{"id":"F2006B06360","name":"AD/PT6A/20 - No. 2 Bearing Cover","slug":"ad-pt6a-20-no-2-bearing-cover","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47594,"registerId":"commonwealth-F2006B06360-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PT6A/20 - No. 2 Bearing Cover","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 - 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Pratt and Whitney Canada Turbine Engines - PT6A Series\n\n \n\nAD/PT6A/20 No. 2 Bearing Cover 10/85\n\nApplicability: PT6A-6, -6A, -6B, -20, -20A, -20B, -6/C20 and PT6B-9 with S/Nos. prior to PC- E22659.\n\n \n\nDocument: 1. Pratt & Whitney Aircraft of Canada SB No. 1188, Rev. 1;\n\n \n\n2.    Transport Canada AD No. CF-78-14; or\n\n \n\n3.    AD/UAC-T/32.\n\n \n\nCompliance: At next overhaul completed after 30 November 1978.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\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":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused on a specific mechanical component. It has not expanded beyond its original purpose of addressing the No. 2 Bearing Cover issue in specified engines."},"complexity_factors":["Very short document (approximately 200 words)","Only 4 defined elements: applicability, document references, compliance deadline, and subject matter","No cross-references to other legislation beyond citing the enabling regulations (Civil Aviation Regulations 1988, Part 39)","Simple conditional logic: if engine model matches AND serial number is prior to threshold, then compliance required at next overhaul","No nested exceptions or subordinate provisions","Single compliance pathway with clear deadline"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1988. It mandates a safety inspection or modification for specific Pratt & Whitney Canada PT6A series turbine engines.\n\n**What it does:**\n- Requires operators to address a defect in the \"No. 2 Bearing Cover\" on certain PT6A and PT6B engines\n- Affected engines are those with serial numbers prior to PC-E22659\n- Compliance is required at the next engine overhaul after 30 November 1978\n\n**Who it affects:**\n- Owners and operators of aircraft with PT6A-6, -6A, -6B, -20, -20A, -20B, -6/C20, and PT6B-9 engines (older serial numbers)\n- These are commonly used in regional aircraft, agricultural aircraft, and some helicopters\n\n**Why it matters:**\nAirworthiness Directives are legally binding safety orders. Non-compliance means an aircraft cannot legally fly in Australian airspace. This particular AD addresses a potential mechanical failure in a critical engine component that could affect flight safety."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The provided text sets out applicability, the specific external documents that prescribe the technical action, and a single compliance timing rule. The AD text itself does not indicate any expansion or narrowing of scope beyond those elements, nor does it show amendments to the original applicability or compliance requirement within the excerpt provided."},"complexity_factors":["Narrow technical scope limited to No. 2 bearing cover on specific PT6A/PT6B engine serial ranges (reduces breadth). (Applicability)","Mandatory compliance relies entirely on external documents (Service Bulletin and other ADs) for procedural detail, creating cross‑reference complexity. (Document)","Temporal compliance rule tied to the next overhaul after a historical date, which requires operators to map maintenance schedules to the AD timing. (Compliance)","Potential for variation in implementation because compliance can be met by any one of three different referenced documents, creating possible differences in method or parts. (Document)","Minimal in‑text procedural detail increases reliance on maintenance/technical expertise and on availability of the referenced documents. (Document)"],"plain_english_summary":"This Airworthiness Directive mandates that owners/operators of specified Pratt & Whitney Canada PT6A (and PT6B‑9 with SN before PC‑E22659) complete the No. 2 bearing cover remedial/modification work at the next engine overhaul after 30 November 1978 by following one of three referenced service/AD documents. It shifts the technical method to those documents, imposes one‑time cost and scheduling burdens on operators, and ensures the required corrective work is incorporated during overhaul."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pt6a-20-no-2-bearing-cover","history":"/api/acts/ad-pt6a-20-no-2-bearing-cover/history","analysis":"/api/acts/ad-pt6a-20-no-2-bearing-cover/analysis","conflicts":"/api/acts/ad-pt6a-20-no-2-bearing-cover/conflicts","importantCases":"/api/acts/ad-pt6a-20-no-2-bearing-cover/important-cases","documents":"/api/acts/ad-pt6a-20-no-2-bearing-cover/documents"}}