COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bell Helicopter Textron Canada (BHTC) 206 and Agusta Bell 206 Series Helicopters AD/BELL 206/66 Tail Rotor Control Tube - Inspection 4/75 Applicability: Models 206A, 206B, AB206A and AB206B with S/Nos. referenced in requirement documents. Document: Bell SB 206-75-2, or Agusta SB No. BT206-94. Compliance: Within 100 hours time in service after 30 April 1975. Background: AD/Agusta 206/52 equivalent.