COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES GAF N22 and N24 Series Aeroplanes AD/GAF-N22/27 Rudder Tab - Modification 8/79 Applicability: All models N22 and N22B not modified in accordance with GAF SB No. NMD-27-3, Rev. 1. Requirement: Modify in accordance with GAF SB No. NMD-27-3, Rev. 1. Note: The speed of 180 Kts IAS should not be exceeded on aircraft not yet modified. Compliance: Before 1 December 1979. Background: Manufacturer's tests indicate that wear and backlash which may develop in the rudder tab system during normal service may erode the tab/rudder flutter speed margins.