Airworthiness Directives; Williams International, L.L.C. Model FJ44-1A Turbofan Engines

This amendment adopts a new airworthiness directive (AD) that is applicable to Williams International, L.L.C. Model FJ44-1A turbofan engines. This action requires initial and repetitive eddy current inspections (ECI) for possible cracks in high pressure turbine (HPT) disk blade retention posts. In addition, this AD requires the installation of advanced design HPT disks as terminating action to the inspection requirements of this AD. This amendment is prompted by two incidents of HPT disk blade retention post separations. The actions specified in this AD are intended to locate possible cracks in HPT disk blade retention posts, thereby preventing the separation of these posts and the liberation of the turbine blades that they retain, and a subsequent loss of engine power. In addition, the actions specified in this AD are intended to prevent the possible high disk speed uncontained liberation of disk posts and turbine blades, which could cause aircraft damage.