COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES AlliedSignal (Lycoming) Turbine Engines - ALF502 and LF507 Series AD/ALF/5 Fourth Stage Turbine Rotors Assembly P/N 2-141-170-23 and -27 - Replacement 1/86 Applicability: All Avco Lycoming ALF 502 Series Turbo fan engines as listed in the requirement document. Document: 1. Avco Lycoming SB ALF 502-72-0038, Rev. 1; or 2. AD/LYC-T/22. Note: FAA AD T83-03-51 refers. Compliance: Within the next 10 engine operating hours. Background: This Directive is issued to ensure compliance with the manufacturer's requirement document that introduces an improved fourth turbine rotor incorporating blades which were inspected for casting defects by more stringent inspection procedures. Compliance with the document supersedes those requirements of the Avco Lycoming SB ALF502-72-0027 listed in AD/LYC-T/21.