{"id":"F2006B10973","name":"AD/JT8D/10 - Eighth Stage Compressor Disc P/N 496908 - Removal from Service","slug":"ad-jt8d-10-eighth-stage-compressor-disc-p-n-496908-removal-from-service","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56552,"registerId":"commonwealth-F2006B10973-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/JT8D/10 - Eighth Stage Compressor Disc P/N 496908 - Removal from Service","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 Turbine Engines - JT8D Series\n\n \n\nAD/JT8D/10  Eighth Stage Compressor Disc P/N 496908 - Removal from Service\n\n\n3/77\n\n \n\nApplicability: JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A and -11 engines containing eighth stage compressor disc P/N 496908.\n\n \n\nDocument: 1. FAA AD 76-24-01 : Amendment 39-2775; or\n\n \n\n2. AD/PW-T/40.\n\n \n\nCompliance: Prior to Reaching 6000 cycles in service, or by June 30, 1977 whichever comes later.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\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 safety directive focused specifically on one defective engine part. It has not expanded beyond its original purpose of mandating removal of the P/N 496908 compressor disc. The scope remains tightly constrained to the specific technical defect identified in 1976-1977."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 2 defined terms implicitly used (cycles in service, part number)","No cross-references to other legislation beyond citation of source FAA AD","Simple binary applicability test (does the engine have P/N 496908?)","Single compliance requirement with clear deadline (6000 cycles OR 30 June 1977)","No exceptions, exemptions, or conditional logic","Straightforward command structure: identify part → remove by deadline"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires the **removal from service** of a specific aircraft engine part: the **eighth stage compressor disc** (part number 496908) used in certain **Pratt & Whitney JT8D jet engines**.\n\n**Who it affects:**\n- Operators of aircraft with JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, or -11 engines\n- Specifically, those engines containing the problematic compressor disc part number 496908\n\n**What must be done:**\nThe affected compressor disc must be removed from service **before** the engine reaches **6,000 flight cycles** (a takeoff and landing counts as one cycle), **or** by **30 June 1977** — whichever comes later.\n\n**Why it matters:**\nAirworthiness Directives are legally binding safety instructions. This AD was issued because the specified compressor disc was found to have a safety defect that could lead to engine failure. Non-compliance means the aircraft cannot legally fly in Australian airspace.\n\n**Background:**\nThis directive references an earlier US Federal Aviation Administration (FAA) safety order (AD 76-24-01), showing Australia adopted an American safety finding for local use."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument itself sets a clear, limited scope: removal from service of eighth stage compressor discs P/N 496908 in specified JT8D engine models by a stated cycles-or-date threshold (Applicability; Compliance). The text does not indicate any change from an earlier or original scope within the document provided; it establishes the removal requirement and references existing ADs for further detail (Document)."},"complexity_factors":["Narrow applicability limited to engines containing a single part number (P/N 496908) reduces scope complexity (Applicability).","Single, clear compliance condition framed as a cycles-or-date threshold (whichever is later) is simple but requires accurate cycles tracking (Compliance).","Dependence on external documents for technical detail (FAA AD 76-24-01; AD/PW-T/40) adds an external-reference step for implementers (Document).","No alternative compliance paths, exemptions, or procedural detail in the text increases straightforwardness but shifts complexity to obtaining and following the referenced documents (Document).","Date-based deadline combined with usage-based threshold introduces modest scheduling complexity for operators managing fleets with differing utilisation rates (Compliance)."],"plain_english_summary":"This airworthiness directive requires removal from service of the eighth‑stage compressor disc P/N 496908 in specified Pratt & Whitney JT8D engines by 6,000 cycles or by 30 June 1977 (whichever is later). It’s a mandatory, non‑discretionary rule affecting operators/owners, who bear the removal/replacement costs and must consult the referenced FAA AD and AD/PW‑T/40 for procedural details."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jt8d-10-eighth-stage-compressor-disc-p-n-496908-removal-from-service","history":"/api/acts/ad-jt8d-10-eighth-stage-compressor-disc-p-n-496908-removal-from-service/history","analysis":"/api/acts/ad-jt8d-10-eighth-stage-compressor-disc-p-n-496908-removal-from-service/analysis","conflicts":"/api/acts/ad-jt8d-10-eighth-stage-compressor-disc-p-n-496908-removal-from-service/conflicts","importantCases":"/api/acts/ad-jt8d-10-eighth-stage-compressor-disc-p-n-496908-removal-from-service/important-cases","documents":"/api/acts/ad-jt8d-10-eighth-stage-compressor-disc-p-n-496908-removal-from-service/documents"}}