COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Short SD3-60 Series Aeroplanes AD/SD3-60/51 Elevator Control Torque Tube Bearing Housing 3/99 Applicability: All SD3-60 aircraft. Requirement: Action in accordance with Shorts Mandatory Service Bulletin SD360-27-28. Compliance: Before 25 September 1999. This Airworthiness Directive becomes effective on 25 March 1999. Background: Experience shows that existing bolts securing elevator control torque tube bearing housing retaining plate to pilots seat pedestal have been found loose, probably because the significance of the structure was not recognised during maintenance.