 In November, it became a heavy bombardment group, acquiring its first 21 B-17 Flying Fortresss in May 1941.Nine were sent to the Philippines in September 1941 and many of the remainder were destroyed in the attack on Pearl Harbor on 7 December 1941.The 11th Bombardment Group was assigned to the Seventh Air Force in February 1942 and trained with the B-18 Bolo.