Initially the OCU was formed from a nucleus provided by No. 16 OTU and was tasked with training crews of the "wooden wonder", the de Havilland Mosquito, in the light bomber and photo reconnaissance roles.
The OCU began with a core group from No. 16 OTU and was responsible for instructing crews on operating the de Havilland Mosquito, which served as both a light bomber and a photo reconnaissance aircraft.