{"id":"F2007L01377","name":"AD/CT7/12 Amdt 1 - Stage 2 Turbine Aft Cooling Plate","slug":"ad-ct7-12-amdt-1-stage-2-turbine-aft-cooling-plate","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":65687,"registerId":"commonwealth-F2007L01377-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"General Electric Turbine Engines - CT7 S","sectionType":"division","heading":"General Electric Turbine Engines - CT7 Series","content":"### General Electric Turbine Engines - CT7 Series\n\n| AD/CT7/12 Amdt 1 | Stage 2 Turbine Aft Cooling Plate | 6/2007 |\n| ---------------- | --------------------------------- | ------ |\n\n| Applicability: | General Electric Company (GE) CT7-5A2/-5A3/-7A/-7A1/-9B/-9B1/-9B2/-9C/-9C3/-9D/-9D2 turboprop engines with stage 2 turbine aft cooling plates, part number (P/N) 6064T07P01, 6064T07P02, 6064T07P05, or 6068T36P01 installed.Note 1: These engines are installed on, but not limited to, Construcciones Aeronauticas, SA CN-235 series and SAAB Aircraft AB SF340 series airplanes.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Onetime Eddy Current Inspection (ECI)1. Perform a onetime ECI of the stage 2 turbine aft cooling plates P/N 6064T07P01, 6064T07P02, 6064T07P05, or 6068T36P01, that are listed by serial number in Section 4, Appendix A, of GE Alert Service Bulletin (ASB) No. CT7-TP S/B72-A0464, Revision 4, dated 12 December 2005, and that will be returned to service. Use 3.B.(1) through 3.B.(3) of GE ASB No. CT7-TP S/B 72-A0464, Revision 4 or later FAA approved revisions to perform the inspection.2. For stage 2 turbine aft cooling plates that do not pass the Return to Service Criteria, do either of the following:a. Replace the stage 2 turbine aft cooling plate with a new cooling plate that has a serial number that is not listed in Section 4, Appendix A, of GE ASBNo. CT7-TP S/B 72-A0464, Revision 4, orb. Replace the stage 2 turbine aft cooling plate with a cooling plate that meets the acceptance criteria of 3.B.(1) through 3.B.(3) of GE ASB No. CT7-TP S/B 72-A0464, Revision 4.3. After the effective date of this AD, do not install any stage 2 turbine aft cooling plates with serial numbers identified in Section 4, Appendix A, without inspecting the cooling plate as specified in 3.B.(1) through 3.B.(3) of GE ASB No. CT7-TP S/B 72- A0464 Revision 4. |\n\n|             | Previous CreditEddy current inspections of the stage 2 turbine aft cooling plate boltholes done before the effective date of this AD that use GE ASB No. CT7-TP S/B72-A0464, dated 25 February 2003; or Revision 1, dated 12 March 2003; or Revision 2, dated 9 May 2003; or Revision 3, dated 23 July 2004, comply with the requirements specified in this AD.Definition of Engine or Hot Section Module Shop VisitFor the purposes of this AD, an engine or hot section module shop visit is defined as the introduction of the engine or hot section module into a shop that includes separating major case flanges.Note: FAA AD 2007-08-01 Amdt 39-15018 dated 2 April 2007 refers. This AD supersedes FAA AD 2005-18-01. |\n| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | 1. At the next engine or hot section module shop visit, but before accumulating an additional 6,000 cycles-in-service after the effective date of the AD, unless already done.2. From the effective date of this AD.3. From the effective date of this AD.                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |\n|             | This Amendment becomes effective on 7 June 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n| Background: | This AD results from reports of six stage 2 turbine aft cooling plates found cracked during inspection. The actions specified in this AD are intended to prevent stage 2 aft cooling plate separation, resulting in uncontained engine failure and damage to the aeroplane.This amendment results from the manufacturer expanding the list of affected engine models and identifying the affected stage 2 turbine aft cooling plates by serial number.The original issue of this AD became effective on 22 December 2005.                                                                                                                                                                                                     |\n\n![](image.001.png)  \nDavid Punshon  \nDelegate of the Civil Aviation Safety Authority\n\n24 April 2007","sortOrder":0},{"sectionNumber":"AD/CT7/12 Amdt 1","sectionType":"part","heading":"AD/CT7/12 Amdt 1","content":"## AD/CT7/12 Amdt 1","sortOrder":1},{"sectionNumber":"Stage 2 Turbine Aft Cooling Plate","sectionType":"part","heading":"Stage 2 Turbine Aft Cooling Plate","content":"## Stage 2 Turbine Aft Cooling Plate","sortOrder":2},{"sectionNumber":"6/2007","sectionType":"part","heading":"6/2007","content":"## 6/2007","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"The amendment expanded the scope by increasing the list of affected GE CT7 engine models and by identifying affected stage‑2 aft cooling plates by serial number (referenced in Section 4, Appendix A of GE ASB CT7‑TP S/B72‑A0464 Rev 4). It supersedes the earlier AD and therefore broadens the set of engines/plates covered and tightens installation controls (no installation of listed serial numbers without the specified inspection)."},"complexity_factors":["Application tied to specific part numbers and serial numbers listed in an external GE Alert Service Bulletin (ASB Rev 4) rather than fully contained in the AD","Technical inspection method (eddy‑current inspection) with acceptance/return‑to‑service criteria referenced to ASB procedures 3.B.(1)–3.B.(3)","Conditional compliance timing: inspection at next engine or hot‑section module shop visit, or before accruing an additional 6,000 cycles","Multiple remedial paths for non‑conforming parts (replace with an unlisted serial number or a plate meeting ASB acceptance criteria)","Prohibition on installing listed serial‑number plates without prior inspection creates ongoing installation control","Previous‑credit clause accepts older ASB revisions for prior inspections, requiring cross‑checking revision history","Cross‑reference to FAA ADs and superseding earlier AD increases regulatory cross‑linking and traceability requirements","Requirement applies to a range of engine models installed on multiple aircraft types, widening operator pool and logistical coordination"],"plain_english_summary":"This airworthiness directive requires a one‑time eddy‑current inspection of specific stage‑2 turbine aft cooling plates fitted to certain GE CT7 turboprop engines (part and serial numbers identified in GE Alert Service Bulletin CT7‑TP S/B72‑A0464 Rev 4). Plates that fail must be replaced with an unlisted serial number or a plate that meets the acceptance criteria. After the effective date, listed plates may not be installed unless inspected. It affects engine owners/operators and maintenance providers who must schedule inspection and possible replacement at the next shop visit (or within 6,000 cycles)."},"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":4,"scope_assessment":{"changed":true,"description":"This is Amendment 1 to an existing AD. The original AD (effective December 2005) was expanded to cover additional engine models and now identifies affected parts by specific serial numbers rather than just part numbers. The scope grew from the original issue to include more aircraft operators and engines within the CT7 family."},"complexity_factors":["Multiple specific part numbers (4) and serial number lists referenced from an external manufacturer document (GE Alert Service Bulletin)","Cross-referencing to FAA AD 2007-08-01 and superseded FAA AD 2005-18-01","Conditional compliance timeline with dual triggers (next shop visit OR 6,000 cycles, whichever comes first)","Nested options for replacement (two acceptable replacement pathways in Requirement 2a and 2b)","Defined term requiring interpretation ('engine or hot section module shop visit' has specific technical definition)","Credit provisions for previous inspections using four different revision dates of the service bulletin"],"plain_english_summary":"This AD mandates a one‑time eddy‑current inspection of the stage 2 turbine aft cooling plate on specified GE CT7 turboprop engines after cracked plates were found. If a plate fails, it must be replaced; no affected plate may be installed without passing inspection.\n\nIt affects operators and maintenance providers of listed CT7 variants (used on regional types like CN‑235 and Saab 340) and requires inspection at the next shop visit or within 6,000 flight cycles."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ct7-12-amdt-1-stage-2-turbine-aft-cooling-plate","history":"/api/acts/ad-ct7-12-amdt-1-stage-2-turbine-aft-cooling-plate/history","analysis":"/api/acts/ad-ct7-12-amdt-1-stage-2-turbine-aft-cooling-plate/analysis","conflicts":"/api/acts/ad-ct7-12-amdt-1-stage-2-turbine-aft-cooling-plate/conflicts","importantCases":"/api/acts/ad-ct7-12-amdt-1-stage-2-turbine-aft-cooling-plate/important-cases","documents":"/api/acts/ad-ct7-12-amdt-1-stage-2-turbine-aft-cooling-plate/documents"}}