helicopters at war

Helicopters played an inconsequential role in World War II. However, World War II demonstrated that the helicopter could perform useful missions, and they did see service to a limited extent as supply craft and for rescue operations in the China-Burma-India theatre, and were operated by the 1st Air Commando unit. But the helicopters of the day were still limited in their power, size, and hence their capabilities.

By Korea, helicopters were more numerous but were still confined largely to support roles, primarily search and rescue and medical evacuation, not to combat. Both the U.S. Army and the Marine Corps also used in certain logistical roles. Although army leaders thought about using helicopters to ferry troops during Korea, the service was prohibited from operating large aircraft by a law passed when the U.S. Air Force was created in 1947. This situation changed on November 4, 1952, when the army and the air force signed an agreement that continued the limit on the size of army fixed-wing aircraft but redefined helicopters by function performed in the combat zone. This new agreement paved the way for the use of large army helicopters, although it came too late to seriously impact the war. The army did, however, send the 6th Transportation Company (Helicopter) with Sikorsky H-19s to Korea before the war ended.

The CH-47 Chinook was used to transport troops and equipment in and out of battle.

The United States first used this new concept of warfare, soon named "air mobility," during the early years of its involvement in the Vietnam conflict. The Vietnam War was the first real helicopter war. The army quickly began refining its way of fighting as the war escalated.

American H-21 helicopters manufactured by Vertol were used to ferry Army of the Republic of Viet Nam (ARVN) troops into battle against communist Viet Cong guerillas in 1962. At first, communist troops fled when the troop-carrying helicopters landed. But at the important battle of Ap Bac, the Viet Cong soon learned that if they stood their ground, they could bring down the helicopters with relative ease. Communist training manuals described the best ways to shoot at the H-21 and UH-1 Huey helicopters—how to shoot ahead of the target to increase the chance of hitting it and where to shoot to cause the most damage.

Despite the proven vulnerability of helicopters to ground fire, the U.S. Army soon fully embraced the concept of air mobility. By the mid-1960s, as American involvement in Vietnam dramatically increased, the army began moving massive amounts of troops by air, not just the small groups of only a few years earlier. Some combat operations involved more than 100 helicopters at a time, plus fixed-wing air support to drop bombs and fire rockets at enemy troops.

The helicopter ushered in a radically different way of fighting a war: instead of armies engaging each other across vast fronts, advancing slowly, and holding ground, the U.S. Army would quickly carry troops into hostile territory and deploy them, then remove them after the fighting ended. While the overall strategy was questionable—no territory was ever really held—the tactic was often very successful. Helicopters offered high mobility for troops and a tremendous element of surprise. An enemy that had been sitting unchallenged for days or weeks could suddenly, without warning, find itself under assault from troops brought in by helicopter. Large troop transport helicopters like the CH-47 Chinook were developed for this purpose, but the workhorse UH-1 Huey became the most popular helicopter for moving troops into and out of battle.

The army also used armed helicopters to support ground troops, eventually fielding dedicated helicopter gun ships like the AH-1 Cobra. A helicopter could be equipped with guns, grenade launchers, rockets, or even guided missiles, and provide rapid and wide-ranging fire against an adversary on the ground. By the middle of the war, the helicopter had become as important to the army as the tank, the armoured personnel carrier, and the jeep, and the Huey was the most symbolic weapon of the Vietnam War.

Air mobility came at a heavy price, however. During the Vietnam War, between 1962 and 1973, the United States lost 4,869 helicopters to all causes (with more than a thousand lost in 1968 and another thousand in 1969). Fifty-three percent of these losses were due to enemy fire (including enemy attacks on airbases). The rest resulted from operational accidents. The high rate of operational accidents occurred largely because helicopters are prone to mechanical breakdown if not regularly maintained, and during a war, maintenance often suffers. Vietnam's heavy jungle canopy also made helicopter operations difficult, with few places to land a stricken helicopter.

