Man-portable air-defense system
Man-portable air-defense systems (MANPADS or MPADS) are portable surface-to-air missiles. They are guided weapons and are a threat to low-flying aircraft, especially helicopters. Overview. MANPADS were developed in the 1950s to provide military ground forces with protection from jet aircraft. They have received a great deal of attention, partly because armed groups have used them against commercial airliners. These missiles, affordable and widely available through a variety of sources, have been used successfully over the past three decades both in military conflicts, as well as by terrorist organizations. Twenty-five  countries, including the United Kingdom, the United States, Poland, Sweden, Russia, and Turkey, produce man-portable air defense systems. Possession, export, and trafficking of such weapons is officially tightly controlled, due to the threat they pose to civil aviation, although such efforts have not always been successful. The missiles are about in length and weigh about , depending on the model. MANPADS generally have a target detection range of about and an engagement range of about , so aircraft flying at or higher are relatively safe. The acronym MANPADS is commonly altered into a singular form of "MANPAD" to describe a single  weapon of this type. Missile types. Infrared. Infrared homing missiles are designed to home-in on a heat source on an aircraft, typically the engine exhaust plume, and detonate a warhead in or near the heat source to disable the aircraft. These missiles use passive guidance, meaning that they do not emit signals to detect a heat source, which makes them difficult to detect by targeted aircraft employing countermeasure systems. First generation. The first missiles deployed in the 1960s were infrared missiles. First generation MANPADS, such as the US Redeye, early versions of the Soviet 9K32 Strela-2, and the Chinese  HN-5 (copy of Soviet Strela-2), are considered "tail-chase weapons" as their uncooled spin-scan seekers can only discern the superheated interior of the target's jet engine from background noise. This means they are only capable of accurately tracking the aircraft from the rear when the engines are fully exposed to the missile's seeker and provide a sufficient thermal signature for engagement. First generation IR missiles are also highly susceptible to interfering thermal signatures from background sources, including the sun, which many experts feel makes them somewhat unreliable, and they are prone to erratic behaviour in the terminal  phase of engagement. While less effective than more modern weapons, they remain common in irregular forces as they are not limited by the short shelf-life of gas coolant cartridges used by later systems. Second generation. Second generation infrared missiles, such as early versions of the U.S. Stinger, the Soviet Strela-3, and the Chinese FN-6, use gas-cooled seeker heads and a conical scanning technique, which enables the seeker to filter out most interfering background IR sources as well as permitting head-on and side engagement profiles. Later versions of the Redeye MANPADS are regarded as straddling the first and  second generations as they are gas-cooled but still use a spin-scan seeker. Third generation. Third generation infrared MANPADS, such as the French Mistral, the Soviet 9K38 Igla, and the US Stinger B, use rosette scanning detectors to produce a quasi-image of the target. Their seeker compares input from multiple detections bands, either two widely separated IR bands or IR and UV, giving them much greater ability to discern and reject countermeasures deployed by the target aircraft. Fourth generation. Fourth generation missiles, such as the canceled American FIM-92 Stinger Block 2, Russian Verba, Chinese QW-4, and Japanese Type  91 surface-to-air missile use imaging infrared focal plane array guidance systems and other advanced sensor systems, which permit engagement at greater ranges. Command line-of-sight. Command guidance (CLOS) missiles do not home in on a particular aspect (heat source or radio or radar transmissions) of the targeted aircraft. Instead, the missile operator or gunner visually acquires the target using a magnified optical sight and then uses radio controls to "fly" the missile into the aircraft. One of the benefits of such a missile is that it is virtually immune to flares and other basic countermeasure systems that  are designed primarily to defeat IR missiles. The major drawback of CLOS missiles is that they require highly trained and skilled operators. Numerous reports from the Soviet–Afghan War in the 1980s cite Afghan mujahedin as being disappointed with the British-supplied Blowpipe CLOS missile because it was too difficult to learn to use and highly inaccurate, particularly when employed against fast moving jet aircraft. Given these considerations, many experts believe that CLOS missiles are not as ideally suited for untrained personnel use as IR missiles, which sometimes are referred to as "fire and forget" missiles. Later versions of CLOS  missiles, such as the British Javelin, use a solid state television camera in lieu of the optical tracker to make the gunner's task easier. The Javelin's manufacturer, Thales Air Defence, claims that their missile is virtually impervious to countermeasures. Laser guided. Laser guided MANPADS use beam-riding guidance where a sensor in the missile's tail detects the emissions from a laser on the launcher and attempts to steer the missile to fly at the exact middle of the beam, or between two beams. Missiles such as Sweden's RBS-70 and Britain's Starstreak can engage aircraft from  all angles and only require the operator to continuously track the target using a joystick to keep the laser aim point on the target: the latest version of RBS 70 features a tracking engagement mode where fine aim adjustments of the laser emitter are handled by the launcher itself, with the user only having to make coarse aim corrections. Because there are no radio data links from the ground to the missile, the missile cannot be effectively jammed after it is launched. Even though beam-riding missiles require relatively extensive training and skill to operate, many experts consider these  missiles particularly menacing due to the missiles' resistance to most conventional countermeasures in use today. Countermeasures. Man-portable air defense systems are a popular black market item for insurgent forces. Their proliferation became the subject of the Wassenaar Arrangement's "(WA)22 Elements for Export Controls of MANPADS", the G8 "Action Plan" of 2 June 2003, the October 2003 Asia-Pacific Economic Cooperation (APEC) Summit, "Bangkok Declaration on Partnership for the Future" and in July 2003 the Organization for Security and Co-operation in Europe (OSCE), Forum for Security Co-operation, "Decision No. 7/03: Man-portable Air Defense Systems". Understanding the  problem in 2003, Colin Powell remarked that there was "no threat more serious to aviation" than the missiles, which can be used to shoot down helicopters and commercial airliners, and are sold illegally for as little as a few hundred dollars. The U.S. has led a global effort to dismantle these weapons, with over 30,000 voluntarily destroyed since 2003, but probably thousands are still in the hands of insurgents, especially in Iraq, where they were looted from the military arsenals of the former dictator Saddam Hussein, and in Afghanistan as well. In August 2010, a report by the Federation of  American Scientists (FAS) confirmed that "only a handful" of illicit MANPADS were recovered from national resistance caches in Iraq in 2009, according to media reports and interviews with military sources. Military. With the growing number of MANPADS attacks on civilian airliners, a number of different countermeasure systems have been developed specifically to protect aircraft against the missiles. Weapons by country. Black market. Although most MANPADS are owned and accounted for by governments, political upheavals and corruption have allowed thousands of them to enter the black market. In the years 1998–2018, at least 72 non-state groups have fielded MANPADS. References . "Portions of this article were taken from "Homeland Security: Protecting Airliners from Terrorist Missiles" , CRS Report for Congress RL31741, February 16, 2006 by the Congressional Research Service, division of The Library of Congress which as a work of the Federal Government exists in the public domain."