{"id":"F2006B08637","name":"AD/CON/57 Amdt 1 - Oil Scavenge Pump Gears","slug":"ad-con-57-amdt-1-oil-scavenge-pump-gears","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51654,"registerId":"commonwealth-F2006B08637-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CON/57 Amdt 1 - Oil Scavenge Pump Gears","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)  \nTeledyne Continental Motors Piston Engines\n\nAD/CON/57\n\nAmdt 1\n\n  \nOil Scavenge Pump Gears 10/90\n\nApplicability: TSIO-520B, BB, D, DB, E, EB, J, JB, K, KB, N, NB, UB and VB engines as detailed in TCM Service Bulletin M90-6.\n\nRequirement: Replace scavenge pump gears P/N 635334 and 639388 in accordance with the requirements of TCM SB M90-6.\n\nNote: FAA AD 89-24-01 R1 refers.\n\nCompliance: Effective 4 October 1990; Within 500 hours time in service or at next access to affected parts, whichever occurs first.\n\nBackground: This amendment and FAA AD 89-24-01 Rev 1 reflect advice received after the original issue of these Directives. The advice indicates concern with the integrity of scavenge pump gears is limited to certain part number gears. This advice is reflected in TCM Service Bulletin M90-6.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"The amendment narrows the focus of the original directive to concerns limited to certain scavenge pump gear part numbers and aligns the required action with Teledyne Continental Motors Service Bulletin M90-6 and FAA AD 89-24-01 Rev 1. The Background states this amendment reflects advice that the integrity concern is limited to those part numbers, and the Applicability lists the affected engines (Background; Applicability)."},"complexity_factors":["Narrow technical scope: applies to specific part numbers (P/N 635334 and 639388) and specific engine models (Applicability).","Reference to external technical material: compliance requires following TCM Service Bulletin M90-6 (Requirement), so full compliance depends on another document.","Fixed compliance window: two-part timing requirement (within 500 hours TIS or at next access) adds scheduling considerations (Compliance).","Cross-reference to foreign directive: Note refers to FAA AD 89-24-01 R1, requiring reconciliation between documents for complete context (Note)."],"plain_english_summary":"What this instrument does\n\n- Requires replacement of two specific oil scavenge pump gears (part numbers P/N 635334 and 639388) on a defined set of Teledyne Continental Motors piston engines (various TSIO-520 series engines) in accordance with Teledyne Continental Motors Service Bulletin M90-6 (Requirement; Applicability).\n\nWho it affects\n\n- Aircraft owners/operators and maintenance organisations who operate or service the listed TSIO-520 engine models (Applicability).\n- Maintenance providers that perform the required gear replacement and that follow TCM Service Bulletin M90-6 (Requirement).\n\nWhen and how it must be done\n\n- The replacement must be carried out as described in TCM SB M90-6 (Requirement).\n- Compliance is required by 4 October 1990 and must be completed within 500 hours time in service or at the next access to the affected parts, whichever occurs first (Compliance).\n\nWhy it matters (official rationale and what that implies)\n\n- The Background states the amendment (and FAA AD 89-24-01 Revision 1) reflects advice that the concern about scavenge pump gear integrity is limited to the specific part numbers listed; the service bulletin aligns with that advice (Background; Note).\n\nPractical implications, incentives and costs\n\n- Who pays: Aircraft owners/operators bear the direct costs — parts, labour and any aircraft downtime required to access and replace the gears (Requirement; Compliance).\n- Who decides and enforces: The Civil Aviation Safety Authority issued this item in the Schedule of Airworthiness Directives; the text frames the action as a required replacement to meet the Directive (header; Requirement).\n- Compliance burden and scheduling: The 500-hour or next-access deadline forces operators to schedule maintenance within a finite window, which can shift maintenance sequencing and cause short-term labour and access costs (Compliance).\n- Dependency on manufacturer guidance: The replacement must follow TCM Service Bulletin M90-6, so maintenance methods, parts sourcing and records will follow that manufacturer's instructions (Requirement).\n- Potential implementation risks: If replacement parts are scarce or if the service bulletin requires particular tooling or access procedures, operators may face delays or higher service costs. The instrument itself does not supply parts, prices or alternative methods (Requirement; Background).\n\nTrade-offs and effects on market actors\n\n- The directive imposes a private cost on many operators (diffuse) while addressing integrity concerns limited to particular part numbers (narrowly targeted per Background). The text does not quantify safety benefits or costs, nor does it provide alternatives to following the service bulletin (Background; Requirement).\n- Independent maintenance providers must follow the manufacturer's service bulletin when complying, which channels the technical method and parts sourcing through the bulletin's specifications (Requirement).\n\nLimitations of the instrument's text\n\n- The AD references the TCM service bulletin and FAA AD but does not include technical detail, cost estimates or alternative compliance methods in the schedule entry itself (Requirement; Note; Background)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":true,"description":"This is Amendment 1 to the original AD/CON/57. The scope has been narrowed from the original directive. The amendment reflects new technical advice showing the safety concern was limited to specific part numbers (635334 and 639388), rather than applying more broadly to all scavenge pump gears in these engine models. This reduces the regulatory burden by targeting only the actually defective components."},"complexity_factors":["Very short document (under 200 words)","Only 2 defined part numbers referenced","Single, clear compliance requirement with straightforward time limit","No nested exceptions or conditional logic","Cross-reference to one FAA directive and one manufacturer service bulletin only","No interpretation section or defined terms"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of specific Teledyne Continental Motors aircraft engines to replace certain oil scavenge pump gears.\n\n**What it does:**\n- **Targets specific engines:** TSIO-520 series engines (various models listed) used in aircraft.\n- **Requires a parts swap:** Mechanics must replace two specific part numbers of oil scavenge pump gears (P/N 635334 and 639388) with updated versions.\n- **Sets a deadline:** The work must be done within 500 flight hours or at the next time the engine is opened for maintenance — whichever comes first.\n\n**Why it matters:**\nThe original safety concern about these pump gears was broader. New information showed the problem only affects specific part numbers. This directive narrows the fix to just those problematic gears, saving operators from unnecessary repairs while ensuring unsafe parts get replaced.\n\n**Who must comply:**\nAnyone operating or maintaining aircraft with the listed engine models must follow this directive. Non-compliance means the aircraft cannot legally fly in Australia."}},"importantCases":[],"_links":{"self":"/api/acts/ad-con-57-amdt-1-oil-scavenge-pump-gears","history":"/api/acts/ad-con-57-amdt-1-oil-scavenge-pump-gears/history","analysis":"/api/acts/ad-con-57-amdt-1-oil-scavenge-pump-gears/analysis","conflicts":"/api/acts/ad-con-57-amdt-1-oil-scavenge-pump-gears/conflicts","importantCases":"/api/acts/ad-con-57-amdt-1-oil-scavenge-pump-gears/important-cases","documents":"/api/acts/ad-con-57-amdt-1-oil-scavenge-pump-gears/documents"}}