CAA SAFETYSENSE LEAFLET 14 - PISTON ENGINE ICING
It’s that time of year again, so a summary of the CAA’s advice on the above ….
• Icing forms stealthily.
• Some aircraft/engine combinations are more susceptible than others.
• Icing may occur in warm humid conditions and is a possibility at any time of the year in the UK.
• MOGAS makes carb icing more likely.
• Low power settings, such as in a descent or in the circuit, are more likely to produce carb icing.
• Warming up the engine before take-off improves the effectiveness of any carb body heat.
• Use full carb hot air frequently when flying in conditions where carb icing is likely.
• Remember the RPM gauge is the primary indication for a fixed pitch propeller; manifold pressure for variable pitch.
• Treat the carb hot air as an ON/OFF control – either full hot or full cold.
• It takes time for the heat to work and the engine may run roughly while ice is clearing.
• Timely use of appropriate procedures can PREVENT THIS PROBLEM.
Finally, In the event of carb heat system failure in flight:
• Avoid likely carb icing conditions.
• Maintain high throttle settings – full throttle if possible.
• Weaken the mixture slightly.
• Land as soon as reasonably possible.