{"id":"F2006B06119","name":"AD/PC-6/17 - Landing Gear Strut - Modification","slug":"ad-pc-6-17-landing-gear-strut-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46883,"registerId":"commonwealth-F2006B06119-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PC-6/17 - Landing Gear Strut - Modification","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)  Pilatus Porter PC-6 Series Aeroplanes\n\n \n\nAD/PC-6/17 Landing Gear Strut - Modification N/K\n\nApplicability: All models prior to S/No. 570. Document: Pilatus SB No. 35.\n\nCompliance: Before 2 November 1967.\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\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument, as supplied, sets a single, targeted requirement (modify landing gear strut) for a defined set of aircraft (all PC-6 models prior to S/No. 570) and a fixed compliance date. There is no material in the supplied text indicating an expansion or narrowing of that scope from any earlier statement; therefore there is no evidence in this text that the scope has changed."},"complexity_factors":["Narrow and specific applicability limited to aircraft with serial numbers prior to 570 (Applicability).","Single, clearly identified technical action (landing gear strut modification) with an external technical reference (Pilatus SB No. 35) (Document).","Firm single compliance deadline rather than phased or conditional compliance (Compliance: Before 2 November 1967).","Lack of procedural detail in the directive itself — technical method delegated to an external service bulletin (Document), which requires consulting another source to implement.","Absence of expressed enforcement, cost-allocation, or exemption rules in the text increases the need to consult other regulatory or administrative materials for full implementation."],"plain_english_summary":"### What this directive does (mechanically)\n\nThis airworthiness directive (AD/PC-6/17) requires a physical modification of the landing gear strut on Pilatus Porter PC-6 series aeroplanes that have serial numbers earlier than 570. The work must be carried out in accordance with Pilatus Service Bulletin No. 35 (Document: Pilatus SB No. 35) and completed before 2 November 1967 (Compliance: Before 2 November 1967). (See: \"Applicability\", \"Document\", \"Compliance\".)\n\n### Who makes the rule and who must act\n\n- The directive is issued under the Commonwealth Civil Aviation Regulations, Part 39, by the Civil Aviation Safety Authority (See heading: \"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\").\n- The requirement applies to all PC-6 aeroplanes with serial numbers prior to 570, so operators/owners of those specific aeroplanes are the parties required to ensure the modification is done (See: \"Applicability\").\n\n### Official rationale\n\n- The directive text provided does not include an explicit statement of purpose or safety rationale. The instrument simply prescribes the modification, references Pilatus SB No. 35 for the technical method, and sets the compliance date (See: entire text). Any stated rationale in other sources or explanatory material is not included in the text supplied.\n\n### Practical implications and implementation points (mechanics of effects)\n\n- Action required: A specified physical modification must be performed on affected aeroplanes following the external technical document identified as Pilatus SB No. 35 (See: \"Document: Pilatus SB No. 35\").\n- Timing: The modification had to be completed by the fixed date set in the directive (See: \"Compliance: Before 2 November 1967\").\n- Scope: The requirement is narrow in scope — it targets a defined set of aircraft by serial number (See: \"Applicability: All models prior to S/No. 570\").\n- Who decides how to comply: The directive points operators to the manufacturer’s service bulletin for the technical procedure; the issuing authority determines the obligation and deadline (See: header and \"Document\").\n\n### Costs, incentives, trade-offs and implementation risks (source-grounded)\n\n- The directive creates an obligation on the specified operators to have the modification carried out by the deadline (See: \"Applicability\" and \"Compliance\"). The text supplied does not specify who pays, how compliance is verified, compensation, or any enforcement mechanism.\n- The technical method and specifications to be followed are delegated to the identified Pilatus service bulletin (See: \"Document: Pilatus SB No. 35\"). The directive therefore shifts technical implementation detail to an external manufacturer document; the AD itself does not set step-by-step technical instructions.\n- Because the AD supplies only the affected serial-number range, the action is targeted; the instrument does not provide exemptions, alternatives, or staged compliance windows in the text supplied.\n- The text does not include explicit information about administrative burden, parts availability, labour requirements, downtime, costs, or who bears those costs. Those are potential consequential effects of any mandatory modification, but they are not quantified or allocated in this instrument.\n\n### Effects on private parties and service providers (source-grounded questions)\n\n- The directive imposes a compliance requirement on owners/operators of affected aircraft (See: \"Applicability\" and \"Compliance\").\n- The technical work is to follow Pilatus SB No. 35; independent maintenance organisations or authorised service centres would be the likely providers of that work, but the directive text itself does not name or require particular service providers (See: \"Document\").\n\n### Summary statement\n\nMechanically, this AD mandates that all Pilatus PC-6 aeroplanes with serial numbers before 570 must receive a modification to the landing gear strut according to Pilatus Service Bulletin No. 35, completed by 2 November 1967. The directive identifies the affected fleet, the required action and method reference, and the deadline. The text supplied contains no explicit statement of rationale, cost allocation, enforcement procedures or implementation detail beyond the service-bulletin reference and the compliance date (See: entire text)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused solely on landing gear strut modification for a specific aircraft type. It has not expanded beyond its original narrow safety purpose."},"complexity_factors":["Extremely short document — only 4 substantive lines of regulatory text","No defined terms section — all language is plain and technical-aviation specific rather than legally defined","No cross-references to other legislation or regulations beyond the header citation","Single, unambiguous compliance requirement with a fixed deadline","No conditional logic, exceptions, or nested provisions","Simple applicability test (serial number threshold)"],"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:**\n- Requires owners and operators of **Pilatus Porter PC-6 series aeroplanes** (specifically those built before serial number 570) to modify their **landing gear struts** (the shock-absorbing legs that support the aircraft on the ground).\n\n**Who it affects:**\n- Anyone who owns or operates an early-model Pilatus PC-6 aircraft in Australia.\n\n**Why it matters:**\n- Landing gear failures can be catastrophic during takeoff or landing. This directive mandates a specific safety modification to prevent structural failure of the landing gear strut.\n\n**Key details:**\n- **Compliance deadline:** Before 2 November 1967 (this is a historical directive — long past its due date).\n- **Technical reference:** Pilatus Service Bulletin No. 35 (the manufacturer's official instructions for the fix).\n- **Aircraft covered:** All PC-6 models with serial numbers below 570."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pc-6-17-landing-gear-strut-modification","history":"/api/acts/ad-pc-6-17-landing-gear-strut-modification/history","analysis":"/api/acts/ad-pc-6-17-landing-gear-strut-modification/analysis","conflicts":"/api/acts/ad-pc-6-17-landing-gear-strut-modification/conflicts","importantCases":"/api/acts/ad-pc-6-17-landing-gear-strut-modification/important-cases","documents":"/api/acts/ad-pc-6-17-landing-gear-strut-modification/documents"}}