Close air support

Close air support (abbreviated as CAS) is the use of military aircraft in a ground attack role against targets in close proximity to friendly forces, in direct suppport of and requiring detailed integration with the fire and movement of ground troops. In this role, aircraft serve a purpose similar to that of artillery.

Close air support is a part of modern combined arms doctrine. The term is used to distinguish from air interdiction, the use of aircraft to attack ground target not in close proximity to friendly units. A closely related subset of air interdiction, battlefield air interdiction denotes interdiction against units with near term-effects on friendly units, but which does not require integration with friendly troop movements.

Close air support requires excellent coordination with ground forces. In advanced modern militaries, this coordination is typically handled by specialists such as Joint Fires Observers, Joint Terminal Attack Controllers, and airborne Forward Air Controllers (aka FAC-A).

History

WWI

The use of aircraft in the close air support of ground forces dates back to World War I, the first significant use of aerial units in warfare. Since air warfare was in its infancy the tiny, 25 pound bombs had little effect, but the aircraft still had an extraordinary psychological impact. The aircraft was a visible and personal enemy, unlike artillery - presenting a personal threat to enemy troops , while providing friendly forces assurance that their superiors were concerned about their situation. Though the practice of air-ground cooperation was in its infancy by the end of the war, most successful attacks of 1917 - 1918 included planning for coordination between aerial and ground units. It was very hard at this early date to coordinate these attacks. Though most airpower proponents sought independence from ground commanders and hence pushed the importance of interdiction and strategic bombing, they notheless recognized the need for close air support.

The British Royal Flying Corps and the U.S. Army Air Service saw CAS as another task for ordinary pursuit or fighter aircraft, such as the S.E. 5a and Sopwith Camel, and did not seek out specialized units or equipment until the late months of the war. Since pilots lacked specific training, and their aircraft were rather fragile, they suffered heavy casualties while flying low over enemy positions. For example, No. 80 Squadron of the RAF averaged 75% losses for the last 10 months of the war. The Germans and French, however, developed tactics, training, and formations for ground support. Germany would also modify aircraft by placing armor around the cockpitsof German J-1 aircraft to protect from small-arms fire. By spring 1918, Germany had thirty-eight Schlachtstaffeln (battle squadrons) as support, trained to bomb and strafe below 200 feet.

Inter-War Period - Framing the Debate

During the inter-war period, airpower advocates crystallized their views on the role of airpower in warfare. Aviators and ground officers developed largely opposing views on the importance of CAS, views that would frame institutional battles for CAS in the 20th century. The inter-war period also saw the use of CAS in a number of conflicts, principally Spain and China. Observers and participants from the major parties of World War II would base their CAS strategies on experience and observation from these conflicts.

Aviators, who wanted institutional independence from the Army, pushed for a view of airpower centered around interdiction, which would relieve them of the necessity of integrating with ground forces and allow them to operate as an independent military arm. They saw close air support as both the most difficult and most inefficient use of aerial assets. Close air support was the most difficult mission, requiring identifying and distinguishing between friendly and hostile units. AT the same time, targets engaged in combat are dispersed and concealed, reducing the effectiveness of air attacks. They also argued that the CAS mission merely duplicated the abilities of artillery, whereas interdiction provided a unique capability.

Ground officers contended that there was rarely sufficient artillery available, and the flexibility of aircraft would be ideal for massing firepower at critical points, while producing a greater psychological effect on friendly and hostile forces alike. Moreover, unlike massive, indescriminate artillery strikes, small aerial bombs wouldn't render ground untrafficable, slowing attacking friendly forces.

WWII

World War II marked the universal acceptance of the integration of air power into combined arms warfare as close air support. Though the German Luftwaffe lead the way, all the major parties had developed effective air-ground coordination techniques by the war's end.

