COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Douglas DC4 Series Aeroplanes AD/DC4/32 Master Ignition Switch - Modification NK Applicability: All models. Requirement: 1. Remove the master ignition switches from the switch boxes mounted on the header panel and modify the ignition control system so that there are no separate master ignition switches for the port and starboard pairs of engines. Note: This Order does not prohibit the fitment of a single master ignition switch for all four engines. 2. Label each individual engine ignition switch so that no confusion can arise in recognising which engine is connected to the switch; or ANO 105.1.16.2.5.30.