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/TFE731/6 High Pressure Rotor and Nozzle Assembly Bolt - Replacement Applicability: TFE731-2-1C; TFE731-2-2B; TFE731-2-2J; TFE731-2-2L. Document: AiResearch SB No. 72-3138, or AD/AIR-T/38. 3/86 Compliance: During the next hot end inspection completed after 30 September 1980 or during the next unscheduled exposure of the area, whichever occurs first. Background: This Directive is issued to reduce the possibility of damaging the curvic coupling and the forward side of the H.P. turbine rotor by pieces of failed bolts.