{"id":"F2014L00502","name":"AD/CFM56/33 - Inspection of Fan Blades with 25 Degree Mid-span Shrouds","slug":"ad-cfm56-33-inspection-of-fan-blades-with-25-degree-mid-span-shrouds","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":91640,"registerId":"commonwealth-F2014L00502-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"CFM International Turbine Engines - CFM5","sectionType":"division","heading":"CFM International Turbine Engines - CFM56 Series","content":"### CFM International Turbine Engines \\- CFM56 Series\n\n| AD/CFM56/33 | Inspection of Fan Blades with25 Degree Mid-span Shrouds | 10/2014 |\n| ----------- | ------------------------------------------------------- | ------- |\n\n| Applicability: | This AD applies to CFM International (CFM) CFM56-3 turbofan engines, all serial numbers, when equipped with fan blades with 25 degree mid-span shrouds: Part Numbers (P/N) 9527M99P08, 9527M99P09, 9527M99P10, 9527M99P11, and 1285M39P01, or fan blade pairs P/N 335-088-901-0, 335-088-902-0, 335-088-903-0, and 335-088-904-0.Note 1: These engines are known to be installed on, but not limited to, Boeing 737 series aeroplanes.Note 2: The installation of fan blades with 25 degree mid-span shrouds is not allowed on the CFM56-3C engine model.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirements:  | 1. INSPECTIONPerform an inspection of fan blades P/N 9527M99P08, 9527M99P09, 9527M99P10, 9527M99P11, and 1285M39P01, or fan blade pairs P/N 335‑088‑901-0, 335-088-902-0, 335‑088‑903‑0, and 335-088-904-0 in accordance with paragraphs 3.A (On-wing) or 3.B (In-shop) of CFM Service Bulletin (SB) CFM56-3/3B/3C 72-1067 original issue.Note 3: Inspections completed in accordance with CFM SB CFM56-3/3B/3CS/B 72-1067 original issue, within the last 3,000 Flight Cycles (FC) before the effective date of this AD satisfies Requirement 1 of this AD.2. If any damage is found, remove and replace the blades as instructed in the accomplishment instructions of CFM SB CFM56-3/3B/3C 72-1067 original issue.3. Do not install on any CFM56-3 engine model fan blades P/N 9527M99P08, 9527M99P09, 9527M99P10, 9527M99P11, and 1285M39P01, or fan blade pairs P/N 335-088-901-0, 335-088-902-0, 335-088-903-0, and 335-088-904-0 unless they have been previously inspected in accordance with paragraph 3 of the accomplishment instructions of CFM SB CFM56-3/3B/3C 72-1067 original issue.Note 4: The use of later approved revisions of CFM SB CFM56-3/3B/3C 72-1067 original issue is acceptable for compliance with the requirements of this AD.Note 5: EASA AD 2009-0036 dated 20 February 2009 refers. |\n| Compliance:    | 1, 2 and 3. The actions in Requirements 1, 2 and 3 must be taken as follows:(a) for Requirement 1: if not previously complied with, before further flight. Otherwise, at intervals not exceeding 3,000 FC from the last inspection.(b) for Requirement 2: before further flight.(c) for Requirement 3: after the effective date of this AD.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n|                | This Airworthiness Directive becomes effective on 9 May 2014.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| Background:    | The requirements of this AD address the same unsafe condition as EASA AD 2009‑0036 with an effective date of 20 February 2009.A multiple fan blade failure event was reported on a CFM56-3 engine model. Severe wear was observed on the underside of the fan blade platforms at the contact location with the fan blade dampers. This resulted in poor damping of the fan blade set and contributed to high dynamic stress of the blades.For the reasons stated above, this AD requires repetitive inspections of fan blades with 25 degrees mid-span shrouds as defined by CFM SB CFM56-3/3B/3C 72-1067 original issue in order to reduce the risk of a multiple fan blade failure event which could result in an uncontained engine rotor failure.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n\n![](image.001.png)\n\nMike Higgins  \nDelegate of the Civil Aviation Safety Authority\n\n30 April 2014","sortOrder":0},{"sectionNumber":"AD/CFM56/33","sectionType":"part","heading":"AD/CFM56/33","content":"## AD/CFM56/33","sortOrder":1},{"sectionNumber":"Inspection of Fan Blades with25 Degree M","sectionType":"part","heading":"Inspection of Fan Blades with25 Degree Mid-span Shrouds","content":"## Inspection of Fan Blades with  \n25 Degree Mid-span Shrouds","sortOrder":2},{"sectionNumber":"10/2014","sectionType":"part","heading":"10/2014","content":"## 10/2014","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"This AD continues and formalises the original safety response to the same unsafe condition described in EASA AD 2009‑0036: addressing wear at the blade platform/damper contact and reducing the risk of multiple blade failure by mandating inspections, removal of damaged blades, and restricting installation without inspection. It does not broaden the subject matter beyond that original purpose; it targets the same blade designs and the same failure mode and relies on the manufacturer service bulletin for the technical method."