COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES SAAB SF340 Series Aeroplanes AD/SF340/72 MLG Hydraulic Swivel Brackets 10/99 Applicability: Model SF340A aircraft, serial numbers 004 through 159, and Model 340B aircraft, serial numbers 160 through 339. Requirement: Action in accordance with SAAB Aircraft AB Mandatory Service Bulletin 340-29- 009 Revision 2, dated 2 July 1999. Note: LFV AD 1-145 refers. Compliance: Before 2 July 2000. This Airworthiness Directive becomes effective on 7 October 1999. Background: A misalignment of the downlock or brake swivels in the main landing gear dragbrace and shock strut trunnions has, due to excessive loads during extension/retraction of the landing gear, resulted in abnormally high failure rate of the hydraulic swivels; and subsequent loss of hydraulic systems.