331st Air Expeditionary Group The 331st Bombardment Group is an inactive United States Air Force unit . It was last assigned to the 315th Bombardment Wing , being stationed at Northwest Field , Guam . It was inactivated on 15 April 1946 . During World War II , the unit was initially a B - 17 Flying Fortress and B - 24 Liberator operational training unit ( OTU ) . Redesignated as a replacement training unit ( RTU ) in December 1943 . Inactivated on 1 April 1944 when Second Air Force switched to B - 29 Superfortress training . Late in the war the group was reactivated and trained as a Very Heavy ( VH ) B - 29 Superfortress group The group served in the Pacific Ocean theater of World War II as part of Twentieth Air Force . The 331st Bomb Group ' s aircraft engaged in very heavy bombardment B - 29 Superfortress operations against Japan . Hurricane Ike ( 2008 ) . The unit was reactivated at Randolph AFB , Texas , in 2008 as the 331st Air Expeditionary Group , a special unit formed to support Hurricane Ike relief efforts . Units and personnel assigned to the 331st came from both the active and reserve components of the Air Force and Navy . History . Constituted as 331st Bombardment Group ( Heavy ) on 1 July 1942 and activated on 6 July at Salt Lake City AAB , Utah . Assigned to Second Air Force . The mission of the 331st was initially that of a replacement training unit . Equipped with B - 17 ' s and B - 24 ' s for duty as a replacement training unit at Casper AAFld , Wyoming . Inactivated on 1 April 1944 . Redesignated 331st Bombardment Group ( Very Heavy ) . Activated on 12 July 1944 at Dalhart AAFld , Texas . Assigned to Second Air Force . Trained for combat with B - 29B ' s initially at Dalhart , then to McCook AAFld , Nebraska . The 331st was assigned the B - 29B model . This model was built at Bell - Atlanta . The B - 29B was a limited production aircraft , built solely by Bell - Atlanta . It had all but the tail defensive armament removed , since experience had shown that by 1944 the only significant Japanese fighter attacks were coming from the rear . The tail gun was aimed and fired automatically by the new AN / APG - 15B radar fire control system that detected the approaching enemy plane and made all the necessary calculations . The elimination of the turrets and the associated General Electric computerized gun system increased the top speed of the Superfortress to 364 mph at 25 , 000 feet and made the B - 29B suitable for fast , unescorted hit - and - run bombing raids and photographic missions . Moved to Northwest Field , Guam , April – June 1945 , and assigned to the 315th Bomb Wing , Twentieth Air Force . Bombed Japanese - held Truk late in June 1945 . Flew first mission against the Japanese home islands on 9 July 1945 and afterward operated principally against the enemy ' s petroleum industry on Honshū . Despite the hazards of bad weather , fighter attacks , and heavy flak , the 331st bombed the coal liquefaction plant at Ube , the Mitsubishi - Hayama petroleum complex at Kawasaki , and the oil refinery and storage facilities at Shimotsu , in July and August 1945 , and received a Distinguished Unit Citation for the missions . After the war the group dropped food and supplies to Allied prisoners of war in Japan . Inactivated on Guam on 15 April 1946 .