Western Front

=Luftwaffe

= As a continental power, Germany was unable to ignore the need for aerial support of ground operations. Though the Luftwaffe, like its counterparts, focused on strategic bombing, they were unique in their willingness to commit forces to CAS. In joint exercises with the Swedes in 1934, the Germans were first exposed to dive-bombing, which permitted greater accuracy while making them harder to track by antiaircraft gunners. As a result, Ernst Udet, chief of the Luftwaffe's development, initiated procurement of close support dive-bombers on the model of the U.S. Navy's Curtiss Helldiver, resulting in the famous JU-87 Stuka. Experience in the Spanish Civil War lead to the creation of five ground-attack groups in 1938, four of which would be equipped with Stukas. The Luftwaffe matched its material acquisitions with advances in the air-ground coordination. General Wolfram von Richthofen organized a limited number of air liaison detachments that were attached to ground units of the main effort. These detachments existed to pass requests from the ground to the Luftwaffe, and receive reconnaissance reports, but they were not trained to guide aircraft onto targets.

These preparations did not prove fruitful in the invasion of Poland, where the Luftwaffe focused on interdiction and dedicated few assets to close air support. But the value of CAS was demonstrated at the crossing of the Meuse River. General Heinz Guderian, creator of the combined-arms doctrine commonly known as blitzkrieg, believed the best way to provide cover for the crossing would be a continuous stream of ground attack aircraft on French defenders. Though few guns were hit, the attacks kept the French under cover and prevented them from manning their guns. Aided by the sirens attached to Stukas, the psychological impact was greatly disproportional to the destructive power of close air support. In addition, the reliance on air support over artillery reduced the demand for logistical support through the Ardennes. Though there were difficulties in coordinating air support with the rapid advance, the Germans demonstrated consistently superior CAS tactics to those of the British and French defenders. Later, on the Eastern front, the Germans would devise visual ground signals to mark friendly units and to indicate direction and distance to enemy emplacements.

Despite these accomplishments, German CAS was not perfect and suffered from the same interservice misunderstanding and rivalry that plagued other nation's air arms, and friendly fire was not uncommon. On the eve of the Meuse offensive, Guderian's superior cancelled his CAS plans and called for high-altitude strikes from medium bombers, which would have required halting the offensive until the air strike was complete. Fortunately for the Germans, his order was issued too late to be implemented, and the Luftwaffe commander followed the schedule that he had previously worked out with Guderian. As late as November 1941, the Luftwaffe refused to provide Erwin Rommel with an air liason officer for the Afrika Korps, because it "would be against the best use of the air force as a whole."

=Royal Air Force and U.S. Army Air Forces

The Americans and British entered the war woefully unprepared to provide CAS. In 1940, the RAF and army headquarters in France were located at separate positions, resulting in unreliable communications between the two. After the RAF was withdrawn in May, Army officers had to telephone the War Office in London to arrange for air support. The stunning effectiveness of German air-ground coordination spurred change. On the basis of tests in Northern Ireland in August 1940, RAF Group Captain A. H. Wann and Army Colonel J.D. Woodall issued the Wann-Woodall Report, that recommended the creation of a distinct tactical air force and liasons (known coloquially as tentacles), to accompany Army divisions and brigades. Their report spurred the RAF to create an Army Co-Operation Command develop tentacle equipment and procedures to place an Air Liason Officer with each brigade.

Operating with the principal mission of strategic bombing, the U.S. Army Air Forces (AAF) operated independently of the rest of the Army. AAF doctrine's priorities for tactical aviation were, in order, air superiority, isolation of the battlefield via supply interdiction, and thirdly, close air support. However, in 1941, in response to the success of the Stuka, AAF commander Lt. Gen. Henry (Hap) Arnold acquired 2 groups of A-24 dive bombers, the army version of the Navy's SPD-2. Later, the AAF would modify the P-51 with dive brakes into the A-36. However, there was no training to match the purchases. Though Gen. Lesley McNair, commander of Army Ground Forces, pushed to change AAF priorities, the latter failed to provide aircraft for even manjr training exercises. Six months before the invasion of Normandy, 33 divisions had received no joint air-ground training. In 1943, the AAF changed their radios to a frequency incompatible with ground radios.

