COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES S.L. Industries Commander 100 Series and Volair 10 Series Aeroplanes AD/AC-100/12 Exhaust Muffler - Modification 3/73 Applicability: Models 100 and 100-180 as detailed in the compliance document. Document: 1. Aero Commander SB 1019; OR 2. FAA AD 73-1-1. Compliance: Modify within 100 hours' time in service after 30 March 1973.