Forward air controllers in the Vietnam War Forward air control is the provision of guidance to Close Air Support ( CAS ) aircraft intended to ensure that their attack hits the intended target and does not injure friendly troops . This task is carried out by a forward air controller ( FAC ) . The rugged jungle terrain of South East Asia readily hid enemy troop movements . U . S . fighter - bombers were so fast that pilots had great difficulty in distinguishing between enemy troops , friendly troops , and civilians . Forward air controllers directing air strikes thus became essential in usage of air power . Visual reconnaissance formed the core FAC mission during the Vietnam War , as the FAC flew light aircraft slowly over the rough terrain at low altitude to maintain constant aerial surveillance . By patrolling the same area constantly , the FACs grew very familiar with the terrain , and they learned to detect any changes that could indicate enemy forces hiding below . Tracks on the ground , misplaced vegetable patches , an absence of water buffalo , smoke from cooking fires in the jungle , too many farmers working the fields — all could indicate enemy troops in a vicinity . Flying low and slow over enemy forces was very dangerous ; however the enemy usually held his fire to avoid discovery . Each of the O - 1 FAC aircraft originally used carried three different radios for coordinating with everyone involved in an air strike : an FM radio for the ground forces , a UHF radio for the fighter aircraft , and a VHF radio for contact with the Air Force Tactical Air Control Party to coordinate approvals and requests for air support . The FAC radioed for strike aircraft after spotting the enemy . He marked the target with smoke grenades or white - phosphorus rockets to pinpoint targets . After directing the fighter - bombers ' attacks , the FAC would fly low over the target to assess the damage . Forward air control advisors in Vietnam . In 1961 , the USAF sent five FACs to Bien Hoa Air Base to train the Vietnam Air Force in directing air strikes from O - 1 Bird Dog s . The USAF FACs were fighter pilots with expertise in delivering air - to - ground ordnance . American and South Vietnamese FACs began to fly combat missions together , but only the Vietnamese could control air strikes by delivering ordnance . Also , all air strikes required the approval of the South Vietnamese government . In December , 1961 , the Tactical Air Control System was set up as part of Operation Farm Gate to handle air offensive operations , including airborne forward air control . On 8 February 1962 , the Air Operations Center for Vietnam was set up at Tan Son Nhut on the outskirts of Saigon ; it would be the command and control network for forward air control . On 15 April 1962 , two FAC O - 1s from Marine Observation Squadron 2 were with the first U . S . Marine Corps troops to enter Vietnam . They would fly along with the Air Force . In early 1962 , American ground FACs began to supply on - the - job training to South Vietnamese counterparts in Tactical Air Control Parties , in an effort to improve poor performance by the local FACs . However , rough terrain , limited sight lines , and difficulty in communication plagued ground FAC efforts in Southeast Asia . Also in 1962 , the communists began to attack convoys moving supplies within South Vietnam . A program of shadowing truck convoys with FAC O - 1s began ; no escorted convoy was ambushed during early 1963 . As the war escalated , the VNAF needed more FACs . The USAF responded by activating the 19th Tactical Air Support Squadron at Bien Hoa in July 1963 to train South Vietnamese pilots in forward air control , visual reconnaissance , combat support , and observer procedures . After one year , the 19th TASS was to turn its O - 1s over to the VNAF , but the Tonkin Gulf incident in August 1964 changed everything . Forward air control expansion . After the Gulf of Tonkin incident , the United States began to add large numbers of ground and air forces in South Vietnam . As of January , 1965 , there were only 144 USAF airborne FACs , as well as 68 VNAF FACs ; yet the Rules of Engagement mandated a forward air controller direct all air ordnance used in South Vietnam . To direct close air support of the U . S . units , a rapid expansion of the forward air control effort was needed . By April 1966 , five Tactical Air Support Squadrons filled out the Air Force combat units of the 504th Tactical Air Support Group . The Group served mostly for logistics , maintenance , and administrative functions . It comprised only 250 O - 1 Bird Dog FACs for all South Vietnam . They were supposed to be assigned two per maneuver battalion . However , they were assigned to brigades and lived and worked with the battalions that needed them for operations . In the midst of the FAC buildup , in September 1965 , the first Airborne Command and Control Center was launched . ABCCC would become the inflight nerve center of the Vietnam air war . It not only kept track of all other aircraft , it served " to assure proper execution of the fragged missions and to act as , a central control agency in diversion of the strike force to secondary and lucrative targets . " ABCCC would expand into a twenty - four hour per day program directing all air activity in the war . In 1966 , the U . S . used FACs to increase its interdiction efforts into the southern portion of the Democratic Republic of Vietnam . FACs from the 20th TASS , flying O - 1s and later O - 2s , directed air strikes . They also adjusted gunfire from U . S . Navy ships if a U . S . Marine artillery