{"id":"F2007L04529","name":"AD/V2500/4 - High Pressure Turbine Stage 2 Air Seal","slug":"ad-v2500-4-high-pressure-turbine-stage-2-air-seal","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":71013,"registerId":"commonwealth-F2007L04529-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"International Aero Engines AG V2500 seri","sectionType":"division","heading":"International Aero Engines AG V2500 series","content":"### International Aero Engines AG V2500 series\n\n| AD/V2500/4 | High Pressure Turbine Stage 2 Air Seal | 13/2007 |\n| ---------- | -------------------------------------- | ------- |\n\n| Applicability: | International Aero Engines (IAE) model V2500-A1, V2522-A5, V2524-A5,V2527-A5, V2527E-A5, V2527M-A5, V2530- A5, V2533-A5, V2525-D5, and V2528-D5 turbofan engines with high pressure turbine (HPT) stage 2 air seals, part numbers (P/Ns) 2A0487, 2A1159, 2A1160, 2A3108, 2A3179, 2A3185, 2A3425, and 2A3596, installed.Note 1: These engines are installed on, but not limited to, Airbus A319, A320, A321, and Boeing MD-90 aeroplanes. |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with FAA AD 2007-21-05.Definition: For the purposes of this AD, \"At Opportunity'' is defined as when the engine is disassembled, the HPT stage 2 seal is exposed, and the HPT stage 1 and 2 rotors are separated after 2,000 Cycles Since New (CSN).Note 2: FAA AD 2007-21-05 Amdt 39-15223 dated 2 October 2007 refers.                                                                                            |\n| Compliance:    | As detailed in FAA AD 2007-21-05 with a revised effective date of20 December 2007.                                                                                                                                                                                                                                                                                                                                                       |\n|                | This Airworthiness Directive becomes effective on 20 December 2007.                                                                                                                                                                                                                                                                                                                                                                      |\n| Background:    | This AD results from a report that HPT stage 2 air seals have developed cracks. The issuing of this AD is intended to prevent uncontained failure of the HPT stage 2 air seal.                                                                                                                                                                                                                                                           |\n\n![](image.001.png)  \nDavid Punshon  \nDelegate of the Civil Aviation Safety Authority\n\n25 October 2007","sortOrder":0},{"sectionNumber":"AD/V2500/4","sectionType":"part","heading":"AD/V2500/4","content":"## AD/V2500/4","sortOrder":1},{"sectionNumber":"High Pressure Turbine Stage 2 Air Seal","sectionType":"part","heading":"High Pressure Turbine Stage 2 Air Seal","content":"## High Pressure Turbine Stage 2 Air Seal","sortOrder":2},{"sectionNumber":"13/2007","sectionType":"part","heading":"13/2007","content":"## 13/2007","sortOrder":3}],"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 is a standard, narrow airworthiness directive addressing a specific safety defect in specific engine models. It has not expanded beyond its original purpose of mandating inspection/repair of cracked HPT stage 2 air seals."},"complexity_factors":["Short, single-purpose instrument (approximately 250 words)","Only 1 defined term ('At Opportunity')","Incorporates external document by reference (FAA AD 2007-21-05) — operators must cross-reference US regulations for full requirements","Technical aviation terminology requires engineering knowledge to fully understand (HPT, CSN, part numbers)","Conditional compliance trigger based on maintenance events rather than calendar time","No nested exceptions or complex conditional logic"],"plain_english_summary":"This AD mandates inspections and repairs of high‑pressure turbine stage‑2 air seals on certain IAE V2500 engines (common on Airbus A319/A320/A321 and Boeing MD‑90) to prevent cracks that could cause uncontained engine failure. It forces affected operators and maintenance organisations to comply with the FAA’s AD (with Australian timing), making inspections mandatory when the engine is opened after 2,000 flight cycles."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The instrument adopts FAA AD 2007-21-05 for the listed engines and part numbers with a revised effective date; the text shows no expansion or narrowing of applicability beyond that adoption. There is no indication within the instrument that the scope has been altered from the referenced FAA AD (Requirement; Applicability; Compliance)."},"complexity_factors":["Cross-reference to an external regulatory instrument (FAA AD 2007-21-05) creates dependency on another document for full compliance details (Requirement; Compliance).","Detailed applicability: multiple engine variants and eight specific part numbers must be checked to determine effect (Applicability).","Operational trigger tied to maintenance status and life metric: applies ‘At Opportunity’ when engine disassembled and after 2,000 cycles since new, which affects maintenance scheduling and downtime (Definition).","Safety-critical technical work (inspection/repair of HPT seals) requires specialised maintenance skills and parts, raising direct costs and supply risks (Requirement; Background).","Regulatory adoption with a revised effective date creates an immediate compliance deadline for affected operators (Compliance).","Limited delegated discretion: CASA adopts FAA requirements rather than prescribing alternative compliance paths, reducing local flexibility (Requirement; Compliance)."],"plain_english_summary":"This Airworthiness Directive requires operators of specific International Aero Engines V2500 variants with listed high-pressure turbine (HPT) stage 2 air seals to follow the inspections and corrective actions set out in FAA AD 2007-21-05. It applies when the engine is disassembled and the HPT stage 2 seal is exposed after 2,000 cycles since new. The stated purpose is to prevent uncontained seal failure after reports of cracking; operators and maintenance organisations bear the inspection and repair costs (Applicability; Requirement; Definition; Background)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-v2500-4-high-pressure-turbine-stage-2-air-seal","history":"/api/acts/ad-v2500-4-high-pressure-turbine-stage-2-air-seal/history","analysis":"/api/acts/ad-v2500-4-high-pressure-turbine-stage-2-air-seal/analysis","conflicts":"/api/acts/ad-v2500-4-high-pressure-turbine-stage-2-air-seal/conflicts","importantCases":"/api/acts/ad-v2500-4-high-pressure-turbine-stage-2-air-seal/important-cases","documents":"/api/acts/ad-v2500-4-high-pressure-turbine-stage-2-air-seal/documents"}}