{"id":"F2006B08526","name":"AD/CFM56/22 - EGT Harnesses and EGT Couplings","slug":"ad-cfm56-22-egt-harnesses-and-egt-couplings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51279,"registerId":"commonwealth-F2006B08526-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\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.\n\n![](image.001.png)\n\nCFM International Turbine Engines \\- CFM56 Series","sortOrder":0},{"sectionNumber":"AD/CFM56/22 EGT Harnesses and EGT Coupli","sectionType":"part","heading":"AD/CFM56/22 EGT Harnesses and EGT Couplings 3/2003","content":"# AD/CFM56/22 EGT Harnesses and EGT Couplings 3/2003\n\nApplicability: CFM56-5 and -5B series turbofan engines that have an exhaust gas temperature (EGT) upper harness part number (P/N) CA170-00, with a serial number (S/N) of YC021674 or lower, or an EGT lower harness P/N CA171-00, with a S/N of YC026641 or lower, or an EGT coupling P/N CA172-02 with a S/N of YC166736 or lower.\n\nNote 1: These engines are installed on, but not limited to, Airbus Industrie A318, A319, A320 and A321 aeroplanes.\n\nNote 2: Harnesses or couplings having a serial number that is followed by the letter \"W\" are not affected by this Directive.\n\nRequirement: 1. If EGT harnesses and EGT couplings have accumulated less than 3,000 engine flight hours since installation, carry out either of the following actions:\n\n    Replace affected EGT harnesses and EGT couplings, not being trend monitored, with serviceable parts in accordance with CFM International Service Bulletins CFM56-5 S/B 77-0020 or CFM56-5B S/B 77-0008, both dated 4 March 2002, as applicable, or\n\n    b. Review the smooth data EGT trend via the System for Analysis of Gas Turbine Engines (SAGE), or equivalent, since the affected components were first installed on the current engine. This trend monitoring must continue for the affected EGT harnesses and couplings to ensure that the system does not show a minimum of 30oC downward (i.e. cooler) indication, or more, without a corresponding change in other associated engine parameters such as N1 (LPT rotor speed), N2 (HPT rotor speed), and fuel flow.\n\n2. If the Requirement 1b. SAGE monitoring shows a minimum of 30oC downward indication, or more, without a corresponding change in other associated engine parameters such as N1, N2 and fuel flow, provided that there is sufficient actual EGT margin to do so, replace the EGT harnesses and couplings.\n\nNote 3: FAA AD 2003-02-04 Amdt 39-13020 and DGAC AD 2003-001(B) refer.","sortOrder":1}],"analysis":{"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD is narrowly targeted to specific EGT harness and coupling part numbers and serial-number ranges on CFM56-5 / -5B engines and does not broaden coverage to other parts or engine types. The instrument retains a focused corrective scope—either replacement or monitoring and conditional replacement on a measured trend—consistent with the stated safety purpose. There is no textual evidence in this AD that the scope has been expanded beyond that original, narrowly defined corrective objective."},"complexity_factors":["Narrow technical scope limited to three specific P/N and S/N thresholds","Single conditional branch: for affected parts with <3,000 engine flight hours, operator must choose between two options (replace or monitor)","Monitoring option requires ongoing data-trend analysis (SAGE or equivalent) and continuation of that monitoring","Trigger for mandatory replacement during monitoring is a specific numeric threshold (>=30°C unexplained drop) tied to cross-checks with other engine parameters (N1, N2, fuel flow)","Exception: serial numbers ending with letter 'W' are excluded","References to external documents (two CFM Service Bulletins, FAA and DGAC ADs) create operational cross-references","Minor ambiguity about engines/parts with >=3,000 engine flight hours since installation (no explicit instruction in this AD text for that case)"],"plain_english_summary":"**What this Airworthiness Directive (AD) does — mechanically**\n\n- Applies to CFM International CFM56-5 and CFM56-5B turbofan engines that have specific exhaust gas temperature (EGT) harnesses or EGT couplings by part number (P/N) and by serial number (S/N):\n  - EGT upper harness P/N CA170-00 with S/N YC021674 or lower;\n  - EGT lower harness P/N CA171-00 with S/N YC026641 or lower;\n  - EGT coupling P/N CA172-02 with S/N YC166736 or lower.\n- Harnesses/couplings whose serial number is followed by the letter “W” are explicitly not affected.\n- If any affected harness or coupling has been installed on an engine for less than 3,000 engine flight hours, the operator must do one of the following:\n  - Replace the affected part(s) with serviceable parts in accordance with the cited CFM International Service Bulletins (CFM56-5 S/B 77-0020 or CFM56-5B S/B 77-0008, dated 4 March 2002); or\n  - Begin and maintain trend monitoring of the EGT data using SAGE (System for Analysis of Gas Turbine Engines) or an equivalent system from the time the part was installed on that engine.\n- If monitoring shows a downward EGT reading of 30°C or more that is not matched by changes in other engine parameters (N1, N2, fuel flow), then, provided the engine has enough actual EGT margin to continue safe operation, the operator must replace the affected harnesses and couplings.