ICING

SUMMARY OF NOTABLE POINTS

• 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.