{"id":"F2006B11027","name":"AD/JT9D/33 - Diffuser Case Inspection","slug":"ad-jt9d-33-diffuser-case-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56635,"registerId":"commonwealth-F2006B11027-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.","sortOrder":0},{"sectionNumber":"AD/JT9D/33 Diffuser Case Inspection 8/20","sectionType":"part","heading":"AD/JT9D/33 Diffuser Case Inspection 8/2000","content":"# AD/JT9D/33 Diffuser Case Inspection 8/2000\n\nApplicability: Pratt and Whitney JT9D-3A, \\-7, \\-7H, \\-7A, \\-7AH, \\-7F, \\-7J, \\-20 and \\-20J turbofan engines.\n\nRequirement: Inspect and replace as necessary diffuser cases that do not comply with the technical requirements of FAA AD 93-19-02 R1 amendment 39-9038.\n\nNote: P&W Alert SB No 6076 R1, P&W SB No 5591 R7 and 5591 R4 refers.\n\nCompliance: As detailed in the Requirement Document with a revised effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 10 August 2000.\n\nBackground: This Directive raised to inspect diffuser cases for cracking, and also reduces the crack length allowed before removal of the diffuser case is required. Such cracks could result in an uncontained engine failure and damage to the aircraft.\n\n![Signature of Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority](image.003.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 26 June 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 12 July 2000.","sortOrder":1}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific safety defect in specific engine models. It does not expand beyond the original intent of preventing uncontained engine failures due to diffuser case cracking."},"complexity_factors":["Very short document (under 300 words)","Only 1 defined term (the AD itself)","Single straightforward requirement with clear cross-reference to FAA technical standard","No nested conditions or exceptions","Simple applicability list (9 engine models)","Background section provides clear safety rationale without legal complexity"],"plain_english_summary":"This AD mandates inspections and required replacement of diffuser cases on Pratt & Whitney JT9D-3A, -7, and -20 series engines, tightening allowable crack limits. It applies to owners/operators of aircraft (notably older Boeing 747/767 and Airbus A300/A310 types) using those engines.\n\nIt matters because diffuser-case cracks can cause uncontained engine failure; the rule forces earlier detection and removal of unsafe parts. Effective 10 August 2000; comply with FAA AD 93-19-02 R1 and referenced Pratt & Whitney service bulletins."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"The Directive tightens the acceptance criterion by reducing the allowable crack length before diffuser-case removal, increasing removals and inspection stringency compared with prior practice. It implements this change by mandating compliance with FAA AD 93-19-02 R1 and related Pratt & Whitney service bulletins, thereby expanding the practical scope of mandatory maintenance and parts replacement obligations."},"complexity_factors":["Cross-reference to FAA AD 93-19-02 R1 rather than standalone technical criteria (requires reading another instrument).","References to multiple Pratt & Whitney service bulletins (P&W Alert SB No 6076 R1; SB No 5591 R7 and R4) for technical implementation.","Technical judgement required on crack detection and acceptable crack length (inspection standard and replacement threshold).","Applicability spans multiple JT9D engine variants, requiring fleet-by-fleet applicability checks.","Compliance timing tied to an external 'Requirement Document' with a revised effective date rather than explicit calendar-based intervals.","Operational impacts for operators: inspection scheduling, downtime, parts procurement and repair costs.","Enforcement and discretion by CASA delegate under subregulation 39.1(1) of CAR 1998 (administrative enforcement pathway).","Safety urgency due to risk of uncontained engine failure raises priority and may compress maintenance windows."],"plain_english_summary":"This Airworthiness Directive requires operators of specified Pratt & Whitney JT9D turbofan engines to inspect diffuser cases and replace any that do not meet the technical criteria of FAA AD 93‑19‑02 R1, following the referenced Pratt & Whitney service information. It takes effect 10 August 2000.\n\nOperators bear the costs and scheduling burden of inspections, repairs and part replacements; the CASA delegate enforces compliance under CAR 1998. The AD also shortens the allowable crack length before removal, increasing the likelihood of part replacement."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jt9d-33-diffuser-case-inspection","history":"/api/acts/ad-jt9d-33-diffuser-case-inspection/history","analysis":"/api/acts/ad-jt9d-33-diffuser-case-inspection/analysis","conflicts":"/api/acts/ad-jt9d-33-diffuser-case-inspection/conflicts","importantCases":"/api/acts/ad-jt9d-33-diffuser-case-inspection/important-cases","documents":"/api/acts/ad-jt9d-33-diffuser-case-inspection/documents"}}