Air assault
Air Assault (or air mobile, in the U.S. Air Cavalry) is the movement of forces by helicopter or aircraft to engage and destroy enemy forces or to seize and hold key terrain. In addition to regular infantry training, these forces usually receive training in rappelling and air transportation, and their equipment is sometimes modified as well to allow better transportation in aircraft. Due to the transport load restrictions of those aircraft, air assault troops are usually light infantry though light tracked armored fighting vehicles like the M113, Russian BMD, German Wiesel 1 and Swedish Bv206 now enable these forces to "air-mech"; have mobility on the ground even in the face of enemy fire.
If dropped by parachute instead, the troops are called paratroopers.
Organization and Employment
Air assault units can vary in organization, but all include infantry as the primary fighting element, supported heavily by helicopter transport, close air fire support, medical evacuation and resupply. Most include some air mobile artillery. Units vary in size, but typically are brigade or division sized units.
Airmobile units are designed and trained for air insertion (sometimes referred to as vertical envelopment), air resupply, and if necessary air extraction.
History
Air mobility has been a key concept since World War II. Initial approaches to air mobility focused on airborne units, which consisted of paratroopers and sometimes glider-borne troops.
Paratroopers were dropped from the skies at Sicily, Normandy, Holland and Crete. Meanwhile, the Germans were using the autogyro to airlift downed Luftwaffe pilots back to friendly lines.
Airborne tactics in WWII differed between nationalities and theaters of war. In Europe, Allied airborne tactics often involved broad area landings in advance of conventional forces with limited reinforcement. The airborne forces then linked up with the conventional forces when they arrived.
The German tactic in Holland and Crete was to establish an airhead at an airfield using parachute and glider infantry—similar to a beachhead in amphibious tactics—and rapidly reinforce the airhead with specially trained troops, such as the 22.Luftlande Infantrie Division, in transport aircraft. In the Pacific, Allied forces performed a similar operation at Nadzab in 1943, with American paratroopers of the 503rd Parachute Infantry Regiment taking the airhead and the Australian 7th Division providing the reinforcing infantry in conventional transports. This is closer to the air assault tactics of today.
Units like the 1st Air Commando Group performed extensive aerial resupply using gliders and conventional transports in the China-Burma-India theater (CBI). The Germans fielded the first troop carrying helicopter, the FA-223 in WW2 and would have used it to rescue Italian dictator Mussolini after the glider assault had their machine not needed repairs. In its stead, a short take-off and landing (STOL) Fieseler Storch observation plane was used to fly him to safety. The United States Army Air Forces flew Sikorsky R-4 helicopters in the CBI theater, performing the first helicopter casualty evacuation. It could only carry one person other than the pilot. They also used the R-6 which could carry two casualties in pods on the side of the helicopter. All Allied helicopter pilots in WWII were trained by the United States Coast Guard at Brooklyn Air Station.
In 1946 US 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 the beachhead. The Commandant of the Marine Corps convened a special board, the Hogaboom Board, that recommended that the USMC develop transport helicopters in order to allow a more diffuse attack on enemy shores. It also recommended that the USMC stand up an experimental helicopter squadron and 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 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.
After the start of the Korean War, four HMX-1 helicopters were attached to VMO-6 and sent to the Pusan Perimeter in 1950. They were used for battlefield observation and control as well as medical evacuation and the rescue of fliers. During the Battle of Chosin Reservoir they were used for liaison between the different Marine units strung along the western edge of the Chosin Reservoir. The Marines began commissioning transport helicopter squadrons flying Sikorsky HRS-1s in 1951. After moving to Korea, these units began performing aerial resupply and aerial assault. HMR-161 transported over 200 Marines and 18,000 pounds of cargo in the first combat helicopter air assault in history in Operation Summit in September 1951. The first battalion-sized combat helicopter air assault was that of the 3rd Battalion 7th Marines in October 1951 in Operation Bumblebee.
In addition, the U.S. Army had their first combat test of the CH-21 helicopter in Korea. It was unofficially called the "Flying Banana" because of its banana-like appearance.
