520th Air Defense Group
Active1944–1945, 1953–1955
Country United States
Branch United States Air Force
TypeFighter interceptor
RoleAir Defense

The 520th Air Defense Group is a disbanded United States Air Force organization. Its last assignment was with the 4706th Air Defense Wing at Truax Field, Wisconsin, where it was inactivated in 1955. The group was originally activated as the 520th Air Service Group, a support unit for the 340th Bombardment Group at the end of World War II in Italy and then redeployed to the United States where it was inactivated in 1945.

The group was activated once again in 1953, when Air Defense Command (ADC) established it as the headquarters for a dispersed fighter-interceptor squadron and the medical, aircraft maintenance, and administrative squadrons supporting it. It was replaced in 1955 when ADC transferred its mission, equipment, and personnel to the 327th Fighter Group in a project that replaced air defense groups commanding fighter squadrons with fighter groups with distinguished records during World War II.


World War II

The group was first activated during World War II in Italy in late 1944 as the 520th Air Service Group[1] as part of a reorganization of Army Air Forces (AAF) support groups in which the AAF replaced service groups that included personnel from other branches of the Army and supported two combat groups with air service groups including only Air Corps units. Designed to support a single combat group.[2] Its 946th Air Engineering Squadron provided maintenance that was beyond the capability of the combat group,[3] its 770th Air Materiel Squadron handled all supply matters,[4] and its Headquarters & Base Services Squadron provided other support.[2][4] The group supported the 340th Bombardment Group in Italy. The group returned to the US and was inactivated in late 1945. It was disbanded in 1948.[5]

Cold War

During the Cold War, the group was reconstituted, redesignated as the 520th Air Defense Group, and activated at Truax Field in 1953[6] with responsibility for air defense of the Great Lakes area.[citation needed] It was assigned the 432d and 433d Fighter-Interceptor Squadrons (FIS), which were already stationed at Truax Field, as its operational components.[7] The 432d FIS was flying North American F-86 Sabres,[8] while the 433d FIS was flying Northrop F-89 Scorpions equipped with airborne intercept radar.[8] Both squadrons had been assigned directly to the 31st Air Division.[7] The group also replaced the 78th Air Base Squadron as the USAF host unit for Truax Field. It was assigned three squadrons to perform its support responsibilities.[9][10]

F-89 of the 432d FIS[b]

In March 1953, the 432d FIS converted to a later radar equipped and Mighty Mouse rocket armed model of the "Sabre".[8] In July 1954, the 433d FIS moved to Alaska and was reassigned.[7] The following month, the 456th Fighter-Interceptor Squadron was activated to replace the 433d FIS.[11] The 456th FIS was also equipped with Sabres.[12] The group was inactivated[6] and replaced by the 327th Fighter Group (Air Defense)[13] as part of Air Defense Command's Project Arrow, which was designed to bring back on the active list the fighter units which had compiled memorable records in the two world wars.[14] The group was disbanded once again in 1984.[15]


Activated on 27 December 1944[1]
Inactivated c. 7 November 1945
Disbanded 8 October 1948[5]
Activated on 16 February 1953[6]
Inactivated on 18 August 1955[6]
Disbanded on 27 September 1984[15]






See also



Explanatory notes
  1. ^ Aircraft are North American F-86D-40-NA Sabres, serials 52-3622 and 52-3717. 52-3622 ran out of fuel on a gunnery range in South Dakota and crashed on 23 March 1954; 52-3717 was transferred to the Yugoslav Air Force. Taken in November 1953. Baugher, Joe (7 April 2023). "1952 USAF Serial Numbers". Joe Baugher. Retrieved 10 April 2023.
  2. ^ Aircraft is Northrop F-89H-5-NO Scorpion, serial 54-409. This image shows a later model of the F-89 than the one the squadron flew while it was part of the 520th. This aircraft was used as a chase plane for Operation Plumbbob and the John shot, the only live firing of the AIR-2 Genie armed with a nuclear warhead. Baugher, Joe (7 April 2023). "1954 USAF Serial Numbers". Joe Baugher. Retrieved 10 April 2023.
  3. ^ Probably XII Air Force Service Command until c. July 1945, Third Air Force after August 1945.
  4. ^ There is an obvious error in the departure date from Italy recorded in the unit history, since it requires a crossing of the Atlantic by ship in a day.
  1. ^ a b c d "Abstract, History 520 Air Service Group Dec 1944 – Jan 1945". Air Force History Index. Retrieved 7 January 2012.
  2. ^ a b Coleman, p. 208
  3. ^ "Abstract, History 946 Air Engineering Squadron Dec 1944 – Jan 1945". Air Force History Index. Retrieved 7 January 2012.
  4. ^ a b "Abstract, History 770 Air Materiel Squadron Dec 1944 – Jan 1945". Air Force History Index. Retrieved 7 January 2012.
  5. ^ a b Department of the Air Force Letter, 322 (AFOOR 887e), 8 October 1948, Subject: Disbandment of Certain Inactive Air Force Units
  6. ^ a b c d e f Cornett & Johnson, p. 82
  7. ^ a b c d e Maurer, Combat Squadrons, pp. 534–535
  8. ^ a b c d e f Cornett & Johnson, p.128
  9. ^ Cornett & Johnson, p.147
  10. ^ a b "Abstract, History 520 Infirmary Jan–Jul 1955". Air Force History Index. Retrieved 21 June 2012.
  11. ^ Maurer, Combat Squadrons, p. 562
  12. ^ Cornett & Johnson, p. 129
  13. ^ Maurer, Combat Units, p. 209
  14. ^ Buss, Sturm, Volan, & McMullen, p.6
  15. ^ a b Department of the Air Force/MPM Letter 575q, 27 September 1984, Subject: Disbandment of Units
  16. ^ a b c d e "Abstract, History 520 Air Service Group Jun–Sep 1945". Air Force History Index. Retrieved 7 January 2012.
  17. ^ See Mueller
  18. ^ Bailey, Carl E. (3 April 2009). "Factsheet 433 Weapons Squadron (ACC)". Air Force Historical Research Agency. Archived from the original on 14 September 2011. Retrieved 3 March 2012.


Public Domain This article incorporates public domain material from the Air Force Historical Research Agency

Further reading