Once the United States had pioneered the use of helicopters in combat, other countries soon followed. None could create large "airborne cavalry" units like the U.S. Army, but many countries copied the concept of using helicopters to ferry troops into and out of combat areas quickly, particularly when fighting rebel groups. They often used U.S. helicopters for this purpose. Countries like Great Britain and the Soviet Union usually chose to move primarily elite troops by helicopter. U.S. Army airborne cavalry units like the famed 101st Airborne and the 82nd Airborne tended to be better trained than most cavalry units.

By the 1970s, as Vietnam came to an end and the U.S. Army refocused its attention on the threat of a Soviet ground offensive in Europe, army leaders began to rethink some aspects of the air mobility concept. Before the war, the army had only a limited aviation capability. But by the end of the war, the army had a substantial air force of its own—centred on the helicopter—and could take on missions that were previously the domain of the U.S. Air Force but which were often ignored by that service.

Attack helicopters like the HueyCobra were more heavily armed and were given targets deep behind enemy lines, such as command posts and tanks, attacking them with missiles. The new strategy was also to fight at night, using advanced navigation and imaging systems, and hiding down among the trees and hills using "Nap Of the Earth" (NOE) flying. By doing so, the army could take advantage of superior American technology to compensate for larger numbers of Soviet ground forces. U.S. helicopters were equipped with infrared and night imaging systems, and pilots were given night vision goggles so they could see in the dark. By the 1980s, the United States also fielded heavily armed helicopters dedicated primarily to the mission of destroying tanks and equipped with laser-guided Hellfire missiles.

These changes in tactics proved themselves during the Persian Gulf War, when U.S. attack helicopters could freely range the battlefield during the night, easily destroying Iraqi tanks and other vehicles. Large numbers of U.S. troops were also ferried deep inside Iraqi territory, establishing facilities for supporting the attack helicopters as well as ground troops. Once again, other countries adopted the U.S. tactics and brought their helicopters.

While helicopters have revolutionized infantry warfare, they have had less of an impact on other areas of combat. This is primarily because they are still relatively slow, vulnerable, and cannot carry the large payloads that fixed-wing aircraft can carry.

The HueyCobra was a dedicated helicopter gunship that supported ground troops.

Other than infantry and anti-tank operations, helicopters have most notably been used for Combat Search and Rescue (CSAR), where they retrieve downed pilots deep inside enemy lines. This technique was really perfected during Vietnam, but several well-publicized rescues took place during the Bosnia crisis and later during the 1999 bombing of Yugoslavia. These helicopters are often equipped with highly sophisticated navigation systems and are supported by other armed helicopters and fixed-wing aircraft during their rescue mission.

Helicopters have also been used in the maritime surveillance and anti-shipping role. During the Falklands War in 1981, a British Lynx helicopter fired a missile and sank an Argentine submarine moored at dock. U.S. helicopters have also been equipped with missiles for attacking small ships and boats.

The Lynx helicopter, produced jointly by Westland and A‚rospatiale, saw action in the Falklands War. It was used in an anti-shipping role, where one sank a moored Argentine submarine in 1981.

Other than search and rescue of downed aviators, the primary purpose of naval helicopters has been submarine hunting and over-the-horizon targeting. Helicopters hunting submarines can hover and lower a large sonar into the water using a winch and cable. They are far more mobile than a ship and are invulnerable to the submarine they are hunting. Helicopters equipped with radar are also used to detect targets that a ship's sensors cannot see because they are over the horizon. They relay this data to the ship and can also guide ship-launched missiles to their targets. This has helped change the role of surface warships from defensive platforms used to protect aircraft carriers, to offensive platforms capable of attacking other ships at long range. In addition, helicopters have proven their utility at clearing mines. By towing large sleds along the water, the helicopter can stay away from any potentially harmful mines.

Although the helicopter is a highly useful military aircraft, it still suffers from slow speed, short range and limited lifting capabilities, leading aircraft manufacturers to search for ways to combine the attributes of both helicopters and conventional airplanes.