With the focus on atomic weapons, in early December 1946, Kirtland Field was again transferred, this time to the Air Materiel Command (AMC), specifically the Directorate, Research and Development, HQ, AMC. AMC was responsible for all USAF R&D, including atomic weapons. The transfer took place due to Kirtland Field's close proximity to Sandia Base and the Z Division. The AMC mission at Kirtland Field was "to provide flight services for the Manhattan District at Sandia and Los Alamos in atomic bomb testing".