COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES AlliedSignal (Garrett/AiResearch) Turbine Engines - TFE731 Series AD/TFE731/11 H.P. Turbine Blades P/N 3072455-10 Replacement 3/86 Applicability: TFE 731-2-1C; -2-2B fitted with H.P. Turbine Rotor assemblies P/N 3072570-6, -7, -9, -10, with blades P/N 3072455-10 not frequency inspected or mixed with any other P/N H.P. Turbine blades. Requirement: Garrett S.B. TFE 731-72-3291 Rev 1 of 24 May 1985; or AD/AIR-T/52 Amdt 1. Note: This document refers to S.B. TFE 731-72-3220 which is to be reviewed and accomplished, if applicable, coincident with this directive, to remove from service those blades P/N 3072455-10 manufactured from GMR 235 material. Effectivity: Unless already accomplished, at the next removal of the H.P. Turbine Rotor assembly or at the next scheduled major periodic inspection after 31 March 1985 whichever is the sooner. Background: a. As a result of investigation into 39 fatigue related blade separations the manufacturer has developed a frequency scan inspection. Blades not frequency inspected were fitted to rotor assemblies by the manufacturer prior to March 1980. This directive removes from service those blades P/N 3072455-10 which have not been frequency inspected, or which have been mixed with other P/N blades, or which were manufactured from GMR 235 material. b. This Amendment reflects the manufacturer's Revision 1 advice to the Requirement Document which now includes H.P. Turbine Rotor Assemblies P/N. 3072570-6, -9 that may contain H.P. Turbine Blades P/N 3072455-10 improperly identified as P/N 3072455-12.