{"id":"F2006L01033","name":"AD/CF34/10 - Stage 5 and 6 Low Pressure Turbine Disks","slug":"ad-cf34-10-stage-5-and-6-low-pressure-turbine-disks","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":58314,"registerId":"commonwealth-F2006L01033-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"General Electric Turbine Engines - CF34 ","sectionType":"division","heading":"General Electric Turbine Engines - CF34 Series","content":"### General Electric Turbine Engines - CF34 Series\n\n| AD/CF34/10 | Stage 5 and 6 Low Pressure Turbine Disks | 5/2006 |\n| ---------- | ---------------------------------------- | ------ |\n\n| Applicability: | General Electric Company (GE) CF34-3A1 and -3B1 series turbofan engines with stage 5 low pressure turbine (LPT) disks, part number (P/N) 6078T92P01 or stage 6 LPT disks P/N 6078T89P01, or both, with serial numbers (SNs) listed in Figure 3 or Figure 4 of GE Alert Service Bulletin (ASB) No. CF34-AL S/B 72-A0173,Revision 05, dated 24 May 2005; andGE CF34-1A, -3A, -3A1, -3A2, and -3B series turbofan engines with stage 5 LPT disks P/N 4922T16P01, 5024T53P01, 5024T53P02, or 6078T92P01 or stage 6 LPT disks P/Ns 4922T17P01, 5023T45P03, 5023T45P04, or 6078T89P01, or both, with SNs listed in Figure 3 or Figure 4 of GE ASB No. CF34-BJ S/B 72-A0148,Revision 02, dated 24 May 2005.Note 1: These engines are installed on Bombardier Canadair Models CL-600-2B19 Regional Jet (RJ) aeroplanes, and CL-600-2A12 (CL-601), CL-600-2B16(CL-601-3A), (CL-601-3R), and (CL- 604) Business Jet (BJ) aeroplanes. |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Carry out initial and repetitive inspections and replacement of the Stage 5 and Stage 6 LPT disks as detailed in paragraphs (f) through (s) of FAA AD 2006-04-12.Note 2: FAA AD 2006-04-12 provides actions with regard to optional terminating action and definitions with regard to piece part, replacement engine or replacement LPT module.Note 3: FAA AD 2006-04-12 Amdt 39-14494 refers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |\n| Compliance:    | As detailed in FAA AD 2006-04-12 with a revised effective date of 11 May 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |\n|                | This Airworthiness Directive becomes effective on 11 May 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |\n\n| Background: | This AD results from the discovery of a population of suspect stage 5 LPT disks and stage 6 LPT disks that could fail due to low-cycle fatigue cracking that may start at the site of an electrical arc-out on the disk. We are issuing this AD to prevent low-cycle-fatigue (LCF) failure of stage 5 LPT disks and stage 6 LPT disks, which could lead to uncontained engine failure. |\n| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n29 March 2006","sortOrder":0},{"sectionNumber":"AD/CF34/10","sectionType":"part","heading":"AD/CF34/10","content":"## AD/CF34/10","sortOrder":1},{"sectionNumber":"Stage 5 and 6 Low Pressure Turbine Disks","sectionType":"part","heading":"Stage 5 and 6 Low Pressure Turbine Disks","content":"## Stage 5 and 6 Low Pressure Turbine Disks","sortOrder":2},{"sectionNumber":"5/2006","sectionType":"part","heading":"5/2006","content":"## 5/2006","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"This AD adopts the FAA AD 2006‑04‑12 actions and applies them to the CF34 engines and serial numbers listed in the GE Alert Service Bulletins; it does not introduce additional engine types or substantive new requirements beyond those in the referenced FAA AD, but sets an Australian effective date (Compliance)."},"complexity_factors":["Cross‑reference to FAA AD 2006‑04‑12 for the substantive inspection and replacement procedure and definitions (Requirement; Note 2).","Multiple engine series, numerous part numbers and serial‑number lists referenced in GE ASB figures (Applicability: references to GE ASB No. CF34‑AL S/B 72‑A0173 and CF34‑BJ S/B 72‑A0148, Figures 3 & 4).","Incorporation by reference of external service bulletins and an overseas authority increases tracking and legal‑interpretation work (Applicability; Requirement; Compliance).","Repetitive inspection schedules and possible replacement/terminating actions create ongoing operational and cashflow implications for operators (Requirement; Compliance).","Effective date coordination and amendment language (revised effective date 11 May 2006) imposes a fixed compliance start that operators must meet (Compliance).","Technical cause is specific (low‑cycle‑fatigue originating at electrical arc‑out) which requires specialised inspection/repair capabilities and may limit service providers able to perform compliant work (Background)."],"plain_english_summary":"**Mandates initial and repetitive inspections and replacement of stage 5 and stage 6 low‑pressure turbine (LPT) disks on specified GE CF34 engine series by adopting the actions in FAA AD 2006‑04‑12.** It applies to engines and serial numbers listed in GE Alert Service Bulletins and affects operators of Bombardier CL‑600/CL‑601/CL‑604 aircraft fitted with those engines. CASA enforces compliance; operators pay inspection and replacement costs. The stated purpose is to prevent low‑cycle‑fatigue cracking that could lead to uncontained engine failure."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This appears to be a standard airworthiness directive implementing a safety-critical inspection requirement. The scope remains tightly focused on the specific turbine disk defect issue as originally identified. The incorporation of FAA AD requirements is standard practice for Australian aviation safety regulation and does not represent scope creep."},"complexity_factors":["Heavy reliance on external documents: The directive references but does not reproduce the actual inspection requirements from FAA AD 2006-04-12, meaning operators must cross-reference US regulations","Extensive part number and serial number specificity: Multiple part numbers (P/N) and serial number lists in referenced GE service bulletins create complex applicability determination","Nested applicability conditions: The directive applies to different engine series (-3A1, -3B1, -1A, -3A, -3A2, -3B) with different disk part numbers requiring cross-checking against two separate GE Alert Service Bulletins","Conditional compliance structure: Different actions required based on whether disks are stage 5, stage 6, or both, and whether optional terminating actions are taken","Technical aviation terminology throughout: References to LPT modules, piece parts, turbofan configurations, and service bulletin revisions assume specialized knowledge"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspections and, if needed, replacement of Stage 5 and 6 low-pressure turbine disks on General Electric CF34 engines (used on Bombardier regional and business jets). It addresses an electrical \"arc-out\" manufacturing defect that can cause low-cycle fatigue cracks and risk uncontained engine failure. The requirement is mandatory for affected operators, aligns with the FAA directive, and became effective 11 May 2006."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf34-10-stage-5-and-6-low-pressure-turbine-disks","history":"/api/acts/ad-cf34-10-stage-5-and-6-low-pressure-turbine-disks/history","analysis":"/api/acts/ad-cf34-10-stage-5-and-6-low-pressure-turbine-disks/analysis","conflicts":"/api/acts/ad-cf34-10-stage-5-and-6-low-pressure-turbine-disks/conflicts","importantCases":"/api/acts/ad-cf34-10-stage-5-and-6-low-pressure-turbine-disks/important-cases","documents":"/api/acts/ad-cf34-10-stage-5-and-6-low-pressure-turbine-disks/documents"}}