On April 19, 1967, Maj. Leo Thorsness (pilot) and Capt. Harold Johnson (EWO) led a Wild Weasel formation on a mission against the Xuan Mai army barracks about 30 miles southwest of Hanoi. After they silenced one SAM site and destroyed another, enemy anti-aircraft artillery (AAA) shot down the accompanying F-105F carrying Majs. Tom Madison and Tom Sterling. Now alone, Thorsness and Johnson remained behind to cover them and radio rescue forces. Johnson spotted a MiG-17, and Thorsness shot it down with 20mm fire.
Low on fuel, they sped off to a tanker to fill up. Returning to cover the rescue forces, Thorsness and Johnson engaged three MiG-17s, damaging one of them. Then Johnson spotted four MiGs coming up behind them, and Thorsness evaded the MiGs by speeding away at low altitude through nearby mountain passes. Despite being out of ammunition, Thorsness and Johnson yet again returned to draw the MiGs off the rescue forces, but fighter support arrived to take over. Unfortunately, in spite of their heroic efforts, the rescue had to be called off due to the overwhelming enemy defenses, and Madison and Sterling were captured.
