COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Piaggio P166 Series Aeroplanes AD/P166/13 Hydraulic Pressure Switch - Provision of Guards 9/61 Applicability: S/Nos. prior to 376. Document: Piaggio SB P166-5. Compliance: Forthwith.