The FAA recently issued a revised Special Airworthiness Information Bulletin–SAIB SW-08-03R1–to warn helicopter operators of the “hazards of snow and ice,” according to the FAA Rotorcraft Directorate’s Safety Management Group in Fort Worth. The bulletin, “Recommendations for Rotorcraft During Icing Conditions,” was released in 2003, and new data has been added following additional FAA testing.
The revised bulletin offers procedures “to reduce the probability of an engine in-flight shutdown due to ice and snow ingestion.” On the ground, with the engine(s) off or operating at low power, snow and ice can build up in the engine intakes and plenums.
When engine power is increased, the accumulation can be ingested into the engine, which can result in decreased power or complete engine failure. Ice or snow should be removed with heated air or deicing fluid, “not by chipping or scraping,” said the SAIB.
The bulletin added that “most rotorcraft are not approved for flight in known icing conditions,” and warned that icing can occur at any time when operating in visible moisture, such as fog, rain or clouds, when the temperature is below 41 degrees F.