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-N22/13 Amdt 1 Fuel Crossfeed Selector Knob - Inspection and Replacement 8/77 Applicability: All models N22 and N22B. Document: 1. GAF Alert SB No. N22.28.4' and 2. GAF SB No. N22.28.5. Compliance: For GAF Alert SB No. N22.28.4: Before further flight after 7 February 1977 and thereafter at intervals not exceeding 100 hours time in service until GAF SB No. N22.28.5 is incorporated. For GAF SB No. N22.28.5: Before 1 November 1977.