spotter was flying with them . As part of this effort , the Marines pioneered Fast FACs in Vietnam , using two - seated F9F Panther jets in this area , as well on deep targets on the Ho Chi Minh Trail . By October , 1965 , the U . S . Air Force realized it had an insufficient number of FACs . Although the Rules of Engagement were changed to lessen the workload on the FAC force , the USAF continued short of trained Forward Air Controllers until the U . S . drawdown of troops lessened demand . One hundred percent manning of the FAC effort would finally come in December , 1969 . Marine Observation Squadron 2 came ashore in its entirety in May 1966 . Shortly thereafter , they would transition from the O - 1 to UH - 1E helicopters . June , 1966 saw the first Australian FAC join the 19th TASS . Before their assignments ended in December , 1971 , 36 Australians would have served with the USAF , with one of them , Flight Lieutenant Gerry Cooper , being recommended for the Medal of Honor by Major General Julian Ewell . Following the Australians ’ lead , New Zealand also placed 14 of its FACs under U . S . command over much the same time span . The U . S . Army also had aviation companies of O - 1 Bird Dogs operating in Vietnam ; at least seven of these companies directed air strikes upon occasion , in addition to their artillery direction duties . The U . S . Army had eight aviation companies of O - 1 Bird Dogs operating in Vietnam , but official doctrine limited them to what they had been trained for : visual reconnaissance and directing artillery . Nonetheless , despite only USAF FACs being authorized to direct air strikes , Army pilots did so when there was a pressing tactical requirement and Air Force FACs were not immediately available . The 220th Reconnaissance Airplane Company ‘ Catkillers ’ , under operation control of 3rd MARDIV in I Corps , was the only Army company officially authorized to direct air strikes . Due to the Marine pilots of VMO - 6 being overstretched by the intensity of combat operations in the DMZ , pilots of the 220th were , uniquely , given the Marine designation of Tactical Air Coordinator ( Airborne ) . As TACAs , they were formally approved to run air strikes in addition to directing artillery and Naval gunfire . By November , 1968 , a minimum of 736 FACs were deemed necessary ; however , only 612 were available . New tactics and equipment . Fast FACs . The communists ’ reaction to FAC efforts was to gradually improve their antiaircraft defenses . In addition to antiaircraft artillery , the communists deployed surface - to - air missiles southward . As they became available , communist troops also started using man - portable , shoulder - fired SA - 7 Grail missiles . The USAF had to change its tactics in turn . By 1967 , the threat from communist antiaircraft defenses made it too dangerous for propeller - driven FACs to support the interdiction campaign in the southern part of North Vietnam . Therefore , the Air Force ’ s response was the use of fast FACs . The F - 100 Super Sabre Fast FACS , call sign Misty , were armed with 20 mm cannon and two rocket launchers for marking targets and fast enough to survive in a high - threat area . In 1968 , the 8th Tactical Fighter Wing , based at Ubon Royal Thai Air Force Base , started using F - 4 Phantom II s , call sign Wolf , in the Fast FAC role , and other F - 4 units soon followed . A further refinement of the Fast FAC mission was the use of photo reconnaissance planes in conjunction with the Fast FAC . The photo plane performed visual reconnaissance for the FAC , as well as pre - and post - strike photography of targets , leading to an increase of strike control and the tripling of bomb damage assessment . FAC losses still ran high ; in the three years following July 1967 , 42 Fast FACs were shot down . The program was not cancelled because it was considered too valuable . The same was not true for night - time Fast FAC operations . Owl FACs using laser designators to guide 500 , 1 , 000 , and 2 , 000 pound bombs from fighter - bombers began flying missions on 18 October 1969 , but were cancelled in January , 1970 due to unacceptable losses . Search for better Slow FAC planes . The Air Force also looked for a better FAC aircraft . The O - 1 Bird Dog had many shortcomings . Its speed made it slow to arrive over target . It was vulnerable to enemy small arms fire . Its small size limited its payload . Its radio system was makeshift , with only one channel available at a time for any radio . Also , the Bird Dog lacked night flight instruments . An interim solution was the O - 2 Skymaster , an adaptation of the civilian Cessna 337 . With twin engines , the O - 2 had greater speed , could carry more equipment and ordnance , and had night instrumentation . Nevertheless , this aircraft also had limited capabilities . In 1968 , the Vietnam FACs received the first purpose - built forward air control aircraft . The OV - 10 Bronco was armored , was nearly twice as fast as the O - 1 , and carried its own onboard ordnance for attacking targets of opportunity . Performance wasn ’ t all . The Bronco had unparalleled visibility ; the pilot could lean outboard in the bubble canopy and see directly below the plane . There were self - sealing fuel tanks , all systems had a backup , and it had ejection seats . Most important of all were the radios . Instead of three radios , only one of which could be used at a given moment , the OV - 10 had eight radios , usable simultaneously , all with a scrambler system available to disguise messages . By 1968 , there were 668 Air Force FACs in country , scattered at 70 forward operating locations throughout South Vietnam . As a result , the communists largely ceased daytime activities in areas surveilled by FACs . This led to a shift to night FAC operations by O - 2s . Coordination of operations . Fast FACs and slow ones both found advantages in cooperation with one another . A slow FAC could flee AAA fire and call for a fast FAC to take over . A fast mover that couldn ' t make out sufficient details of a target could call for a slow FAC who could loiter and observe closely . U . S . Navy aviation , as late as December 1967 , was having difficulty flying missions in support of the navy ’ s riverine patrols in the Mekong Delta . A short loiter time to seek targets resulted in only one combat sortie that month . On 3 January 1969 , the U . S . Navy raised its own forward air control squadron , Light Attack Squadron 4 , using OV - 10 Broncos borrowed from the Marine Corps . VAL - 4 was stationed at Binh Thuy and Vung Tau , and would fly 21 , 000 combat sorties before its disbandment on 10 April 1972 . Those sorties would be a mix of light strike missions and forward air control . Forward air control in Laos . Beginning in 1959 , the communists began building a secret logistical road system through neutral Laos and Cambodia . The Truong Son Road — called by Americans the Ho Chi Minh Trail — consisted of a network of roads and hiding places concealed by the jungle . It would eventually develop into an intricate system of over 3 , 000 miles of interweaving roadways and trails . Associated with it were other roads running into northern Laos , to Sam Neua and through Dien Bien Phu across the border into Laos . Laotian neutrality prevented the overt use of American ground troops to block the Trail . However , the U . S . obtained permission from the Laotian government in 1964 to conduct aerial interdiction strikes along the trail . Stringent Rules of Engagement over Laos mandated the use of FACs . Since the U . S . could not legally send military personnel to Laos , the USAF initially used enlisted Combat Controllers garbed as civilians , with the call sign Butterfly , to direct air strikes from civilian aircraft flown by Air America . In 1965 , the air war over Laos expanded into two different operations . In 1966 , the USAF FACs began guiding air interdiction missions against the Truong Son Road from both east and west . Friendly forces were also supported . Another forward air control unit was created in 1966 for service in Laos , as a successor to the Butterfly program . Volunteer FACs in Vietnam with at least six months experience could join the Raven FACs . They were temporarily assigned to the 56th Special Operations Wing at Udorn Royal Thai Air Force Base , but operated within and throughout Laos in direct support of Laotian ground forces . Even as the Butterflies before them , these pilots carried no military identification and wore civilian clothing . They flew unmarked O - 1s , U - 17s , and T - 28 Trojans . They supported indigenous troops in Laos who opposed the North Vietnamese invaders , and they flew with " Backseaters " provided by local commanders . The Ravens ' unique situation was their authority to attack any target in Laos . The other FACs operating over Laos — Covey FACs from Da Nang and the Nail FACs from Nakhon Phanom — could only attack targets in their assigned areas . The FAC effort in Laos ended with the withdrawal of the last of the Ravens in September , 1973 . Operations in Cambodia . The communists stockpiled large amounts of military supplies in Cambodia that they had brought down the Ho Chi Minh Trail and up the Sihanouk Trail from the port of Kompong Son on the Gulf of Thailand . Also , they had attacked South Vietnam from sanctuaries in Cambodia . On 30 April 1970 , the U . S . and South Vietnam sent ground forces into Cambodia to destroy communist supplies and sanctuaries . Although American ground forces withdrew from Cambodia , the air interdiction campaign continued ; USAF FACs were there to support the effort . A detachment of the 19th TASS patrolled Cambodia in support of the Cambodian troops and used the call sign Rustic . To communicate with the Cambodian forces , the Rustics flew with French - speaking interpreters . The American FACs would covertly support the Cambodian non - communists by directing massive U . S . air strikes until 15 August 1973 . Legacy . During the Vietnam War , FACs participated in every major military action against the enemy except the strategic bombing campaign against North Vietnam . American fighter - bombers dropped over four times the weight of bombs dropped in all of World War II — nine and a half million tons . Laos became the most heavily bombed country in history . All fighter - bomber ordnance dropped in that nation was directed via forward air control . Much of the bombing in South Vietnam and Cambodia was also FACed ; so was the bombing in southern North Vietnam . A total of 338 USAF forward air controllers were lost in action . Moreover , the FACs in Southeast Asia also helped pioneer many of the weapons and tactics used today . Flying O - 2As equipped with flares and Starlight night vision scopes , they directed air power against the communists at night . Experimenting with laser designators , they helped lead the way toward today ' s laser - guided precision munitions , and the development of the Fast FACs led to the modern versions used effectively in the heavily defended skies over the Balkans and Southwest Asia . Nevertheless , the United States once again closed down Forward Air Control at the war ' s end .