COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Twin Commander (Gulfstream/Rockwell/ Aerocommander 500, 600 and 700) Series Aeroplanes AD/AC/30 Replacement of Fuel System Aluminium NK Drain Tubing and Fittings and Wing Trailing Edge - Modification Applicability: Models 520 and 560: S/Nos. 1 to 230. Document: 1. Aero Commander SBs No. 77 and 79; or 2. FAA AD 62-8-2. Compliance: Forthwith.