Carburettor icing can have serious safety implications for aircraft. This was shown most recently in an accident near Miranda Downs in Queensland. On 6 July 2012, a Robinson R22 Beta was conducting mustering operations when the right skid struck a tree and collided with terrain.
The operator’s investigation into the accident—which examined GPS and Bureau of Meteorology data— found that the combination of temperature and dew point indicated a moderate carburettor icing risk at cruise power and a serious icing risk at descent power.
Pilots are reminded to maintain awareness of the weather conditions that are conducive to carburettor ice formation and closely monitor their aircraft performance during times when the risk exists.
Carburettor ice can occur in temperatures as high as 32° C with high humidity.
The investigation report AO-2012-091 provides important advice about carburettor icing. You can find this and other investigations in the ATSB’s Aviation Short Investigation Bulletin issue 13. The bulletin highlights valuable safety lessons for pilots, operators and safety managers.
More information:
The following publications provide useful information on carburettor icing and avoidance:
- Robinson Safety Notice SN-25 – Carburettor Ice
- Robinson Safety Notice SN-31 – Governor Can Mask Carb Ice
- Ice Advice, in Flight Safety Australia, March-April 2006, pages 26-33
- Ice Blocked, in Flight Safety Australia, November-December 2004, pages 31-33
- The ATSB educational fact sheet titled Melting Moments: Understanding Carburettor Icing
The Civil Aviation Safety Authority (CASA) Carburettor icing probability chart can be downloaded from the web or purchased from the CASA Shop
The Robinson Safety Notice SN-38 – Practice Autorotations Cause Many Training Accidents
The following ATSB investigation reports provide further reading on carburettor icing: