{"id":"F2006B11206","name":"AD/LYC/81 Amdt 3 - Oil Pump Impellers","slug":"ad-lyc-81-amdt-3-oil-pump-impellers","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56919,"registerId":"commonwealth-F2006B11206-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LYC/81 Amdt 3 - Oil Pump Impellers","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)  \nLycoming Piston Engines\n\nAD/LYC/81\n\nAmdt 3\n\n  \nOil Pump Impellers 3/95\n\nApplicability: All Lycoming piston engines other than; dual magneto 540 wide deck series engines built with high capacity oil pumps and O-320-H2AD, O-360-E1A6D, LO-360- E1A6D, TO-360-E1A6D and LTO-360-E1A6D 76 series engines.\n\nRequirement: Replace scintered iron oil pump impellers in accordance with Textron Lycoming Service Bulletin No. 456F.\n\nCompliance: Effective 2 March 1995: Unless previously accomplished in accordance with a previous issue of SB 456;\n\n    At next engine overhaul, bulk strip or 31 December 1995, whichever occurs first.\n\n    2. Prior to installation in an aircraft.\n\n    3. Prior to issue of an Australian Certificate of Airworthiness.\n\nNote: Previous compliance with the requirements of this Directive can be established by a review of the engine log books and/or engine records.\n\nBackground: This Directive requires the replacement of sintered iron oil pump impellers in certain Lycoming engines. This amendment has been issued to reflect industry advice that the 76 series engines have a different oil pump and are therefore, not applicable. The amendment also includes a sunset clause in the compliance requirements. The change to the compliance requirements reflects advice of a recent major engine failure in a Cessna 172M/O-320-E2D. The engine had been last overhauled in the USA in 1986 and an investigation of the oil system related failure revealed sintered iron oil pump impellers were fitted.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is Amendment 3 to an existing Airworthiness Directive. The amendments narrow the scope by excluding additional engine models (76 series) based on industry advice, and add a sunset clause (31 December 1995 deadline). These are refinements to the original safety mandate rather than scope creep."},"complexity_factors":["Single technical requirement with clear applicability exclusions","Simple three-part compliance deadline structure","No defined terms section","No cross-references to other legislation","Straightforward conditional logic (whichever occurs first)","Short document (approximately 250 words)"],"plain_english_summary":"Owners, operators and maintainers of Lycoming piston engines must replace sintered-iron oil-pump impellers with approved alternatives, except for certain excluded 540- and 76-series models. The parts can fail and lead to catastrophic engine loss.\n\nReplacement must occur by the earlier of next overhaul, next bulk strip, or 31 December 1995, and before engine installation or issuance of an Australian airworthiness certificate — a safety response to a Cessna 172 crash."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Yes. The amendment narrows applicability by excluding 76‑series engines (Background; Applicability) and introduces a sunset/deadline in the compliance schedule (Compliance). The Background records that the change follows industry advice and a specific engine failure investigation."},"complexity_factors":["Targeted applicability with enumerated exclusions narrows scope but requires careful model checks (Applicability).","Multiple compliance triggers and a hard date create conditional timing obligations: next overhaul, bulk strip, or 31 Dec 1995 (Compliance).","Additional pre‑installation and pre‑certificate requirements add administrative checkpoints for maintainers and certifiers (Compliance).","Permits proof of prior compliance via engine log books/records, shifting burden to owners to hold/document evidence (Note).","Amendment explicitly excludes 76‑series engines due to different pumps, requiring implementers to track revised applicability (Background; Applicability).","Directive issued in response to a documented engine failure linked to fitted sintered impellers, tying technical risk to the compliance requirement (Background)."],"plain_english_summary":"Requires replacement of sintered iron oil pump impellers in specified Lycoming piston engines, excluding certain 540 wide‑deck and listed 76‑series models. It affects aircraft owners/operators, maintenance organisations and certificating authorities by imposing mandatory part replacement at the next overhaul, bulk strip, by 31 December 1995, or before installation/issue of an Australian Certificate of Airworthiness. Owners pay for the replacement, maintenance organisations perform the work, and CASA enforces compliance (Requirement; Compliance; Applicability)."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-lyc-81-amdt-3-oil-pump-impellers","history":"/api/acts/ad-lyc-81-amdt-3-oil-pump-impellers/history","analysis":"/api/acts/ad-lyc-81-amdt-3-oil-pump-impellers/analysis","conflicts":"/api/acts/ad-lyc-81-amdt-3-oil-pump-impellers/conflicts","importantCases":"/api/acts/ad-lyc-81-amdt-3-oil-pump-impellers/important-cases","documents":"/api/acts/ad-lyc-81-amdt-3-oil-pump-impellers/documents"}}