{"id":"F2021L01122","name":"AD/TPE 331/41 Amdt 3 Third Stage Turbine Stators","slug":"ad-tpe-331-41-amdt-3-third-stage-turbine-stators","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":102034,"registerId":"commonwealth-F2021L01122-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Honeywell International Turbine Engines ","sectionType":"part","heading":"Honeywell International Turbine Engines - TPE 331 Series","content":"# Honeywell International Turbine Engines - TPE 331 Series\n\n| AD/TPE 331/41 Amdt 3 | Third Stage Turbine Stators | 17/2021 |\n| -------------------- | --------------------------- | ------- |\n\n| Applicability: | Honeywell International (formerly AlliedSignal / Garrett/AiResearch) TPE331-1, -2,-2UA, -3U, -3UW, -5, -5A, -5AB, -5B, -6, -6A model engines fitted with third stage turbine stator assemblies Part Number (P/N) 868379-1 or 868379-3.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Inspect third stage stator assemblies P/N 868379-1 and 868379-3 in accordance with Honeywell Alert Service Bulletin (ASB) TPE331-A72-559, as in force from time to time, and2. Re-identify P/N 868379-1 third stage stator assemblies in accordance with Honeywell ASB TPE/TSE331-A72-0384, as in force from time to time.Note 1: United States of America Federal Aviation Administration (FAA) Airworthiness Directive (AD) 93-05-09 is the basis of this AD.Note 2: CASA AD/ENG/7 requires third stage turbine stators be replaced at intervals as detailed in the latest issue of Honeywell Service Bulletin TPE/TSE331‑72-0019 \"Service Life Limits\".Note 3: Where the cycle count of a third stage turbine stator assembly is unknown, the total component hours in service since new shall be multiplied by 1.5 to establish component cycles. |\n| Compliance:    | At next access to the affected part or within 200 cycles after the commencement date of this AD, whichever occurs first, unless previously accomplished in accordance with a previous issue of this Directive.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n|                | This AD commences on 27 August 2021.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n| Background:    | This Directive was originally issued to require inspection, re-identification and replacement of certain third stage turbine stator assemblies.Amendment 1 reduced the life limits for certain stator assemblies.Amendment 2 deleted from this Directive, the requirement to replace certain stator assemblies. The requirements for removal of third stage stator assemblies are now detailed in CASA AD/ENG/7.                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n\n|     | Amendment 3 of this AD removes obsolete references and makes minor editorial changes to reflect current requirements. |\n| --- | --------------------------------------------------------------------------------------------------------------------- |\n\n![Text\nDescription automatically generated](image.001.jpeg)\n\nDavid Punshon  \nDelegate of the Civil Aviation Safety Authority\n\n12 August 2021","sortOrder":0},{"sectionNumber":"AD/TPE 331/41 Amdt 3","sectionType":"part","heading":"AD/TPE 331/41 Amdt 3","content":"## AD/TPE 331/41 Amdt 3","sortOrder":1},{"sectionNumber":"Third Stage Turbine Stators","sectionType":"part","heading":"Third Stage Turbine Stators","content":"## Third Stage Turbine Stators","sortOrder":2},{"sectionNumber":"17/2021","sectionType":"part","heading":"17/2021","content":"## 17/2021","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"The original directive required inspection, re-identification AND replacement of stator assemblies. Through amendments, the replacement requirement was stripped out and moved to a separate directive (AD/ENG/7). Amendment 3 further narrows scope by removing obsolete references. The directive has shrunk from a comprehensive maintenance mandate to a focused inspection and identification order."},"complexity_factors":["Short, single-purpose directive with only 2 substantive requirements","Heavy reliance on external documents (Honeywell Service Bulletins) — compliance requires cross-referencing 3 separate technical documents","Simple conditional logic for compliance timing ('whichever occurs first')","Minimal defined terms (only standard aviation acronyms: P/N, ASB, FAA, AD)","Clear amendment history explaining evolution of requirements","No nested exceptions or complex jurisdictional provisions"],"plain_english_summary":"This CASA airworthiness directive requires operators of Honeywell TPE331 engines (models -1, -2, -2UA, -3U, -3UW, -5 series, -6 series) fitted with third‑stage stator parts 868379‑1 or 868379‑3 to inspect those stators and re‑identify them for tracking. Compliance is due at the next engine opening or within 200 flight cycles after 27 Aug 2021, whichever comes first. The aim is to detect heat‑/stress‑related defects that could cause engine power loss or failure."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"Yes. The Directive originally required inspection, re‑identification and replacement. Amendment 1 reduced life limits; Amendment 2 removed the replacement requirement from this AD and delegated removal/replacement intervals to CASA AD/ENG/7. Amendment 3 makes editorial updates and removes obsolete references but does not restore replacement requirements. Practically, the current AD narrows its direct scope to inspection and re‑identification while relying on external ASBs and CASA AD/ENG/7 for replacement and life‑limit rules."},"complexity_factors":["Cross-reference to Honeywell Alert Service Bulletins “as in force” creates a moving standard for compliance","Interplay between this AD and separate CASA AD/ENG/7 for removal/replacement obligations","Model- and part-number-specific applicability (multiple TPE331 variants and two P/Ns)","Compliance timing tied to operational events (next access) or a cycle-count deadline (200 cycles)","Conversion rule where cycle count unknown (multiply hours in service by 1.5) adds calculation burden","Historical amendments changed life-limits and removed prior replacement requirements, requiring reading of amendment history","Source references to FAA AD and various Honeywell service documents require cross-checking external documents","Minor editorial changes in Amendment 3 reduce ambiguity but require review to confirm no substantive change"],"plain_english_summary":"This AD requires operators of specified Honeywell TPE331 engines fitted with third-stage turbine stators P/N 868379-1 or 868379-3 to inspect those stators per Honeywell Alert Service Bulletins and to re-identify P/N 868379-1 as directed. Compliance is required at next access or within 200 cycles. CASA issues the AD; engine owners/operators bear inspection and re‑identification costs. The AD no longer mandates replacements here (those limits are in CASA AD/ENG/7) and ties compliance to Honeywell ASBs “as in force”, so future bulletin updates affect obligations."},"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-tpe-331-41-amdt-3-third-stage-turbine-stators","history":"/api/acts/ad-tpe-331-41-amdt-3-third-stage-turbine-stators/history","analysis":"/api/acts/ad-tpe-331-41-amdt-3-third-stage-turbine-stators/analysis","conflicts":"/api/acts/ad-tpe-331-41-amdt-3-third-stage-turbine-stators/conflicts","importantCases":"/api/acts/ad-tpe-331-41-amdt-3-third-stage-turbine-stators/important-cases","documents":"/api/acts/ad-tpe-331-41-amdt-3-third-stage-turbine-stators/documents"}}