{"id":"F2006B11410","name":"AD/OM-P/2 - Cylinder Heads - Inspection and Replacement","slug":"ad-om-p-2-cylinder-heads-inspection-and-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":57312,"registerId":"commonwealth-F2006B11410-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/OM-P/2 - Cylinder Heads - Inspection and Replacement","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Omnipol Piston Engines\n\n \n\nAD/OM-P/2 Cylinder Heads - Inspection and Replacement NK\n\nApplicability: Walter Minor 4-111 and 6-111 engines with S/Nos. 34405 and below. Requirement:  1. Inspect for evidence of cracked cylinder heads in accordance with Omnipol SB\n\nNo. M4-111/20 or M6-111/17.\n\n \n\n2. Replace cylinder heads with modified types.\n\n \n\nNote: Replacement with modified cylinder heads will render inspection in accordance with paragraph 1 redundant.\n\n \n\nCompliance: For para. 1 - At intervals not exceeding 50 hours time in service..\n\n \n\nFor para. 2 - Before installation following next complete overhaul after 1 September 1963.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2043},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive remains tightly focused on its original purpose of addressing the cylinder head cracking defect in specific Walter Minor engine models. It has not expanded to cover other engine types, additional components, or broader operational requirements."},"complexity_factors":["Extremely brief directive containing only two operative paragraphs","Applicability limited to specific engine models and a defined serial number cutoff","No nested exceptions or conditional logic—requirements apply uniformly","Minimal cross-referencing (only to two identified manufacturer Service Bulletins)"],"plain_english_summary":"**What this is about:** This is a safety directive requiring owners of specific aircraft engines to check for and fix a dangerous defect—cracked cylinder heads that could cause engine failure.\n\n**Who it affects:** Anyone operating aircraft with **Walter Minor 4-111 or 6-111 engines** bearing serial numbers **34405 and below**.\n\n**What you must do:**\n- **Inspect regularly:** Check the cylinder heads for cracks at least every 50 hours of flight time, following the technical procedures in Service Bulletins M4-111/20 or M6-111/17 (manufacturer guidance documents).\n- **Replace eventually:** Install modified, improved cylinder heads before returning the engine to service following its next complete overhaul after 1 September 1963.\n\n**Important note:** Once you install the modified cylinder heads, you can stop doing the repetitive 50-hour inspections because the replacement parts permanently solve the cracking problem."}},"importantCases":[],"_links":{"self":"/api/acts/ad-om-p-2-cylinder-heads-inspection-and-replacement","history":"/api/acts/ad-om-p-2-cylinder-heads-inspection-and-replacement/history","analysis":"/api/acts/ad-om-p-2-cylinder-heads-inspection-and-replacement/analysis","conflicts":"/api/acts/ad-om-p-2-cylinder-heads-inspection-and-replacement/conflicts","importantCases":"/api/acts/ad-om-p-2-cylinder-heads-inspection-and-replacement/important-cases","documents":"/api/acts/ad-om-p-2-cylinder-heads-inspection-and-replacement/documents"}}