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/G164/21 Elevator Pushrods 12/89 DM Applicability: All models. Requirement: Action in accordance with Schweizer G164 SB No 85. Note: FAA AD 89-18-02, Amendment 39-6300 refers. Compliance: Prior to 18 November 1989 and thereafter at periods not exceeding 12 months. Background: The manufacturer has reported corrosion and cracking of the elevator pushrods which in one case led to loss of the aircraft.