At 0840 Eastern Standard Time on 6 July 2012, during mustering operations near Miranda Downs aeroplane landing area, Queensland, the right skid of a Robinson R22 Beta, registered VH-STK (STK), struck a tree and the helicopter collided with terrain. The pilot, the only occupant, was seriously injured and the helicopter sustained substantial damage.
The operator conducted an investigation into the accident and, using Global Positioning System (GPS) data, determined that STK had climbed to about 2,500 ft above sea level before commencing a left spiral descent. Bureau of Meteorology data, obtained by the operator, indicated that the temperature was 14.7° C and the dew point 1.3° C. The operator determined that the combination of temperature and dew point would indicate a moderate carburettor icing risk at cruise power and a serious icing risk at descent power.
As a result of this occurrence, the aircraft operator has advised the ATSB that they have reminded their pilots of documentation in relation to carburettor icing and auto-rotations.
Pilots are reminded to maintain awareness of the weather conditions that are conducive to carburettor ice formation and closely monitor aircraft performance during times when the risk exists.