{"id":"F2006B07021","name":"AD/SF340/90 Amdt 2 - Main Landing Gear Assistor Spring and Bearing Replacement","slug":"ad-sf340-90-amdt-2-main-landing-gear-assistor-spring-and-bearing-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48686,"registerId":"commonwealth-F2006B07021-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)  \n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/SF340/90 Amdt 1 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","sortOrder":0},{"sectionNumber":"AD/SF340/90","sectionType":"part","heading":"AD/SF340/90","content":"# AD/SF340/90\n\nAmdt 2\n\n  \n\nMain Landing Gear Assistor Spring and Bearing Replacement\n\n  \n9/2003","sortOrder":1},{"sectionNumber":"DM","sectionType":"part","heading":"DM","content":"# AD/SF340/90\n\nAmdt 2\n\n  \n\nMain Landing Gear Assistor Spring and Bearing Replacement\n\n  \n9/2003\n\n# DM","sortOrder":2}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"This instrument expressly revokes AD/SF340/90 Amdt 1 and issues AD/SF340/90 Amdt 2, thereby changing the operative airworthiness directive that applies to SAAB SF340 series aeroplanes. The supplied text changes the legal instrument in force (revocation and replacement) and therefore alters the previous scope or obligations established by Amdt 1; the exact nature and extent of those changes depend on the requirement, applicability and compliance details contained in the full AD text (which are not included in the excerpt). (See: \"revokes Airworthiness Directive (AD) AD/SF340/90 Amdt 1 and issues the following AD...\" and the AD title.)"},"complexity_factors":["Legal cross-reference to CASR 1998 subregulation 39.1(1), which locates the AD in delegated regulatory authority and requires reading the parent regulation for full legal context.","Revocation and re-issuance of a prior AD (\"revokes... Amdt 1 and issues... Amdt 2\"), which requires comparing instruments to determine what changed.","Separation of content across named sections (applicability, requirement, compliance), meaning readers must assemble obligations from multiple interdependent parts.","Technical maintenance action (replacement of main landing gear assistor spring and bearing) that presumes domain-specific procedures and parts — the AD delegates the technical detail to the requirement/instructions section.","Operational impacts on private parties (operators, maintenance organisations) including costs, scheduling and certification that are not specified in the excerpt but are implied by the AD’s structure.","Administrative discretion vested in the CASA delegate to determine the corrective action and timing, creating potential variability in enforcement and implementation.","Absence of the detailed requirement and compliance text in the supplied excerpt increases interpretative complexity for affected parties seeking immediate, actionable steps."],"plain_english_summary":"### What this instrument does, in plain terms\n\nThis document revokes the earlier Airworthiness Directive AD/SF340/90 Amdt 1 and replaces it with AD/SF340/90 Amdt 2. It is an Airworthiness Directive issued under subregulation 39.1(1) of CASR 1998 and is titled “Main Landing Gear Assistor Spring and Bearing Replacement” for SAAB SF340 series aeroplanes. (See: “revokes Airworthiness Directive (AD) AD/SF340/90 Amdt 1 and issues the following AD under subregulation 39.1 (1) of CASR 1998.” and the title.)\n\nMechanically, the AD requires that the corrective action described in the AD’s requirement section be carried out for the aircraft identified in the applicability section. The AD states that the action must be taken: (a) in the circumstances specified in the requirement section; (b) according to the instructions set out in the requirement section; and (c) at the time specified in the compliance section. (See: \"the AD requires that the action set out in the requirement section... be taken... (a)... (b)... (c)...\")\n\n### Who this affects\n\n- Aircraft owners and operators of SAAB SF340 series aeroplanes listed in the AD’s applicability section. (Applicability is referenced in the AD text.)\n- Maintenance organisations and engineers who will perform the replacement work and certify compliance.\n- The CASA delegate (the decision-maker identified in the instrument) who exercises the statutory power to issue and revoke ADs under CASR. (See: issuance under subregulation 39.1(1) of CASR 1998 and the delegate who revokes and issues the AD.)\n\n### Who pays and who decides\n\n- Operators/owners pay for parts, labour and any aircraft downtime needed to carry out the replacement and to meet record-keeping or certification requirements. (The AD requires specified action to be taken for affected aircraft at the time mentioned in the compliance section.)\n- The CASA delegate decides the content of the AD and when to revoke or replace a prior AD, exercising delegated regulatory authority under CASR 1998. (See: text revoking the prior AD and issuing the AD under subregulation 39.1(1).)