COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Short SD3-60 Series Aeroplanes AD/SD3-60/49 Engine Controls - Inspection and Replacement 1/99 Applicability: All Short Brothers SD3-60 Sherpa aircraft. Requirement: Inspect and replace as necessary all power control cables and pulleys in accordance with Short Brothers Service Bulletin SD3-60 Sherpa - 76-1. Note: UK CAA AD 004-07-98 dated 22 October 1998 refers. Compliance: At the next scheduled maintenance programme 'D' check or 1200 flight hours after the effective date of this Directive, whichever is the sooner. This Airworthiness Directive becomes effective on 28 January 1999. Background: Experience has shown that the 7 x 7 power control cables are subject to breakage of wires. This Service Bulletin introduces more flexible cables which are of 7 x 19 construction and requires the changing of certain pulleys to improve the reliability of the cables.