{"id":"F2006B07420","name":"AD/TPE 331/12 - Fuel Control Unit - New Lee Plug Installation","slug":"ad-tpe-331-12-fuel-control-unit-new-lee-plug-installation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49672,"registerId":"commonwealth-F2006B07420-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TPE 331/12 - Fuel Control Unit - New Lee Plug Installation","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 331/12 Fuel Control Unit - New Lee Plug Installation 3/86\n\nApplicability: All TPE-331 series.\n\n \n\nDocument: AiResearch SB No. TPE-331-73-0003, or AD/AIR-T/13. Compliance: Prior to fitment of a FCU to an engine after 31 August 1972.\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\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2882},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This maintains the original narrow technical scope — a specific hardware installation mandate for fuel control units on TPE-331 engines."},"complexity_factors":["Single compliance requirement referencing external technical standard","No interpretation section or defined terms","Applicability limited to one specific engine series","Straightforward effective date with no conditional exceptions or nested clauses"],"plain_english_summary":"**What it does:** This Airworthiness Directive mandates a safety modification for aircraft engines. It requires mechanics to install **new Lee plugs** (specialized sealing components) in the **Fuel Control Unit (FCU)** — the device that regulates fuel flow to the engine.\n\n**Who it affects:** Aircraft operators and maintenance organizations using **TPE-331 series turbine engines** manufactured by AlliedSignal (formerly Garrett/AiResearch). These engines are commonly found in turboprop aircraft.\n\n**The requirement:** Before fitting a Fuel Control Unit to any engine, you must follow the technical instructions in **AiResearch Service Bulletin TPE-331-73-0003** (or comply with earlier directive AD/AIR-T/13). This requirement applies to any FCU fitted to an engine after 31 August 1972.\n\n**Why it matters:** This prevents potentially dangerous fuel leaks or engine control failures caused by inadequate sealing plugs in the fuel system."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tpe-331-12-fuel-control-unit-new-lee-plug-installation","history":"/api/acts/ad-tpe-331-12-fuel-control-unit-new-lee-plug-installation/history","analysis":"/api/acts/ad-tpe-331-12-fuel-control-unit-new-lee-plug-installation/analysis","conflicts":"/api/acts/ad-tpe-331-12-fuel-control-unit-new-lee-plug-installation/conflicts","importantCases":"/api/acts/ad-tpe-331-12-fuel-control-unit-new-lee-plug-installation/important-cases","documents":"/api/acts/ad-tpe-331-12-fuel-control-unit-new-lee-plug-installation/documents"}}