The CH-54A heavy helicopter was successfully used by the US Army in Vietnam during the war. It carried a variety of weapons, ammunition, and vehicles including excavators, bulldozers, trucks, and boats. In addition to carrying combat equipment, the CH-54A was also used as a carrier for the M-121 super-heavy bomb. Such bombs were dropped in order to quickly clear the forest under the helipad. This allowed for a shorter landing time and a more flexible response to a tactical situation. For these tasks, the M-121 was partially upgraded – the rear hull and tail stabilizers were removed and a special parachute was added to slow its fall. The bombs were also equipped with an elongated nose detonator to provide a blast height of about 3 feet off the ground. These upgraded bombs were used until they were out of stock, the last being used on 8 August 1970.