AD/SF340/75 - Bolt and Bushing Installation at WS 123.38 (Cth)

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES

SAAB SF340 Series Aeroplanes

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

AD/SF340/75 Bolt and Bushing Installation at WS 123.38 3/2000

Applicability: Model SF340A, serial numbers 004 through 159, and Model 340B, serial numbers 160 through 459; with flap assembly and serial numbers listed below:

- 7257800-507, serial numbers 1258 through 1270.

- 7257800-508, serial numbers 1257 through 1269.

Requirement: Action in accordance with SAAB Aircraft Mandatory Service Bulletin (SB) 340-57- 035, dated 18 January 2000.

Note: LFV AD 1-152 refers.

Compliance: Identification and initial inspection to be accomplished within 800 hours time in service after 23 March 2000. Inspect thereafter at intervals not to exceed 800 hours time in service.

Replacement to be accomplished within 4800 hours time in service after 23 March 2000.

This Airworthiness Directive becomes effective on 23 March 2000.

Background: Some discrepancies have been found in the bolt and bushing installation at WS 123.38. The most likely cause was at implementation of SB 340-57-027. Bushings of incorrect length may have been installed at the forward attachment point to the triangular fitting. Bolts and bushings may also have been installed at the aft attachment point. As a consequence, high bearing stresses may lead to worn bushings, elongated holes, vibrations and cracked flap fittings.