{"id":"F2006B07451","name":"AD/TPE 331/40 - Scavenge Oil Pump Assembly","slug":"ad-tpe-331-40-scavenge-oil-pump-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49784,"registerId":"commonwealth-F2006B07451-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TPE 331/40 - Scavenge Oil Pump Assembly","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 331/40 Scavenge Oil Pump Assembly 6/89\n\nApplicability: TPE 331-25; \\-43; \\-47; \\-55; \\-61; \\-1; \\-2; \\-3; \\-5; \\-6; \\-8; \\-10 and \\-11 series turbo prop and TSE 331-3U turbo shaft engines.\n\nRequirement: Inspect and modify applicable engines in accordance with Garrett (Allied Signals) Service Bulletin TPE 331-72-0533 Revision 2.\n\nNote: FAA AD 89-07-07 Amdt 39-6140 refers.\n\nCompliance: Unless already accomplished; at next access to affected parts, or within 1800 hours time in service after 15 June 1989 or prior to further operation after 1 January 1991 whichever is the sooner.\n\nBackground: This Directive is issued to prevent turbine failure. There have been several instances of severe erosion and/or fracture of the berryllium copper main shaft nut. SOAP sampling for berryllium has not been completely effective in detecting nut erosion (cancelled AD/TPE 331/34 refers). SB TPE 331-72-0533 Rev 2 embodies an oil scavenge pump with improved outlet port which reduces pump susceptibility to nut erosion.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted airworthiness directive addressing a specific mechanical defect in specific engine models. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific mechanical issue with clear applicability criteria","Straightforward compliance timeline with three alternative triggers (next access, hours limit, or date limit)","References one external technical document (Service Bulletin) but does not reproduce its contents","Minimal defined terms — only engine model numbers and technical component names","No nested exceptions or conditional logic beyond the 'whichever is sooner' compliance clause","Short document (approximately 200 words) with single purpose"],"plain_english_summary":"This AD requires owners/operators and maintenance organisations of AlliedSignal (Garrett/AiResearch) TPE/TSE 331 series engines to inspect and modify the scavenge oil pump per Garrett Service Bulletin TPE 331-72-0533 Rev 2. A beryllium-copper main shaft nut can erode or fracture, risking turbine failure; the bulletin fits an improved pump outlet to eliminate that hazard. Work must be done at next access, within 1,800 flight hours after 15 June 1989, or before flight after 1 Jan 1991."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The directive moves scope from reliance on sampling-based detection (SOAP sampling referenced under the cancelled AD/TPE 331/34) to mandatory inspection and physical modification of the scavenge oil pump per SB TPE 331-72-0533 Rev 2. This replaces a monitoring approach with a hardware-change obligation across the listed engine models and imposes time/access-based compliance triggers (Requirement; Background; Compliance)."},"complexity_factors":["Technical hardware modification required via an external Service Bulletin (Requirement: SB TPE 331-72-0533 Rev 2).","Applicability covers multiple engine variants (Applicability: long list of TPE/TSE 331 series).","Conditional compliance timing and triggers increase operational planning complexity (Compliance: next access, or within 1800 hours after 15 June 1989, or prior to operation after 1 Jan 1991).","Prior mitigation (SOAP sampling) proved ineffective, shifting obligation from detection to physical modification (Background: SOAP sampling not completely effective; cancelled AD/TPE 331/34 refers).","Safety‑critical consequence (prevent turbine failure) raises urgency and inspection/maintenance workload (Background: prevent turbine failure).","Cross-reference to FAA AD adds regulatory alignment considerations (Note: FAA AD 89-07-07 Amdt 39-6140)."],"plain_english_summary":"This airworthiness directive requires operators of specified AlliedSignal (Garrett/AiResearch) TPE/TSE 331 engine variants to inspect and modify the scavenge oil pump according to Garrett Service Bulletin TPE 331-72-0533 Revision 2. It responds to repeated erosion and fracture of a beryllium‑copper main shaft nut that can cause turbine failure; compliance is set for the next access to affected parts, within 1800 hours after 15 June 1989, or before further operation after 1 January 1991."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tpe-331-40-scavenge-oil-pump-assembly","history":"/api/acts/ad-tpe-331-40-scavenge-oil-pump-assembly/history","analysis":"/api/acts/ad-tpe-331-40-scavenge-oil-pump-assembly/analysis","conflicts":"/api/acts/ad-tpe-331-40-scavenge-oil-pump-assembly/conflicts","importantCases":"/api/acts/ad-tpe-331-40-scavenge-oil-pump-assembly/important-cases","documents":"/api/acts/ad-tpe-331-40-scavenge-oil-pump-assembly/documents"}}