504th Bombardment Group, USAAF

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The 504th Bombardment Group (Very Heavy) was a B-29 Superfortress group that took part in the bombing campaign against Japan and the mining campaign that helped to cut Japan off from the remnants of her empire.

The group was activated in March 1944 and initially received the B-17 Flying Fortress. It soon converted to the B-29 Superfortress and prepared to move to the Pacific.

By January 1945 the 504th had reached North Field, Tinian. It was joined by the rest of the 313th Bombardment Wing by the end of February. The 504th was felt to be under-trained and an in-combat training regime was put in place, but by the start of February the group was judged to be ready to take part in an attack on the Japanese Home Islands.

The group's combat debut came in January 1945 when it took part in attacks on Japanese bases on Maug, Iwo Jima and Truk, as part of the training process.

On 4 February 1945 the group took part in the first multi-wing attack on the Japanese Home Islands, taking part in a 129-aircraft attack on Kobe. Only 69 aircraft from the 129 reached their target, but the raid was judged to have been effective.

This began a period in which the group took part in high level daylight attacks on Japanese industrial targets. These missions continued after the start of night-time incendiary raids, and the group was awarded a Distinguished Unit Citation for a raid on the industrial centre of Yokohama in late May 1945.

Low level night-time incendiary raids began in March 1945, and these attacks devastated Japan's cities.

In the same month the group began to drop mines in Japan's vital shipping lanes, targeting the routes to Korean, the Shimonoseki Strait and harbours in the Inland Sea.

In April and May 1945 the group was used to attack the airfields being used by Japanese kamikaze aircraft that were targeting the invasion fleet at Okinawa.

From 24 July to 14 August 1945 the group was used to continue the programme of dropping mines in Japanese waters, taking part in a effort in which 3,578 mines were dropped (the 6th Bombardment Group also played a part in this effort, operating from 8 to 20 July). The group received a Distinguished Unit Citation for the July-August mining operations.

After the war the group dropped supplies to Allied POWs and took part in show of force missions over Japan. It was also used on over-flights to assess the impact of the bombing campaign.

The group moved to the Philippines in March 1946, where it was inactivated on 15 June.




1944: Boeing B-17 Flying Fortress
1944-1945: Boeing B-29 Superfortress


Constituted as 504th Bombardment Group (Very Heavy) 28 February 1944
Activated 11 March 1944
To Pacific Late 1944
Combat begins January 1945
To Philippines March 1946
Inactivated 15 June 1946

Commanders (with date of appointment)

Capt Basil D Murray: Mar 1944
Col James T Connally: 6 Apr 1944
Col Glen W Martin: 6 Feb 1945
Col Charles B Root: 18 Sep 1945
Col John P Kenny: 2 Apr-15 Jun 1946.

Main Bases

Dalhart AAFM, TexL 11 Mar 1944
Fairmont AAFld, Neb 12 Mar- 5 Nov 1944
North Field, Tinian: 23 Dec 1944
Clark Field, Luzon: 6 Mar-15 Jun 1946

Component Units

393rd Bombardment Squadron: 1944
398th Bombardment Squadron: 1944-46
421st Bombardment Squadron: 1944-46
507th Bombardment Squadron: 1944
680th Bombardment Squadron: 1944-46

Assigned To

1944: 313rd Bombardment Wing; XXI Bomber Command; Second Air Force (training in US)
December 1944-1946: 313rd Bombardment Wing; XXI Bomber Command; Twentieth Air Force

How to cite this article: Rickard, J (31 December 2013), 504th Bombardment Group, USAAF , http://www.historyofwar.org/air/units/USAAF/504th_Bombardment_Group.html

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