prevents the shaped charge from detonating should the booster in the OOLD inadvertently detonate due to causes such as high impact. The unit has an additional safety feature that causes it to �reset� within nine to thirteen units of gravity, such as the acceleration experienced during missile launch. This feature prevents the system from functioning during missile free flight so that the associated aerodynamic pressures do not inadvertently enable the TIVS and thereby degrade missile performance. An indicator is on the wiring harness cover showing the condition of the TIVS, either �ENABLE� or �DISABLE�. Only TIVS equipped missiles are deployed aboard Aircraft Carriers (CV/CVN). The WPU-6/B Propulsion Section (with TIVS) meets the fast cook-off and sympathetic detonation requirements of the IM program and the policy delineated in OPNAV Instruction (OPNAVINST) 8010.13B. The other requirements (bullet impact, fragment impact, and slow cook-off) have not been met with the current configuration. However, the WPU-6/B has been granted the appropriate waivers for shipboard use.
Wing and Fin Assemblies
Wing and fin assemblies provide for flight control of the missile. The four wings are detachable, stationary flight surfaces with ball fasteners to facilitate quick installation and removal. The four fins provide the movable control surfaces. The AIM-120C has �clipped� wings and fins which are not interchangeable with AIM-120A and AIM-120B missiles. The AIM-120C utilizes �clipped� wings and fins in order to meet the internal carriage requirements of the F-22.
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| NASAMS launcher on a Scania 113H truck. |
The AMRAAM system includes three new Missile Rail Launchers (MRLs): the LAU-127A/A, in conjunction with the LAU-115, used on the F/A-18C/D aircraft; the LAU-128A/A, and the LAU-129A/A, used on the F-15 and F-16 aircraft, respectively. Additional interface cables are not required between the aircraft and the launcher. The MRL can be installed and operated at all current AIM-9 Sidewinder positions on all candidate aircraft, except F/A-18C/D wing tip stations; and is also capable of launching AIM-9 Sidewinder missiles. The MRL supplements the Sidewinder launchers (except F/A-18C/D wing tip) on AMRAAM capable aircraft.
Variants and upgrades
Air-to-air missile versions
There are currently four main variants of AMRAAM, all in service with the United States Air Force, United States Navy, and the United States Marine Corps. The AIM-120A is no longer in production and shares the enlarged wings and fins with the successor AIM-120B. The AIM-120C has smaller "clipped" aerosurfaces to enable internal carriage on the USAF F-22 Raptor. AIM-120B deliveries began in 1994.
The AIM-120C deliveries began in 1996. The C-variant has been steadily upgraded since it was introduced. The AIM-120C-6 contained an improved fuse (Target Detection Device) compared to its predecessor. The AIM-120C-7 development began in 1998 and included improvements in homing and greater range (actual amount of improvement unspecified). It was successfully tested in 2003 and is currently being produced for both domestic and foreign customers. It helped the U.S. Navy replace the F-14 Tomcats with F/A-18E/F Super Hornets – the loss of the F-14's long-range AIM-54 Phoenix missiles (already retired) is offset with a longer-range AMRAAM-D. The lighter weight of the advanced AMRAAM enables an F/A-18E/F pilot greater bring-back weight upon carrier landings.
The AIM-120D is an upgraded version of the AMRAAM with improvements in almost all areas, including 50% greater range (than the already-extended range AIM-120C-7) and better guidance over its entire flight envelope yielding an improved kill probability (Pk). Raytheon began testing the D model on August 5, 2008, the company reported that an AIM-120D launched from an F/A-18F Super Hornet passed within lethal distance of a QF-4 target drone at the White Sands Missile Range.
The AIM-120D (P3I Phase 4, formerly known as AIM-120C-8) is a development of the AIM-120C with a two-way data link, more accurate navigation using a GPS-enhanced IMU, an expanded no-escape envelope, improved HOBS (High-Angle Off-Boresight) capability, and a 50% increase in range. The AIM-120D is a joint USAF/USN project, and is currently in the testing phase. The USN was scheduled to field it from 2014, and AIM-120D will be carried by all Pacific carrier groups by 2020, although the 2013 sequestration cuts could push back this later date to 2022.
There are also plans for Raytheon to develop a ramjet-powered derivative of the AMRAAM, the Future Medium Range Air-Air Missile (FMRAAM). It is not known whether the FMRAAM will be produced since the target market, the British Ministry of Defence, has chosen the Meteor missile over the FMRAAM for a BVR missile for the Eurofighter Typhoon aircraft.
Raytheon is also working with the Missile Defense Agency to develop the Network Centric Airborne Defense Element (NCADE), an anti-ballistic missile derived from the AIM-120. This weapon will be equipped with a Ramjet engine and an infrared homing seeker derived from the Sidewinder missile. In place of a proximity-fused warhead, the NCADE will use a kinetic energy hit-to-kill vehicle based on the one used in the Navy's RIM-161 Standard Missile 3.
The −120A and −120B models are currently nearing the end of their service life while the −120D variant has just entered full production. AMRAAM was due to be replaced by the USAF, the U.S. Navy, and the U.S. Marine Corps after 2020 by the Joint Dual Role Air Dominance Missile (Next Generation Missile). This was unexpectedly terminated in the 2013 budget plan, and so the future replacement is uncertain.
