One of the most famous missions of the Vietnam air war was the Carrier Air Wing Nine (CVW-9) Alpha Strike on the Bai Duong railway yards on 10 May 1972. Because of actions earlier in the day, a strong North Vietnamese defence comprising SAMs, AAA and MiGs was expected. The dual mission of Iron Hand/ RESCAP for this strike was assigned to Lt Cdr Tom Gravley and Lt Norm Birzer. Iron Hand was the suppression of enemy fire-control radiation, the latter being crucial for the accurate guiding of surface-to-air missiles. For this mission, each A-7E Corsair II was loaded with two AGM-45 Shrike anti-radiation missiles. While this was the same mission performed by the well-known US Air Force ‘Wild Weasels’ with dedicated crews and aircraft, all Navy attack aircraft and pilots were equipped and trained to perform this function on a routine basis. The secondary mission of RESCAP, which stood for Rescue Combat Air Patrol, involved the coordination of the rescue of downed airmen.
The offensive armament for this mission included 6 CBUs (cluster bomb units) and 1000 rounds of HE (high explosive) 20mm ammunition. Because of the extreme effectiveness of the Shrike missile, enemy SAM crews typically countered by manually firing the SA-2s toward an incoming flight and delaying radar guidance signals until it was too late to fire a Shrike. As the Weapons Training Officer for VA-147, Lt Birzer developed a counter-counter tactic that he employed on this mission.
Taking advantage of the Corsair II’s inertial-based weapons delivery system, he initiated an attack from 22 miles out on the SAM site near Haiphong that intelligence reports indicated was most likely to fire upon the strike group. Pitching up steeply to launch the Shrike, Birzer had calculated that he would position the missile to descend vertically on the SAM site, with its search aperture at maximum, just at the moment guidance signals would likely be sent, causing the Shrike to home in within a few seconds on the SAM control vans. Lt Cdr Gravley launched a similar pre-emptive Shrike toward his target site near Hanoi.
The strategy seemed to work, because 15-20 SAMs were launched and no guidance radiation signals were detected. Two strike aircraft were lost and a third badly damaged, but none due to guided SAMs.