Surface-to-air weapons fire providing direct protection from aerial attack.
Ground-based antiaircraft gunnery began in 1871 during the Franco-Prussian War (1870-1871), when the Prussian army used a Krupp-produced weapon to shoot at message balloons being sent out from the besieged garrison of Paris. The first weapons expressly designed as antiaircraft weapons were manufactured in Germany in 1908 as quick-firing, car-mounted field pieces and were used to shoot down observation balloons.
During World War I (1914-1918), as positive results of aerial combat indicated the utility of aircraft as offensive weapons, specialized antiaircraft artillery became a priority. Such guns required mounts that allowed a high angle of fire, an all-around traverse, a high rate of fire, and a high muzzle velocity for a straight trajectory, and an improved accuracy.
By the start of World War II (1939-1945), two general types of antiaircraft gun were being produced: heavy, single-shot guns for attacking high-altitude aircraft and light, fast-firing machine guns and small-caliber cannons for low-level defense. The heavy guns could cycle as many as twenty-five rounds per minute to altitudes of 5,500 meters. The lighter weapons could fire nearly one thousand machine-gun rounds per minute. Small cannons, such as the 40-millimeter double-gun-mount Bofors, could fire 120 rounds per minute per gun.
Due to the poor general performance of early aircraft, antiaircraft gunners managed to bring down about one aircraft for every one thousand rounds of ammunition, excluding machine-gun ammunition, fired. As advances in aviation rapidly progressed, antiaircraft defense lagged behind in development. In 1939, German military planners determined that it would take fifty rounds of antiaircraft artillery to bring down one enemy airplane. On this basis, they established their air defense doctrine. Aircraft design and performance developed rapidly during World War II, outpacing antiaircraft weaponry. The German military found that it expended more than twelve thousand shells for each aircraft destroyed.
Between 1950 and 1980, surface-to-air antiaircraft missiles predominated as air defense weapons. The technology of the guided missile was thought to make other antiaircraft defenses obsolete. The reality, however, was that approximately fifty missiles were fired to bring down one enemy plane, at a cost much greater than that of the required twelve thousand artillery shells of World War II. Despite these results, heavy, single-shot artillery guns have been largely replaced by vehicle-mounted, in-place, or shoulder-held guided surface-to-air missiles. The advantage of a guided missile is its ability to completely destroy its target. Shrapnel from artillery rounds may only disable modern aircraft equipped with double- and triple-redundancy systems: A single missile hit will destroy an aircraft.
Since 1945, very high-flying bombers and guided missiles have made large antiaircraft artillery obsolete, but there remains the need to engage low-flying attack aircraft and helicopters. Although data suggest that missiles are barely as effective as antiaircraft artillery, the mere threat of surface-to-air missiles often forces aircraft to fly low enough to be shot at by smaller-caliber automatic weapons. At lower altitudes, where antiaircraft gunners can clearly see their targets, most aircraft losses to air defense happen.
During the Vietnam War (1961-1975), 80 percent of aircraft losses came from low-altitude machine-gun fire requiring about ten thousand small-caliber cannon and machine-gun rounds to down each airplane. The philosophy of rapid close-range fire as the most effective antiaircraft defense has resulted in the design and use of multi-barreled unmanned radar-controlled systems such as the 20-millimeter Vulcan-Phalanx Close-In Weapon System (CIWS). This weapon fires 6,600 rounds of uranium-tipped ammunition up to 5,000 meters, providing a so-called wall of steel to down approaching aircraft or missiles.
Antiaircraft fire is known to combat pilots by slang names such as “Archie,” “Ack-Ack,” “Flak,” and “Triple A.” The goal and lethal mission of air defense antiaircraft fire is attrition and deterrence. These goals are accomplished by forcing enemy aircraft either to abort their missions or to take heavy losses.
A four-step procedure establishes the basic tactics for providing successful antiaircraft fire. First, the enemy aircraft must be detected as early as possible. Second, the aircraft must be acquired to determine its direction and possible destination. Third, the aircraft must be tracked so weapons can be quickly targeted. Fourth and finally, the target must be destroyed.
Air defense artillery is employed to protect individual rear-area installations and vital military bases. Air defense weapons are deployed according to their range and mobility. Long-range, less mobile weapons are set far back from the fighting fronts to protect rear installations and to give high-altitude protection to front-line units. Mobile, short-range weapons are deployed nearer the fighting, where they can respond quickly to battlefield dynamics. The key to any successful air defense is the layering of defense at multiple depths and altitudes. In the past, air defenses had short ranges and low altitude. Modern surface-to-air systems can protect areas more than 100 kilometers from their bases and more than 10,000 meters high. A complete system can cover an entire operational theater of more than 1,600,000 square kilometers. The performance of antiaircraft fire is dependent on the destructive power of its ammunition, gained from high-impact velocities, explosive content, shrapnel, and blast and incendiary effect.
Historically, air defense has provided an impediment, and often a deterrent, to air attacks, but it has not in the long run been able to stop aerial attacks. Although aircraft have been touted as the preeminent weapon of modern warfare, they have failed to be overpowering, not because of air defense, but rather because of limitations in aircraft performance, weapons, and piloting. Modern air warfare tactics suggest that the best defense from enemy air attack is to destroy or suppress the enemy air force through air superiority.
Hogg, Ian V. Anti-Aircraft: A History of Air Defense. London: Garland, 1988. A good general reference with excellent illustration for researching changes in air defense weaponry and tactics throughout the twentieth century. Kreis, J. F. Air Warfare and Airbase Air Defense. Office of Air Force History: Washington, D.C.: United States Air Force, 1988. A difficult to obtain yet thorough treatment of the history of American air defense doctrine. Werrell, K. P. Archie, Flak, AAA, and SAM: A Short Operational History of Ground-Based Air Defense. Washington, D.C.: Government Printing Office, 1988. A concise review of antiaircraft defense from World War I to the late twentieth century.
Antiaircraft fire, often called “ack-ack,” lights up the sky over London during World War II.