{"id":"F2006B07022","name":"AD/SF340/91 - Main Landing Gear Separation Bolt Electrical Harness Replacement","slug":"ad-sf340-91-main-landing-gear-separation-bolt-electrical-harness-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48690,"registerId":"commonwealth-F2006B07022-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/SF340/91 - Main Landing Gear Separation Bolt Electrical Harness Replacement","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Safety Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \n\nAIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\nFor 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 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/SF340/91 Main Landing Gear Separation Bolt Electrical\n\nHarness Replacement\n\n  \n6/2003\n\nApplicability: Model SF340A aeroplanes with serial numbers (S/N) 004 through 159 inclusive and Model 340B aeroplanes with S/N 160 through 459 inclusive\n\nRequirement: Replace the main landing gear (MLG) separation bolt harness in accordance with Saab Aircraft Mandatory Service Bulletin SAAB 340-32-128 dated 28 March 2003.\n\nNote: LFV AD 1-189 refers.\n\nCompliance: Before 1 April 2004.\n\nThis Airworthiness Directive becomes effective on 12 June 2003.\n\nBackground: Saab has received a number of reports of MLG separation bolt electrical harnesses having broken wires and corroded connectors. If the harness is incorrectly installed or repaired, the function of the separation bolt could be inhibited and consequently the emergency landing gear extension system will not be fully available.\n\nThis Directive requires the replacement MLG separation bolt electrical harness with a new improved harness and supersedes AD/SF340/88, which provided for an interim inspection and repair of the existing harness.\n\n![Signature of Jim Coyne Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nJim Coyne\n\nDelegate of the Civil Aviation Safety Authority 24 April 2003\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 21 May 2003.\n\n  \nPage 1 of 1","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive addressing a specific identified safety defect in a specific aircraft type. The scope remains tightly focused on the original safety purpose — correcting a known wiring harness failure mode. The directive supersedes an earlier interim measure but does not expand beyond the original safety intent."},"complexity_factors":["Single, specific mechanical action required (harness replacement)","Clear applicability criteria limited to specific serial number ranges","Single compliance deadline with no conditional exceptions","Only one cross-reference (to superseded directive and Swedish aviation authority AD)","No nested definitions or interpretive provisions","Total length: approximately 300 words"],"plain_english_summary":"This CASA Airworthiness Directive orders owners/operators of Saab SF340A (s/n 004–159) and SF340B (s/n 160–459) to replace the main landing gear separation bolt electrical harness with the improved unit per Saab Service Bulletin SAAB 340-32-128 (28 Mar 2003). It replaces a prior inspection-only AD because harness failures (broken wires/corroded connectors) can disable emergency gear extension. Compliance required before 1 April 2004."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"Yes. Compared with the earlier AD it supersedes (AD/SF340/88), this version broadens the regulatory obligation: it moves from an interim inspection-and-repair approach to a mandatory, one-time replacement of the MLG separation bolt electrical harness for the specified serial-numbered aircraft. That change increases the compliance burden on affected operators (cost of replacement parts, labour, and downtime) and replaces a monitoring/repair regime with a definitive hardware modification specified in the Saab service bulletin."},"complexity_factors":["Short, single-subject instrument (one mandatory action).","Clear applicability limited to two serial-number ranges (SF340A S/N 004–159; SF340B S/N 160–459).","Single external reference: Saab Mandatory Service Bulletin SAAB 340-32-128 (dated 28 March 2003).","One fixed compliance deadline (before 1 April 2004) and one effective date (12 June 2003).","Supersedes one earlier AD (AD/SF340/88) and cross-references a foreign AD (LFV AD 1-189), but contains no nested exceptions or detailed conditional logic.","No defined-terms list, no multiple compliance pathways, and no continuing reporting or monitoring obligations."],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Applies to Saab SF340A aeroplanes with serial numbers 004–159 and SF340B aeroplanes with serial numbers 160–459 (see \"Applicability\").