The de Havilland Canada DHC-4 Caribou is a Canadian-designed and produced specialized cargo aircraft with short takeoff and landing (STOL) capability. The Caribou was first flown in 1958 and although mainly retired from military operations, is still in use in small numbers as a rugged "bush" aircraft.
The Royal Australian Air Force ordered 18 in 1963, with further orders for 7 in 1964 and 4 more aircraft ordered individually between 1968 and 1971. The RAAF finally retired it last Caribou in 2009, shortly after I took these photos.