COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Sikorsky S-76 Series Helicopters AD/S-76/9 Cyclic Torque Tube - Inspection of Centre Support Bearing Housing 3/80 Applicability: Model S-76. Document: Sikorsky CSB 76-67-7. Compliance: Within 10 hours time in service after 14 February 1980. Background: Some bearing support housings have been incorrectly manufactured, with the bearing retaining shoulder on the wrong side. This would permit axial displacement of the bearing along the torque tube.