||This article has multiple issues. Please help improve it or discuss these issues on the talk page.
Air assault is the movement of ground-based military forces by vertical take-off and landing (VTOL) aircraft—such as the helicopter—to seize and hold key terrain which has not been fully secured, and to directly engage enemy forces. In addition to regular infantry training, air-assault units usually receive training in rappelling and air transportation, and their equipment is sometimes designed or field-modified to allow better transportation within aircraft.
The US Army field manual FM 1-02 (FM 101-5-1) describes an "air assault operation" as an (DOD) Operation in which assault forces (combat, combat service, and combat service support), using the firepower, mobility, and total integration of helicopter assets, maneuver on the battlefield under the control of the ground or air maneuver commander to engage and destroy enemy forces or to seize and hold key terrain.
Due to the transport load restrictions of helicopters, air assault forces are usually light infantry, though some armored fighting vehicles, like the Russian BMD-1 are designed to fit most heavy lift helicopters, which enable assaulting forces to combine air mobility with a certain degree of ground mechanization. Invariably the assaulting troops are highly dependent on aerial fire support provided by the armed helicopters or fixed-wing aircraft escorting the VTOL.
Moreover, air assault should not be confused with an airborne assault, which occurs when paratroopers, and their weapons and supplies, are dropped by parachute from transport aircraft, often as part of a strategic offensive operation. Air assault should also not be confused with forms of military transport operations known as air landing, airlift, or airbridge, that all require an already secured place to land—an airhead.
Organization and employment 
Air assault and air mobility are related concepts. However, air assault is distinctly a combat insertion rather than transportation to an area in the vicinity of combat. "Air assault operations are not merely movements of soldiers, weapons, and materiel by Army aviation units and must not be construed as such." 
Air assault units can vary in organization; using helicopters not only in transport but also as close air fire support, medical evacuation helicopters and resupply missions. Airmobile artillery is often assigned to air assault deployments. Units vary in size, but are typically company- or brigade-sized units.
Airmobile units are designed and trained for air insertion and vertical envelopment ("a maneuver in which troops, either air-dropped or air-landed, attack the rear and flanks of a force, in effect cutting off or encircling the force".), air resupply, and if necessary air extraction.
One specific type of air assault unit is the US Army air cavalry. It differs from regular air assault units only in fulfilling a traditional cavalry reconnaissance and short raids role. Britain's 16 Air Assault Brigade was formed in 1999 following an amalgamation of elements of 5th Infantry Brigade (5 Airborne Brigade) and 24 Airmobile Brigade, bringing together the agility and reach of airborne forces with the potency of the attack helicopter. Similarly, the US 101st Airborne Division was originally classed as airborne, then airmobile and now air assault.
Air mobility has been a key concept in offensive operations since the 1930s. Initial approaches to air mobility focused on airborne and glider-borne troops. During World War II many assaults were done by military gliders. Following the war faster aircraft led to the abandonment of the flimsy wooden gliders with the then new helicopters taking their place. Four YR-4B helicopters saw limited service in the China Burma India theatre with the 1st Air Commando Group
In 1946, U.S. Marine General Roy S. Geiger observed the atomic bomb tests at Bikini Atoll and instantly recognized that atomic bombs could render amphibious landings difficult because of the dense concentrations of troops, ships and material at beachheads. During this time, The Commandant of the Marine Corps, Alexander Vandegrift, convened a special board known as the Hogaboom Board. This board recommended that the USMC develop transport helicopters in order to allow a diffused attack on enemy shores. It also recommended that the USMC form an experimental helicopter squadron.HMX-1 was commissioned in 1947 with Sikorsky HO3S-1s. In 1948 the Marine Corps Schools came out with Amphibious Operations—Employment of Helicopters (Tentative), or Phib-31, which was the first manual for helicopter airmobile operations. The Marines used the term vertical envelopment instead of air mobility or air assault. HMX-1 performed its first vertical envelopment from the deck of an aircraft carrier in an exercise in 1949.
