{"id":"F2006B11019","name":"AD/JT9D/26 - Diffuser Case Inspection","slug":"ad-jt9d-26-diffuser-case-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56623,"registerId":"commonwealth-F2006B11019-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/JT9D/26 - Diffuser Case Inspection","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 - JT9D Series\n\n \n\nAD/JT9D/26 Diffuser Case Inspection 9/94\n\nApplicability: Pratt and Whitney JT9D-7F engines.\n\n \n\nRequirement:  Action in accordance with the requirements of FAA AD 93-19-02. Compliance: Effective 18 August 1994, as specified in the FAA AD.\n\nBackground: There have been reports of cracking in the diffuser case at the rear rail location.\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":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument does not expand or narrow the set of engines beyond the stated model (Pratt & Whitney JT9D-7F) and expressly adopts the actions in FAA AD 93-19-02. It therefore remains aligned with its original, stated intent to require inspections and any corrective actions specified in that FAA AD for the identified engines."},"complexity_factors":["Incorporation by reference of an external technical document (FAA AD 93-19-02) rather than restating technical steps","Technical nature of required inspections and possible repairs (requires specialist maintenance personnel and facilities)","Limited applicability to a single engine model (Pratt & Whitney JT9D-7F) which narrows scope but concentrates effects","Timing/ compliance tied to an effective date (18 August 1994) and to the FAA AD's specified intervals, requiring operators to track an external schedule","Instrument is procedurally simple but operationally dependent on external, technical detail not included in the text"],"plain_english_summary":"The Civil Aviation Safety Authority requires operators of Pratt & Whitney JT9D-7F engines to carry out the inspections, repairs and other actions specified in FAA Airworthiness Directive 93-19-02 (effective 18 August 1994) to address reported diffuser-case rear‑rail cracking. Compliance—including inspection costs, repairs and downtime—falls to engine owners/operators; CASA incorporates the FAA AD by reference, so operators must consult it for the technical details."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive with a single, specific purpose: addressing a known cracking defect in a particular engine model. It has not expanded beyond its original safety intent. The document adopts by reference the FAA requirements rather than reproducing them, maintaining tight scope control."},"complexity_factors":["Extremely short document — only 4 substantive paragraphs","No defined terms section; all terminology is standard aviation engineering language","Single cross-reference to external FAA document (AD 93-19-02) — the actual technical requirements are contained there, not here","No conditional logic, exceptions, or nested provisions","Straightforward applicability test: specific engine model only (JT9D-7F)","Compliance date is absolute (18 August 1994) with no alternative compliance methods stated"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** issued by Australia's Civil Aviation Safety Authority (CASA) that mandates safety inspections for a specific type of aircraft engine.\n\n**What it does:**\n- Requires owners and operators of **Pratt & Whitney JT9D-7F jet engines** to conduct inspections of the **diffuser case** (a component that helps manage airflow in the engine)\n- The inspections must follow the exact procedures set out in a US Federal Aviation Administration (FAA) directive numbered **93-19-02**\n- Compliance became mandatory from **18 August 1994**\n\n**Why it matters:**\n- **Safety issue:** Cracks had been discovered in the diffuser case at the \"rear rail location\" — a structural weak point\n- If left unchecked, these cracks could lead to **engine failure**, potentially causing catastrophic accidents\n- This directive ensures Australian aircraft with these engines meet the same safety standards as those in the United States\n\n**Who it affects:**\n- Airlines and aircraft operators using Pratt & Whitney JT9D-7F engines (commonly found on older Boeing 747 aircraft)\n- Maintenance engineers responsible for engine inspections\n- CASA inspectors who verify compliance\n\nThis is a routine but critical safety measure — essentially a \"recall notice\" for aircraft engines, requiring specific checks to prevent mechanical failures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jt9d-26-diffuser-case-inspection","history":"/api/acts/ad-jt9d-26-diffuser-case-inspection/history","analysis":"/api/acts/ad-jt9d-26-diffuser-case-inspection/analysis","conflicts":"/api/acts/ad-jt9d-26-diffuser-case-inspection/conflicts","importantCases":"/api/acts/ad-jt9d-26-diffuser-case-inspection/important-cases","documents":"/api/acts/ad-jt9d-26-diffuser-case-inspection/documents"}}