COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Douglas DC3 Series Aeroplanes AD/DC3/30 Front (Pilots) Seats Restraint NK Installations - Modification Applicability: All models. Requirement: Modify each front (pilot) seat restraint installation by fitting a symmetric safety harness incorporating an inertia reel in with a scheme approved by the Secretary. Compliance: Before 1 July 1973 unless already accomplished.