IV Fighter Command

GHQ Air Force (GHQ AF) had been established with two major combat functions, to maintain a striking force against long range targets, and the air defense of the United States.[2] In the spring of 1941, the War Department established four strategic defense areas and GHQ AF reorganized its Southwest Air District as 4th Air Force with responsibility for air defense planning and organization along the west coast and in the southwest.[3] 4th Air Force activated 4th Interceptor Command at March Field, California on 8 July 1941, under the command of Major General Millard F. Harmon.[1][note 3]

The attack on Pearl Harbor put all units in the Western Theater of Operations on heightened alert. The first Lockheed P-38 Lightnings of the 1st Pursuit Group arrived in San Diego, California on 8 December 1941, and the entire group had arrived in California from Michigan to reinforce the command's air defenses by 22 December. Additional reinforcements in mid-December arrived in the form of the 1st Marine Aircraft Wing, which moved from Virginia.[4] The command was charged with control of "active agents" for air defense in its area of responsibility, which included interceptor aircraft, antiaircraft artillery and barrage balloons. Civilian organizations provided air raid warnings and enforced blackouts and came under the authority of the Office of Civilian Defense. Radar was initially not sufficiently developed to be included in air defense systems, There were only ten radars to guard the Pacific coast, but the command worked "feverishly" to create a ground observer corps and coastal radar net as elements of its Aircraft Warning Service.[5] However, it soon became apparent that having two commands responsible for air defense in the Western Theater of Operations was impractical, and in early 1942, the 4th took over responsibility for air defense of the entire Pacific coast, replacing 2d Interceptor Command in the northwest.[6] In June it moved its headquarters north to Oakland Airport, California, which was more centrally located for its increased area of responsibility.[1]

Along the Pacific coast, Western Defense Command established a "vital air defense zone", extending from the coast approximately 150 miles (240 km) inland and 200 miles (320 km) to sea, with long range bombers from 4th Bomber Command flying patrols over the ocean. 14th Antiaircraft Command, an artillery unit, was placed under the operational control what was now 4th Fighter Command.[7] Regional air defense wings were established in August 1942 at San Diego, Los Angeles, San Francisco and Seattle[8] Fifteen new radar sites were established, and several of the original ten were resited due to unsuitability of their locations. Coverage was extended northwards and southwards when arrangements were made for the Royal Canadian Air Force to provide information from radar sites in British Columbia and three sites were constructed in Baja California, Mexico. With the Japanese attacks on Midway and the Aleutians, additional balloon and antiaircraft units were moved to the Pacific coast and the command was reinforced by units from 2nd Air Force. Additional reinforcements were prepared, but the victory at Midway led to cancellation of their movements.[9] As the possibility of an attack on the Pacific coast grew more remote, the air defense wings became increasingly concerned with the training mission. The command continued to support the air defense mission until September 1943.[10]

In 1942, Air Force Combat Command had established an Operational Training Unit (OTU) system for 2nd and 3d Air Forces. The system was later extended to 4th Air Force. Although it was originally intended to confine the OTU system to 2d and 3rd Air Forces, too much of the Army Air Forces (AAF)'s aircrew and aircraft were assigned to 4th Air Force to permit the command to forego training responsibilities entirely. In May 1942, all pursuit groups assumed OTU responsibility.[11] Even though AAF designated the units of the command to form the first "parent" and "satellite" of the program, it was not until October that Fourth Air Force even submitted a plan to operate OTUs, and not until January 1943 did the first unit, the 354th Fighter Group, begin to train under the OTU system.[12] However, the command's training program was "seriously jeopardized" during early 1943, when Bell P-39 Airacobras programmed for delivery to command units were diverted to the Soviet Air Forces.[13] Similar problems affected the command's P-38 Lightning training programs. Curtiss-Wright AT-9 Jeeps were not available to qualify fighter pilots on twin engine operations, and during the command's active period, there were never enough P-38s on hand, requiring some fighter training for P-38 units to be conducted with single engine P-39s.[14]

