COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES SIAI Marchetti S205 and S208 Series Aeroplanes AD/SM-205/33 Exhaust System Muffler Assembly - Inspection - Replacement 9/83 Applicability: All S205-22R aircraft fitted with muffler assembly P/Ns. 870-8 or P/Ns. 870-9. Document: SIAI Marchetti SB No. 205B56. Compliance: Within 100 hours time in service after 30th September 1983, or, when muffler assembly has accumulated 500 hours time in service, which- ever occurs later, after 30 September 1983. Thereafter, at intervals of 100 hours time in service. Background: Instances of detachment of the muffler baffling have been reported by the manufacturer which can result in partial or complete loss of engine power.