At 7:30 p.m. on Dec. 18, 1972, Hanoi time, U.S. Air Force F-111 Aardvark attack aircraft initiated Operation Linebacker II by striking six North Vietnamese airfields. One minute later, EB-66 Destroyer electronic warfare planes started to jam enemy radars, and F-4 Phantom II fighter-bombers began laying corridors of small metal strips of chaff to confuse enemy radar and protect the first wave of B-52 Stratofortress bombers approaching Hanoi and Haiphong.
Completely surprised and blinded, Hanoi’s Air Defense Command aimed its anti-aircraft artillery fire along the routes and altitudes used by B-52s during the Linebacker I bombings of May-October 1972, conducted in response to the North’s massive ground offensive started during Easter weekend. Surface-to-air missile sites launched Soviet SA-2 Guideline SAMs based on the Linebacker I pattern, only to come under attack from F-105G Thunderchief fighters-bombers code-named “Wild Weasels,” carrying missiles that homed in on the SAM sites.
The North Vietnamese launched MiG fighters toward the points where they had intercepted Linebacker I planes. Meanwhile, U.S. Marine Corps aircraft protected Air Force KC-135 Stratotanker aerial refueling planes while the U.S. Navy’s Task Force 77 struck coastal targets. The Vietnam War’s final bombing campaign had begun. Unlike earlier bombing operations, Linebacker II, Dec. 18-29, was a maximum effort to cripple if not destroy North Vietnam’s capacity to continue the war in the South.
Hanoi’s intelligence services had known since Dec. 16 that a major air operation was imminent but assumed the targets would be south of the 20th parallel, sparing Hanoi and the surrounding area, including the big port at Haiphong. After bombing the Hanoi area in Linebacker I, the U.S. had shifted its bombing strikes to targets below the 20th Parallel and interdiction missions to disrupt supply movements.
If the big bombers should come farther north, Hanoi’s leaders believed they were prepared. A study of B-52 Stratofortress operations indicated that the bombers tended to abort their missions when they knew they had been detected by the Fan Song SAM fire-control radar that tracked and targeted enemy aircraft.
With that in mind, the defenders moved two SAM and two MiG fighter regiments to cover central and southern