Shortly thereafter, it was decided that one of the command's groups would be manned at 50% overstrength in order to train and supply replacement pilots for overseas units. This was the beginning of the Replacement Training Unit (RTU) program, which replaced a system in which individuals were selected from existing units to fill overseas vacancies. Replacement training at Muroc Army Air Field began in the fall.[15] Unlike I Fighter Command, which specialized in OTUs and III Fighter Command, which consisted mostly of RTUs, the command's training included both types of units[16] In time, however, the RTU program became the major type of training in all the continental air forces. As early as September 1943, Hq AAF announced that no more fighter OTUs would be formed. The last OTU fighter groups completed training early in 1944, and training turned sharply to replacement training.[15]

The command also participated in joint fighter-bomber training with units of II Bomber Command. In these exercises, command fighters would provide escort for bombers searching for enemy vessels or act as interceptors against bombers simulating attacks on coastal targets.[17]

The AAF was finding that standard military units, whose manning was based on relatively inflexible tables of organization were not well adapted to the training mission, even less so to the replacement mission. Accordingly, the AAF adopted a more functional system in which each base was organized into a separate numbered unit.[18] In connection with this general reorganization, Fourth Air Force disbanded IV Fighter Command and transferred its responsibilities to wings that were headquartered by AAF base units.[1][19][20][21]

Command

• 4th Antiaircraft Command: operational control 1942 – unknown[22]

Wings

• 85th Fighter Wing: 28 November 1943 – 10 January 1944[23]
• Los Angeles Air Defense Wing (later Los Angeles Fighter Wing): 20 August 1942 – 31 March 1944[24]
• San Diego Air Defense Wing (later San Diego Fighter Wing): 20 August 1942 – 31 March 1944[25]
• San Francisco Air Defense Wing (later San Francisco Fighter Wing): 20 August 1942 – 31 March 1944[26]
• Seattle Air Defense Wing (later Seattle Fighter Wing): 20 August 1942 – 31 March 1944[27]

Groups

Squadrons

• 426th Night Fighter Squadron: 1 January – 7 February 1944[41]
• 427th Night Fighter Squadron: 1 January – 11 June 1944 (attached to 481st Night Fighter Operational Training Group)[42]
• 547th Night Fighter Squadron: 31 March – 4 September 1944[43]

• March Field, California, 8 July 1941
• Riverside Municipal Airport, California, c. July 1941
• Oakland Airport, California, June 1942 – 31 March 1944[1]

Explanatory notes

Citations

• Cate, James L.; Williams, E. Kathleen (1948). "Prelude to War, Chapter 4, The Air Corps Prepares for War, 1939-41". In Craven, Wesley F; Cate, James L (eds.). The Army Air Forces in World War II (PDF). Vol. I, Plans and Early Operations. Chicago, IL: University of Chicago Press. LCCN 48003657. OCLC 704158. Retrieved 17 December 2016.
• Goss, William A. (1955). "Tactical Demands, Chapter 8, Air Defense of the Western Hemisphere". In Craven, Wesley F; Cate, James L (eds.). The Army Air Forces in World War II (PDF). Vol. I, Plans and Early Operations. Chicago, IL: University of Chicago Press. LCCN 48003657. Retrieved 17 December 2016.
• Goss, William A. (1955). "The Organization and its Responsibilities, Chapter 2 The AAF". In Craven, Wesley F.; Cate, James L. (eds.). The Army Air Forces in World War II (PDF). Vol. VI, Men & Planes. Chicago, IL: University of Chicago Press. LCCN 48003657. OCLC 704158. Retrieved 17 December 2016.
• Maurer, Maurer, ed. (1983) [1961]. Air Force Combat Units of World War II (PDF) (reprint ed.). Washington, DC: Office of Air Force History. ISBN 0-912799-02-1. LCCN 61060979. Retrieved 17 December 2016.
• Maurer, Maurer, ed. (1982) [1969]. Combat Squadrons of the Air Force, World War II (PDF) (reprint ed.). Washington, DC: Office of Air Force History. ISBN 0-405-12194-6. LCCN 70605402. OCLC 72556. Retrieved 17 December 2016.
• White, Jerry (August 1949). "Combat Crew and Unit Training in the AAF 1939-1945, USAF Historical Study No. 61" (PDF). Air Historical Office, United States Air Force. Retrieved 30 January 2022.