{"id":"F2006B07437","name":"AD/TPE 331/28 Amdt 4 - Repl. and/or Life Limitation of P/N 868630-1/-2/-3/-4/-7/-8, P/N 895539-1/-2/-3/-4 3rd Stage Turbine Wheels, P/N 867569-1/-7 1st Stage Turbine Wheels,","slug":"ad-tpe-331-28-amdt-4-repl-and-or-life-limitation-of-p-n-868630-1-2-3-4-7-8-p-n-895539-1-2-3-4-3rd-st","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49727,"registerId":"commonwealth-F2006B07437-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TPE 331/28 Amdt 4 - Repl. and/or Life Limitation of P/N 868630-1/-2/-3/-4/-7/-8, P/N 895539-1/-2/-3/-4 3rd Stage Turbine Wheels, P/N 867569-1/-7 1st Stage Turbine Wheels,","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nAlliedSignal (Garrett/AiResearch) Turbine Engines \\- TPE 331 Series\n\nAD/TPE 331/28\n\nAmdt 4\n\n  \nRepl. and/or Life Limitation of P/N 868630-1/-2/-3/- 4/-7/-8, P/N 895539-1/-2/-3/-4 3rd Stage Turbine Wheels, P/N 867569-1/-7 1st Stage Turbine Wheels, P/N 868272-1/-2/-3/-4 2nd Stage Turbine Wheels, P/N 868379-1 and P/N 868259-1 3rd Stage Turbine Seal\n\n  \n6/93\n\nApplicability: TSE 331-3, TPE 331-1,-2,-3,-5 and \\-6 series engines.\n\nRequirement: For first, second and third stage turbine wheels and third stage turbine seal, inspect and/or action I.A.W. FAA AD 84-01-04 Amdt 39-4792 Paras (a) (b) (c) (d) (e) and (f).\n\nNote: The following Garrett Turbine Engine Company Service Bulletins are reference documents in connection with this AD but may not equate to the FAA AD requirements at this time.\n\nGarrett Service Bulletin Garrett Service Bulletin Garrett Service Bulletin Garrett Service Bulletin Garrett Service Bulletin Garrett Service Bulletin Garrett Service Bulletin Garrett Service Bulletin\n\n  \nTPE 331-72-0300 R3\n\nTPE/TSE 331-72-0319\n\nTPE 331-72-0326 R1 TPE/TSE-72-0327 TPE/TSE-72-0350 R1 TPE/TSE-72-0351 R1 TPE/TSE-72-0375 TPE/TSE-72-0380\n\nCompliance: As detailed in the requirement Document, FAA AD 84-01-04.\n\nBackground: This Directive is amended to delete the requirements applying to the third stage stator as these have now been incorporated into AD/TPE 331/41 Amdt 1.","sortOrder":0}],"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"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This amendment narrows the scope slightly by removing third stage stator requirements (moving them to AD/TPE 331/41), but otherwise maintains the original purpose of regulating specific turbine wheel and seal components. The core safety intent — preventing turbine wheel failures — remains unchanged since the original 1993 issue."},"complexity_factors":["Heavy reliance on external documents: The AD does not contain the actual inspection procedures but defers entirely to FAA AD 84-01-04 and multiple Garrett Service Bulletins (8 referenced), requiring cross-referencing","Dense part number nomenclature: Multiple part number ranges with suffix variations (-1, -2, -3, -4, -7, -8) create visual clutter and require careful matching","Amendment structure: The document modifies previous versions, requiring historical awareness (deletion of 3rd stage stator requirements moved to AD/TPE 331/41)","Dual regulatory framework: Operators must comply with both Australian CASA requirements and referenced US FAA requirements simultaneously","Technical aviation terminology: Assumes familiarity with terms like '1st/2nd/3rd stage turbine wheels', 'fluorescent penetrant inspection', and 'life limitation'"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspections, replacements, and operating-life limits for rotating turbine wheels and seals on AlliedSignal/Garrett TPE331-series engines to prevent catastrophic in‑flight engine failures. It directs operators and maintenance organisations to follow the inspection and retirement measures aligned with FAA AD 84-01-04.