COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Instruments and Automatic Pilots AD/INST/11 Automatic Pilot Servo Actuators - Inspection 6/74 Applicability: Automatic Pilot Servo Actuators Type PA500A below S/No. 3000, Type PA520A below S/No. 2800, and Type PA520B below S/No. 1500, without a white dot painted either adjacent to or on the actuator nameplate. Document: 1. Cessna Avionics SL AV 74-3 and ARC SB No. 171; or 2. FAA AD 74-08-01. Compliance: Within 100 hours time in service after 28 June 1974.