Air armament

(ordnance) All equipment through which a combat aircraft can release destructive power on a target.

That category of weapons which are typically delivered on target by fixed or rotary-wing aircraft, with the exception of nuclear weapons. Specifically included are guns and ammunition, rockets, free-fall bombs, cluster weapons that consist of a dispenser and submunitions, air-to-air and air-to-surface guided weapons, mines, and antiradiation missiles. Nuclear weapons such as the air-launched cruise missile and nuclear bombs, which are delivered by aircraft, are considered strategic weapons, a specific class of air armament.

The most widely used aircraft guns outside the former Communist countries are the French DEFA and British Aden 30-mm guns, followed by the United States 20-mm M61 Vulcan. The most modern aircraft guns are the 27-mm Mauser developed for multirole use on the German, Italian, and British multirole combat aircraft (MRCA) Tornado, and the large 30-mm GAU-8 and GAU-13 antiarmor guns which carry high-explosive incendiary (HEI) and armor-piercing incendiary (API) ammunition.

Free rockets, or unguided rockets, developed during World War II, are more accurate than bombs but less accurate than guns. Although rocket systems are often considered obsolete, virtually all major powers maintain one or more in their arsenal. See also Rocket.

Conventional bombs employing TNT or TNT-based mixtures have been made in many types and sizes. Armor-piercing bombs were designed for use against concrete fortifications and submarine pens. Demolition bombs have thin steel cases and maximum explosive loads. General-purpose bombs are a compromise between armor-piercing and demolition. Bombs have been made to deliver virtually anything against any type of target. Some examples are incendiary bombs to ignite wooden buildings; napalm or jellied gasoline for use against anything that can be damaged by flame; underwater bombs for use against hydroelectric dams; cluster bombs, which separate and disperse to saturate an area; and leaflet bombs to deliver propaganda.

An entirely new class of aircraft armament known as cluster weapons has evolved since the 1950s. It is partly an outgrowth of cluster bombs from World War II and partly a result of the realization that many targets, notably personnel and light vehicles, could be destroyed more efficiently with several small bombs than with one large bomb. The primary advantage of cluster weapons over unitaries is their large footprint or area covered, which compensates for delivery errors and target uncertainty errors incurred by unguided weapons.

Although not normally included as part of the field of aircraft armament, fire control is the term that covers the sighting, aiming, and computation which enables the pilot or aircrew to hit the target. Basically, it examines the conditions of the engagement and indicates when to release the armament in order to obtain hits.

Guided weapons is a generic term which applies to any of the previously described ballistic systems when they are deliberately perturbed from their ballistic path after launch in order to increase the probability of hitting a target. There are three fundamental problems in guided weapons: determining where the target is or will be, determining where the weapon is, and correcting the weapon's location to coincide with the target's location at the time of closest encounter. The first two problems are called guidance; the third, control. Control is usually accomplished by aerodynamic-control-surface deflection. See also Autopilot; Flight controls.

There are five fundamental concepts of guidance, namely inertial guidance, command guidance, active guidance, semiactive guidance, and passive guidance, and many different implementations of each. In command guidance, the weapon system operator or on-board sensors observe the relative location of weapon and target and direct trajectory corrections. In an active guidance system, electromagnetic emissions, for example, radar, microwave, or laser, are transmitted from the weapon to the target, and the return energy reflections are measured to determine range and angle to the target. Semiactive guidance resembles active guidance except that the illumination of the target is provided by a designator not located on the weapon. Passive guidance uses the natural emissions radiating from targets to uniquely acquire a target and subsequently guide the weapon to the target. See also Lidar; Radar.

The ultimate objective of a weapon system is to be completely autonomous. An example of an autonomous system is one combining inertial and passive or active terminal guidance, and the appropriate algorithms to acquire the target after launch without operator intervention. In this case, the weapon is launched into an area where targets are known to exist, and, upon reaching the area, the weapon searches and finds its own target, homes in on it, and destroys it. The trend toward weapons that can autonomously acquire targets allows weapons to be built that have a substantial standoff capability which increases the survivability of the launch platform, improves accuracy, increases proficiency, and reduces the logistical burden.

There are two classes of smart weapons. The first class consists of those guided weapons that possess some form of terminal guidance and home in on the target. Weapon systems in this class include laser-guided bombs. The second class of smart weapons includes those that autonomously acquire the target after launch, and are usually termed lock-on-after-launch, fire-and-forget, or brilliant weapons.