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-N22/24 Audio System Modification 11/78 Applicability: All N22 and N22B aircraft fitted with Customer option G50 and not modified to Nomad Mod. N97 standard. Document: GAF SB NMD-23-1 or an alternative modification which has been approved by the Secretary. Compliance: Within 100 hours time in service after 30 November 1978.