Exasperated by the North Vietnamese reluctance to negotiate a peace treaty, President Nixon ordered an all-out bombing campaign of limited duration to commence on the night of 18th December 1972.  Although originally only planned to last for three days, the campaign eventually lasted 11 days and extended over the Christmas break.  The campaign, named Linebacker II, saw the use of B-52s over Hanoi and Haiphong for the first time during the war in a truly strategic air campaign.  In February 1972 B-52 reinforcements started arriving at both Andersen and U-Tapao under the code name Operation Bullet Shot and these deployments accelerated after the Easter Invasion.  By the beginning of December a total of 206 B-52s were available for operations by the Eighth Air Force in Southeast Asia, more than half of SAC’s entire inventory of the type.  Andersen AFB on Guam had 99 B-52Gs and 53 B-52Ds while U-Tapao in Thailand had a further 54 B-52Ds.  The Andersen aircraft had to fly a 6,000-mile round trip lasting 14 hours and some missions had to route further north to meet their tankers from Kadena resulting in a 8,200 mile, 18-hour round trip.  The length of the missions had a major impact on the planning process particularly with regard to the time required to make modifications to tactics, targets and routings.  This lack of flexibility was to cost the B-52 force dearly in the early days of the campaign.  SAC’s KC-135 tanker force in Southeast Asia, which totalled some 172 aircraft by mid-1972, made Linebacker II possible and throughout the campaign the tankers flew a total of 1,312 sorties involving 4,593 refuellings.  Two different models of the B-52 were used, the B-52D that had been performing Arc Light missions for many years and the newer B-52G.  Although a more recent model with a better performance the B-52G did not have such a sophisticated ECM fit as the D models.  A modification programme was under way to improve the B-52G’s ECM equipment but many of the aircraft deployed to Andersen had yet to be modified and SAC felt what turned out to be justifiable concern for the survivability of the B-52G in combat over North Vietnam.  Also the B-52G was not fitted with external bomb racks nor had it had the Big Belly bomb bay conversions that the B-52D had and so could carry only 27 bombs whereas the B-52D could carry a staggering total of 108 x 500lb bombs.  In practice while the U-Tapao aircraft did indeed carry 108 bombs, the Andersen-based aircraft normally only carried 66 as these aircraft had a much greater distance to travel on each mission.

The B-52s did not operate in total isolation.  As well as tanker support, the whole range of USAF and US Navy tactical air power was employed, much of it in an effort to support the B-52 raids that were hoped would break North Vietnamese resistance and force them to the negotiating table.  Tactical aircraft including USAF and Navy F-4s and A-7s during the day and A-6s and F-111s during the night concentrated on enemy defences including airfields, AAA and SAM sites, assisted by F-105G Wild Weasels and Navy Iron Hand aircraft.  Electronic warfare support was provided by EB-66s, EA-3s and EA-6As and the new EA-6B Prowlers for stand off jamming, while chaff was dropped by flights of F-4s to obscure enemy radar screens.  Other F-4s flew MiGCAP missions during the raids while command and control was provided, as it had been for much of the war, by EC-121s orbiting over Laos and the Gulf of Tonkin and by Red Crown, a Navy ship sailing in the northern part of the Gulf.  Added to this armada was the ever-present SAR task force of HC-130s, HH-53s, and the new Sandys, the A-7s.  Each B-52 raid was supported by as many as 120 tactical aircraft, all requiring the most detailed and precise planning to ensure that the various components acted as a whole.  However, no matter how many precautions or preparations could be taken beforehand, the viability of the B-52 force over Hanoi and Haiphong was still very much an unknown quantity.  In the final analysis, SAC’s reputation, indeed the reputation of US air power as a whole, depended largely on the men and machines that flew the Linebacker II missions.