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/67 Goodyear Fuel Cells - Inspection 6/78 Applicability: Models: 500, 500A, 500B, 500U, 560A, 560E, 560F, 680, 680E, 680F, 680F(P), 680FL, 680FL(P), 680T, 680V, 680W and 720 with S/Nos. 231 to 1969; 500S with S/Nos. 3050 and on; 681 with S/Nos. 6001 to 6072; 685 with S/Nos. 12000 to 12066; 690, 690A and 690B with S/Nos. 11001 and on; fitted with Goodyear BTC-39 fuel cells. Document: Rockwell International SB No. 165. Compliance: Within 100 hours' time in service after 30 June 1978 and annually thereafter as detailed in Rockwell International SB No. 165.