Believing it was useless to continue arguing with Cao, Vann climbed back into his L-19 reconnaissance aircraft and left Tan Hiep. Throughout the afternoon, he continued to press Cao to quickly deploy the South Vietnamese paratroopers. He was fearful that the battle would turn out to be the largest defeat of South Vietnamese forces up to that point of the war. Cao promised to deploy the second Civil Guard battalion which had just arrived at the southwest flank of Ap Bac, and to drop the ARVN 8th Airborne Battalion at around 16:00 behind Ba's armored personnel carriers. Late in the afternoon, a flight of C-123 Providers, with about 300 South Vietnamese paratroopers aboard, closed in on their objective and quickly drew machine gun fire from the hamlet. The C-123 pilots changed course to avoid the ground fire, but either the South Vietnamese jump master or the American flight leader did not compensate for the change. As a result, the paratroopers landed right in front of the entrenched VC positions, instead of behind the 4th Mechanized Rifle Squadron and the Civil Guards.