{"id":"F2006B08482","name":"AD/CF6/40 - Fan Mid Shaft","slug":"ad-cf6-40-fan-mid-shaft","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51162,"registerId":"commonwealth-F2006B08482-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/CF6/40 Fan Mid Shaft 7/2000","sectionType":"part","heading":"AD/CF6/40 Fan Mid Shaft 7/2000","content":"# AD/CF6/40 Fan Mid Shaft 7/2000\n\nApplicability: General Electric CF6-80C2 series turbofan engines incorporating fan mid shafts, Part No. 9326M74P04 or 9326M74P05.\n\nRequirement: Remove affected fan mid shafts from service.\n\nNote 1: FAA AD 2000-03-04 also refers.\n\nNote 2: General Electric SB’s CF6-80C2 SB 72-750 and CF6-80C2 SB 72-958 also refer.\n\nCompliance: For mid shafts that have accumulated 9,000 or more cycles since new (CSN) as of the effective date of this Directive remove from service within 3,500 cycles in service (CIS) or prior to accumulating 15,000 CSN, whichever occurs first.\n\nFor mid shafts that have accumulated 1,800 CSN or more, but less than 9,000 CSN as of the effective date of this Directive, remove from service within 5,000 CIS or prior to accumulating 12,500 CSN, whichever occurs first.\n\nFor mid shafts that have accumulated less than 1,800 CSN as of the effective date of this Directive remove from service prior to accumulating 6,800 CSN.\n\nThis Airworthiness Directive becomes effective on 13 July 2000.\n\nBackground: The FAA advises that recent component test data requires removal of certain fan mid shafts from service at a revised lower cycle life limit.\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 2 June 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 14 June 2000.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific safety-critical component failure risk in identified engine models. The tiered compliance deadlines reflect proportionate regulatory response based on usage patterns, not scope creep."},"complexity_factors":["Short, single-purpose directive with one clear requirement (removal of specific parts)","Only 2 defined part numbers in applicability section","Three-tiered compliance structure based on accumulated flight cycles, but logic is straightforward (if-then-else structure)","Minimal cross-referencing: only 2 FAA/manufacturer documents noted in non-mandatory notes","No nested exceptions or conditional sub-clauses","Total length: approximately 300 words of substantive text"],"plain_english_summary":"This AD mandates removal of specific fan mid shafts (parts 9326M74P04/05) from GE CF6-80C2 engines because new test data show they can fail earlier than expected. It affects airlines, operators and maintenance shops using those engines and matters because shaft failure risks catastrophic engine damage in flight.\n\nCompliance deadlines vary by accumulated cycles — more‑used shafts must be removed sooner — with the AD effective 13 July 2000."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"This AD stays within the normal remit of an airworthiness directive: it prescribes required corrective action (removal of a component) to address a safety concern with a specific aeronautical product. It tightens the allowable life limit for a particular part (fan mid shaft) but does not expand the regulatory scope beyond the original purpose of correcting an identified unsafe condition for affected engines."},"complexity_factors":["Three distinct compliance branches based on cycles since new (CSN) thresholds (<1,800; 1,800–8,999; ≥9,000) with different CIS limits and alternate 'whichever occurs first' endpoints","Use of two related cycle-count metrics (CSN and CIS) which require accurate operational record-keeping","References to external documents (FAA AD 2000-03-04; GE Service Bulletins SB 72-750 and SB 72-958) for technical details and procedures","Narrow applicability limited to two specific part numbers (9326M74P04, 9326M74P05) but covering an entire engine family (CF6-80C2), creating the need to match parts to engines and records","Conditional timing language ('within X CIS or prior to accumulating Y CSN, whichever occurs first') introducing simple but multiple stopping conditions","No detailed replacement/repair procedure in the text itself — operators must consult external service bulletins, adding procedural cross-referencing"],"plain_english_summary":"**What this directive does (mechanics)\n\n- Applies to: General Electric CF6-80C2 series turbofan engines that have fan mid shafts with part number 9326M74P04 or 9326M74P05. (Applicability)\n\n- Mandatory action: Remove the affected fan mid shafts from service according to the schedule below. (Requirement)\n\n- Compliance timing (three categories based on cycles since new, CSN):\n  - If a mid shaft has 9,000 or more CSN as of the directive's effective date, it must be removed within 3,500 cycles in service (CIS) or before it reaches 15,000 CSN, whichever comes first. (Compliance)\n  - If it has 1,800 CSN or more but less than 9,000 CSN as of the effective date, it must be removed within 5,000 CIS or before 12,500 CSN, whichever comes first. (Compliance)\n  - If it has less than 1,800 CSN as of the effective date, it must be removed before it reaches 6,800 CSN. (Compliance)\n\n- The directive points operators to related documents: FAA Airworthiness Directive 2000-03-04 and GE Service Bulletins CF6-80C2 SB 72-750 and SB 72-958. (Notes)\n\n- Effective date: 13 July 2000. (Compliance)\n\nWhy the regulator says this is needed\n\n- The background states that recent component test data (reported by the FAA) showed the existing life limit for these fan mid shafts should be reduced, so civil aviation authorities require earlier removal to address an identified unsafe condition. (Background)\n\nWho this affects and who pays\n\n- Affected parties: Aircraft operators, lessors, and maintenance organisations that operate or service aircraft fitted with GE CF6-80C2 engines using the specified fan mid shaft part numbers. (Applicability)\n\n- Who makes the decision: The Civil Aviation Safety Authority (CASA) delegate issued the directive; operators must comply with the removal schedule. (Header/Signature)\n\n- Who bears the cost: Operators pay for the physical removal and replacement of the shafts, any necessary inspections, engine downtime, logistics for spare parts, and labour. Maintenance organisations incur planning and execution costs. Any downstream cost (e.g. lease terms, passenger disruption) flows from operator actions. (Requirement; Compliance)\n\nBehavioral and operational effects (concrete mechanisms)\n\n- Operators must track or verify each mid shaft's cycles since new (CSN) and cycles in service (CIS) and schedule removals accordingly.\n- Operators may need to bring forward maintenance, obtain spare shafts, or reallocate aircraft/engines to cover for removed parts.\n- Maintenance providers will follow GE service bulletins and the FAA AD for removal/replacement procedures and record-keeping.\n\nTrade-offs, implementation risks and compliance burden\n\n- Trade-off: The directive shortens the allowed service life of these parts to reduce the risk of in‑service failure, at the cost of earlier replacement and increased near‑term maintenance expenditure. (Background)\n- Compliance burden: Accurate cycle counting, planning for spares and shop capacity, and ensuring all affected units are identified and removed on schedule. (Compliance)\n- Implementation risks: Limited spare-part availability or logistics delays could force unscheduled aircraft disruptions; errors in CSN/CIS records could cause non‑compliance or unnecessary removals. (Compliance; Notes)\n\nCross-references and practical steps\n\n- The AD cross-references FAA AD 2000-03-04 and GE SBs CF6-80C2 SB 72-750 and SB 72-958 for further technical instructions. Operators should consult those documents for removal/replacement procedures and any additional inspection requirements. (Notes)\n\nNet effect summary in plain terms\n\n- This is a targeted safety order requiring earlier removal of certain fan mid shafts on GE CF6-80C2 engines, based on revised life limits from testing. It forces operators to retire and replace those specific parts sooner than previously allowed, increasing maintenance activity and costs for affected fleets while aiming to reduce the risk of part failure. (Requirement; Background)\n"},"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-cf6-40-fan-mid-shaft","history":"/api/acts/ad-cf6-40-fan-mid-shaft/history","analysis":"/api/acts/ad-cf6-40-fan-mid-shaft/analysis","conflicts":"/api/acts/ad-cf6-40-fan-mid-shaft/conflicts","importantCases":"/api/acts/ad-cf6-40-fan-mid-shaft/important-cases","documents":"/api/acts/ad-cf6-40-fan-mid-shaft/documents"}}