{"id":"F2006B11216","name":"AD/LYC/98 - Push Rod Inner Diameter Scoring","slug":"ad-lyc-98-push-rod-inner-diameter-scoring","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56934,"registerId":"commonwealth-F2006B11216-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LYC/98 - Push Rod Inner Diameter Scoring","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\n| AD/LYC/98      | Push Rod Inner Diameter Scoring                                                                            | 6/95 |\n| -------------- | ---------------------------------------------------------------------------------------------------------- | ---- |\n| Applicability: | All Textron Lycoming O-235 series engines detailed in Textron Lycoming Mandatory Service Bulletin No. 522. |      |\n\nNote: Only engines shipped from Textron Lycoming in the period 22 February 1993 to 2 September 1994 and O-235 engines fitted with new push rods, for whatever reason, since 22 February 1993 are affected.\n\nRequirement: Inspect applicable engine push rods in accordance with Textron Lycoming Mandatory Service Bulletin No. 522.\n\nReplace push rods identified as P/N 73806 with revision letters \"V\" or \"W\" before further flight.\n\nNote: FAA Airworthiness Directive 95-03-10 refers.\n\nCompliance: Effective 25 May 1995; unless previously accomplished and recorded by a certification in the engine log book, within 10 hours time in service or prior to 1 July 1995, whichever occurs first.\n\nBackground: This Directive requires the inspection of certain O-235 engines for fitment of suspect push rods. The requirement follows advice of the investigation of several O-235 engine failures. The investigation determined the failures to have initiated from scoring of the push rod tube inner diameter. The internal scoring was introduced during extrusion of the tube at the supplier.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted airworthiness directive addressing a specific manufacturing defect in a specific engine series. It has not expanded beyond its original purpose of addressing the push rod scoring issue identified in the 1993-1994 production batch."},"complexity_factors":["Single, specific mechanical issue (push rod scoring)","Narrow applicability limited to specific engine model, date range, and part numbers","Clear, single compliance action (inspect and replace if necessary)","Simple time-based compliance deadline (10 hours or fixed date)","No nested exceptions or conditional logic","Only 2 defined terms effectively (applicability and requirement)","No cross-references to other legislation beyond a single FAA directive reference"],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Textron Lycoming O-235 engines (shipped 22 Feb 1993–2 Sep 1994, or with push rods installed after 22 Feb 1993) to inspect push rods for internal scoring per Lycoming Service Bulletin No. 522 and replace any PN 73806 with revision V or W before further flight, and log the work.  \n\nAction must be completed by 1 July 1995 or within 10 flight hours after the AD’s 25 May 1995 effective date to prevent engine failure from manufacturing-induced scoring."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The instrument confines scope to O-235 engines identified in the Textron Lycoming Mandatory Service Bulletin and to engines shipped or fitted within specified dates. The text does not indicate any expansion or contraction of that stated scope beyond the listed applicability and notes (Applicability; Note)."},"complexity_factors":["Technical inspection requirement (detection of inner-diameter scoring in push-rod tubes) increases maintenance complexity and requires specialist knowledge/equipment (Requirement; Background).","Narrow, time‑bounded applicability tied to manufacture/shipment dates and to engines fitted with new push rods since a specific date, creating eligibility questions for operators (Applicability; Note).","Mandated reliance on a manufacturer Mandatory Service Bulletin for inspection procedure, creating dependency on external technical guidance (Requirement).","Specific part identification and replacement rule (push rods P/N 73806 with revision letters \"V\" or \"W\") raises parts-tracking and procurement burden for operators and maintainers (Requirement).","Short compliance window (within 10 flight hours or by 1 July 1995 unless earlier recorded) imposes immediate operational consequences and scheduling pressure (Compliance).","Record-keeping requirement (engine log book certification) introduces administrative compliance and potential enforcement checks (Compliance).","Reference to supplier manufacturing defect (extrusion-induced scoring) ties regulator action to upstream supply-chain quality, but remedial cost is allocated to operators (Background).","Cross-reference to FAA Airworthiness Directive creates multi-jurisdictional alignment considerations for internationally operated aircraft (Requirement/Note)."],"plain_english_summary":"This airworthiness directive requires inspection of certain Textron Lycoming O-235 engines for internal scoring of push-rod tubes and mandates replacement of suspect push rods before further flight. It targets engines shipped 22 Feb 1993–2 Sep 1994 and engines fitted with new push rods since 22 Feb 1993. Operators must follow Textron Lycoming Mandatory Service Bulletin No. 522, record compliance in the engine logbook, and act within 10 flight hours or by 1 July 1995. Costs and operational downtime fall on aircraft operators; the regulator sets and enforces the deadline (Applicability; Requirement; Compliance; Background)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-lyc-98-push-rod-inner-diameter-scoring","history":"/api/acts/ad-lyc-98-push-rod-inner-diameter-scoring/history","analysis":"/api/acts/ad-lyc-98-push-rod-inner-diameter-scoring/analysis","conflicts":"/api/acts/ad-lyc-98-push-rod-inner-diameter-scoring/conflicts","importantCases":"/api/acts/ad-lyc-98-push-rod-inner-diameter-scoring/important-cases","documents":"/api/acts/ad-lyc-98-push-rod-inner-diameter-scoring/documents"}}