{"id":"F2006B06999","name":"AD/SF340/7 Amdt 1 - Power Turbine Speed Signal - Overspeed Protection","slug":"ad-sf340-7-amdt-1-power-turbine-speed-signal-overspeed-protection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48621,"registerId":"commonwealth-F2006B06999-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/SF340/7 Amdt 1 - Power Turbine Speed Signal - Overspeed Protection","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  SAAB SF340 Series Aeroplanes\n\n \n\nAD/SF340/7\n\nAmdt 1\n\n\nPower Turbine Speed Signal - Overspeed Protection\n\n\n8/87\n\n \n\nApplicability: SAAB 340A Aircraft.\n\n \n\nRequirement: Action in accordance with SAAB Service Bulletin SF 340-76-018.\n\n \n\nNote: Swedish Airworthiness Directive SAD NO. 1-021 refers.\n\n \n\nEffectivity: 31 July 1987.\n\n \n\nBackground:  This amendment has been raised to incorporate the final closing action for overspeed protection to prevent engine power turbine overspeed and with it the risk of uncontained engine failure. The amendment supersedes the FAA Telegraphic AD T86-10-51.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The amendment incorporates a \"final closing action\" for overspeed protection by mandating compliance with SAAB Service Bulletin SF 340-76-018 and in doing so supersedes the earlier FAA Telegraphic AD T86-10-51 (Background; Requirement). That alters the regulatory path by replacing or updating prior regulatory direction with a requirement to follow the manufacturer’s specified corrective action."},"complexity_factors":["Narrow applicability (only Saab 340A aircraft) — reduces legal scope but concentrates effect (Applicability).","Delegation to an external technical document (SAAB Service Bulletin SF 340-76-018) for the substantive work — readers must consult that bulletin to know required actions (Requirement).","Safety‑critical technical content not reproduced in the AD — enforcement and compliance assessment depend on external maintenance records and expert judgment (Requirement; header).","Cross‑references to foreign airworthiness directives and to a superseded FAA AD — creates interjurisdictional linkage that requires attention to other documents (Note; Background).","Effectivity date and amendment history are short and fixed, but the AD does not describe verification, timelines, or exemptions within the text supplied — practical implementation relies on regulator procedures not included here (Effectivity; header)."],"plain_english_summary":"The AD requires Saab 340A operators to carry out the corrective work specified in SAAB Service Bulletin SF 340-76-018, effective 31 July 1987, to provide final power‑turbine overspeed protection and prevent uncontained engine failure.\n\nCompliance is mandatory under CASA; operators must arrange, resource and pay for the maintenance, while technical specifics and costs are determined by the referenced service bulletin."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive focused on a specific technical safety issue (turbine overspeed protection) for a specific aircraft model. It has not expanded beyond its original safety purpose. The amendment simply updates the directive to incorporate the final closing action and supersede an earlier emergency order, maintaining the same core scope."},"complexity_factors":["Very short document (approximately 150 words)","Only 1 defined applicability criterion (SAAB 340A Aircraft)","Single requirement referencing an external technical document (SAAB Service Bulletin)","No nested conditional logic or exceptions","No cross-references to other legislation beyond a note about a Swedish directive","Straightforward command structure: identify aircraft → apply service bulletin → done"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nThis directive requires owners or operators of **SAAB 340A aircraft** to carry out specific maintenance or modifications to fix a safety problem with the **power turbine speed signal**. The goal is to prevent the engine's power turbine from spinning too fast (\"overspeed\"), which could cause the engine to break apart uncontrollably — a catastrophic failure that could damage the aircraft or injure passengers.\n\n**Who it affects:**\n- Operators of SAAB 340A aircraft in Australia\n- Maintenance organisations servicing these aircraft\n\n**What must be done:**\nOperators must follow the instructions in **SAAB Service Bulletin SF 340-76-018** — a technical document from the manufacturer detailing the exact repair or inspection steps required.\n\n**Why it matters:**\nUncontained engine failure is extremely dangerous. This directive closes out a safety issue by ensuring the final protective measures are in place to stop turbine overspeed before it happens. It replaces an earlier emergency order from the US Federal Aviation Administration (FAA Telegraphic AD T86-10-51), bringing the Australian requirement up to date with the permanent fix."}},"importantCases":[],"_links":{"self":"/api/acts/ad-sf340-7-amdt-1-power-turbine-speed-signal-overspeed-protection","history":"/api/acts/ad-sf340-7-amdt-1-power-turbine-speed-signal-overspeed-protection/history","analysis":"/api/acts/ad-sf340-7-amdt-1-power-turbine-speed-signal-overspeed-protection/analysis","conflicts":"/api/acts/ad-sf340-7-amdt-1-power-turbine-speed-signal-overspeed-protection/conflicts","importantCases":"/api/acts/ad-sf340-7-amdt-1-power-turbine-speed-signal-overspeed-protection/important-cases","documents":"/api/acts/ad-sf340-7-amdt-1-power-turbine-speed-signal-overspeed-protection/documents"}}