COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Allison Turbine Engines - 250 Series AD/AL 250/9 Engine Operating Restrictions to Reduce Torque-Meter Shaftgears Stress Applicability: All 250-C18 Series fitted with P/N 6854147 or P/N 6871186 Torque-meter Shaftgears. Document: Allison 250 CSL No. 34. 9/69 Compliance: For para. 1 - at next daily or overnight inspection after 5 Sept.69. For para. 2 - Forthwith.