\n- The AD cross-references related directives from FAA and DGAC.\n\n**Why the regulator issues this AD (the stated purpose), and what that means in practice**\n\n- The AD is issued to correct an identified unsafe condition linked to these EGT harnesses/couplings. The text makes clear the regulator’s concern: an erroneous downward EGT indication (of 30°C or more) that is not accompanied by changes in other engine parameters. The requirement addresses that by forcing either immediate replacement of suspect parts or ongoing electronic trend monitoring so that such a fault is detected and acted on.\n\n**Who this affects and who pays**\n\n- Aircraft operators, maintenance organisations and engine shops that operate or maintain aeroplanes fitted with the specified CFM56-5/5B engines bear the practical obligations and costs. They pay for parts, labour and the monitoring (SAGE subscription/use or equivalent monitoring capability). If replacement is needed, operators also bear the aircraft downtime and associated scheduling or lease costs.\n\n**Who decides and how behaviour must change**\n\n- The regulator (CASA, via its delegate) imposes the AD. Operators decide whether to replace affected parts immediately or commence/continue SAGE (or equivalent) monitoring; they must act if monitoring shows the specified 30°C unexplained downward EGT indication and there is sufficient EGT operating margin.\n\n**Implementation, compliance and trade-offs**\n\n- Implementation requires: checking part and serial numbers against engine records; tracking cumulative engine flight hours since installation; accessing and using SAGE (or a reliable equivalent) and retaining trend records; following the cited service bulletins when performing replacements.\n- Costs and trade-offs: immediate replacement is an up-front parts-and-labour cost plus downtime. Monitoring defers that cost but requires reliable trend analysis and continuing surveillance; monitoring also creates an ongoing compliance burden and the operational risk that a fault will be discovered later and require replacement at short notice. The AD conditions replacement on both a monitored threshold (>=30°C unexplained drop) and on having sufficient EGT margin to continue operation, which imposes an operational judgment and recordkeeping responsibility on the operator.\n\n**Market and incentives effects (practical, mechanistic)**\n\n- Demand for replacement parts and maintenance work rises for affected engines; operators with affected parts pay more in maintenance/replacement or monitoring costs. Operators may prefer to avoid affected serial-number ranges when sourcing parts in future. Maintenance organisations and parts suppliers gain concentrated business; costs are distributed across operators that run the affected engines. The AD does not change ownership or contract rights directly; it imposes operational and maintenance obligations.\n\n**Notes and cross-references**\n\n- The AD cites specific CFM service bulletins as the replacement procedure and references analogous FAA and DGAC directives for the same issue.\n\n(Information above is taken from the AD’s applicability, notes and requirement sections. The AD states its aim is to correct an unsafe condition; the text of the requirements indicates that the unsafe condition of concern is an unexplained downward EGT indication of 30°C or more.)"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with a focused, single-purpose scope: addressing a specific unsafe condition in defined engine components. The scope remains tightly constrained to the identified EGT harness and coupling defects."},"complexity_factors":["Multiple conditional branches: two main requirement paths (replacement vs monitoring) with nested conditions","Technical aviation terminology requiring domain knowledge (EGT, SAGE, N1/N2 rotor speeds, serviceable parts)","Specific part number and serial number ranges requiring careful cross-referencing","Reference to external technical documents (CFM Service Bulletins) for compliance instructions","Cross-reference to foreign aviation safety directives (FAA AD and DGAC AD)"],"plain_english_summary":"This safety order targets specific CFM56-5 and -5B engines fitted with EGT harnesses/couplings that can under-report exhaust gas temperature by about 30°C. It affects operators and maintenance personnel for aircraft fitted with the listed parts.\n\nOperators must either replace the suspect parts per the manufacturer or monitor engines electronically with SAGE and replace any parts that exhibit the false low readings. The directive prevents hidden overheating that could cause engine damage or in-flight shutdown."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cfm56-22-egt-harnesses-and-egt-couplings","history":"/api/acts/ad-cfm56-22-egt-harnesses-and-egt-couplings/history","analysis":"/api/acts/ad-cfm56-22-egt-harnesses-and-egt-couplings/analysis","conflicts":"/api/acts/ad-cfm56-22-egt-harnesses-and-egt-couplings/conflicts","importantCases":"/api/acts/ad-cfm56-22-egt-harnesses-and-egt-couplings/important-cases","documents":"/api/acts/ad-cfm56-22-egt-harnesses-and-egt-couplings/documents"}}