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/34 Main Landing Gear Upper Bearing - Modification 12/67 Applicability: Models 500A, 500B, 560F, 680F, 680FL and 680FL(P) with S/Nos. 871, 875, 893 to 1535 except 1496, 1515, 1517, 1527, 1531, 1532 and 1534. Document: Aero Commander SB No. 83, Rev. A. Compliance: Forthwith.