RAAF 200 Liberator Special Duties Flight/Z Force. Combination stone and propellor memorial, unveiled by then Qld Governor, Sir Walter Campbell, a Liberator pilot, whose brother was killed in a Z Force raid on Japanese shipping in Singapore Harbour. Comet propeller was added later when anticipated Liberator propeller was not available. Additional Information During 1945, secrecy surrounded the RAAF 200 Liberator Special Duties Flight and Z Services Reconnaissance Department operating out of Leyburn aerodrome and dropping commandos behind enemy lines in Borneo. In September 1949 the first Australian Grand Prix was held at the former Leyburn airstrip, now farms.