VH-NFD departed Jandakot WA at 1822 WST for Busselton WA as a medical priority flight. The pilot reported that at 1851 he made a straight in approach to runway 21 at Busselton Airport. After establishing the aircraft on final approach and lowering the undercarriage, approach flap was selected at approximately 700 ft. The pilot selected full flap with the speed at 120 knots.
Passing 500 feet, the pilot experienced yaw towards the left and a complete loss of engine power from the left engine, followed by a loud backfire. The pilot shut the engine down and continued to land on runway 21. After landing the pilot managed to clear the runway by using a series of large circles to work his way to the taxiway and to the tarmac area where he cancelled the SAR, and advised Perth FSE what had happened.