COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Beechcraft 36 (Bonanza) Series Aeroplanes AD/BEECH 36/21 Amdt 1 Aft Facing Seat Back Supports 7/74 Applicability: All models 36 and A36 equipped with optional aft facing seats. Requirement: Action in accordance with Beechcraft SI No. 0591-314. Compliance: Within 100 hours time in service after 31 December 1973.