COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Beechcraft 60 (Duke) Series Aeroplanes AD/BEECH 60/23 Amdt 1 Aft Facing Seat Back Supports 7/74 Applicability: All models 60 and A60 equipped with optional aft facing seats. Requirement: Action in accordance with Beechcraft SI No. 0591-314, Rev. 1. Compliance: Within 100 hours' time in service after 7 June 1974.