The fatal crash of Glasair VH-HRG near Wedderburn, NSW, last year has highlighted the danger posed by carburettor icing.
The aircraft was on downwind for Wedderburn on 19 July 2015 when the engine quit and the pilot was unable to get the aircraft to a safe landing. The pilot survived the crash, but the passenger did not.
In an investigation report released today, the Australian Transport Safety Bureau (ATSB) said "... during the turn onto final approach to land, the aeroplane’s engine ceased operating. Following the loss of power, the pilot was unable to control the aircraft’s descent to an appropriate forced landing area before colliding with the ground.
"The ATSB also found that the loss of power was probably due to carburettor icing. No defects were identified that would have precluded normal operation of the aircraft or its engine prior to the accident. However, the environmental conditions at the time were conducive to serious carburettor icing at all power settings.
"The pilot reported using a low power setting during the downwind leg of the circuit to slow the aircraft down and did not use the carburettor heat system."
In their safety message, the ATSB advised all pilots of aircraft fitted with carburettors to check the weather condition before every flight an consider the chances of experiencing carburettor icing, referring also to the Civil Aviation Safety Authority's Carburettor Icing Probability Chart.
Carburettor icing can occur in temperatures up to 38oC.
The full report into the crash of VH-HRG is on the ATSB website.