General James Gavin, the famous US Army airborne officer wrote "Cavalry, and I Don't Mean Horses" in Harper's, April 1954. This article was influential in getting the US Army to start considering airmobile type operations, but the Army was held back by the US Air Force, which thought that it should control all aircraft including helicopters that would be used to support the Army.
Helicopter use in Indochina and North Africa, by the French Army was limited in the 1950s by the limited availability and capability of the helicopters of the time. Most application was in medical evacuation. However the utility of the helicopter was obvious to forward looking military planners.
An early attempt to apply air mobility to warfare was the Battle of Dien Bien Phu in 1954. French military leaders believed that they could resupply the garrison there by air indefinitely. However, the air technology available, the means in which it was applied, and the terrain and geography led to failure.
The French Army subsequently gained a lot of valuable experience during the Algerian War between 1954 and 1962. The French used American helicopters for what was termed "Aeromobilité". The first air assault operations were small, but quickly grew in size and scope to full battalion sized actions. ALAT (Aviation Legère Armee de Terre, Army Light Aviation) helicopters were used as flying command posts, equipped with radios and to carry troops directly into battle. Helicopters were also used to supply units in the field and outposts.
On November 5, 1956 the Royal Marines' 45 Commando performed the first combat amphibious helicopter assault as part of Operation Musketeer, in Suez, Egypt. They were flown in Westland Whirlwind Mark 2s of 845 Naval Air Squadron from the deck of the HMS Theseus, and Whirlwinds and Bristol Sycamore HC.12s and HC.14s of the Joint Experimental Helicopter Unit (JEHU) of the RAF from the deck of HMS Ocean.
In 1956 the US Navy modified and recommissioned the USS Thetis Bay, a WWII escort carrier, as an Assault Helicopter Aircraft Carrier (CVHA-1). It was the first ship purposely modified for air assault operations. The Marines started receiving their beloved Sikorsky HUS helicopters in 1957. They would be redesignated as UH-34s in 1962. Later three WWII Essex-class fleet carriers were also converted and in 1961 the US Navy commissioned the USS Iwo Jima, the first carrier planned and built as a platform for air assault operations.
Vietnam War
US Army H-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 Ap Bac on February 1962, 14 of 15 helicopters were hit and four shot down. The Army began adding machine guns and rockets to their smaller UH-1 Huey helicopters and developed the first purpose built gunship, the UH-1B with the M-6E3 armament system.
US 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 US Marine helicopters and ARVN troops. After April 1963 as losses began to mount, US 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 south of Chu Lai, while the 3rd Battalion 3rd Marines landed 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 (Howze) Board of the US Army in 1962 when they saw a new kind of war heading their way. The Army saw that Vietnam was varied in terrain, having jungles, mountains, and rivers, making ground movement very difficult. To circumvent this problem, they developed the idea to use helicopters to move troops in and out and around a battlefield area, carry out the wounded, and drop off supplies.
Initially a new experimental unit was formed, the 11th Air Assault Division on 11 February 1964, combining light infantry with integral helicopter transport and air support. Following training and testing, the unit was activated for Vietnam service with the designation 1st Air Cavalry Division, continuing the tradition of the 1st Cavalry Division.
The first unit of the new division to see action was the 1st Battalion/U.S. 7th Cavalry Regiment, led by Lieutenant Colonel Harold G. Moore, an old army paratrooper. The 7th Cavalry was the same regiment that Custer had commanded at the ill fated Battle of the Little Bighorn. On November 14, 1965, he 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.
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.
Today
In the United States military, the air assault mission is now the primary role of the 101st Airborne Division. 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.
All US Marine Corps ground units are trained in only basic air assault tactics and capable of performing heliborne operations that only require them to walk off the airlanded helicopter.
Since the 101st has relinquished its parachute capability the 82nd Airborne Division is the United States Army's only parachute division.
There are other major "conventional" units in the United States Army that have parachute capabilities; the 173rd Airborne Brigade, based in Italy and the 4th Brigade of the 25th Infantry Division in Alaska. The former unit parachuted into Northern Iraq during Operation Iraqi Freedom in 2003. These units are considered regional quick reaction parachute forces for the Pacific and Atlantic regions.