\n- Requires a mandatory replacement of the main landing gear (MLG) separation bolt electrical harness using the parts and procedure in Saab Aircraft Mandatory Service Bulletin SAAB 340-32-128 dated 28 March 2003 (see \"Requirement\").\n- Sets a compliance deadline: the replacement must be completed before 1 April 2004 (see \"Compliance\").\n- Takes effect 12 June 2003 (see heading and signature block).\n- Notes that a related foreign authority directive (LFV AD 1-189) is relevant (see \"Note\").\n\n**Why CASA issued it (stated reason and mechanical effect)**\n\n- The background says Saab received reports of broken wires and corroded connectors in the MLG separation bolt harness. If the harness is incorrectly installed or repaired, the separation-bolt function could be inhibited, reducing availability of the emergency landing gear extension system (see \"Background\").\n- The AD replaces an earlier directive (AD/SF340/88) that required only interim inspection and repair; this AD mandates fitting a new, improved harness (see \"Background\").\n\n**Who is affected and who pays**\n\n- Aircraft owners/operators of the affected SF340 serial numbers must ensure the harness is replaced in accordance with the Saab service bulletin; they bear the cost of parts, labour, and any associated aircraft downtime.\n- Maintenance organisations performing the work must follow the manufacturer’s instructions to satisfy the AD.\n\n**What this changes in behaviour and decisions**\n\n- Operators must schedule the mandatory modification and source the new harness and associated materials (or an approved alternative if allowed by the AD and the regulator).\n- Maintenance organisations will perform the replacement to the service bulletin specification and record compliance in maintenance logs as required by aviation safety regulations.\n\n**Costs, incentives and trade-offs**\n\n- Direct costs to operators: purchase of replacement harnesses, labour, and aircraft downtime while work is carried out. The AD does not specify funding or subsidies, so operators pay.\n- Safety benefit (as stated): reduces the risk that an impaired harness will disable the separation bolt and, by extension, the emergency gear-extension system.\n- Opportunity cost: scheduled maintenance slots and resources are diverted to this mandated modification; smaller operators may feel this more acutely if parts or capacity are constrained.\n- Incentives for suppliers: demand for the improved harness increases for the specified serial ranges; authorised maintenance providers gain revenue from performing the work.\n\n**Implementation and compliance risks**\n\n- Availability of the new harness parts by the compliance deadline could constrain operators and temporarily increase aircraft downtime.\n- Work must follow the Saab service bulletin precisely; incorrect installation or use of non‑approved parts could leave the unsafe condition uncorrected and risk non‑compliance.\n- The AD cross-references a foreign AD (LFV AD 1-189), so operators who use foreign maintenance approvals should ensure regulatory alignment.\n\n**How it changed from the prior AD**\n\n- The AD supersedes AD/SF340/88, moving from an interim inspection/repair regime to a mandatory replacement with an improved harness (see \"Background\"). That changes the compliance obligation from periodic inspection/repair to a one‑time replacement for the listed aircraft.\n\nSections cited: Applicability; Requirement (refers to Saab Service Bulletin SAAB 340-32-128 dated 28 March 2003); Compliance (before 1 April 2004); Background; Note (LFV AD 1-189)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-sf340-91-main-landing-gear-separation-bolt-electrical-harness-replacement","history":"/api/acts/ad-sf340-91-main-landing-gear-separation-bolt-electrical-harness-replacement/history","analysis":"/api/acts/ad-sf340-91-main-landing-gear-separation-bolt-electrical-harness-replacement/analysis","conflicts":"/api/acts/ad-sf340-91-main-landing-gear-separation-bolt-electrical-harness-replacement/conflicts","importantCases":"/api/acts/ad-sf340-91-main-landing-gear-separation-bolt-electrical-harness-replacement/important-cases","documents":"/api/acts/ad-sf340-91-main-landing-gear-separation-bolt-electrical-harness-replacement/documents"}}