COMMONWEALTH OF AUSTRALIA CIVIL AVIATION ORDERS CIVIL AVIATION SAFETY AUTHORITY PART 105 SCHEDULE OF AIRWORTHINESS DIRECTIVES GULFSTREAM (GRUMMAN) G.159 SERIES AEROPLANES AD/G159/4 Main Landing Gear Retract Cylinder Attach Fitting - Inspection and Modification 9/63 Applicability: S/Nos. 1 to 118. Document: 1. Grumman Customer Bulletin No. 172; or 2. FAA AD 63-21-2.