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-12/5 Hydraulic Hand Pump 2/97 Applicability: All PC-12 aircraft from S/N 101 up to and including S/N 153. Requirement: Incorporate Pilatus modification 960341 as detailed in Pilatus PC XII Service Bulletin No 29-001 dated Jul 01, 96. Note: Swiss FOCA AD HB96-139 dated 18-03-1996 refers. Compliance: Unless previously carried out action within 300 hours time in service from an effective date of 30 January 1997 or by 30 April 1997, whichever occurs first. Background: The manufacturer has advised of a hand pump non return valve failure which resulted in main system hydraulic pressure entering the hand pump. This pressure caused the hand pump handle to come in contact with the top of the nose wheel well which then forced the pump body to move upwards and impact on the PCL quadrant assembly. This caused the PCL movement to be stiff during flight.