COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES SAAB SF340 Series Aeroplanes AD/SF340/68 Power Plant - Engine Mount Inspection 2/99 DM Applicability: SAAB Model SF340A, serial numbers -004 through -159 and SAAB Model 340B aeroplanes, serial numbers -160 through -459. Requirement: 1. Perform engine mount inspection in accordance with SAAB Aircraft Mandatory Service Bulletin No. SAAB 340-71-057 Rev 01 dated 18 December 1998, or later revision. 2. Repeat inspection at 1. Above. Note: LFV Airworthiness Directive 1-135 R1 dated 18 December 1998 refers. Compliance: 1. Unless already accomplished, within 400 flight hours of the effective date of this Directive. 2. Every 250 flight hours if required in para 2.B(6) of SAAB Aircraft AB Mandatory Service Bulletin SAAB 340-71-057 R01, dated 18 December 1998. Initial compliance against SAAB 340-71-057, dated 20 November 1998 is an acceptable means of compliance with requirement 1) and 2) above if achieved before the effective date of this Directive. This Airworthiness Directive becomes effective on 13 January 1999. Background: Certain bottom forward engine mounts have been found to be degraded after a short period in service. This degradation reduces the redundancy and damping effects of the engine support system and can lead to heavy chafing of the nacelle structure and fire sensor loop with consequent reduction in safety of the structure and sensor system. This Directive mandates a Country of Origin inspection to locate degraded mounts and replace as necessary.