{"id":"F2006B06112","name":"AD/PC-6/10 - Engine Mount - Modification","slug":"ad-pc-6-10-engine-mount-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46867,"registerId":"commonwealth-F2006B06112-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PC-6/10 - Engine Mount - 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-6/10 Engine Mount - Modification 3/66\n\nApplicability: All model PC-6/A with Nos. prior to 592. Document: Pilatus SB No. 51.\n\nCompliance: At next engine change after 15 April 1966.\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's stated scope is the aircraft identified in the Applicability line (all PC-6/A with serial numbers prior to 592) and the action is defined as the engine-mount modification to be carried out per Pilatus SB No. 51 at the next engine change after 15 April 1966. There is no indication within the text provided that the scope has been altered from that stated intent."},"complexity_factors":["Narrow applicability (single model series and serial-number cut-off) reduces complexity (Applicability).","Simple compliance timing rule tied to next engine change reduces scheduling complexity (Compliance).","Technical detail is outsourced to an external document (Pilatus SB No. 51), so the AD itself is short but requires consultation of the service bulletin for full technical complexity (Document).","Historical date reference (15 April 1966) introduces archival/contextual ambiguity for modern readers.","Key administrative details (cost allocation, enforcement mechanism, alternative compliance options) are not specified in the AD, creating procedural ambiguity for implementers."],"plain_english_summary":"### What this instrument does\n- It requires a modification of the engine mount on specified Pilatus Porter PC-6/A aeroplanes. (Title: \"AD/PC-6/10 Engine Mount - Modification\".)\n\n### Who it affects\n- Operators and owners of Pilatus PC-6/A aircraft with serial numbers prior to 592. (See: \"Applicability: All model PC-6/A with Nos. prior to 592.\")\n\n### How it works, mechanically\n- The airworthiness directive references Pilatus Service Bulletin No. 51 as the technical instruction for the modification. (See: \"Document: Pilatus SB No. 51.\")\n- Compliance is required at the next engine change that occurs after 15 April 1966. In other words, when an affected aircraft next has its engine changed after that date, the operator must carry out the modification described in the referenced service bulletin. (See: \"Compliance: At next engine change after 15 April 1966.\")\n\n### What is explicitly not specified in the text\n- The AD itself does not set out the detailed steps for the work; it points to Pilatus SB No. 51 for the technical procedure. (See: \"Document: Pilatus SB No. 51.\")\n- The AD does not state who pays for the modification, how enforcement will be done, whether costs are recoverable, or whether any alternative methods of compliance are permitted. Those matters are not recorded in the instrument text provided.\n\n### Practical effects and incentives (source-grounded)\n- Who decides: The directive is issued under the Civil Aviation Safety Authority framework (header: \"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 ... CIVIL AVIATION SAFETY AUTHORITY\"). The AD imposes the obligation on operators of the identified aircraft types.\n- Who pays: The instrument does not specify cost allocation; therefore, the financier (operator, owner, or other party) is not identified in this document.\n- Behaviour change required: Operators must ensure the engine-mount modification called up by Pilatus SB No. 51 is completed when the next engine change occurs after 15 April 1966 for affected airframes. (See: \"Compliance\" and \"Applicability.\")\n- Compliance burden: The burden is limited in timing (only at the next engine change after the stated date) but could involve labour, parts, and downtime; the AD does not quantify that burden.\n- Discretion and detail: Technical discretion and procedural detail are delegated to the referenced Pilatus service bulletin; the AD itself contains no technical steps or permissible alternatives.\n\n### Trade-offs and practical notes\n- The AD narrows its intervention by linking compliance to a natural maintenance event (engine change). That schedules the work into an already expected maintenance occurrence rather than imposing an immediate out-of-cycle action. (See: \"Compliance: At next engine change after 15 April 1966.\")\n- The actual scope and cost impact depend on the content of Pilatus SB No. 51, which is referenced but not reproduced in this text. Because the AD points to an external technical document, operators must consult that bulletin to know the exact work, parts, and likely cost/time implications.\n\nSource citations: the statements above are drawn directly from the instrument text: the AD title, the applicability line, the document reference, and the compliance line."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a vintage 1966 airworthiness directive that has remained unchanged in scope. It addresses a specific, narrow technical issue (engine mount modification) for a limited fleet of aircraft (early model PC-6/A). There is no evidence of scope creep; the directive does exactly what its title suggests and no more."},"complexity_factors":["Extremely short document — only 4 substantive lines of regulatory text","Zero defined terms in the directive itself (relies on external understanding of 'engine change' and 'service bulletin')","No cross-references to other legislation beyond the enabling regulation (CAR 1998, Part 39)","Simple conditional trigger: 'at next engine change after specified date'","Single applicability criterion (serial number range)","No exceptions, exemptions, or nested conditions"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of specific Pilatus Porter PC-6 aircraft to modify the **engine mount** (the structural frame that holds the engine to the airframe) according to instructions in Pilatus Service Bulletin No. 51.\n\n**Who it affects:** All Pilatus PC-6/A model aircraft with serial numbers **prior to 592**.\n\n**When to comply:** The modification must be done **at the next engine change after 15 April 1966**.\n\n**Why it matters:** Engine mounts are critical safety components. If they fail, the engine could detach from the aircraft in flight. This AD ensures a known defect or weakness is fixed before it causes an accident. Non-compliance means the aircraft cannot legally fly in Australian airspace."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pc-6-10-engine-mount-modification","history":"/api/acts/ad-pc-6-10-engine-mount-modification/history","analysis":"/api/acts/ad-pc-6-10-engine-mount-modification/analysis","conflicts":"/api/acts/ad-pc-6-10-engine-mount-modification/conflicts","importantCases":"/api/acts/ad-pc-6-10-engine-mount-modification/important-cases","documents":"/api/acts/ad-pc-6-10-engine-mount-modification/documents"}}