COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Piper PA-22 (Tri-Pacer and Colt) Series Aeroplanes AD/PA-22/20 Exhaust System - Inspection 9/62 Applicability: All models. Document: Piper SL No. 324B. Compliance: Inspection at intervals not exceeding 100 hours time in service after 21 January 1963.