As a result, CAS would be poorly executed, if at all, by the AAF in the North African campaign. So few aerial assets were assigned to U.S. troops that they fired on anything in the air. While the RAF sorted out its CAS doctrine in London, officers in North Africa improvised their own coordination techniques. In October 1941, Sir Arthur Tedder and Arthur Coningham, senior RAF commanders in North Africa, created joint RAF-Army Air Support Control staffs at each corps and armored division headquarters, and placed a Forward Air Support Link at each brigade to forward air support requests. When trained tentacle teams arrived in 1942, they cut response time on support requests to thirty minutes.. It was also in the North Africa desert that the cab rank strategy was developed.

The situation would improve during the Italian campaign, where American and British forces, working in close cooperation, exchanged CAS techniques and ideas. There, the AAF's XII Air Support Command and the Fifth U.S. Army shared headquarters, meeting every evening to plan strikes and devising a network of liasons and radios for communications. However, friendly fire continued to be a concern - pilots did not not know recognition signals and regularly bombed friendly units, until an A-36 was shot down in self-defense by Allied tanks. Friendly fire from the ground prompted the black and white stripes painted on all Allied aircraft after 1944.

The AAF would see the greatest innovations in 1944 under Gen. Elwood A. Quesada, commander of IX Tacical Air Command, supporting the First U.S. Army. He developed the "armored column cover", where on-call fighter-bombers maintained a high-level of availability for important tank advances, allowing armor units to maintain a high tempo of exploitation even when they outran their artillery assets. He also used a modified antiaircraft radar to track friendly attack aircraft to redirct them as necessary, and experimented with assigning fighter pilots to tours as foward air controllers to familiarize them with the ground perspective. In July 1944, Quesada provided VHF aircraft radios to tank crews in Normandy. When the armored units broke out of the Normany beachhead, tank commanders were able to communicate directly with overhead fighter-bombers. However, despite the innovation, Quesada focused his aircraft on CAS only for major offensives. Typically, both British and American attack aircraft were tasked primarily to interdiction, even though later analysis showed them to be twice as dangerous as CAS.

Eastern Front

The Red Air Force was not slow to recognize the value of ground support aircraft. Even as far back as the Nomonhan incident, Russian aircraft were tasked with disrupting enemy ground operations. This use increased markedly after the German invasion. Purpose-built aircraft such as the Ilyushin Il-2 Sturmovik were highly effective in blunting the activity of the Panzers.

German CAS reached its peak on the Eastern Front during the period 1941-1943. Their decline was caused by the growing strength of the Red Air Force and the redeployment of assets to defend against American and British strategic bombardment. The introduction of improved Soviet tanks, the T-34 and KV-1 reduced the effectiveness of close air support, even after the adoption of 30mm cannon and shaped-charge bombs. While German procedures for CAS lead the way, their loss of air superiority and technological advantage, combined with a declining supply of aircraft and fuel, crippled their ability to provide CAS after 1943.

The Pacific Theater

The Navy and Marine Corps would similarly adopt CAS as a substitute the lack of available artillery or naval gunfire.

Korean War

From Navy experiments with the V-1|KGW-1 Loon, the Navy designation for the German V-1 remotely guided missile, Marine Captain Marian Cranford Dalby developed the AN-MPQ-14, a system that enabled radar-guided bomb release at night or in poor weather.

Though the Marine Corps continued its tradition of intimate air-ground cooperation, the newly created Air Force again moved away from CAS, now to strategic bombers and jet interceptors. Though eventually the Air Force supplied sufficient pilots and forward air controllers to provide battlefield support, coordination was still lacking. Since pilots operated under centralized control, ground controllers were never able to familiarize themselves with pilots, and requests were not procssed quickly. Harold K. Johnson, then commander of 8th Cavalry Regiment, 1st Cavalry Division(later Army Chief of Staff) commented regarding CAS: "If you want it, you can't get it. If you can get it, it can't find you. If it can find you, it can't identify the target. If it can identify the target, it can't hit it. But if it does hit the target, it doesn't do a a great deal of damage anyway." p.577

It's unsuprising, then, that MacArthur excluded USAF aircraft from the airspace over the Inchon Landing in September 1950, instead relying on Marine Aircraft Group 33 for CAS. In December 1951, Lt. Gen. James Van Fleet, commander of the Eighth U.S. Army, formally requested the U.N. commander, Gen. Mark Clark, to permanently attach an attack squadron to each of the four army corps in Korea. Though the request was denied, Clark allocated much more Navy and Air Force aircraft to CAS. Despite the rocky start, the USAF would also work to improve its coordination efforts. It eventually required pilots to serve 80 days as forward air controllers (FACs), which gave them an understanding of the difficulties from the ground perspective and helped cooperation when they returned to the cockpit. The USAF also provided airborne FAC's in critical locations. The Army also learned to assist, by suppressing anti-aircraft fire prior to air strikes.