\n\n### What behaviour changes are required\n\n- Operators must schedule and undertake the component replacement and any related maintenance required by the AD’s requirement and compliance sections; they must follow the instructions set out in the AD. (See: requirement that action be taken in accordance with instructions and at the time mentioned in the compliance section.)\n- Maintenance organisations must perform or supervise the specified replacement work and record compliance as required by regulatory practice for ADs.\n\n### Stated purpose and practical trade-offs\n\n- The AD is presented as necessary to \"correct the unsafe condition\" (the AD text describes the action as \"being action that the delegate considers necessary to correct the unsafe condition\"). That is the instrument’s stated purpose.\n\n- Practical trade-offs and implementation considerations arising mechanically from the AD include: parts and labour costs to operators; scheduling and potential aircraft downtime to meet any compliance deadline; reliance on available approved parts and maintenance capability; and administrative actions to record and demonstrate compliance. These follow from the AD’s structure requiring specified actions, instructions and timing for affected aircraft. (See: requirement that action be taken for applicable aircraft in accordance with the instructions and timing in the compliance section.)\n\n### Implementation and discretion\n\n- The instrument is an exercise of delegated regulatory power: the CASA delegate revoked the prior amendment and issued this amendment under CASR. That creates administrative discretion over the AD’s content and timing. (See: revocation and issuance language and the reference to subregulation 39.1(1) of CASR 1998.)\n\n### What is not contained here\n\n- The text supplied does not include the detailed requirement section, the specific applicability criteria (such as serial numbers or serial ranges), the technical instructions, or the compliance deadlines. Those details determine the precise scope of affected aircraft, the exact replacement procedure, and the timing obligations. Operators must consult the full AD document (requirement, applicability and compliance sections) to know the precise obligations."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is Amendment 2 of an existing Airworthiness Directive. It replaces Amendment 1 but maintains the same core purpose: addressing the main landing gear assistor spring and bearing issue in SAAB SF340 aircraft. The scope remains tightly focused on this specific safety issue and aircraft type."},"complexity_factors":["Short, single-purpose directive focused on one specific mechanical component","Standard CASA AD structure with clearly separated sections (applicability, requirement, compliance, background)","No nested definitions or extensive cross-referencing to other legislation","Refers to subregulation 39.1(1) of CASR 1998 as enabling power only","Mechanical task described in plain language ('Main Landing Gear Assistor Spring and Bearing Replacement')","Limited conditional logic — applies to specific aircraft series only"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by the Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nThis directive requires owners and operators of **SAAB SF340 series aeroplanes** to replace specific parts in the main landing gear — namely the \"assistor spring\" and its bearing. These parts help the landing gear function properly during takeoff and landing.\n\n**Why it matters:**\nThe previous version of this safety order (Amendment 1) is being cancelled and replaced with this updated version (Amendment 2). The replacement is necessary to fix an unsafe condition that could affect the aircraft's landing gear performance.\n\n**Who must comply:**\nAnyone who owns, operates, or maintains SAAB SF340 aircraft must follow the instructions in this directive. The directive specifies:\n- **What** must be done (replace the spring and bearing)\n- **When** it must be done (compliance timeframe in the compliance section)\n- **How** it must be done (instructions in the requirement section)\n\n**Key point:** Airworthiness Directives are legally binding. Failure to comply means the aircraft cannot be flown legally in Australia."}},"importantCases":[],"_links":{"self":"/api/acts/ad-sf340-90-amdt-2-main-landing-gear-assistor-spring-and-bearing-replacement","history":"/api/acts/ad-sf340-90-amdt-2-main-landing-gear-assistor-spring-and-bearing-replacement/history","analysis":"/api/acts/ad-sf340-90-amdt-2-main-landing-gear-assistor-spring-and-bearing-replacement/analysis","conflicts":"/api/acts/ad-sf340-90-amdt-2-main-landing-gear-assistor-spring-and-bearing-replacement/conflicts","importantCases":"/api/acts/ad-sf340-90-amdt-2-main-landing-gear-assistor-spring-and-bearing-replacement/important-cases","documents":"/api/acts/ad-sf340-90-amdt-2-main-landing-gear-assistor-spring-and-bearing-replacement/documents"}}