},"complexity_factors":["Cross‑reference to a single manufacturer Service Bulletin (CFM SB CFM56-3/3B/3C 72‑1067) for the detailed inspection procedure (paragraphs 3.A and 3.B).","Multiple specific part numbers listed (9 P/Ns across single blades and blade pairs).","Conditional compliance timing (before further flight if not already complied with; otherwise repeat at intervals not exceeding 3,000 flight cycles).","Installation prohibition conditioned on prior inspection (creates a procedural precondition for part use).","Allowance for later approved SB revisions (adds a layer of regulatory flexibility and potential version control).","Reference to a prior foreign AD (EASA AD 2009‑0036) and reliance on shared safety rationale.","Distinction in applicability (note excluding CFM56‑3C model from installation) which requires operators to track engine sub‑models."],"plain_english_summary":"**What this directive mechanically requires**\n\n- This Airworthiness Directive (AD) applies to CFM56-3 engines fitted with specific fan blades that have 25° mid‑span shrouds (listed part numbers). (Applicability)\n- It orders operators to inspect those fan blades in accordance with paragraphs 3.A (on-wing) or 3.B (in‑shop) of CFM Service Bulletin (SB) CFM56-3/3B/3C 72-1067 (Requirements ¶1).\n- If inspections find any damage, the blades must be removed and replaced following the SB instructions (Requirements ¶2).\n- You may not install any of the listed blades on a CFM56-3 engine unless those blades have already been inspected per the SB (Requirements ¶3).\n- If you have already done an inspection within the last 3,000 flight cycles before this AD took effect, that satisfies the initial inspection requirement (Requirements Note 3). Later approved revisions of the service bulletin are acceptable (Requirements Note 4). (Requirements & Compliance)\n\n**Who this affects**\n\n- Aircraft operators and maintenance organisations that operate or service CFM56-3 turbofan engines fitted with the listed blade part numbers (Applicability). These engines are commonly installed on Boeing 737 aircraft, among others (Applicability Note 1).\n- Suppliers, overhaul shops and MROs that build, stock or install the listed blade part numbers will also be affected because installation is restricted unless the blades have been inspected (Requirements ¶3).\n\n**Why it matters (stated purpose and the safety risk addressed)**\n\n- The AD responds to a reported multiple fan‑blade failure event where severe wear was found under the blade platforms where they contact dampers. That wear reduced damping and increased dynamic stress on blades, contributing to failure (Background).\n- The stated intent is to reduce the risk of a multiple fan‑blade failure that could lead to an uncontained engine rotor failure by mandating repetitive inspections and removal of damaged blades (Background).\n\n**Practical effects, incentives and trade‑offs**\n\n- Who pays: aircraft operators pay for the inspections, any in‑shop work, and replacement blades if damage is found. Maintenance organisations may charge for inspection labour and parts. (Requirements & Compliance)\n- Who decides and acts: the regulator (via the AD) mandates the inspections; operators schedule and carry out inspections; licensed maintenance organisations perform the work using the CFM service bulletin as the technical procedure (Requirements ¶1, Note 4).\n- Operational impact: if a blade has not been inspected as required, the engine cannot be flown until the inspection is done (Compliance ¶1(a): \"before further flight\"). This can cause aircraft downtime and scheduling disruption.\n- Compliance cadence and burden: initial compliance is required before further flight if not already done; otherwise inspections must be repeated at intervals not exceeding 3,000 flight cycles (Compliance ¶1(a)). This is a recurring maintenance burden that increases operating costs and maintenance planning complexity.