The rescue of Bat 21 Bravo, the call sign for Iceal "Gene" Hambleton, from behind North Vietnamese lines was the "largest, longest, and most complex search-and-rescue" operation during the Vietnam War. On April 2, 1972, the third day of the Easter Offensive, the largest combined arms operation of the entire Vietnam War, Hambleton was a navigator aboard one of two United States Air Force EB-66 aircraft escorting a cell of three B-52s. Bat 21 was configured to gather signals intelligence including identifying North Vietnamese anti-aircraft radar installations to enable jamming. Bat 21 was destroyed by a SA-2 surface-to-air missile and Hambleton was the only survivor, parachuting behind the front lines into a battlefield filled with thousands of North Vietnamese Army soldiers.