{"id":"F2006B10976","name":"AD/JT8D/14 - First Stage Compressor Hub Blade Slots","slug":"ad-jt8d-14-first-stage-compressor-hub-blade-slots","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56558,"registerId":"commonwealth-F2006B10976-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/JT8D/14 - First Stage Compressor Hub Blade Slots","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/14 First Stage Compressor Hub Blade Slots 2/84\n\nApplicability: JT8D-9, -9A, -11, -15, -15A, -17, -17A, -17R, -17AR.\n\n \n\nDocument: 1. Pratt & Whitney Aircraft Alert SB No. 4841, Revision 6.\n\n \n\nNote: FAA AD 78-17-02 R2 with subsequent amendments is listed for reference purposes only.\n\n \n\nor\n\n \n\n2. AD/PW-T/47 Amdt 6.\n\n \n\nCompliance: As detailed in the Requirement Document.\n\n \n\nBackground:  This Directive is raised in issue to ensure compliance with the latest revision of the requirement document which adds to the effectivity listing those 'A' series engines that have, or will be, obtained by conversion.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\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":3,"scope_assessment":{"changed":false,"description":"This directive maintains its original narrow scope — ensuring compressor hub integrity on specific JT8D engine variants. The amendment simply expands the applicability list to include 'A' series engines resulting from conversions, which is a logical extension of the original safety purpose rather than scope creep. The core regulatory mechanism (mandating compliance with Pratt & Whitney SB 4841) remains unchanged since the original 1984 issue."},"complexity_factors":["Very short document (approximately 250 words)","Only 1 substantive requirement: comply with external technical document (Pratt & Whitney SB 4841 Rev 6)","No defined terms section — relies entirely on external aerospace engineering terminology","Simple conditional logic: if you operate these specific engine models, you must comply","Single cross-reference to equivalent Australian directive (AD/PW-T/47 Amdt 6) and reference-only mention of FAA AD 78-17-02 R2","No nested exceptions or conditional sub-clauses within the directive itself","Complexity is externalized: the actual technical requirements live in the Pratt & Whitney service bulletin, which is a separate, highly technical engineering document"],"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). Think of it like a compulsory recall notice, but for aircraft engines rather than cars.\n\n**What it does:** It requires owners and operators of specific Pratt & Whitney **JT8D jet engines** to inspect and maintain the **first stage compressor hub blade slots** — a critical rotating component that holds the compressor blades in place. If these slots crack or wear out, blades can break loose, potentially destroying the engine and endangering the aircraft.\n\n**Who it affects:** Anyone operating aircraft with these specific engine models:\n- JT8D-9, -9A, -11, -15, -15A, -17, -17A, -17R, -17AR\n\nThese engines power older Boeing 727s, 737s, and McDonnell Douglas DC-9s still flying in Australia.\n\n**What must be done:** Operators must follow the technical instructions in **Pratt & Whitney Service Bulletin No. 4841** (Revision 6) or an equivalent Australian directive. The exact inspection schedule and repair procedures are contained in that document rather than spelled out here.\n\n**Why it matters:** This directive was updated to include \"A\" series engines (like the -9A, -15A) that were converted from earlier models. Without this update, converted engines might have slipped through safety cracks. Compressor hub failures can cause **uncontained engine failures** — where shrapnel bursts through the engine casing, potentially damaging the aircraft or injuring passengers."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"The AD's scope was changed by the latest requirement document: the revision expands effectivity to include certain 'A' series engines obtained by conversion, bringing additional engine variants within the AD's scope (Background; Applicability)."},"complexity_factors":["Reliance on an external technical requirement document (Pratt & Whitney Alert SB No. 4841, Revision 6) for the substantive compliance actions (Document; Compliance).","Cross-references to other airworthiness directives and national/international regulatory materials (AD/PW-T/47 Amdt 6; FAA AD referenced for information) (Document; Note).","Precise applicability limited to a set of engine models plus additional converted 'A' series variants introduced by the requirement document, requiring operators to verify variant status (Applicability; Background).","Delegation of procedural detail to the service bulletin creates an information-obtainment requirement for operators (Document; Compliance)."],"plain_english_summary":"This AD expands its effectivity to include certain converted 'A'‑series JT8D engines and requires affected owners/operators to comply with the actions set out in Pratt & Whitney Alert Service Bulletin No. 4841, Revision 6.  \n\nIssued by CASA, the directive makes compliance (inspections/repairs/modifications) mandatory, shifts associated costs to engine owners/operators, and cross‑references existing regulatory and service documents for implementation."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jt8d-14-first-stage-compressor-hub-blade-slots","history":"/api/acts/ad-jt8d-14-first-stage-compressor-hub-blade-slots/history","analysis":"/api/acts/ad-jt8d-14-first-stage-compressor-hub-blade-slots/analysis","conflicts":"/api/acts/ad-jt8d-14-first-stage-compressor-hub-blade-slots/conflicts","importantCases":"/api/acts/ad-jt8d-14-first-stage-compressor-hub-blade-slots/important-cases","documents":"/api/acts/ad-jt8d-14-first-stage-compressor-hub-blade-slots/documents"}}