Ground-launched systems
Raytheon successfully tested launching AMRAAM missiles from a five-missile carrier on a M1097 Humvee. This system will be known as the SLAMRAAM (Surface Launched (SL) and AMRAAM). They receive their initial guidance information from a radar not mounted on the vehicle. Since the missile is launched without the benefit of an aircraft's speed or high altitude, its range is considerably shorter. Raytheon is currently marketing an SL-AMRAAM EX, purported to be an extended range AMRAAM and bearing a resemblance to the RIM-162 ESSM.
The Norwegian Advanced Surface-to-Air Missile System (NASAMS), developed by Kongsberg Defence & Aerospace, consists of a number of vehicle-pulled launch batteries (containing six AMRAAMs each) along with separate radar trucks and control station vehicles. A more recent version of the program is the High Mobility Launcher, made in cooperation with Raytheon (Kongsberg Defence & Aerospace was allready a subcontractor on the SLAMRAAM system), where the launch-vehicle is a Humvee (M1152A1 HMMWV), containing four AMRAAMs each.
While still under evaluation for replacement of current US Army assets, the SL-AMRAAM has been deployed in several nations' military forces. The United Arab Emirates (UAE) has requested the purchasing of SL-AMRAAM as part of a larger 7 billion dollar foreign military sales package. The sale would include 288 AMRAAM C-7 missiles.
The US Army has test fired the SL-AMRAAM from a HIMARS artillery rocket launcher as a common launcher, as part of a move to switch to a larger and more survivable launch platform.
The National Guard Association of the United States has sent a letter asking for the United States Senate to stop the Army's plan to drop the SLAMRAAM program because without it there would be no path to modernize the Guard's AN/TWQ-1 Avenger Battalions.
On January 6, 2011, Secretary of Defense Robert Gates announced that the U.S. Army has decided to terminate acquisition of the SLAMRAAM as part of a budget-cutting effort.
On February 22, 2015 Raytheon announced an Extended Range upgrade to NASAMS-launched AMRAAM, calling it AMRAAM-ER.
AIM-120 AMRAAM international orders and deliveries
The AMRAAM is in service with the US Air Force (USAF), US Navy (USN), and over 25 US-allied nations.
Canadair, now Bombardier, had largely helped with the development of the AIM-7 Sparrow and Sparrow II, and assisted to a less extent in the AIM-120 development. Canada had placed an order for 256 AIM-120's, but cancelled half of them after engine ignition problems due to cold weather conditions. The AIM-9X & AIM-7 were ordered as replacements.
In early 1995 South Korea ordered 88 AIM-120A missiles for its KF-16 fleet. In 1997 South Korea ordered additional 737 AIM-120B missiles.
In August 2004, the UK Ministry of Defence (MoD) placed a $144m contract with Raytheon Missile Systems for the latest AIM-120 C5 variant. Raytheon received a $200m contract from the US Air Force for 434 missiles in December 2004.
The Pakistan Air Force (PAF) placed an order in early 2006 for 500 AIM-120C-5 AMRAAM missiles as part of a $650 million F-16 ammunition deal to equip its F-16C/D Block 50/52+ and F-16A/B Block 15 MLU fighters. The PAF got the first three F-16C/D Block 50/52+ aircraft on July 3, 2010 and first batch of AMRAAMs on July 26, 2010.
In September 2006, the USAF placed a $66m Foreign Military Sales (FMS) contract to deliver 123 AIM-120C5 missiles for Saudi Arabia and Singapore. Poland received the AIM-120C-5 missiles for its new F-16C/D Block 52+ fighters in 2006.
In 2007, the US Government agreed to sell 218 AIM-120C-7 missiles to Taiwan under a $421m arms sales package. The Finnish MoD placed an order for 300 AMRAAMs in 2008. Deliveries have been delayed due to the malfunction of rocket motors during cold weather tests.
In November 2009, the US Government exercised separate Letters of Offer and Acceptance with three of its allies, Kuwait, Morocco and Jordan, to acquire the AIM-120C-7 AMRAAM. Chile requested a sale of 100 missiles in November 2009. Switzerland requested a sale of 150 missiles in December 2010.
Specifications
Weight 335 pounds (152 kg)
Length 12 feet (3.7 m)
Diameter 7 inches (180 mm)
Warhead
High explosive blast-fragmentation
• AIM-120A/B: WDU-33/B, 50 pounds (22.7 kg)
• AIM-120C-5: WDU-41/B, 40 pounds (18.1 kg)
Detonation mechanism
Active RADAR Target Detection Device (TDD)
Quadrant Target Detection Device (QTDD) in AIM-120C-6 – lots 13+.
Engine Solid-fuel rocket motor
Wingspan 20.7 inches (530 mm) (AIM-120A/B)
Operational range
• AIM-120A/B: 55–75 km (30–40 nmi)[3][4]
• AIM-120C-5: >105 km (>57 nmi)[5]
• AIM-120D (C-8): >160 km (>97 nmi)[6]
Speed Mach 4 (4,900 km/h; 3,045 mph; 1.3612 km/s)
Guidance system
inertial guidance, terminal active radar homing
Launch platform Aircraft:
Boeing F/A-18E/F Super Hornet
Eurofighter Typhoon
General Dynamics F-16 Fighting Falcon
Lockheed Martin F-22 Raptor
Lockheed Martin F-35 Lightning II
McDonnell Douglas AV-8B+ Harrier II
McDonnell Douglas F-15 Eagle
McDonnell Douglas F-15E Strike Eagle
McDonnell Douglas F/A-18 Hornet
Northrop F-5S/T
Panavia Tornado ADV
Saab JAS 39 Gripen
Surface-launched:
NASAMS and others