COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Gulfstream (Rockwell) 114 Series Aeroplanes AD/ROCK-114/13 Amdt 1 Vertical Stabiliser Forward Spar Attachment Structure 3/88 Applicability: Models 114 and 114A serial number 14001 to 14540. Requirement: 1. Inspect for cracks in the fuselage frame and the vertical fin attachment fitting as shown in Part I of Gulfstream Aerospace SB 114-23A. Note: This inspection requirement is unchanged from the previous issue of this Directive. 2. Modify the vertical fin attachment in accordance with Part II of Gulfstream Aerospace SB 114-23A. Note: Simple AC 43.13 type repairs are not equivalent. Compliance: For Requirement Para 1: Within 10 hours time in service after 7 May 1987. For Requirement Para 2: Before further flight if cracks are found. Otherwise not later than 24 March 1989. Background: Numerous reports have now been received of cracking in the vertical stabiliser forward spar attachment structure. The manufacturer has analysed the load paths through this critical area and determined that substantial reinforcement is required to prevent further cracking.