Airworthiness Directives; Gulfstream Model G-159 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Gulfstream Model G-159 series airplanes, that requires an inspection to determine the type of pneumatic deicing boots, and an Airplane Flight Manual (AFM) revision only for those airplanes equipped with "modern" boots. This amendment is prompted by reports of inflight incidents and an accident that occurred in icing conditions where the airframe pneumatic deicing boots were not activated. The actions specified by this AD are intended to ensure that flightcrews activate the pneumatic wing and tail deicing boots at the first signs of ice accumulation. This action will prevent reduced controllability of the aircraft due to adverse aerodynamic effects of ice adhering to the airplane prior to the first deicing cycle.