 Initially, it controlled the third phase of training, in which each bombardment group split into tactical components and operated from squadron sized airfields under simulated combat conditions.Later, the 17th supervised the first and second phases of heavy bombardment group and crew training.In 1943 assumed mission for training B-29 Superfortress Very Heavy bombardment groups prior to their deployment to Twentieth Air Force in the Pacific Theater until April 1946 when it ceased all activity.