{"id":"F2006B07438","name":"AD/TPE 331/29 - Combustion Section - Plenum Chamber Forward Drain Boss - Inspection","slug":"ad-tpe-331-29-combustion-section-plenum-chamber-forward-drain-boss-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49730,"registerId":"commonwealth-F2006B07438-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TPE 331/29 - Combustion Section - Plenum Chamber Forward Drain Boss - Inspection","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\n# AD/TPE 331/29 Combustion Section - Plenum Chamber\n\nForward Drain Boss - Inspection\n\nApplicability: TPE331-8-401S, 402S, 403S, 404S.\n\n \n\nDocument: Garrett Turbine Engine Company SB No. TPE331-72-0373; or AD/AIR-T/45.\n\nCompliance: Within 25 hours time in service after 1 February 1983.\n\n# 3/86\n\n \n\nBackground:  This Directive is issued as the result of notification from the engine manufacturer that cracks have been found at the forward plenum chamber drain boss of the engine combustion section.\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":1390},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive remains tightly focused on its original purpose: mandating a one-time safety inspection for a specific manufacturing defect in defined engine models."},"complexity_factors":["Narrow applicability limited to four specific engine model numbers","Single compliance action (visual inspection for cracks)","Simple temporal trigger (25 hours time-in-service after fixed date)","Minimal cross-referencing (only to manufacturer Service Bulletin TPE331-72-0373)"],"plain_english_summary":"**What it does:** This directive mandates a safety inspection of a specific engine part—the forward drain boss located on the plenum chamber within the combustion section—on certain aircraft turbine engines.\n\n**Who it affects:** Owners and operators of AlliedSignal (Garrett/AiResearch) TPE331-8-401S, 402S, 403S, and 404S model turbine engines.\n\n**What must be done:** Inspect the forward plenum chamber drain boss for cracks within 25 hours of flight time (measured from when the aircraft is operating) after 1 February 1983.\n\n**Why it matters:** The engine manufacturer discovered cracks developing in this component, which could lead to engine failure or compromise flight safety. This rule ensures potential defects are identified and repaired before they cause serious incidents."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tpe-331-29-combustion-section-plenum-chamber-forward-drain-boss-inspection","history":"/api/acts/ad-tpe-331-29-combustion-section-plenum-chamber-forward-drain-boss-inspection/history","analysis":"/api/acts/ad-tpe-331-29-combustion-section-plenum-chamber-forward-drain-boss-inspection/analysis","conflicts":"/api/acts/ad-tpe-331-29-combustion-section-plenum-chamber-forward-drain-boss-inspection/conflicts","importantCases":"/api/acts/ad-tpe-331-29-combustion-section-plenum-chamber-forward-drain-boss-inspection/important-cases","documents":"/api/acts/ad-tpe-331-29-combustion-section-plenum-chamber-forward-drain-boss-inspection/documents"}}