{"id":"F2006B08686","name":"AD/CT7/11 - 2nd Stage Turbine Aft Cooling Plates","slug":"ad-ct7-11-2nd-stage-turbine-aft-cooling-plates","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51837,"registerId":"commonwealth-F2006B08686-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 CASR 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\nGeneral Electric Turbine Engines \\- CT7 Series","sortOrder":0},{"sectionNumber":"AD/CT7/11 2nd Stage Turbine Aft Cooling ","sectionType":"part","heading":"AD/CT7/11 2nd Stage Turbine Aft Cooling Plates 11/2004","content":"# AD/CT7/11 2nd Stage Turbine Aft Cooling Plates 11/2004\n\nApplicability: General Electric Company (GE) CT7-2D1 turboshaft engines with 2nd stage turbine aft cooling plates, part number (P/N) 6064T07P02, and serial numbers (SN) starting with GFFN\\*\\*\\*\\*, GFFP\\*\\*\\*\\*, GFFR0\\*\\*\\* through GFFR7\\*\\*\\*, GFFR81\\*\\* through GFFR89\\*\\*, GFFR8A\\*\\* through GFFR8G\\*\\*, GFFR8H92 through GFFR8H99, and GFFR8H9A through GFFR8H9N installed.\n\nAsterisks represent any subsequent number or letter that follow the root SN.\n\nNote 1: These engines are installed on, but not limited to, Sikorsky S-70 helicopters.\n\nRequirement: 1. Replace any turbine stage 2 aft cooling plate, P/N 6064T07P02, with SNs starting with GFFN\\*\\*\\*\\*, GFFP\\*\\*\\*\\*, GFFR0\\*\\*\\* through GFFR7\\*\\*\\*, GFFR81\\*\\* through GFFR89\\*\\*, GFFR8A\\*\\* through GFFR8G\\*\\*, GFFR8H92 through GFFR8H99, and GFFR8H9A through GFFR8H9N, with a cooling plate that does not have a SN specified in this Directive.\n\n2. Do not install stage 2 aft cooling plate, P/N 6064T07P02, SNs GFFN\\*\\*\\*\\*, GFFP\\*\\*\\*\\*, GFFR0\\*\\*\\* through GFFR7\\*\\*\\*, GFFR81\\*\\* through GFFR89\\*\\*, GFFR8A\\*\\* through GFFR8G\\*\\*, GFFR8H92 through GFFR8H99, and GFFR8H9A through GFFR8H9N into any engine.\n\nNote 2: FAA AD 2004-16-07 Amdt 39-13763 refers.\n\nNote 3: GE CT7-TS Alert Service Bulletin 72-A0032, dated 11 June 2003, provides additional information regarding the disassembly of the gas generator turbine rotor assembly.\n\nCompliance: For Requirement 1: At the next disassembly of the gas generator turbine rotor assembly but not later than 5,000 cycles-since-new.\n\nFor Requirement 2: After the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 28 October 2004.","sortOrder":1}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific defective part in a specific engine model. The serial number specificity and targeted applicability show no scope creep from the original safety purpose."},"complexity_factors":["Extensive serial number ranges with wildcards (asterisks) creating multiple overlapping identification patterns","Two distinct requirements with different compliance timelines (maintenance-triggered vs. immediate)","Cross-reference to FAA AD and manufacturer service bulletin for technical implementation details","Technical aviation terminology requiring specialised knowledge (turboshaft, gas generator turbine rotor assembly, cycles-since-new)"],"plain_english_summary":"CASA requires removal and replacement of certain 2nd-stage turbine aft cooling plates (P/N 6064T07P02 with specified serial numbers) fitted to GE CT7‑2D1 turboshaft engines. Operators must replace these parts at the next engine teardown or within 5,000 flight cycles, and installation of affected plates is prohibited from the AD effective date.\n\nThis affects operators, maintainers and owners of helicopters using these engines and prevents potential engine failure from cooling-plate faults."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive is narrowly targeted to correct an identified unsafe condition associated with specific serial-numbered aft cooling plates on GE CT7-2D1 engines. It does not broaden regulatory scope beyond that technical remedy (no new regulatory powers, no additional affected parts or engine types beyond the listed applicability). Therefore the scope remains consistent with the instrument's original safety-focused purpose."},"complexity_factors":["Short, single-issue AD focused on one part number (P/N 6064T07P02).","Multiple serial-number ranges specified using wildcard asterisks (high count of SN patterns to check).","Two distinct mandatory actions: (1) replace affected plates at next disassembly or within 5,000 cycles; (2) prohibit installation of listed SNs after effective date.","Cross-references to external instruments: FAA AD 2004-16-07 and GE CT7-TS Alert Service Bulletin 72-A0032.","Simple conditional timing (next disassembly OR 5,000 cycles) rather than layered or nested exceptions."],"plain_english_summary":"**What this directive does (mechanically)**\n\n- It requires owners/operators of General Electric (GE) CT7-2D1 turboshaft engines to remove and replace certain 2nd stage turbine aft cooling plates (part number 6064T07P02) that have particular serial-number ranges listed in the directive (see \"Applicability\").  \n- It also bans installing any of those listed serial-numbered plates into any engine after the directive takes effect.  \n- The replacement must be done either the next time the gas-generator turbine rotor assembly is disassembled for maintenance or no later than 5,000 cycles-since-new, whichever comes first. (See \"Requirement\" and \"Compliance\".)\n\n**Who is affected**\n\n- Aircraft and engine owners/operators that use GE CT7-2D1 engines with 2nd stage turbine aft cooling plates having the listed serial numbers. The directive notes these engines are installed on, but not limited to, Sikorsky S-70 helicopters. (Applicability; Note 1.)\n\n**Why the rule exists (official claim)**\n\n- The directive is issued to correct an identified \"unsafe condition\" associated with those specific aft cooling plates. The AD references a related FAA AD and a GE Alert Service Bulletin for background and additional maintenance instructions. (Requirement; Notes 2–3.)\n\n**Practical effects and mechanics of compliance**\n\n- Who pays: the owner/operator of the aircraft or engine pays for parts and labour to replace the cooling plate.  \n- Who decides: the CASA delegate issues the AD; individual maintenance organisations or operators decide scheduling and which approved replacement parts to buy and install, subject to the prohibition on the listed serial numbers.  \n- Behaviour changes required: operators must inspect inventories and engine records for the listed serial-number plates, schedule replacements at the next disassembly (or within 5,000 cycles), and ensure those serial-numbered parts are not installed after the AD effective date.  \n\n**Costs, incentives and trade-offs**\n\n- Direct costs: purchase price of compliant replacement plates and shop labour; potential out-of-service time when replacements occur.  \n- Timing trade-off: if an engine is due for disassembly soon, the replacement may be absorbed into planned maintenance; if not, operators may need to schedule an earlier disassembly or wait until the 5,000-cycle limit, creating either nearer-term cost or longer-term operational risk if the plate condition deteriorates.  \n- Supply-side effects: demand for compliant replacement plates will rise; that can raise prices or create short-term supply constraints. Independent maintenance organisations must obtain compliant plates and track serial numbers to remain eligible to perform the work.  \n- Administrative burden and implementation risk: accurate tracking of serial numbers in maintenance records and parts inventories is necessary to identify affected engines and to ensure prohibited parts are not installed.  \n\n**References in the directive**\n\n- Applicability (lists affected part number and serial-number ranges).  \n- Requirement 1 (replace affected plates) and Requirement 2 (do not install affected plates).  \n- Compliance (time limits: next disassembly or 5,000 cycles; prohibition effective immediately after the AD date).  \n- Notes: cites FAA AD 2004-16-07 and GE CT7-TS Alert Service Bulletin 72-A0032 for additional background and disassembly guidance.\n\n**Net practical summary**\n\nThis AD compels operators of GE CT7-2D1 engines to identify certain aft cooling plates by serial number, replace them within specified maintenance windows, and stop installing any plate with those serial numbers. The operator bears the replacement cost and the logistical burden of tracking serial numbers and scheduling the work. The directive relies on an FAA AD and a GE service bulletin for technical context and disassembly instructions."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ct7-11-2nd-stage-turbine-aft-cooling-plates","history":"/api/acts/ad-ct7-11-2nd-stage-turbine-aft-cooling-plates/history","analysis":"/api/acts/ad-ct7-11-2nd-stage-turbine-aft-cooling-plates/analysis","conflicts":"/api/acts/ad-ct7-11-2nd-stage-turbine-aft-cooling-plates/conflicts","importantCases":"/api/acts/ad-ct7-11-2nd-stage-turbine-aft-cooling-plates/important-cases","documents":"/api/acts/ad-ct7-11-2nd-stage-turbine-aft-cooling-plates/documents"}}