{"id":"F2006B06120","name":"AD/PC-6/18 - Horizontal Stabiliser Tip Plates - Modification","slug":"ad-pc-6-18-horizontal-stabiliser-tip-plates-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46885,"registerId":"commonwealth-F2006B06120-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PC-6/18 - Horizontal Stabiliser Tip Plates - 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-6/18 Horizontal Stabiliser Tip Plates - Modification N/K\n\nApplicability: All models with S/Nos. 514, 523, 530, 531, 534, 547, 551, 552, 557 and 563. Document:               Pilatus SB No. 71.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused specifically on horizontal stabiliser tip plate modifications for a limited set of aircraft serial numbers. It has not expanded beyond its original narrow technical scope."},"complexity_factors":["Extremely short document (under 200 words)","No defined terms section","No cross-references to other legislation beyond basic enabling regulation (Civil Aviation Regulations 1998, Part 39)","Simple conditional logic: if your aircraft has these serial numbers, you must comply","Single compliance requirement with clear deadline","No exceptions or nested conditions"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations.\n\n**What it does:**\nRequires owners and operators of specific Pilatus Porter PC-6 aircraft to modify the horizontal stabiliser tip plates (small aerodynamic surfaces on the tail of the plane).\n\n**Who it affects:**\nOwners and operators of Pilatus Porter PC-6 aircraft with specific serial numbers: 514, 523, 530, 531, 534, 547, 551, 552, 557, and 563.\n\n**Why it matters:**\nAirworthiness Directives are legally binding safety instructions. If you don't comply, you cannot legally fly the aircraft. This particular directive addresses a specific design issue with the tail section that could affect flight safety. The modification must be done following Pilatus Service Bulletin No. 71.\n\n**Key deadline:**\nThe work had to be completed before 2 November 1967 — meaning this is a historical directive that would only be relevant today for historical aircraft preservation or if an aircraft was returning to service after long-term storage."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The source text specifies a single, time‑limited modification obligation for a defined set of aircraft and references a manufacturer service bulletin for the technical work (Applicability; Document; Compliance). The text contains no indication that the scope has been altered from the original requirement; based on the supplied text there is no evidence of a change in scope."},"complexity_factors":["Narrow, discrete applicability limited to a short list of serial numbers (Applicability).","Fixed historical compliance deadline creates a simple but time‑bound obligation (Compliance).","No technical details in the AD itself; it references an external manufacturer service bulletin for execution (Document: Pilatus SB No. 71).","No text in the AD describing costs, exemptions, verification procedures, or alternative compliance methods — implementers must seek those details elsewhere.","Archival/historical nature (1967 deadline) may complicate locating parts, records, or the referenced service bulletin."],"plain_english_summary":"This airworthiness directive requires owners/operators of ten specific Pilatus PC‑6 (serials 514, 523, 530, 531, 534, 547, 551, 552, 557, 563) to modify the horizontal stabiliser tip plates as specified in Pilatus Service Bulletin No. 71. The modification was mandatory by 2 November 1967 and the AD supplies the legal requirement while the SB provides the technical steps; costs and exemptions are not specified."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pc-6-18-horizontal-stabiliser-tip-plates-modification","history":"/api/acts/ad-pc-6-18-horizontal-stabiliser-tip-plates-modification/history","analysis":"/api/acts/ad-pc-6-18-horizontal-stabiliser-tip-plates-modification/analysis","conflicts":"/api/acts/ad-pc-6-18-horizontal-stabiliser-tip-plates-modification/conflicts","importantCases":"/api/acts/ad-pc-6-18-horizontal-stabiliser-tip-plates-modification/important-cases","documents":"/api/acts/ad-pc-6-18-horizontal-stabiliser-tip-plates-modification/documents"}}