COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Pilatus Porter PC-6 Series Aeroplanes AD/PC-6/33 Lifting Sling and Aircraft Lifting Points - Limitations 8/71 Applicability: All models. Document: Pilatus SB No. 010. Compliance: Within 100 hours time in service after 30 September 1971.