{"id":"F2006B07433","name":"AD/TPE 331/24 - Propeller Pitch Control Sleeve - Replacement","slug":"ad-tpe-331-24-propeller-pitch-control-sleeve-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49715,"registerId":"commonwealth-F2006B07433-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TPE 331/24 - Propeller Pitch Control Sleeve - Replacement","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  AlliedSignal (Garrett/AiResearch) Turbine Engines - TPE 331 Series\n\n \n\nAD/TPE 331/24 Propeller Pitch Control Sleeve - Replacement 3/86\n\nApplicability: All TPE-331-1, -2, -3, -5 and -6. series engines. Document:  1. AiResearch SB No. TPE-331-72-0115, Rev. 1;or\n\n2.    FAA AD No. 78-05-02, amendment No. 39-3145, or\n\n \n\n3.    AD/AIR-T/33.\n\n \n\nCompliance: Before installation in an aircraft after 1 April 1979 or within 500 hours time in service after 30 April 1978 whichever occurs first.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text supplied sets a specific mandatory replacement requirement for specified TPE-331 engine models and provides compliance deadlines and references to external technical documents. The supplied instrument does not indicate any change to that scope from an earlier or original intent; no modification of the affected engine classes, deadlines or referenced documents is stated in the text provided (Applicability; Document; Compliance)."},"complexity_factors":["Narrow technical applicability limited to specific engine models (Applicability).","Reliance on external technical documents (AiResearch service bulletin; FAA AD; AD/AIR-T/33) for procedural detail (Document).","Dual compliance deadline structure (before installation after 1 April 1979 OR within 500 hours after 30 April 1978), requiring operational tracking of installation dates and service hours (Compliance).","No procedural detail in the directive itself, increasing administrative steps to obtain and apply the referenced documents (Document).","Potential operational coordination (scheduling downtime, sourcing parts) for owners/operators, which is an implementation complexity but not legally intricate (Compliance)."],"plain_english_summary":"This directive requires owners/operators of specified AlliedSignal (Garrett/AiResearch) TPE‑331 turboprop engines to replace the propeller pitch control sleeve within a set compliance window or before installation. The Civil Aviation Safety Authority mandates the action but delegates the technical procedure to referenced service bulletins and an FAA AD. Operators bear the cost and must schedule work and follow the external documents to achieve compliance."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1986 (indicated by '3/86' in the reference). It addresses one specific safety issue with one component on specific engine models. There is no evidence of scope creep; it remains tightly focused on its original purpose of mandating replacement of a defective or suspect part."},"complexity_factors":["Single, specific mechanical component addressed (propeller pitch control sleeve)","Straightforward applicability clause listing only 5 engine model variants","Simple binary compliance deadline (date-based OR hours-based, whichever first)","Only 3 referenced documents, all external technical standards","No defined terms section, no cross-references to other legislation, no conditional exceptions","Extremely short — approximately 150 words of substantive content"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of specific **AlliedSignal (Garrett/AiResearch) TPE 331 series turbine engines** to replace a part called the **\"propeller pitch control sleeve.\"** This component controls the angle (pitch) of the propeller blades, which affects thrust and engine performance.\n\n**Who it affects:** Anyone operating aircraft with these specific engine models:\n- TPE-331-1, -2, -3, -5, and -6 series engines\n\n**What must be done:** The propeller pitch control sleeve must be replaced **before** the engine is installed in an aircraft after 1 April 1979, **OR** within 500 hours of flight time after 30 April 1978 — whichever comes first.\n\n**Why it matters:** Airworthiness Directives are legally binding safety instructions. They typically follow incidents or discoveries of defects that could affect flight safety. Non-compliance means the aircraft cannot legally fly in Australian airspace.\n\n**Technical references:** The directive points to three technical documents for detailed instructions:\n- AiResearch Service Bulletin TPE-331-72-0115 (Revision 1)\n- FAA Airworthiness Directive 78-05-02\n- Australian AD/AIR-T/33"}},"importantCases":[],"_links":{"self":"/api/acts/ad-tpe-331-24-propeller-pitch-control-sleeve-replacement","history":"/api/acts/ad-tpe-331-24-propeller-pitch-control-sleeve-replacement/history","analysis":"/api/acts/ad-tpe-331-24-propeller-pitch-control-sleeve-replacement/analysis","conflicts":"/api/acts/ad-tpe-331-24-propeller-pitch-control-sleeve-replacement/conflicts","importantCases":"/api/acts/ad-tpe-331-24-propeller-pitch-control-sleeve-replacement/important-cases","documents":"/api/acts/ad-tpe-331-24-propeller-pitch-control-sleeve-replacement/documents"}}