COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Aerospatiale Rallye Series Aeroplanes AD/MSR/21 Front Seat Support Beam Protection - Installation 7/74 Applicability: All models. Requirement: Install a front seat support beam protection cover in accordance with a scheme approved by the Secretary. Compliance: Within 100 hours time in service after 30 August 1974.