{"id":"F2006B07015","name":"AD/SF340/84 Amdt 1 - MLG Retract Actuator Bracket Attachment Bolt","slug":"ad-sf340-84-amdt-1-mlg-retract-actuator-bracket-attachment-bolt","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48667,"registerId":"commonwealth-F2006B07015-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/SF340/84 Amdt 1 - MLG Retract Actuator Bracket Attachment Bolt","content":"![](image.001.png)\n\n![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nOn the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/SF340/84 and issues the following AD under subregulation 39.1 (1) of CASR 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 aircraft or 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.\n\n![](image.001.png)\n\nSAAB SF340 Series Aeroplanes\n\nAD/SF340/84\n\nAmdt 1\n\n  \n\nMLG Retract Actuator Bracket Attachment Bolt\n\n  \n9/2004\n\nApplicability: Model SF340A aircraft, serial numbers SF340A-004 through \\-159.\n\nModel 340B aircraft, serial numbers 340B-160 through \\-459.\n\nRequirement: 1. Action in accordance with SAAB Aircraft Service Bulletin 340-32-124, dated 26 February 2002.\n\n2. Action in accordance with SAAB Aircraft Service Bulletin 340-32-131, dated 29 June 2004.\n\nIf corrosion or other damage (except for light fret marks) is found during the Requirement 2 inspection, before further flight, replace the bolt and repair any damage.\n\nNote: LFV AD 1-173 and AD 1-195 refer.\n\nCompliance: 1. Before 5 March 2003.\n\n2. Before 2 March 2005.\n\nThe compliance time remains unchanged for Requirement 1 by this issue. This Amendment becomes effective on 2 September 2004.\n\nBackground: Failure history of the main landing gear retract actuator bracket attachment bolt indicates hydrogen embrittlement as the cause. Bolt failure will cause the bracket to come loose and prevent retraction of the affected main landing gear and result in considerable damage to main gear components. This Directive required installation of improved bolts.\n\nAmendment 1 is issued in response to a new LFV AD, which requires inspection of the bolt installed by the original issue of this Directive, due to the possibility of incorrect installation.\n\nSAAB SF340 Series Aeroplanes\n\nAD/SF340/84 Amdt 1 (continued)\n\nThe original issue of this Airworthiness Directive became effective on 16 May 2002.\n\n![Signature of David Villiers Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority 21 July 2004\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 11 August 2004.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"The original AD required installation of an improved bolt to correct hydrogen embrittlement failures (original issue effective 16 May 2002). Amendment 1 expands the scope of required activity by adding a mandatory inspection of the bolt that was fitted under the original directive because of concerns about possible incorrect installation. In practical terms, the amendment does not broaden which aircraft are covered but it adds an additional mandatory inspection step and a conditional requirement to replace and repair if damage is found (see \"Amendment 1\" and \"Requirement 2\")."},"complexity_factors":["Short, single-topic instrument (main landing gear bolt)","2 required actions (Service Bulletins 340-32-124 and 340-32-131)","Clear applicability defined by two serial number ranges","Two fixed compliance deadlines (Requirement 1 and Requirement 2)","One conditional outcome (replace bolt if corrosion/damage other than light fret marks)","Cross-references to manufacturer service bulletins and two other ADs (LFV AD 1-173 and AD 1-195)"],"plain_english_summary":"**What this directive does (mechanics)**\n\n- Applies to Saab SF340A and 340B aeroplanes within specified serial number ranges (SF340A-004 through -159; 340B-160 through -459) (see \"Applicability\").\n- Requires two specific maintenance actions to be carried out in accordance with Saab Service Bulletins: 340-32-124 (dated 26 Feb 2002) and 340-32-131 (dated 29 Jun 2004) (see \"Requirement\").\n- If corrosion or other damage (other than light fret marks) is found during the second inspection, the bolt must be replaced and any damage repaired before the aircraft flies again (see \"Requirement 2\").\n- Sets latest dates for compliance: the first action had to be done before 5 March 2003; the second before 2 March 2005. The amendment took effect on 2 September 2004 (see \"Compliance\" and heading information).\n\n**Who is affected**\n\n- Aircraft owners/operators and approved maintenance organisations responsible for Saab SF340 aircraft inside the listed serial ranges. Maintenance personnel must follow the referenced Saab service bulletins to carry out the inspections and any replacements/repairs.