{"id":"F2006B07626","name":"AD/Z-242L/1 - Oil Sludge Valve","slug":"ad-z-242l-1-oil-sludge-valve","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":50356,"registerId":"commonwealth-F2006B07626-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/Z-242L/1 - Oil Sludge Valve","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nMoravan Zlin Z-242L Series Aeroplanes\n\nAD/Z-242L/1 Oil Sludge Valve 9/97 DM\n\nApplicability: All Zlin 242L aircraft serial numbers up to 0708 and aircraft serial numbers 0727 and 0728 incorporating an oil system sludge valve as detailed in Moravan Drawing Number L 242L.7100-04.00.\n\nRequirement: To prevent the possible leakage of oil from the engine, inspect the sludge valve for proper locking in accordance with Moravan Mandatory Service Bulletin Number Z 242L/25a.\n\nNote: Czech Republic Airworthiness Directive CAA \\- AD-2 \\- 029/97 refers.\n\nCompliance: Prior to further flight effective 2 July 1997.\n\nBackground: This directive has been issued to require an inspection of the oil system sludge valve for proper locking. The requirement is in response to advice from the manufacturer of a manufacturing error which may cause failure of the valve and the loss of oil from the engine.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive addressing a specific manufacturing defect in a specific aircraft component. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific technical requirement (one inspection task)","Narrow applicability (one aircraft model, specific serial number ranges)","No defined terms section or interpretation provisions","No conditional logic or nested exceptions","Cross-reference to only one external document (manufacturer's service bulletin)","Total length: approximately 150 words","Straightforward compliance deadline (prior to further flight)"],"plain_english_summary":"This is a **safety notice (Airworthiness Directive)** for a specific type of light aircraft — the **Zlin 242L** — made by a Czech manufacturer called Moravan.\n\n**What it does:**\nIt orders owners and operators of certain Zlin 242L planes to **inspect a small valve in the engine's oil system** (called the \"sludge valve\") to make sure it is properly locked in place.\n\n**Why it matters:**\nThe manufacturer discovered a **manufacturing mistake** that could cause this valve to fail. If the valve fails, **engine oil can leak out**, which could lead to engine damage or failure during flight — a serious safety risk.\n\n**Who must comply:**\n- Owners of Zlin 242L aircraft with **serial numbers up to 0708**, plus **serial numbers 0727 and 0728**\n- Only applies if the plane has the specific sludge valve detailed in Moravan drawing number L 242L.7100-04.00\n\n**What must be done:**\n- Inspect the sludge valve following the manufacturer's **Mandatory Service Bulletin Z 242L/25a**\n- Must be done **before the aircraft flies again** (effective 2 July 1997)\n\n**Key point:** This is a **mandatory safety fix** — the aircraft cannot legally fly until this inspection is completed."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive confines its action to a specific, limited set of aircraft and to a single mandatory inspection action to be performed before the next flight (Applicability; Requirement; Compliance). The stated purpose (prevent oil leakage due to a manufacturer-advised manufacturing error) aligns with the described requirement and does not expand or alter the types of regulatory powers exercised; it imposes an immediate safety inspection obligation rather than creating a new ongoing regulatory regime (Background; Requirement)."},"complexity_factors":["Narrow, specific applicability limited to defined serial numbers and a specific valve drawing (Applicability).","Single, short-term required action (inspection) referenced to a manufacturer Service Bulletin rather than multiple regulatory steps (Requirement).","Immediate compliance required prior to further flight, creating operational scheduling constraints (Compliance).","Dependence on identification of a particular part configuration (sludge valve per drawing) increases administrative checking but not legal complexity (Applicability).","Relies on external document (Moravan Mandatory Service Bulletin Z 242L/25a) for inspection procedure, requiring access to and interpretation of that manufacturer material (Requirement)."],"plain_english_summary":"This directive requires a one‑time inspection of the engine oil sludge valve on certain Moravan Zlin Z‑242L aeroplanes (specified serials) per the manufacturer’s Service Bulletin, with completion required before the aircraft may fly again. \n\nIssued after a reported manufacturing error that could let the valve fail and cause oil loss, it forces owners/operators to ground affected aeroplanes, arrange and pay for inspection and any corrective work."}},"importantCases":[],"_links":{"self":"/api/acts/ad-z-242l-1-oil-sludge-valve","history":"/api/acts/ad-z-242l-1-oil-sludge-valve/history","analysis":"/api/acts/ad-z-242l-1-oil-sludge-valve/analysis","conflicts":"/api/acts/ad-z-242l-1-oil-sludge-valve/conflicts","importantCases":"/api/acts/ad-z-242l-1-oil-sludge-valve/important-cases","documents":"/api/acts/ad-z-242l-1-oil-sludge-valve/documents"}}