 Complete the following phrase:  On 8 December 1940, the nineteen-year-old Isaacson enlisted in the Royal Australian Air Force RAAF. After completing his training in Australia and Canada, he was posted to the United Kingdom and joined No. 460 Squadron RAAF at RAAF Breighton, Yorkshire, as a sergeant pilot. Operating Vickers Wellington medium bombers, No. 460 Squadron had been raised under the Article XV provisions of the Empire Air Training Scheme and was one of a number of nominally Australian formations taking part in RAF Bomber Commands strategic air campaign against Germany. The squadron commenced operations in March 1942 and participated in 