Archie to SAM: A Short Operational History of Ground-Based Air ...

AIRMEN VERSUS GUERRILLAS
to hostile fire. The Airmen began long-range aid to navigation
(LORAN) bombing in 1970, which made it possible to operate in
the worst weather conditions and still get bombs within hundreds
of meters of the aiming point. 35 Although this was not precision
bombing, it did permit bombing during bad weather.
The most important new equipment introduced was guided
munitions (smart bombs), which could get bombs within meters
of the target. A number of bridges that had withstood numerous
and costly American strikes quickly fell to these new
weapons. For example, on 13 May 1972, four flights of F-4s attacked
the formidable Thanh Hoa Bridge with guided bombs,
dropping its western span and causing other critical damage.
There were no US losses in the attack, whereas the previous
871 sorties had cost 11 aircraft and had not neutralized the
bridge. The Airmen considered the guided bombs to be 100
times more effective than unguided weapons against bridges
and 100–200 times more effective against such hard targets as
bunkers. 36 Greater accuracy meant fewer aircraft at risk and,
thus, fewer losses.
The Americans also employed new ECM and anti-SAM tactics
to combat the formidable Communist defenses. They introduced
a new electronic jamming platform when in July 1972 US
Marines thrust the EA-6B into action (fig. 63). Against North
Vietnamese electronics, the Airmen employed more chaff, a
World War II device that still worked. Chaff had seldom been
used because the Navy feared its impact on their shipborne
radar, and the US Air Force lacked a suitable dispenser. In
June 1972, American Airmen introduced the ALE-38 chaff dispenser
and, in August, chaff bombs. Both devices greatly enhanced
US ECM capabilities and reduced the vulnerability of
chaff-dispensing aircraft. The Airmen created chaff corridors
within which attackers were almost immune from North Vietnamese
radar-guided SAMs and AAA. Seventh Air Force commander
Gen William W. Momyer noted that only one of seven
losses to SAMs during Linebacker I occurred in a chaff corridor.
One author called the use of chaff corridors “the most significant
tactical change instituted by the Air Force for its 1972
bombing campaign.” 37 In August, the US Air Force also changed
its anti-SAM tactics (Wild Weasel) from Iron Hand—four F-105s
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