The U.S. Army wanted a dedicated U.S.A.F. presence on the battlefield to reduce fratricide, or the harm of friendly forces. The Air liaison officer or ALO was born. The ALO is an aeronautically rated officer that spent a tour away from the cockpit, serving as the primary advisor to the ground commander on the capabilities and limitations of airpower.

Introduction of Helicopters

The 1960's and 70's saw the adoption of attack helicopters in the CAS role. Though helicopters were initially armed merely as defensive measures to support the landing and extraction of troops, their value in this role lead to the modification of early helicopters as dedicated gunship platforms. Though not as fast as fixed-wing aircraft and consequently more vulnerable to anti-aircraft weaponry, helicopters could utilize terrain for cover, and more importantly, had much greater battlefield persistence owing to their low speeds. The latter made them a nautral complement to ground forces in the CAS role. In addition, newly-developed Anti-tank guided missiles, demonstrated to great effectiveness in the 1973 Yom Kippur War, provided aircraft with an effective ranged anti-tank weapon. These considerations motivated armies to promote the helicopter from a support role to a combat arm. Though the U.S. Army controlled rotary-wing assets, coordination continued to pose a problem. During wargames, field commanders tended to hold attack helicopters out of fear of air defenses, committing them too late to effectively support ground units. The earlier debate over control over CAS assets were reiterated between ground commanders and aviators.

In the mid 1970's, after Vietnam, the USAF decided to train an enlisted force to handle many of the tasks the ALO was saturated with, to include terminal attack control. Now the ALO mainly serves in the liaison role, the intricate details of mission planning and attack guidance left to the enlisted members of the Tactical Air Control Party.

The air contingent of the United States Marine Corps also specializes in close air support, using primarily the AV-8B Harrier V/STOL fighter, the F/A-18 C and D, and the AH-1 Cobra gunship in this role.

Aircraft

Various aircraft can fill close air support roles. Helicopters are often used for close air support and are so closely integrated with ground operations that in most countries they are operated by the army rather than the air force. Fighters and ground attack aircraft like the A-10 Thunderbolt II provide close air support using rockets, missiles, small bombs, and strafing runs.

In World War II, dive bombers and fighters were used in close air support. Dive bombing permitted greater accuracy than level bombing runs, while the rapid altitude change made it more difficult for antiaircraft gunners to track. The Junkers Ju 87 is the best known example of an dive bomber designed for CAS. It was fitted with wind-blown whistles on its landing gear to enhance its psychological effect.

Other than the A-36, a P-51 modified with dive brakes, the Americans and British used no dedicated CAS aircraft in WWII, preferring fighters or fighter-bombers that could be pressed into CAS service. While some such as the P-47 Thunderbolt, performed admirably in that role, there were a number of compromises that prevented most fighters from making effective CAS platforms. Fighters were usually optimized for high-altitude operations without bombs or other external ordnance - flying at low level with bombs quickly expended fuel. Cannons had to be mounted differently for strafing - strafing required a further and lower convergence point than aerial combat did.

Today, close support is typically carried out by fighter-bombers or dedicated ground attack aircraft, but even large high-altitude bombers can occasionally fill close support roles thanks to precision guided munitions.

In the Vietnam War, the United States introduced fixed-wing gunships, cargo aircraft refitted as gun platforms to serve as close air support and air interdiction aircraft. The first of these was the AC-47 Spooky. Later models include the AC-119 and the AC-130.

References

External links

DOD dictionary definition of close air support
The Forward Air Controller Association
The ROMAD Locator The home of the current ground FAC

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