The B-52s: Operation Arc Light

B-52 bombing raids at the Battle of Ia Drang Valley in November 1965.

Taking off from bases on Guam, Thailand or Okinawa, Strategic Air Command B-52 bombers headed for targets in Vietnam to dump their huge bomb loads. During these strikes, they concentrated on areas where the most intense enemy presence had been indicated. These sorties were conducted as part of a campaign code-named Operation Arc Light.

During the presidency of Lyndon B. Johnson, fear of provoking China to enter the conflict led to a reversal of aerial roles. Tactical fighters and fighter-bombers flew strategic missions over North Vietnam, while B-52 strategic bombers were limited to ground-support missions over South Vietnam and aerial interdiction sorties over the Ho Chi Minh Trail in Laos. It was not until the Nixon administration's Linebacker I and Linebacker II operations that the strategic bombers were utilized as strategic assets.

The first Arc Light missions were flown from Andersen Air Force Base on Guam on June 18, 1965. In mid-1967, following the expansion of U-Tapao Royal Thai Navy Airfield on the Gulf of Thailand, it became a secondary base of operations. This relieved crowding in Guam and reduced the flight time to Vietnam. Later, some Arc Light missions began to fly from Kadena Air Base in Okinawa to support the increasing operational tempo, which peaked in 1968.

The B-52 Stratofortress in Vietnam

The B-52 is a swept-wing, eight-engined, long range bomber. It can refuel in flight and can carry virtually any weapon. Called BUFFs (for “Big Ugly Fat Fellow”) by crew members, they were originally designed in the 1950s for delivering a nuclear strike against the Soviet Union or the People’s Republic of China. Beginning in late 1965, some B-52s underwent "Big Belly" modifications increasing their bomb load to 60,000 pounds — ten times the capacity of the B-17 Flying Fortress strategic bomber that was used during World War II.

Arc Light missions from Guam were grueling nine hour round-trips. Once over their jungle target the bombers attacked in "arrowhead" formations of three planes each, to maximize destruction in a mile by half-mile area. This was called saturation bombing, or "carpet bombing". When the bomb release-point was reached, each B-52 Stratofortress dropped some 30 tons of explosives on targets more than 30,000 feet below.

Down in the jungle, one could neither see nor hear them coming, due to their lofty elevation. All of a sudden, the ground would erupt in a 30 second earthquake and the terrain was transformed into a "carpet" of destruction.

The B-52s inflicted massive punishment when the enemy could be found, but dense jungle cover and highly mobile Viet Cong forces made targeting difficult. The location of guerrilla units needed to be accurately pinpointed, while the long Arc Light reaction time to reports of enemy concentrations frustrated mission planners. The presence of Viet Cong spies within South Vietnamese army units compounded these challenges.

Close Air Support at the Siege of Khe Sanh

One of the most significant Arc Light operations occurred during the North Vietnamese siege of the Marine combat base at Khe Sanh, which began late in January of 1968. In a Seventh Air Force campaign called Operation Niagara, B-52s flew more than 2,700 sorties and dropped close to 76,00 tons of bombs. An unbroken stream of three to six aircraft was kept aloft, striking enemy targets every three hours. Cells consisting of three BUFFs would arrive over a predesignated interception point, where they would be picked up by Combat Skyspot ground radar stations and directed to specific targets. With this flexible system, targets could be switched up to two hours prior to arrival, and the B-52s could bomb the enemy virtually around the clock.

Initially, enemy staging areas, storage sites, and artillery positions at least 3,300 yards beyond the Marine defenders' outer perimeter were hit. As the campaign progressed, U.S. reconnaissance units discovered a North Vietnamese bunker complex inside the Marine buffer zone. Beginning in late February, B-52s and other U.S. aircraft began to conduct airstrikes within one-sixth of a mile from outer defensive lines. The BUFFs proved their accuracy: Over 589 close-in sorties, no damage was reported to American personnel or facilities.

In a post-battle assessment, MACV Commander William Westmoreland observed The thing that broke their back basically was the fire of the B-52s. A captured North Vietnamese officer estimated that 75 percent of his 1,800-man regiment had been killed by a single Arc Light strike.

What Was Combat Skyspot?

Arc Light “quick run” operations began on July 1, 1966, when six B-52s from Guam and six KC-135 refueling tankers from Kadena Air Base in Japan initiated a modified alert system, which reduced time from notification to time over target to nine hours. The new alert system enabled commanders in the field to concentrate bombing with the support of Combat Skyspot, a ground-directed-bombing system employing Strategic Air Command mobile ground radar units.

This rapid-response targeting system increased targeting latitude, as the selection of targets was no longer dependent on identifying a nearby prominent geographical feature. B-52s could be guided to targets so long as they were within range of a Combat Skyspot radar station, and bombing accuracy was upgraded. The system was integrated into the Tactical Air-Control System, by means of which the Air Force coordinated operations with the other services. Command guidance was provided for tactical fighter-bombers as well as B-52s, enabling the bombing of strategic targets, close air support of ground troops and aerial interdiction at night and in poor weather conditions.

Frequently, the bombers were launched to a predetermined point, where they received directions to the highest priority target from the Skyspot controller. Following a voice countdown by radio, "hack" was announced and the payload was released. The combination of Combat Skyspot and B-52s subjected enemy forces, supply areas and lines of communication to a constant threat of destruction.