An attack helicopter is purpose-built for missions where it will deliver firepower, either in conjunction with armed helicopters and unarmed cargo helicopters, or on independent missions of close air support or battlefield air interdiction. In the U.S. Army, helicopters are under the Army aviation branch. A representative attack helicopter is the U.S. Army's AH-64 Apache. As are all helicopters, it is capable of vertical takeoff and landing (VTOL), so it can operate from any flat open area near ground troops.
Armed helicopters rarely carry weapons heavier than light machine guns and possibly small pods for unguided rockets. Attack helicopters carry heavy armament such as heavy machine guns, autocannon, unguided rockets, and air-to-surface missiles such as the U.S. Hellfire or Russian AT-6 SPIRAL.
Many attack helicopters are also capable of carrying air-to-air missiles, though mostly for purposes of self-defense. These missiles are usually modifications of man-portable air defense system (MANPADS) surface-to-air missiles such as the U.S. FIM-92 Stinger.
The AH-1 Cobra, complementing UH-1 armed helicopters was apt to have a chin turret with two 7.62mm rotating barrel "minigun" 7.62 mm machine guns, two 40mm automatic grenade launchers, or one of each. Some had 20mm autocannon in turrets. It was more likely to carry the M200 launchers for 19 of the 2.75" rockets, rather than 7-round M-178s. There were many field modifications. Current attack helicopters also fire guided missiles, typically anti-tank missiles that also can be used against buildings, but also light antiaircraft missiles such as the Stinger.
As an example of the conflicting demands on a pure attack design, the current U.S. AH-64 Apache is a purpose-built attack helicopter with a seat for a pilot and a seat for a gunner, but when another crew went down and was likely to be captured, the aircrew came up with the idea of riding on the wings using them as crude litters with rescued personnel desperately hanging on outside the helicopter. This measure is now a standard, so aircrews carry a custom strap with them to clip on to the wings. This is a similar technique that was used in Vietnam when an AH-1 Cobra would use the ammunition storage doors the side of the fuselage as seats to extract personnel.
Today's attack helicopter has two main roles: first, to provide direct and accurate close air support for ground troops, and the second, in the anti tank role to destroy enemy armor concentrations. Attack helicopters are also used to supplement lighter helicopters in the armed scout role. Scout helicopters may use laser designators or other equipment to provide guidance to the heavier weapons fired from the attack helicopters. fter Vietnam, and especially into the 1990s, US Army, and some Soviet, attack helicopters became more and more optimized for the antitank mission.
Battle of Karbala
In the 2003 invasion of Iraq, one of the major differences from 1991 was that the ground campaign did not wait for an extensive preparation by the Central Command air components. In part because there was no viable Iraqi Air Force, Army and Marine aviation were used extensively, with Air Force and Navy high-performance aircraft in close air support and battlefield air interdiction rather than extensive strike operations. The operation described here was, strictly, an independent attack helicopter operation rather than an air assault, but the experience gives strong lessons on the environments in which air assault can, and cannot, succeed.
While there had been limited use of attack helicopters in BAI in 1991, with the literal first strike of that war by Special Operations helicopters on a critical early warning radar, the 2003 plan expected to use the AH-64 Apache extensively in the BAI role.
An example of this role was a pair of raids on Iraqi armor in Karbala, Iraq. From those raids, a good lesson was that the AH-64 is, indeed, highly survivable even when damaged. A bad lesson was that attack helicopters, without coordinated SEAD (Suppression of Enemy Air Defense), cannot fight through an alerted defense and complete the BAI mission.
In the first raid, on March 24, 2003, US V Corps sent 32 Apache helicopters, against Medina Division armor in Karbala. The corps commander told reporters that post-strike analysis revealed that Iraqi observers had seen the preparation of assembly areas in the desert, and had alerted the defense using cellular telephones. During the approach to Karbala, Iraq shut the power grid to darken the night, and aggressively directed ground-based air defense at the helicopters. While no crew were killed, one helicopter was destroyed, and enough damaged to force the raid to be stopped before its objective.
Two days later, the Army again used Apaches to carry out another nighttime deep attack. Tactics used, however, were quite different than those on March 24. This attack had no helicopter losses, destroyed some enemy targets, and degraded the defense well enough for the 3rd U.S.Infantry Division to have little difficulty moving through the Iraqi Medina Division, as the 3rd moved to Baghdad.
On March 26, other air and ground resources supported the attack, beginning with a four-minute artillery bombardment to distract the gunners. As the helicopters moved through the Najaf area, the lights again went off, and the intensity of antiaircraft fire increased as they approached the target.
The Apaches themselves used different tactics, and also operated in combination with other forces. First, the helicopters accepted reduced accuracy to shoot missiles while moving, rather than hovering and thus becoming better targets. Fixed-wing fighter-bombers initially destroyed some Iraqi air defenses, then attacked additional ones spotted by the helicopters. The idea of helicopters and fixed-wing aircraft cooperating to take out air defense as well as tanks and artillery had long been a NATO concept.
No final determination has been made if the Apache can, or cannot, carry out deep attack, or be adequate to escort deep air assault. In the short term, the AH-64s went back to a primary CAS role.
In special operations, either regular land-orient attack helicopters may be guided by special operations helicopters with superior sensors, and there are some purpose-built attack helicopters with unusual flexibility.
In some special operations missions, a large, usually armed rather than attack, helicopter with extensive electronics may navigate for a formation of lighter armed helicopters. An example of this was having United States Air Force MH-53 PAVE LOW helicopters guide Army Apache attack helicopters to the first targets hit in the Gulf War, early warning radars on the Saudi-Iraqi border.
160th Special Operations Aviation Regiment
For urban operations and other cases requiring small size and great flexibility, the U.S. Army Special Operations Command's 160th Special Operations Aviation Regiment has used both MH-6 light assault transport helicopters, and a series of AH-6 attack helicopters using different airframes. Weapons available to the current AH-6 include armed with two seven-tube 2.75 inch rocket launchers and two 7.62mm M134 "miniguns" as the basic configuration, but also .50 Cal. machine guns, MK19 40mm automatic grenade launcher, AGM-114 Hellfire air-to-surface missiles, and Air-to-Air FIM-92 Stinger (ATAS) missiles.
Many of their operations remain classified, but they have been observed in Panama and Somalia.
- Mazarella, Mark N (1994). Adequacy of U.S. Army Attack Helicopter Doctrine to Support the Scope of Attack Helicopter Operations in a Multi-Polar World. U.S. Army Command and General Staff College.
- Ryan O'Rourke (June 4, 2003), Iraq War: Defense Program Implications for Congress, Congressional Research Service, at CRS-36
- "OH-6A Cayuse/AH-6J Little Bird/Defender 500", Federation of American Scientists