{"id":"F2006B08498","name":"AD/CF6/9 - High Pressure Turbine Impeller Spacer Eddy Current Inspection","slug":"ad-cf6-9-high-pressure-turbine-impeller-spacer-eddy-current-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51203,"registerId":"commonwealth-F2006B08498-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CF6/9 - High Pressure Turbine Impeller Spacer Eddy Current 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)  General Electric Turbine Engines - CF6 Series\n\n \n\n# AD/CF6/9  High Pressure Turbine Impeller Spacer Eddy Current Inspection\n\nApplicability: CF6-50/-45 Series.\n\n# 2/88 TX\n\n \n\nRequirement: Eddy current inspection of impeller spacers in accordance with General Electric Service Bulletin SB72-906 and their removal from service.\n\n \n\nCompliance: In accordance with paras (a), (b), (c) and (d) of FAA AD 87-23-06 General Electric: Amendment 39-5746, effective from 1 December 1987.\n\n \n\nBackground:  Fatigue cracks attributed to high stress low cycle fatigue (LCF) can originate in bolt holes on certain GE CF6-50 and -45 impeller spacers. These components have been subject to special inspection in the past but now must be subject to a particular eddy current inspection process specified in GE Service Bulletin 72-906. The FAA has imposed more stringent initial and repetitive inspection periods on the components than those specified by GE, and it specifies requirements for their removal from service. This AD supersedes AD/CF6/4.\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, targeted safety directive focused on a specific mechanical defect in specific engine models. It has not expanded beyond its original purpose of addressing fatigue cracks in impeller spacers. The document explicitly states it supersedes a previous directive (AD/CF6/4) on the same subject matter, indicating continuity of scope rather than expansion."},"complexity_factors":["Very short document (under 300 words)","Only 4 defined elements: applicability (engine series), requirement (inspection standard), compliance (reference to FAA AD), and background (technical rationale)","Single condition: compliance with referenced FAA directive 87-23-06","No nested exceptions or conditional logic — straightforward mandate","Heavy reliance on external technical documents (GE Service Bulletin 72-906, FAA AD 87-23-06) rather than spelling out procedures in the text itself"],"plain_english_summary":"This CASA Airworthiness Directive mandates eddy‑current inspections of the impeller spacer in General Electric CF6‑50 and CF6‑45 engines used on aircraft like the 747, DC‑10 and A300. It requires more stringent inspection timing than before and removal of cracked spacers to prevent fatigue‑related engine failure. The AD replaces a prior order with tougher measures after concerns that earlier requirements were insufficient."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Compared with earlier special inspections and the superseded AD/CF6/4, this AD mandates a specific eddy‑current inspection process (GE SB72‑906) and adopts the FAA's more stringent initial and repetitive inspection intervals plus explicit removal-from-service requirements (Background; Requirement; Compliance). Mechanically, it tightens inspection frequency, prescribes the test method, and replaces the prior AD's regime."},"complexity_factors":["Cross-references to external technical documents (GE SB72-906) and FAA AD 87-23-06 (paras (a)–(d)) — requires operators to obtain and follow multiple sources","Technical inspection method (eddy-current non-destructive testing) with detection and removal criteria — needs specialist skills and equipment","Operational scheduling: initial and repetitive inspection intervals tighter than manufacturer guidance — affects maintenance planning and aircraft downtime","Enforcement and applicability under Civil Aviation Regulations Part 39 and the AD structure, including supersession of AD/CF6/4","Potential cost and logistics of removing and replacing spacers that fail inspection (parts, labour, AOG risk)","Risk of inconsistent implementation where GE guidance and FAA-prescribed intervals differ, resolved by adopting FAA timing"],"plain_english_summary":"This AD requires operators of GE CF6‑50 and CF6‑45 engines to carry out an eddy‑current inspection of high‑pressure turbine impeller spacers per GE Service Bulletin SB72‑906 and to remove spacers that fail the inspection. Compliance follows FAA AD 87‑23‑06 (paras (a)–(d)).\n\nThe rule places inspection timing and removal obligations on operators and maintenance organisations, imposing tighter initial and repetitive intervals than GE set. Operators pay for inspections, specialised testing equipment and replacement parts; CASA enforces the AD (Requirement; Compliance; Background)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf6-9-high-pressure-turbine-impeller-spacer-eddy-current-inspection","history":"/api/acts/ad-cf6-9-high-pressure-turbine-impeller-spacer-eddy-current-inspection/history","analysis":"/api/acts/ad-cf6-9-high-pressure-turbine-impeller-spacer-eddy-current-inspection/analysis","conflicts":"/api/acts/ad-cf6-9-high-pressure-turbine-impeller-spacer-eddy-current-inspection/conflicts","importantCases":"/api/acts/ad-cf6-9-high-pressure-turbine-impeller-spacer-eddy-current-inspection/important-cases","documents":"/api/acts/ad-cf6-9-high-pressure-turbine-impeller-spacer-eddy-current-inspection/documents"}}