COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Beechcraft 76 (Duchess) Series Aeroplanes AD/BEECH 76/9 Amdt 1 Engine Mount Assembly 7/82 Applicability: All models 76 with S/Nos. ME 1 to ME-415. Requirement: Action in accordance with Beechcraft SI No. 1147 R1. Compliance: As per Requirement Document. Background: Cracks may develop in the lower tubes of the engine mount assembly. Amdt. 1 is issued to extend aircraft serial number effectivity.