Flight Lieutenant William H. Scott, Royal Australian Air Force, the 28-year-old Chief Test Pilot of the Government Aircraft Factories (Commonwealth Aircraft Corporation, Pty. Ltd.), had been testing the CA-26 Sabre, A94-101 since August 1st.
On August 14, 1953, Scott put the prototype into shallow dive from 25,000 feet (7,620 meters) over Port Phillip Bay. This was the new airplane’s sixth test flight. On this day, Scott passed 670 miles per hour (1,078 kilometers per hour) and broke the “sound barrier.” A triple sonic boom was heard throughout the Melbourne area. (1)
In 1951, CAC obtained a license agreement to build the F-86F Sabre. In a major departure from the North American blueprint, it was decided that the CA-27 would be powered by a license-built version of the Rolls-Royce Avon R.A.7, rather than the General Electric J47. In theory, the Avon was capable of more than double the maximum thrust and double the thrust-to-weight ratio of the US engine. This necessitated a re-design of the fuselage, as the Avon was shorter, wider and lighter than the J47.[2] Because of the engine change, the type is sometimes referred to as the Avon Sabre.
Source: (1) This Day in Aviation by Bryan R. Swopes, Wikipedia