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-N22/17 Amdt 1 Horizontal Stabiliser Trim Tab System - Inspection and Modification 1/79 Applicability: All models N22 and N24 series delivered from the factory prior to 21 September 1978. Document: GAF Alert SB No. AN22-55-4, Rev. 2. Compliance: Unless already accomplished, within 100 hours time in service after 31 January 1979.