COMMONWEALTH OF AUSTRALIA CIVIL AVIATION ORDERS CIVIL AVIATION SAFETY AUTHORITY PART 105 SCHEDULE OF AIRWORTHINESS DIRECTIVES GULFSTREAM (GRUMMAN) G.159 SERIES AEROPLANES AD/G159/21 Wing Rear Beam Upper Cap Splice Angles - Inspection 6/73 Applicability: All models. Document: Grumman Customer Bulletin No. 230. Compliance: Unless already accomplished, before next issue of MR or 31 July 1973 whichever occurs first and thereafter at intervals not exceeding 1 year.