page_title: 509th Composite Group
section_title: Organization, training, and security
hierarchical_section_title: 509th Composite Group / History / Organization, training, and security
caption_attribution_description: English: First Ordinance Squadron Area
context_page_description: The 509th Composite Group was a unit of the United States Army Air Forces created during World War II and tasked with the operational deployment of nuclear weapons. It conducted the atomic bombings of Hiroshima and Nagasaki, Japan, in August 1945.
  The group was activated on 17 December 1944 at Wendover Army Air Field, Utah. It was commanded by Lieutenant Colonel Paul W. Tibbets. Because it contained flying squadrons equipped with Boeing B-29 Superfortress bombers, C-47 Skytrain, and C-54 Skymaster transport aircraft, the group was designated as a "composite", rather than a "bombardment" formation. It operated Silverplate B-29s, which were specially configured to enable them to carry nuclear weapons.
  The 509th Composite Group began deploying to North Field on Tinian, Northern Mariana Islands, in May 1945. In addition to the two nuclear bombing raids, it carried out 15 practice missions against Japanese-held islands, and 12 combat missions against targets in Japan dropping high-explosive pumpkin bombs.
context_section_description: The 509th Composite Group was constituted on 9 December 1944, and activated on 17 December 1944, at Wendover Army Air Field, Utah. It was commanded by Lieutenant Colonel Paul W. Tibbets, who received promotion to full colonel in January 1945. It was initially assumed that the group would divide in two, with half going to Europe and half to the Pacific.  In the first week of September Tibbets was assigned to organize a combat group to develop the means of delivering an atomic weapon by airplane against targets in Germany and Japan, then command it in combat.  Because the organization developed by Tibbets was self-sustained, with flying squadrons of both Boeing B-29 Superfortress bombers and transport aircraft, the group was designated as a "composite" rather than a "bombardment" unit.
  On 8 September, working with Major General Leslie R. Groves, Jr.'s Manhattan Project, Tibbets selected Wendover for his training base over Great Bend Army Air Field, Kansas, and Mountain Home Army Airfield, Idaho, because of its remoteness. On 14 September 1944, the 393d Bombardment Squadron arrived at Wendover from its former base at Fairmont Army Air Base, Nebraska, where it had been in operational training (OTU) with the 504th Bombardment Group since 12 March. When its parent group deployed to the Marianas in early November 1944, the squadron was assigned directly to the Second Air Force until creation of the 509th Composite Group. Originally consisting of twenty-one crews, fifteen were selected to continue training, and were organized into three flights of five crews, lettered A, B, and C. The 393d Bombardment Squadron was commanded by Lieutenant Colonel Thomas J. Classen, who like Tibbets had combat experience in heavy bombers, commanding a Boeing B-17 Flying Fortress with the 11th Bombardment Group.
  The 393d Bombardment Squadron conducted ground school training only until delivery of three modified Silverplate airplanes in mid-October 1944 allowed resumption of flight training. These aircraft had extensive bomb bay modifications and a "weaponeer" station installed. Initial training operations identified numerous other modifications necessary to the mission, particularly in reducing the overall weight of the airplane to offset the heavy loads it would be required to carry. Five more Silverplates were delivered in November and six in December, giving the group 14 for its training operations. In January and February 1945, 10 of the 15 crews under the command of the Group S-3 (operations officer) were assigned temporary duty at Batista Field, San Antonio de los Baños, Cuba, where they trained in long-range over-water navigation.
  The 320th Troop Carrier Squadron, the other flying unit of the 509th, came into being because of the highly secret work of the group. The organization that was to become the 509th required its own transports for the movement of both personnel and materiel, resulting in creation of an ad hoc unit nicknamed "The Green Hornet Line". Crews for this unit were acquired from the five 393d crews not selected to continue B-29 training. All those qualified for positions with the 320th chose to remain with the 509th rather than be assigned to a replacement pool of the Second Air Force. They began using C-46 Commando and C-47 Skytrains already at Wendover, and in November 1944 acquired three C-54 Skymasters. The 320th Troop Carrier Squadron originally consisted of three C-54 and four C-47 aircraft.  In April 1945 the C-47s were transferred to the 216th Army Air Forces Base Unit and two additional C-54s acquired. The 320th Troop Carrier Squadron was constituted and activated on the same dates as the group.
  Other support units were activated at Wendover from personnel already present and working with Project Alberta or in the 216th Army Air Forces Base Unit, both affiliated with the Manhattan project. Project Alberta was the part of the Manhattan Project at Site Y in Los Alamos, New Mexico, responsible for the preparation and delivery of the nuclear weapons. It was commanded by U.S. Navy Captain William S. Parsons, who would acc
caption: First Ordnance Squadron area on Tinian
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