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-6/25 Amdt 1 Aileron Balance Weight Arms - Inspection 11/72 Applicability: All models fitted with aileron mass balance weight assembly P/No. 6106.11. Document: Pilatus SB No. 89A. Compliance: Within 100 hours time in service after 30 November 1972 and there- after at intervals not exceeding 100 hours time in service until replaced by aileron balance weight assembly P/No. 111.45.08.001.