{"id":"F2006B08463","name":"AD/CF6/19 - High Pressure Compressor Rotor Inertia Weld","slug":"ad-cf6-19-high-pressure-compressor-rotor-inertia-weld","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51111,"registerId":"commonwealth-F2006B08463-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CF6/19 - High Pressure Compressor Rotor Inertia Weld","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)  General Electric Turbine Engines - CF6 Series\n\n \n\nAD/CF6/19 High Pressure Compressor Rotor Inertia Weld 9/91\n\nApplicability: CF6 -80A and 80C2.\n\n \n\nRequirement: Action in accordance with the Technical Requirements of FAA AD 91-11-05, Amendment 39-7001.\n\n \n\nNote: GE Service Bulletins 72-531 Revision 2 and 72-314 Revision 2 refer.\n\n \n\nCompliance: As specified in the Requirement Document with a revised effective date of 5 September 1991 for Australian registered aircraft.\n\n \n\nBackground: The FAA AD has been prompted by two high pressure compressor rotor stages 11-14 spool-shaft failures at the inertia weld. Failure of the weld in service will result in major power loss and it could be uncontained.\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 AD maintains its original narrow scope: addressing a specific mechanical failure mode in specific engine models. It does not expand beyond the original safety issue of inertia weld failures in the high pressure compressor rotor."},"complexity_factors":["Extremely short document (under 200 words)","Only 2 defined applicability terms (CF6-80A and 80C2)","Single requirement referencing external technical document rather than spelling out steps","No nested conditions, exceptions, or cross-references within the text itself","Background provides clear safety rationale without legal caveats"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft engines.\n\n**What it does:** It requires owners and operators of specific General Electric jet engines (the CF6-80A and CF6-80C2 models) to take corrective action on a dangerous welding defect. The engines have a \"high pressure compressor rotor\" (a spinning part that squeezes air before it enters the combustion chamber) where two sections are joined by an \"inertia weld\" (a type of friction welding). This weld can crack and fail.\n\n**Why it matters:** Two engines have already suffered catastrophic failures at this weld. If the weld breaks during flight, the engine loses most or all power, and debris could escape the engine casing — potentially damaging the aircraft or injuring people on the ground. This AD makes inspection or repair mandatory to prevent crashes.\n\n**Who must comply:** Anyone operating Australian-registered aircraft with these specific GE engines. They must follow the technical instructions in the referenced US Federal Aviation Administration (FAA) directive (AD 91-11-05) and two GE service bulletins, with a compliance deadline of 5 September 1991."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The AD adopts the FAA technical requirements for the same engine models and does not alter the stated applicability or the technical requirements themselves; the only explicit change recorded in this instrument is a revised effective date for Australian-registered aircraft (Requirement; Applicability; Compliance)."},"complexity_factors":["Document cross-references an external FAA Airworthiness Directive (FAA AD 91-11-05) for the required technical work rather than listing actions in-line (Requirement).","References additional external technical material (GE Service Bulletins 72-531 Rev 2 and 72-314 Rev 2), increasing the number of documents operators must obtain and interpret (Note).","Technical subject-matter is safety-critical (high-pressure compressor rotor inertia weld), which typically requires specialist maintenance capability and detailed engineering judgement (Background).","Narrow applicability (specific engine models CF6-80A and CF6-80C2) simplifies scope identification but concentrates compliance obligations on a defined operator subset (Applicability).","Compliance timing is governed by the referenced Requirement Document with a revised effective date for Australia, creating an administrative layer to track effective dates and legal force (Compliance)."],"plain_english_summary":"This AD requires Australian-registered aircraft with GE CF6-80A or CF6-80C2 engines to comply with FAA AD 91-11-05 and the cited GE service bulletins (effective 5 Sep 1991). It mandates inspections/repairs to address inertia-weld failures on the high-pressure compressor rotor; operators must perform and pay for the work to mitigate risk of major power loss or ejected parts."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf6-19-high-pressure-compressor-rotor-inertia-weld","history":"/api/acts/ad-cf6-19-high-pressure-compressor-rotor-inertia-weld/history","analysis":"/api/acts/ad-cf6-19-high-pressure-compressor-rotor-inertia-weld/analysis","conflicts":"/api/acts/ad-cf6-19-high-pressure-compressor-rotor-inertia-weld/conflicts","importantCases":"/api/acts/ad-cf6-19-high-pressure-compressor-rotor-inertia-weld/important-cases","documents":"/api/acts/ad-cf6-19-high-pressure-compressor-rotor-inertia-weld/documents"}}