COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES General Electric Turbine Engines - CF6 Series AD/CF6/11 High Pressure Turbine Rotor - Stage 2 Disc Forward Embossment Inner Diameter Fillet Radius Applicability: CF6-50/-45 series engines. 3/89 TX Requirement: Rework or inspect and rework stage 2 high pressure turbine rotor discs specified by FAA AD 89-01-02 Amendment 39-6082 in accordance with the requirements of paras (a) or (b), (c) and (d) of the AD. Compliance: Forthwith. The cycle count is to commence on the effective date specified in the AD. Background: The FAA AD incorporates a manufacturer's Service Bulletin which states that cracks have been found in a forward embossment inner diameter fillet and these could adversely affect engine durability. The probable cause is an undersized fillet radius which is increased by the rework specified in the AD.