\n\nThis amendment removes the third-stage stator requirements, which have been transferred to a separate AD, clarifying the scope of affected rotating parts."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"The amendment removes requirements for the third stage stator from this AD and states those requirements have been incorporated into AD/TPE 331/41 Amdt 1 (Background). This narrows the parts covered by AD/TPE 331/28 Amdt 4 and shifts responsibility for third‑stage stator compliance to a separate AD, requiring operators to consult both ADs."},"complexity_factors":["Cross-reference dependency: Compliance is mandated 'I.A.W. FAA AD 84-01-04 Paras (a) (b) (c) (d) (e) and (f)' (Requirement; Compliance). Operators must obtain and follow a separate FAA document for full obligations.","Multiple affected parts and engine models: Lists many part numbers (P/N 868630‑1/‑2/‑3/‑4/‑7/‑8; 895539‑1/‑2/‑3/‑4; 867569‑1/‑7; 868272‑1/‑2/‑3/‑4; 868379‑1; 868259‑1) and engine types (TSE 331‑3, TPE 331‑1, ‑2, ‑3, ‑5, ‑6) (Applicability), increasing inventory and tracking burden.","Implicit compliance schedule and actions: The AD defers timing, inspection methods and corrective actions to the FAA AD (Compliance: 'As detailed in the requirement Document, FAA AD 84-01-04'), so local administrators and maintainers must reconcile two instruments.","Reference (informational) service bulletins: Multiple Garrett Service Bulletins are cited as reference only and 'may not equate to the FAA AD requirements at this time' (Requirement Note), creating potential uncertainty about acceptable procedures.","Regulatory fragmentation: Amendment deletes third‑stage stator rules here and places them in AD/TPE 331/41 Amdt 1 (Background), requiring coordination across ADs to determine full obligations.","Compliance burden allocation: Costs fall to aircraft operators and maintenance organisations (inspect/replace parts, downtime, parts procurement). CASA enforces through its AD regime (Schedule of Airworthiness Directives header).","Enforcement and interpretation discretion: CASA enacts the AD but directs behaviour to FAA AD text; interpreting equivalence or acceptable deviation may require CASA/FAA clarification.","Technical complexity: Inspections and life‑limitation actions on turbine wheels and seals are specialised maintenance tasks requiring qualified personnel and possibly parts lead times."],"plain_english_summary":"**What this AD does:** Requires operators and maintenance organisations to inspect, life‑limit and, if needed, replace specified first, second and third stage turbine wheels and a third‑stage turbine seal on AlliedSignal TPE/TSE 331‑series engines by following FAA AD 84‑01‑04 (paras a–f). It affects aircraft owners, maintenance providers and parts suppliers because inspections, removals and replacements (with associated cost and downtime) are compulsory. The amendment removes third‑stage stator requirements and relocates them to AD/TPE 331/41 Amdt 1."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tpe-331-28-amdt-4-repl-and-or-life-limitation-of-p-n-868630-1-2-3-4-7-8-p-n-895539-1-2-3-4-3rd-st","history":"/api/acts/ad-tpe-331-28-amdt-4-repl-and-or-life-limitation-of-p-n-868630-1-2-3-4-7-8-p-n-895539-1-2-3-4-3rd-st/history","analysis":"/api/acts/ad-tpe-331-28-amdt-4-repl-and-or-life-limitation-of-p-n-868630-1-2-3-4-7-8-p-n-895539-1-2-3-4-3rd-st/analysis","conflicts":"/api/acts/ad-tpe-331-28-amdt-4-repl-and-or-life-limitation-of-p-n-868630-1-2-3-4-7-8-p-n-895539-1-2-3-4-3rd-st/conflicts","importantCases":"/api/acts/ad-tpe-331-28-amdt-4-repl-and-or-life-limitation-of-p-n-868630-1-2-3-4-7-8-p-n-895539-1-2-3-4-3rd-st/important-cases","documents":"/api/acts/ad-tpe-331-28-amdt-4-repl-and-or-life-limitation-of-p-n-868630-1-2-3-4-7-8-p-n-895539-1-2-3-4-3rd-st/documents"}}