First helicopter air assault 
The first helicopter airlift and Helicopter Sling Load mission was conducted on September 13, 1951 during the Korean War. "Operation Windmill I" was conducted by the United States Marine Corps in support of a battalion clearing the enemy from a series of ridges around an extinct volcano called "The Punchbowl." In total seven HRS-1 marine helicopters made 28 flights that delivered 18,848 pounds of supplies and evacuated 74 seriously wounded men.
On November 5, 1956 the Royal Marines' 45 Commando performed the world's first combat helicopter insertion with air assault during an amphibious landing as part of Operation Musketeer, in Suez, Egypt. 650 marines and 23 tons of equipment were flown in ten Westland Whirlwind Mark 2s of 845 Naval Air Squadron from the deck of the HMS Theseus, and six each Whirlwinds and Bristol Sycamore HC.12s and HC.14s off HMS Ocean's embarked Joint Experimental Helicopter Unit (JEHU) (Royal Air Force).
The plan was to use the helicopters to drop No. 45 Commando at Raswa, to the south of Port Said, in order to secure two vital bridges. Last-minute concerns about their vulnerability to ground fire meant that they were replaced in this role by French paratroops who conducted a daring low-level drop on 5 November, securing one of the two bridges intact. Instead No. 45 Commando was landed the following day, disembarking close to the seafront in the aftermath of the seaborne landing that had secured the area. This first-ever operational use of helicopters to land troops during an amphibious assault proved successful. With their carriers lying nine miles offshore, the marines were landed far more quickly than could have been achieved using landing craft, and without the need to get their boots wet. However...they landed the marines in much the same place that old style landing craft would have put them."
In 1956, the United Staes Marine Corps executed the first Division-strength exercise of vertical envelopment when the 1st Marine Division was helicopter-lifted from converted WWII jeep carriers to landing sites at Camp Pendleton, CA, U.S. Marine Corps Base. One of the ships utilized for this exercise was the U.S.S. Thetis Bay. This exercise was the culmination of the Marines' developing strategy of vertical envelopment rather than amphibious assaults on heavily defended beaches. The maneuvers were well-covered by the media of the time, including LIFE Magazine. The Marine Corps subsequently adopted this method as standard operating procedure after proving that helicopters could be used to transport very large numbers of troops and large amounts of supplies in a timely fashion.
Operation Deep Water was a 1957 NATO naval exercise held in the Mediterranean Sea that involved the first units of the United States Marine Corps to participate in a helicopter-borne vertical envelopment operation during an overseas deployment.
Vietnam War 
U.S. Army CH-21 helicopter transports arrived in Vietnam on 11 December 1961. Air assault operations using South Vietnamese (ARVN) troops began 12 days later in Operation Chopper. These were very successful at first but the Viet Cong (VC) began developing counter helicopter techniques, and at the Ap Bac in January 1963, 13 of 15 helicopters were hit and four shot down. The Army began adding machine guns and rockets to their smaller helicopters and developed the first purpose built gunship with the M-6E3 armament system.
U.S. Marine helicopter squadrons began four month rotations through Vietnam as part of Operation SHUFLY on 15 April 1962. Six days later, they performed the first helicopter assault using U.S. Marine helicopters and ARVN troops. After April 1963, as losses began to mount, U.S. Army UH-1 Huey gunships escorted the Marine transports. The VC again used effective counter landing techniques and in Operation Sure Wind 202 on 27 April 1964, 17 of 21 helicopters were hit and three shot down.
The 2nd Battalion 3rd Marines made a night helicopter assault in the Elephant Valley south of Da Nang on 12 August 1965 shortly after Marine ground troops arrived in country. On 17 August 1965 in Operation Starlite the 2nd Battalion 4th Marines landed in three helicopter landing zones (LZs) west of the 1st VC Regiment in the Van Tuong village complex, 12 miles (19 km) south of Chu Lai, while the 3rd Battalion 3rd Marines used seaborne landing craft on the beaches to the east. The transport helicopters were 24 UH-34s from HMM-361 and HMM-261 escorted by Marine and Army Hueys. VC losses were 614 killed, Marine losses were 45 KIA and 203 WIA.
