{"id":"F2007L03509","name":"AD/CFM56/27 - Low Pressure Turbine Rear Frame Life - 5 Series Engines","slug":"ad-cfm56-27-low-pressure-turbine-rear-frame-life-5-series-engines","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":69760,"registerId":"commonwealth-F2007L03509-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/CFM56/27 | Low Pressure Turbine Rear Frame Life - 5 Series Engines | 11/2007 DM |\n| ----------- | ------------------------------------------------------- | ---------- |\n\n| Applicability: | CFM International (CFM) Model CFM56-5B1/P, -5B2/P, -5B3/P, -5B3/P1,-5B4/P, -5B4/P1, -5B5/P, -5B6/P, -5B7/P, -5B8/P and -5B9/P turbofan engines operating in commercial application and Model CFM56-5B6/P and -5B7/P turbofan engines operating in corporate application (conversion per SB 72-0308), if equipped with a low pressure turbine (LPT) rear frame part number (P/N) 338-171-703-0, 338-171-704-0, 338-171-705-0 or 338-171-706-0.Note 1: These engines are known to be installed on, but not limited to, Airbus A318, A319, A320 and A321 series aircraft.                                                                                           |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. For LPT rear frame P/N 338-171-703-0, 338-171-704-0, 338-171-705-0, 338-171-706-0, comply with the LCF life limits in accordance with the chapters 05-12-04, 05-12-24 and 05-21-03 in the CFM56-5B ESM, revision 47, dated 15 January 2007, or later approved revision.2. If the number of cycles accumulated since new by a LPT rear frame P/N 338-171-703-0, 338-171-704-0, 338-171-705-0, 338-171-706-0 cannot be established, remove and replace the LPT rear frame, or perform the inspections in accordance with CFM56-5B Service Bulletin S/B 72-0620 initial issue, or later approved revision.Note 2: EASA AD 2007-0221 dated 13 August 2007 refers. |\n| Compliance:    | 1. Within 7 days after the effective date of this AD, unless previously accomplished.2. Within 300 cycles after the effective date of this AD.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n|                | This Airworthiness Directive becomes effective on 3 September 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n| Background:    | Before the issue of the CFM56-5B Engine Shop Manual (ESM) Temporary Revision (TR) 05-0145, the concerned LPT rear frames were not subject to a life limit in commercial applications, and in corporate applications the CFM56-5B6/P and –5B7/P engines were life limited to 22 500 cycles.                                                                                                                                                                                                                                                                                                                                                                       |\n\n|     | Using a refined damage tolerant approach accounting for crack initiation and propagation to ensure any cracking that is present will not grow to unsafe levels; CFM has now established a low cycle fatigue (LCF) life limit for the concerned LPT rear frames. This requirement was first introduced by revision TR 05-0145 of the CFM56-5B ESM. This revision is approved by EASA and its content has been integrated in revision 47 of the CFM56-5B ESM, dated January 15, 2007.For the reason described above, this AD requires operators to revise their aircraft maintenance programs in accordance with these LCF life limits affecting new P/Ns. |\n| --- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nCharles Lenarcic  \nDelegate of the Civil Aviation Safety Authority\n\n28 August 2007","sortOrder":0},{"sectionNumber":"AD/CFM56/27","sectionType":"part","heading":"AD/CFM56/27","content":"## AD/CFM56/27","sortOrder":1},{"sectionNumber":"Low Pressure Turbine Rear Frame Life - 5","sectionType":"part","heading":"Low Pressure Turbine Rear Frame Life - 5 Series Engines","content":"## Low Pressure Turbine Rear Frame Life - 5 Series Engines","sortOrder":2},{"sectionNumber":"11/2007 DM","sectionType":"part","heading":"11/2007 DM","content":"## 11/2007 DM","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"The AD extends formal LCF life limits to LPT rear frames that were previously not life‑limited in commercial applications (and aligns corporate limits), requiring operators to revise maintenance programs and to inspect or replace frames when cycles‑since‑new cannot be established. This represents an expansion of the parts‑life regulatory scope compared with the prior state described in the Background."},"complexity_factors":["Technical requirement: introduces LCF (low‑cycle fatigue) life limits based on damage‑tolerant analysis (requires engineering understanding).","Cross‑references: relies on CFM56‑5B Engine Shop Manual (rev 47+) and Service Bulletin S/B 72‑0620 (requires operators to obtain and follow external documents).","Recordkeeping: compliance depends on establishing cycles‑since‑new for each affected part, which may be incomplete or difficult to verify.","Dual options: unknown‑cycle frames must be either replaced or inspected, creating operational and commercial tradeoffs.","Applicability nuance: different treatment historically for commercial vs corporate applications (some corporate models previously had a limit), requiring careful applicability checks.","Compliance timing: short mandatory timeframes (within 7 days; within 300 cycles) increase operational and logistical pressure.","Maintenance program changes: requires formally revising approved maintenance programs, triggering administrative and regulatory interaction.","Potential supply/logistics impact: required removals/replacements could create parts lead‑time and cost issues for operators."],"plain_english_summary":"This Airworthiness Directive mandates life limits and follow-up actions for specific low‑pressure turbine (LPT) rear‑frame part numbers on CFM56‑5B engines. Operators must comply with the LCF (low‑cycle fatigue) life limits in the CFM56‑5B Engine Shop Manual (rev. 47 or later) and, if cycles‑since‑new cannot be established, replace the frame or carry out inspections per CFM Service Bulletin S/B 72‑0620. It applies to affected commercial and some corporate engine installations and requires changes to maintenance programs with deadlines of 7 days and 300 cycles.\n\nOperators bear the cost and administrative burden of inspections, replacements and maintenance‑program updates. The stated safety purpose is to control crack initiation and propagation by imposing LCF life limits."},"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 through refined fatigue analysis for specific part numbers in the CFM56-5B engine family. The directive does not expand beyond its original purpose of imposing life limits on identified LPT rear frames."},"complexity_factors":["Single, clearly defined applicability section listing specific engine models and part numbers","Two straightforward compliance requirements with specific timeframes (7 days and 300 cycles)","Minimal cross-referencing — only references to manufacturer manuals (CFM56-5B ESM) and one EASA directive","No nested exceptions or conditional logic — requirements apply uniformly to affected parts","Technical but narrow scope — applies only to specific LPT rear frame part numbers in CFM56-5B engines","Short document structure with clear Background section explaining the safety rationale"],"plain_english_summary":"This CASA Airworthiness Directive imposes mandatory life limits on the low pressure turbine (LPT) rear frame in certain CFM56‑5B engines (used on A318/A319/A320/A321) after fatigue analysis showed risk of cracking. Operators must update maintenance records quickly and, if frame flight cycles are unknown, replace or inspect parts within a short cycle window to prevent in‑service failures."},"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-cfm56-27-low-pressure-turbine-rear-frame-life-5-series-engines","history":"/api/acts/ad-cfm56-27-low-pressure-turbine-rear-frame-life-5-series-engines/history","analysis":"/api/acts/ad-cfm56-27-low-pressure-turbine-rear-frame-life-5-series-engines/analysis","conflicts":"/api/acts/ad-cfm56-27-low-pressure-turbine-rear-frame-life-5-series-engines/conflicts","importantCases":"/api/acts/ad-cfm56-27-low-pressure-turbine-rear-frame-life-5-series-engines/important-cases","documents":"/api/acts/ad-cfm56-27-low-pressure-turbine-rear-frame-life-5-series-engines/documents"}}