COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Schweizer (Grumman) G-164 (Ag-Cat) Series Aeroplanes AD/G164/17 Lower Wing Attachment Fittings - Inspection 12/78 Applicability: All models G-164, G-164A and G-164B which have achieved 500 flying hours or 6 months time in service. Document: Gulfstream American AG-CAT (G164) SB No. 65. Compliance: Within 25 hours time in service after 6 November 1978 and there- after at intervals not exceeding 500 hours time in service or 6 months whichever occurs first.