The need for a new type of unit became apparent to the Tactical Mobility Requirements Board (normally referred to as the Howze Board) of the U.S. Army in 1962. The Board met at a difficult time; the bulk of the military hierarchy were focused primary on the Soviet threat to Western Europe, primarily perceived as requiring heavy, conventional units. The creation of new, light airmobile units could only occur at the expense of heavier units. At the same time, the incoming Kennedy administration was placing a much greater emphasis on the need to fight 'small wars', or counter-insurgencies, and was strongly supportive of officers such as General Howze who were embracing new technologies. The Board concluded that a new form of unit would be required, and commissioned tests - but justified these at the time on the need to fight a conventional war in Europe.
Initially a new experimental unit was formed at Fort Benning, Georgia, the 11th Air Assault Division on 11 February 1963, combining light infantry with integral helicopter transport and air support. Opinions vary as to the level of support for the concept within the Army; some have argued that the initial tests against the context of conventional warfare did not prove promising, and, despite opposition from the Joint Chiefs of Staff, it was primarily the Secretary of Defense Robert McNamara who pushed through the changes in 1965, drawing on support from within the Pentagon which had now begun to establish a counter-insurgency doctrine that would require just such a unit. Others have put more weight on the support of newly appointed senior Army commanders, including the new Chief of Staff General Wheeler, in driving through the changes.
Nonetheless, the 11th Air Assault Division assets were merged with the co-located 2nd Infantry Division and reflagged as the 1st Cavalry Division (Airmobile), continuing the tradition of the 1st Cavalry Division. Within several months it was sent to Vietnam and the concept of air mobility became bound up with the challenges of that campaign, especially its varied terrain - the jungles, mountains, and rivers which complicated ground movement.
The first unit of the new division to see action was the 1st Battalion, 7th Cavalry Regiment, led by Lieutenant Colonel Harold G. Moore. The 7th Cavalry was the same regiment that Custer had commanded at the ill fated Battle of the Little Bighorn. On November 14, 1965, Moore led his troops in the first large unit engagement of the 1960s Vietnam War, which took place near the Chu Pong massif near the Vietnam-Cambodia border. It is known today as the Battle of Ia Drang Valley, and is considered to be the first large scale helicopter air assault.
This unit gave common currency to the U.S. term "Air Cavalry". Units of this type may also be referred to as "Airmobile" or with other terms that describe the integration of air and ground combat forces within a single unit.
In the United States military, the air assault mission is now the primary role of the 101st Airborne Division (Air Assault). This unit is the Army's only division-sized helicopter-borne fighting force. Many of its soldiers are graduates of the Air Assault course qualifying them to insert and extract using fast rope and rappel means from a hover in addition to the ordinary walk on and off from an airlanded helicopter. Since the 101st relinquished its parachute capability in 1968, the 82nd Airborne Division is the United States Army's only remaining parachute division.
The 10th Mountain Division Light Infantry regularly perform air assault operations, as do many other US Army infantry units. On September 19, 1994, the 1st Brigade of the 10th Mountain Division conducted the Army’s first air assault from an aircraft carrier, the USS Dwight D. Eisenhower, as part of Operation Uphold Democracy. This force consisted of 54 helicopters and almost 2,000 soldiers. This was the Army's largest operation from an aircraft carrier since the Doolittle Raid of World War II.
All U.S. Marine Corps ground units are trained in basic air assault tactics and capable of performing helicopter borne operations that require them to fast rope from a hovering helicopter. The U.S. Marines also specialize in conducting air assault that launches from specialized helicopter carrying naval ships during amphibious warfare.
There are other major "conventional" units in the United States Army that have parachute capabilities; the separate 173rd Airborne Brigade Combat Team, based in Italy and Germany, and the Alaska-based 4th Brigade Combat Team, 25th Infantry Division, which has its division headquarters in Hawaii, and the 1st Battalion (Airborne), 509th Infantry Regiment based in Fort Polk, Louisiana supporting the Joint Readiness Training Center as the opposing force for training rotational units. The 173rd ABCT parachuted into Northern Iraq during the invasion of Iraq in 2003. These units are considered regional quick reaction parachute forces for the Pacific and Atlantic regions.
