Airworthiness Directives; Fokker Model F.28 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to all Fokker Model F.28 series airplanes. This action requires revising the Airplane Flight Manual to prohibit operation of the auxiliary power unit (APU) during deicing. This action is necessary to prevent ingestion of deicing fluid into the APU, which could cause uncontained failure of the turbine wheel of the APU, and result in failed and uncontained parts penetrating the aft cabin pressure bulkhead, and consequent possible injury to the cabin crew or passengers. This action is intended to address the identified unsafe condition.