Aerial Rocket Artillery Aerial rocket artillery ( abbreviated ARA , also called aerial artillery ) is a type of armed helicopter unit that was part of the artillery component of the United States Army ' s two airmobile divisions during the Vietnam War . Controlled by division artillery and not the aviation group , the 2nd Battalion , 20th Artillery , 1st Cavalry Division and the 4th Battalion , 77th Artillery , 101st Airborne Division , along with Battery F , 79th Artillery , 1st Cavalry Division , were the only ARA units fielded during that conflict . The ARA concept disappeared from Army aviation by the mid - 1970s , replaced with more generic attack aviation units . Beginnings . After the helicopter demonstrated its battlefield effectiveness in the Korean War , the United States Army began experimenting with expanded roles and missions for them . In 1963 , the 11th Air Assault Division was activated to test the concept of air mobility as developed and advocated by the Howze Board . Because the 155mm howitzer s then assigned to Army divisions as medium support artillery were not transportable by helicopters , ARA was developed as a substitute . The original test unit for aerial rocket helicopters within the 11th Air Assault Division was the 2nd Battalion , 42nd Artillery ( later designated the 3rd Battalion , 377th Artillery ) . When the 11th Air Assault was redesignated as the 1st Cavalry Division and sent to Vietnam , the 3 / 377th became the 2nd Battalion , 20th Artillery ( using the radio call sign " Blue Max " ) . This was the first unit designated and organized as ARA to take part in combat operations . The 4 / 77th Artillery joined the 101st Airborne Division in 1969 when the 101st was converted to an airmobile division , becoming the second active ARA battalion . Battery F , 79th Artillery , was formed to serve with the separate 3d Brigade of the 1st Cavalry Division when the rest of the division was withdrawn from Vietnam . It was the final ARA unit to see combat service . Organization and equipment . While there are current U . S . Army aviation units with an attack mission ( such as the combat aviation brigade ) , ARA was unique because it was controlled by division artillery and not the aviation group ( or an aviation brigade to use 2012 U . S . Army terminology ) . This allowed the artillery commander ( usually a colonel ) to coordinate ARA activities with other fire support missions ( howitzers , air strikes , and so on ) . ARA was not the only location for attack helicopters within the Vietnam - era airmobile division ( both the air cavalry units and standard lift battalions had attack aviation as part of their organization ; with 12 gunships in Company D of each lift battalion and attack helicopters in each air cavalry troop ) , but it was the most concentrated and centralized element of attack aviation . Each ARA battalion consisted of one H & HB ( Headquarters & Headquarters Battery ) and three firing batteries ( Alpha , Bravo and Charlie ) . A firing battery was equipped with 12 attack helicopters . Initially the units were supplied with Bell UH - 1B and UH - 1C model helicopters , but these were replaced with the newer AH - 1G Cobras as they became available . According to one historian ' s authoritative account of the First Cavalry Division ' s actions in Vietnam , the conversion to Cobras gave the 1 / 20th ARA " the firepower equivalent to three conventional artillery batteries . " The primary weapon of the ARA units was the 2 . 75 " Folding Fin Aerial Rocket ( FFAR ) . While the B and C model UH - 1s could carry up to 48 of these rockets in two racks of 24 each ( XM - 3 subsystem ) , the faster , more powerful Cobras could carry 76 . In addition to the rockets , the UH - 1s carried two M60 machine gun s mounted in the cargo doors as defensive weapons operated by the aircraft ' s crew chief and a door gunner , while the Cobras were armed with 7 . 62mm minigun s and 40mm grenade launchers in a nose turret . Some UH - 1s were also armed with the AGM - 22 / SS - 11 wire guided missile . Missions . An ARA battery could perform any type of fire support mission conducted by conventional artillery , but with a much greater range ( limited only by a helicopter ' s combat radius ) than tube artillery . These missions included support of ground troops , landing zone ( LZ ) preps , interdiction , and counter - battery fire . In addition to normal artillery missions , the helicopters were also employed as escorts for medevac and re - supply helicopters . They also were teamed with light observation helicopters to perform reconnaissance missions , although this mission was more commonly performed by the airmobile division ' s air cavalry squadron . Like all aircraft , ARA units had difficulty performing missions during bad weather or at night ( although this was less of a consideration for the more advanced AH - 1G ) . Tube artillery could fire under any conditions ( bad weather , day , or night ) , and the 1st Cavalry Division ended up having a 155mm howitzer battery ( 1st Battalion , 30th Artillery ) attached to the division in Vietnam to provide medium artillery support in situations when ARA might not be able to fly . The 1st Cavalry Division locally designed and produced slings , allowing the 155mm guns to be moved by their heavy CH - 54 " Flying Crane " helicopters . When the 101st Airborne Division converted to an airmobile unit , the 2nd Battalion , 11th Artillery ( 155mm ) was similarly attached . Notable achievements . ARA participated in both the first and last major battles in Vietnam for US ground troops . UH - 1B gunships from the 2 / 20th provided critical fire support during the Pleiku campaign in 1965 , demonstrating the validity of the ARA concept in combat . In 1970 the 4 / 77th provided fire support for ARVN units involved in the invasion of Laos ( Operation Lam Son 719 ) . At the battle of An Loc , on April 13 , 1972 , an AH - 1G from Battery F , 79th Artillery became the first helicopter in history to engage and destroy an enemy tank , thus helping to secure the helicopter ’ s place on the modern battlefield . Perhaps the greatest lasting accomplishment of ARA was to fully validate the concept of helicopter gunships . Evolving from test units , ARA gunships ( along with those assigned to lift companies and air cavalry troops ) provided a source of supporting fire in Vietnam known for its " flexibility , accuracy , and immediate response " to any combat situation within range . The AH - 1G Cobra was a direct result of the successes of the early armed UH - 1Bs and UH - 1Cs and remained in service after the last ARA battery was decommissioned . Further development . In 1970 the designation ARA was changed to AFA ( Aerial Field Artillery ) . As the Army began reorganizing for new missions , many Vietnam - era units and missions changed shape . The 1st Cavalry Division became a test division for the TRICAP concept ( a division that could perform armor , airmobile , and air cavalry missions simultaneously ) , and later shifted to an armored division . The 101st Airborne Division retained an airmobile ( later air assault ) role , but during the various reorganizations of the 1970s its AFA / ARA battalion disappeared . With attack aviation folded into the various aviation groups and brigades , ARA ceased to be a core artillery mission .