COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Pilatus PC-12 Series Aeroplanes AD/PC-12/20 Stick Pusher System - Replacement 10/99 DM Applicability: Model PC-12 and PC-12/45 aircraft up to and including MSN180. Requirement: Replace the Stick Pusher Capstan and Servo in accordance with Pilatus Service Bulletin No.22-003 dated 24 June 1999. Note: FOCA AD HB 99-406 dated 16 August 1999 refers. Compliance: Within four months of the effective date of this Directive. This Airworthiness Directive becomes effective on 25 August 1999. Background: Due to manufacturing tolerances it has been found that the original model stick pusher system can input higher control column forces than required by design. This Directive introduces a modified Stick Pusher Capstan and Servo to ensure that control column forces stay within design limits.