{"id":"F2006B06113","name":"AD/PC-6/11 - Engine Mount Ring - Modification","slug":"ad-pc-6-11-engine-mount-ring-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46869,"registerId":"commonwealth-F2006B06113-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PC-6/11 - Engine Mount Ring - 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-6/11  Engine Mount Ring - Modification 3/66 Applicability:              All model PC-6/B-H2 with S/Nos. 564, 569, 572, 574, 575, 580, 581, 582 and 583. Document:               Pilatus SB No. 56.\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\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive affecting only nine specific aircraft. It has not expanded beyond its original purpose of addressing a specific airworthiness concern with the engine mount ring on these particular serial numbers."},"complexity_factors":["Single, specific technical requirement with no conditional logic","No defined terms section","No cross-references to other legislation beyond the enabling Civil Aviation Regulations 1998","Clear, unambiguous applicability criteria (specific serial numbers)","Single compliance deadline tied to a maintenance event (engine change)","Extremely short document (approximately 100 words of substantive content)"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:** It requires owners/operators of certain Pilatus Porter PC-6/B-H2 aeroplanes to modify the engine mount ring (the structure that attaches the engine to the airframe). The modification must be done according to Pilatus Service Bulletin No. 56.\n\n**Who it affects:** Only nine specific aircraft with serial numbers: 564, 569, 572, 574, 575, 580, 581, 582, and 583.\n\n**When it must be done:** At the next engine change after 15 April 1966.\n\n**Why it matters:** Engine mount rings are critical safety components. If they fail, the engine could detach from the aircraft. This AD ensures a known defect or weakness is fixed before it causes an accident."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The source presents a single, fixed requirement: modification of the engine mount ring for the listed PC-6/B-H2 serial numbers, to be done at the next engine change after 15 April 1966. The AD text contains no amendments, extensions, or alternative scopes; therefore there is no indication in the source that the scope has changed from the instrument as published."},"complexity_factors":["Very narrow applicability: only nine serial numbers of a single model (Applicability).","Simple compliance trigger: obligation tied to the next engine change after a specific date rather than a complex schedule (Compliance).","External technical detail: the AD delegates technical steps to Pilatus SB No. 56, requiring operators to consult another document (Document).","No multi-step administrative procedures or multiple compliance options specified in the AD text.","Historical dating (1966) could create practical ambiguity for record-keeping or repeat applicability, but that is administrative rather than substantive."],"plain_english_summary":"This directive mandates a modification to the engine‑mount ring on nine specific Pilatus PC‑6/B‑H2 aeroplanes (serials 564, 569, 572, 574, 575, 580–583). Owners/operators must have the work done and pay for it at the next engine change after 15 April 1966, following Pilatus Service Bulletin No. 56 for technical details. The AD gives no explicit rationale and applies only to the listed serial‑number aircraft."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pc-6-11-engine-mount-ring-modification","history":"/api/acts/ad-pc-6-11-engine-mount-ring-modification/history","analysis":"/api/acts/ad-pc-6-11-engine-mount-ring-modification/analysis","conflicts":"/api/acts/ad-pc-6-11-engine-mount-ring-modification/conflicts","importantCases":"/api/acts/ad-pc-6-11-engine-mount-ring-modification/important-cases","documents":"/api/acts/ad-pc-6-11-engine-mount-ring-modification/documents"}}