The great majority of Australian aircrew in Bomber Command were graduates of the Empire Air Training Scheme. These men were not concentrated in Australian units, and were instead often posted to the Commonwealth squadron with the greatest need for personnel where they became part of a multi-national bomber crew. Five Australian heavy bomber squadrons (No. 460, No. 462, No. 463, No. 466 and No. 467 squadrons) were formed within Bomber Command between 1941 and 1945, however, and the proportion of Australians in these units increased over time. No. 464 Squadron, which was equipped with light bombers, was also formed as part of Bomber Command but was transferred to the Second Tactical Air Force in June 1943, where it continued to attack targets in Europe. Unlike Canada, which concentrated its heavy bomber squadrons into No. 6 Group RCAF in 1943, the RAAF squadrons in Bomber Command were always part of British units, and the Australian Government had little control over how they were used.