COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Piper PA-31 Series Aeroplanes AD/PA-31/109 Landing Gear Upper Bearing Retaining Pins and Strut Assemblies Applicability: All model PA-31 with S/Nos as listed in Piper Service Bulletin No. 779A. Requirement: Action in accordance with Piper S.B. No 779A. Note: FAA AD 85-08-05 refers. Compliance: Within 100 hours time in service after 31 October 1985. 8/85 Background: Failure of landing gear upper bearing retaining pins could result in unrestricted extension of the piston tube and wheel assemblies. This Directive requires the replacement of the retaining pins and, in addition, an inspection and replacement of the upper bearing as applicable.