The 16th Air Assault Brigade of the British Army is Britain's main air assault body. It comprises units of paratroopers from the Parachute Regiment and light infantry units trained in helicopter insertion, as well as light tanks and artillery.
- 601 Air Assault Regiment
- 68th Special Forces Brigade, 2nd battalion
- Airmobile Operations Division
- Air Assault Brigade 1
- Korps Pasukan Khas Angkatan Udara (Air Force Special Corps)
- Wing I (4 battalions, 4 independent companies)
- Wing II (4 battalions, 2 independent companies)
- Bravo Detachment (Air Force Special Force Unit)
- Kostrad (Army Strategic Command)
- 3rd Air Assault Brigade/ Tri Budi Mahasakti
- 17th Air Assault Brigade/ Kujang I
- 18th Air Assault Bridage/ Trisula
- 601 Air Cavalry Brigade
- 602 Air Cavalry Brigade
- 11 Luchtmobiele Brigade [Combined with the helicopters of the Royal Netherlands Air Force, they form the 11 Air Manoeuvre Brigade (11 AMB)]
- 44 Parachute Regiment (1999 to present)
- 6 South African Infantry battalion
- 61st Air Assault Brigade
- 101st Airborne Division
- 1st Brigade Combat Team
- 2nd Brigade Combat Team
- 3rd Brigade Combat Team
- 4th Brigade Combat Team
- VII Corps 'VANGUARD OF NORTHERN ADVANCE' 7th Assault Unit
- 20th Parachute Battalion
See also 
- Airborne forces
- Battleplan (documentary TV series)
- United States Army Air Assault School
- Air Assault Operations - Global Security
- Vertical Envelopment, encyclopedia.com, Retrieved 2009-12-03. Quotes "The Oxford Essential Dictionary of the U.S. Military").
- 16 Air Assault Brigade
- pp.49-51 Boyne, Walter J. How the Helicopter Changed Modern Warfare Pelican Publishing, 2011
- Rawlins, Eugene W. (1976). Marines and Helicopters 1946-1962. Washington, D.C.: United States Marine Corps History and Museums Division. p. 20.
- Rawlins, Eugene W. (1976). Marines and Helicopters 1946-1962. Washington, D.C.: United States Marine Corps History and Museums Division. p. 35.
- Helicopters at War - US Centenial of Flight Commission
- Whirlybirds - US Marine Helicopters in Korea - Page 46
- 3 Commando Brigade
- Tim Benbow, British Naval Aviation: The First 100 Years, Ashgate Publishing, 2011, p.161
- Freedman, Lawrence Kennedy's Wars: Berlin, Cuba, Laos and Vietnam Oxford University Press: Oxford (2000) pp.334-5.
- Krepinevich, Andrew F. The Army and Vietnam John Hopkins Press: Baltimore (1986) pp.121-2.
- Krepinevich, Andrew F. The Army and Vietnam John Hopkins Press: Baltimore (1986) p.124.
- Stockfisch, J. A. The 1962 Howze board and Army Combat Developments Rand Corporation: Santa Monica, C.A. (1994) pp9-10. Online at http://www.rand.org/pubs/monograph_reports/2007/MR435.pdf
- Whittle, Richard. "The Dream Machine: The Untold History of the Notorious V-22 Osprey" p41. New York: Simon & Schuster, 2010. ISBN 1-4165-6295-8. Retrieved: 6 August 2012.
- USS Dwight D Eisenhower History
- Air Mobile Brigade (Sri Lanka)
- Scales, Robert H. & Scales, Jr., Robert H., Certain Victory: The U.S. Army in the Gulf War, Brassey's, 1994
- Arthur, Max, "There Shall Be Wings", Hodder and Stoughton, 1994, ISBN 0-340-60386-0
|Wikimedia Commons has media related to: Air assaults|
- Vietnam Studies: Airmobility 1961-1971 by Lieutenant General John J. Tolson, 1989
- A 1989 Department of Defense news archive about Task Force Hawk air assault training, Panama.
- The short film STAFF FILM REPORT 66-20A (1966) is available for free download at the Internet Archive [more]