\n- Supply and installation constraints: the prohibition on installing the listed blades unless they have been inspected (Requirements ¶3) limits how quickly operators can replace blades and may constrain the aftermarket for those specific part numbers. Some operators may substitute different blade types if available and permitted.\n- Implementation risk and reliance on industry material: the AD cross‑references a manufacturer service bulletin (CFM SB 72‑1067 original issue) and allows later approved revisions (Requirements Note 4). That delegates the technical inspection method to the manufacturer’s SB; effectiveness depends on the SB’s adequacy and on approved revisions remaining available.\n\n**Costs vs benefits (mechanical assessment, not a value judgement)**\n\n- Expected benefits: earlier detection and removal of worn or damaged blades reduces the probability of a multiple‑blade failure and attendant safety risks (Background).\n- Expected costs: recurring inspection labour, potential in‑shop downtime, replacement blade costs when damage is found, and possible limitations on using certain spare blades until inspected. There is also administrative overhead for tracking flight‑cycle intervals and SB revision approvals (Requirements & Compliance).\n\n**Other measurable effects and limits**\n\n- The AD does not ban the blade part numbers outright for the CFM56-3 (unlike -3C where installation is explicitly not allowed — Applicability Note 2); rather it conditions their installation on prior inspection (Requirements ¶3).\n- The AD reuses the safety analysis done for EASA AD 2009‑0036 (Background). It therefore aligns with an earlier regulatory response rather than introducing a new or broader regulatory purpose.\n\n**Concrete reference points in the AD**\n\n- Applicability and excluded model (Notes 1–2).\n- Inspection method: CFM SB CFM56-3/3B/3C 72‑1067 paragraphs 3.A (On‑wing) or 3.B (In‑shop) (Requirements ¶1).\n- Replacement requirement if damage found (Requirements ¶2).\n- Installation prohibition without prior inspection (Requirements ¶3).\n- Timing: before further flight if not already done; repeat at ≤3,000 flight cycles (Compliance ¶1).\n\nOverall, the AD mechanically forces regular inspection and removal/replacement rules for a defined set of fan blades to address a documented wear‑related failure mechanism. Operators bear the direct costs and scheduling consequences; the regulator prescribes the inspection method via a manufacturer service bulletin and enforces recurrence intervals to manage the safety risk."},"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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope. It addresses a specific safety issue identified in 2009 (referenced EASA AD) and applies only to specific fan blade part numbers on a specific engine series. The requirements remain tightly focused on inspection and replacement of those blades."},"complexity_factors":["Multiple specific part numbers listed (9 different part numbers across single blades and blade pairs)","Cross-reference to external technical document (CFM Service Bulletin CFM56-3/3B/3C 72-1067) for actual inspection procedures — the AD itself doesn't contain the technical 'how-to'","Conditional compliance logic with three different timing requirements (before further flight, 3,000 flight cycle intervals, or after effective date)","Nested applicability exclusions (Note 2 clarifies specific engine model exclusion)","Reference to foreign aviation safety regulation (EASA AD 2009-0036) for background context"],"plain_english_summary":"This AD mandates repetitive inspections of CFM56‑3 fan blades with 25° mid‑span shrouds (commonly on Boeing 737s), requires replacement of any damaged blades, and bars installing these blades unless inspected. It applies to airlines, maintenance organisations and operators of affected engines (primarily B737 operators in Australia). It addresses a prior incident where severe wear led to multiple blade failures and raised risk of uncontained engine rotor failure, so inspections aim to catch damage before catastrophic failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cfm56-33-inspection-of-fan-blades-with-25-degree-mid-span-shrouds","history":"/api/acts/ad-cfm56-33-inspection-of-fan-blades-with-25-degree-mid-span-shrouds/history","analysis":"/api/acts/ad-cfm56-33-inspection-of-fan-blades-with-25-degree-mid-span-shrouds/analysis","conflicts":"/api/acts/ad-cfm56-33-inspection-of-fan-blades-with-25-degree-mid-span-shrouds/conflicts","importantCases":"/api/acts/ad-cfm56-33-inspection-of-fan-blades-with-25-degree-mid-span-shrouds/important-cases","documents":"/api/acts/ad-cfm56-33-inspection-of-fan-blades-with-25-degree-mid-span-shrouds/documents"}}