• 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
·      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.
Tony Birth