On 23 August 1967, the North Vietnamese Air Force employed their newly devised tactic against a U.S. strike formation, while it was conducting raids against a rail yard.
After the U.S. strike formation had fallen into the ambush, MiG-17 pilots radioed their control center and requested to continue with their air patrol.
Initially the first MiG-17 flight fell behind the U.S. strike formation, so Tinh and his formation climbed with full afterburner and they immediately played their part in the attack, by attacking the F-105 formation with their cannons.
However, the MiG-21's transponders were detected by an orbiting EC-121 airborne early warning radar surveillance aircraft, and their positions were relayed to the F-4 fighters that were escorting the strike formation, but they did not respond.
Accordingly the F-4 Phantoms of the 8th TFW would fly in the same profile as an F-105 strike formation, by flying at the same time, altitudes, speed and routes.
Chieu and Coc then dived out from an overcast and swept down on 'Ford' flight and the strike formation; Chieu fired a missile at an F-105 and Coc fired an R-3S Atoll missile which successfully destroyed 'Ford 4' (66-0238, 8TFWTFW), piloted by Major Charles R. Tyler.
The climate and topography that make the region so ripe for viticulture also have created misty forests, petrified trees, striking rock formations and peaks with sweeping views of the vineyards.
VPAF fighter activity diminished to almost nothing for 10 weeks afterwards, thereby accomplishing the main goal of Operation Bolo: to eliminate or diminish the threat of MiGs to the strike formations.
To take advantage of the MiG-21's speed and small size, pilots flying the type were instructed to intercept targets only at high speed behind or above U.S. strike formations.
By 1967, the North Vietnamese Air Force had become more aggressive towards U.S. strike formations, and it indicated to U.S. commanders that it was the right time to launch a decoy operation.
