At the beginning of the Battle of Pusan Perimeter, the night of September 4, North Korean troops established a bridgehead across the Naktong River and were using it to advance across the river and attack Taegu, where the UN's Eighth United States Army was headquartered in defense of the perimeter. On September 5, a T-6 Mosquito forward air controller spotted a North Korea column advancing through the village of Hamchang-eup. Sebille was ordered to lead a flight of three P-51's on an airstrike against the North Korean troops advancing there. Sebille flew a P-51 (tail number 44-74394) loaded with two bombs, six rockets, and six M2 Browning .50 caliber machine guns. He and his wingmen, Captain Martin Johnson and Lieutenant Charles Morehouse, approached the village at an altitude of and spotted a North Korean armored column crossing the river in a shallow area. Sebille positioned himself for a medium-angle dive bomb run, planning to drop both of his bombs on his first attack. Diving, he held steady until about . When he spotted a target column of trucks, artillery guns and armored cars, led by a North Korean Armored Personnel Carrier, he hit the bomb release button on his control stick, and then made a sharp pull-up to the left to stay away from his bomb blast. However, only one of his bombs had released, and the of unbalanced weight under his left wing may have contributed to his near miss on the first run.