Initially the Far East Air Force also included aircraft and personnel of the Philippine Army Air Corps. Outnumbered operationally more than three-to-one by aircraft of the Japanese Navy and Army, FEAF was largely destroyed during the Philippines Campaign of 1941–42. When 14 surviving B-17 Flying Fortresses and 143 personnel of the heavy bombardment force were withdrawn from Mindanao to Darwin, Australia in the third week of December 1941, Headquarters FEAF followed it within days. The B-17s were the only combat aircraft of the FEAF to escape capture or destruction.