{"id":"F2006B07427","name":"AD/TPE 331/19 - Turbine Bearing Support Replacement and Pitch Control Sleeve Pin - Inspection","slug":"ad-tpe-331-19-turbine-bearing-support-replacement-and-pitch-control-sleeve-pin-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49695,"registerId":"commonwealth-F2006B07427-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TPE 331/19 - Turbine Bearing Support Replacement and Pitch Control Sleeve Pin - Inspection","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 331/19 Turbine Bearing Support Replacement and\n\nPitch Control Sleeve Pin \\- Inspection\n\n  \n3/86\n\nApplicability: TPE-331-3U-303G, \\-3UW-303G, \\-5-251C, \\-5-251K, \\-6-251M which are listed in the reference document by their S/Nos. and those additional engines which had SB TPE- 331-72-0055 incorporated.\n\nDocument: 1. AiResearch SB TPE-331-72-0087, Rev. 2; or 2. FAA AD No. 74-24-05, or\n\n3. AD/AIR-T/24A.\n\nCompliance: 1. For engines with less than 100 hours time in service \\- Within 25 hours time in service after 31 January 1975.\n\n    2. For engines with more than 100 hours time in service \\- Within 300 hours time in service after 31 January 1975.\n\n    3. For spare engines \\- Before installation in an aircraft after 31 January 1975.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused on a specific mechanical defect in specific engine models. It has not expanded beyond its original safety purpose. The scope remains tightly constrained to the turbine bearing support and pitch control sleeve pin inspection/replacement requirements as originally issued."},"complexity_factors":["Short, single-purpose directive with one specific mechanical issue to address","Only 5 specific engine models affected, plus a reference to serial numbers in external documents","Simple three-tier compliance structure based on engine usage hours","Heavy reliance on external technical documents (Service Bulletin, FAA AD) for actual implementation details — the directive itself doesn't specify the mechanical procedure","No nested definitions, conditional logic, or cross-references to other legislation beyond the cited technical documents","Historical dating (1975 compliance deadlines) suggests this is an archived/legacy directive"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it like a compulsory recall notice, but for aircraft engines rather than cars.\n\n**What it does:**\nThis directive requires owners and operators of specific AlliedSignal (formerly Garrett/AiResearch) TPE 331 series turbine engines to inspect and replace certain parts — specifically the **turbine bearing support** and **pitch control sleeve pin**. These are critical components that, if they fail, could cause engine damage or failure during flight.\n\n**Who it affects:**\n- Owners and operators of specific TPE 331 engine models: TPE-331-3U-303G, -3UW-303G, -5-251C, -5-251K, and -6-251M (identified by serial numbers in the reference documents)\n- Any engines that had a specific service bulletin (SB TPE-331-72-0055) incorporated\n- This includes engines already installed in aircraft AND spare engines waiting to be installed\n\n**Why it matters:**\nAirworthiness Directives are legally binding. If you don't comply, you cannot legally fly the aircraft. This particular AD addresses a known safety defect that could lead to engine failure. The compliance deadlines are based on how much the engine has been used (flight hours), with stricter deadlines for newer engines (25 hours) versus older ones (300 hours).\n\n**Key deadlines (from 31 January 1975):**\n- New engines (<100 flight hours): Fix within 25 flight hours\n- Used engines (>100 flight hours): Fix within 300 flight hours  \n- Spare engines: Must be fixed before installation in any aircraft"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive applies to the listed TPE‑331 engine serial numbers and to engines that have had SB TPE‑331‑72‑0055 incorporated. The instrument itself contains no language indicating it has expanded or narrowed its scope from an earlier version within the text provided; it plainly states the applicability and the engines additionally covered by prior SB incorporation (Applicability)."},"complexity_factors":["Narrow, technical subject matter limited to specified engine models and serial numbers (Applicability).","Cross-reference to external technical documents (AiResearch Service Bulletin, FAA AD, AD/AIR‑T/24A) for the detailed work to be done (Document).","Different compliance timelines based on engine time‑in‑service and a separate rule for spare engines (Compliance 1–3).","Date‑bound compliance windows (references to actions after 31 January 1975) requiring historical interpretation for applicability to spares or records."],"plain_english_summary":"This directive mandates replacement of the turbine bearing support and inspection of the pitch‑control sleeve pin on specified AlliedSignal (Garrett/AiResearch) TPE‑331 engines, to be carried out per the referenced service/airworthiness documents. It sets firm compliance windows tied to engine hours (including requirements for spares), affects owners/operators and their maintenance organisations, and is issued by CASA under Part 39. Operators are responsible for scheduling, funding and documenting the mandated work."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tpe-331-19-turbine-bearing-support-replacement-and-pitch-control-sleeve-pin-inspection","history":"/api/acts/ad-tpe-331-19-turbine-bearing-support-replacement-and-pitch-control-sleeve-pin-inspection/history","analysis":"/api/acts/ad-tpe-331-19-turbine-bearing-support-replacement-and-pitch-control-sleeve-pin-inspection/analysis","conflicts":"/api/acts/ad-tpe-331-19-turbine-bearing-support-replacement-and-pitch-control-sleeve-pin-inspection/conflicts","importantCases":"/api/acts/ad-tpe-331-19-turbine-bearing-support-replacement-and-pitch-control-sleeve-pin-inspection/important-cases","documents":"/api/acts/ad-tpe-331-19-turbine-bearing-support-replacement-and-pitch-control-sleeve-pin-inspection/documents"}}