\n- Regulators monitoring compliance (Civil Aviation Safety Authority delegate enforced under CASR 1998 subregulation 39.1(1)).\n\n**Why it matters (safety problem and remedy)**\n\n- The background states that failures of the main landing gear (MLG) retract actuator bracket attachment bolt were linked to hydrogen embrittlement. A bolt failure can let the bracket come loose, prevent retraction of the affected main landing gear and cause substantial damage to the gear (see \"Background\").\n- The original directive required installation of an improved bolt to address that failure mode. Amendment 1 adds an inspection of the bolt fitted under the original directive because of concern the bolt may have been installed incorrectly (see \"Amendment 1\").\n\n**Who pays and what changes in behaviour**\n\n- Direct costs fall on aircraft operators/owners: inspections, any replacements, and repairs, plus aircraft downtime while maintenance is performed.\n- Maintenance organisations must perform the inspections and follow Saab service bulletin instructions; if damage beyond light fret marks is found, they must replace the bolt and repair damage before further flight (see \"Requirement 2\").\n\n**Trade-offs, risks and implementation notes**\n\n- Costs vs risk: The directive imposes inspection and replacement costs and downtime in exchange for reduced risk of in‑flight or ground incidents linked to bolt failure.\n- Timing and operational impact: The second inspection had a fixed compliance deadline (before 2 March 2005). If work was not scheduled early, operators faced potential short‑notice maintenance and disruption.\n- Implementation precision: The AD mandates compliance with manufacturer service bulletins; correct interpretation and application by maintenance staff is necessary to achieve the intended safety outcome. The amendment itself arises from concern about incorrect installation, which indicates an implementation risk in the original corrective action.\n- Compliance enforcement: The CASA delegate issued the AD under CASR authority; operators must comply or face regulatory action.\n\n**Relevant cross-references**\n\n- The AD references two Saab service bulletins (340-32-124 and 340-32-131) and other airworthiness directives (LFV AD 1-173 and AD 1-195) for related matters (see the AD \"Requirement\" and Note).\n\n(References in this summary are to the AD sections labelled \"Applicability\", \"Requirement\", \"Compliance\", \"Background\" and \"Amendment 1\".)"},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original purpose: addressing the unsafe condition of the main landing gear retract actuator bracket attachment bolt. Amendment 1 adds a secondary inspection requirement (Requirement 2) in response to new information about potential incorrect installation, but this is a logical extension of the original safety purpose rather than scope creep. The document does not expand to cover unrelated aircraft systems or broader operational matters."},"complexity_factors":["Short, single-purpose document (2 pages)","Only 2 substantive requirements with clear deadlines","Limited applicability (specific aircraft models and serial number ranges)","Simple conditional logic (only one 'if-then' scenario regarding corrosion findings)","Cross-references to 2 external SAAB service bulletins and 2 Swedish aviation directives (LFV ADs), but these are standard aviation practice references","No nested definitions or interpretation sections"],"plain_english_summary":"This AD requires operators of specified SAAB SF340A/340B aeroplanes to install improved bolts on the main landing‑gear retract actuator bracket by March 2003 and to carry out a follow‑up inspection (with replacement and repair if corrosion or damage beyond light surface marks is found) by March 2005. \n\nIt responds to bolt failures from hydrogen embrittlement and incorrect installations that could prevent gear retraction, cause structural damage, and render aircraft unairworthy."}},"importantCases":[],"_links":{"self":"/api/acts/ad-sf340-84-amdt-1-mlg-retract-actuator-bracket-attachment-bolt","history":"/api/acts/ad-sf340-84-amdt-1-mlg-retract-actuator-bracket-attachment-bolt/history","analysis":"/api/acts/ad-sf340-84-amdt-1-mlg-retract-actuator-bracket-attachment-bolt/analysis","conflicts":"/api/acts/ad-sf340-84-amdt-1-mlg-retract-actuator-bracket-attachment-bolt/conflicts","importantCases":"/api/acts/ad-sf340-84-amdt-1-mlg-retract-actuator-bracket-attachment-bolt/important-cases","documents":"/api/acts/ad-sf340-84-amdt-1-mlg-retract-actuator-bracket-attachment-bolt/documents"}}