Airworthiness Directives; de Havilland, Inc. DHC-6 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to de Havilland DHC-6 series airplanes. This action requires revising the Airplane Flight Manual (AFM) to provide the flight crew with recognition cues for, and procedures for exiting from, severe icing conditions, and to limit or prohibit the use of various flight control devices. This amendment is prompted by results of a review of the requirements for certification of the airplane in icing conditions, new information on the icing environment, and icing data provided currently to the flight crews. The actions specified by this AD are intended to minimize the potential hazards associated with operating the airplane in freezing rain or freezing drizzle conditions by providing more clearly defined procedures and limitations associated with such conditions.