{"id":"F2006B07606","name":"AD/WNR/1 - Cylinder Hold-Down Nut - Inspection","slug":"ad-wnr-1-cylinder-hold-down-nut-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":50294,"registerId":"commonwealth-F2006B07606-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/WNR/1 - Cylinder Hold-Down Nut - Inspection","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)  Warner Piston Engines\n\n \n\nAD/WNR/1 Cylinder Hold-Down Nut - Inspection NK\n\nApplicability: All Scarab and Super Scarab engines not modified to Warner SL No. A-15. Document:               1. Warner SL No. A-15; or\n\n2. ANO 106.1.16.0.2.1; or\n\n \n\n3. FAA AD 51-4-2.\n\n \n\nCompliance: At intervals not exceeding 100 hours time in service.\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\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a known mechanical defect in specific engine models. It has not expanded beyond its original purpose of ensuring cylinder hold-down nut integrity."},"complexity_factors":["Single, specific mechanical component addressed (cylinder hold-down nuts)","Only one compliance condition (100-hour interval)","Three alternative reference documents provided for flexibility","Clear applicability criteria (specific engine models, specific modification status)","No defined terms section, no cross-references to other legislation, no conditional exceptions","Extremely short document (approximately 150 words of substantive content)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** issued by Australia's Civil Aviation Safety Authority (CASA). It mandates safety inspections for specific aircraft engines.\n\n**What it does:**\n- Requires regular inspection of **cylinder hold-down nuts** on certain Warner piston engines (Scarab and Super Scarab models)\n- These nuts hold the engine cylinders in place — if they fail, the engine could break apart in flight\n\n**Who it affects:**\n- Owners and operators of aircraft with **Scarab or Super Scarab engines** that have **not** been modified according to Warner Service Letter A-15\n- Maintenance engineers responsible for these engines\n\n**What must be done:**\n- Inspect the cylinder hold-down nuts **every 100 hours of flight time** (\"time in service\")\n- Follow one of three approved technical documents for how to do the inspection:\n  1. Warner Service Letter A-15, or\n  2. Australian National Order 106.1.16.0.2.1, or\n  3. FAA Airworthiness Directive 51-4-2 (the US equivalent)\n\n**Why it matters:**\nAirworthiness Directives are legally binding safety orders. Ignoring this requirement means the aircraft cannot legally fly, and operating without compliance risks catastrophic engine failure."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive, as presented, establishes a focused inspection requirement for a defined set of engines and points to external documents for the inspection procedure. There is no text in the instrument indicating an expansion or narrowing of that scope from an earlier or different stated intent; therefore no change of scope is evident within the supplied text. (Applicability; Document; Compliance)"},"complexity_factors":["Narrow and specific applicability (only Scarab and Super Scarab engines not modified to Warner SL No. A-15) which reduces scope complexity. (Applicability)","Requirement is simple and periodic — single clear interval: every ≤100 hours time in service — which lowers procedural complexity. (Compliance)","The directive delegates procedural detail to external documents (Warner SL No. A-15; ANO 106.1.16.0.2.1; FAA AD 51-4-2). Reliance on outside technical sources raises implementation complexity and potential for inconsistent interpretation. (Document)","The text provides no inspection method, acceptance criteria, corrective actions, or enforcement detail, so practical compliance depends on locating and applying the referenced documents. (Document)","A specific exclusion (engines modified to Warner SL No. A-15) creates an operational decision point — either inspect or rely on the modification — which adds a small compliance choice for operators. (Applicability)","Administrative tasks (scheduling recurring inspections and maintaining records) are implied but not specified, adding moderate administrative overhead. (Compliance)"],"plain_english_summary":"This CASA airworthiness directive requires recurring inspections of the cylinder hold‑down nut on Warner Scarab and Super Scarab piston engines (except those modified per Warner Service Letter No. A‑15), to be performed at intervals no greater than 100 hours and in accordance with specified technical documents.\n\nIt matters because it creates a standing maintenance obligation—and corresponding time, cost and record‑keeping burdens for owners/operators—by turning a safety concern into a mandated, recurring inspection requirement."}},"importantCases":[],"_links":{"self":"/api/acts/ad-wnr-1-cylinder-hold-down-nut-inspection","history":"/api/acts/ad-wnr-1-cylinder-hold-down-nut-inspection/history","analysis":"/api/acts/ad-wnr-1-cylinder-hold-down-nut-inspection/analysis","conflicts":"/api/acts/ad-wnr-1-cylinder-hold-down-nut-inspection/conflicts","importantCases":"/api/acts/ad-wnr-1-cylinder-hold-down-nut-inspection/important-cases","documents":"/api/acts/ad-wnr-1-cylinder-hold-down-nut-inspection/documents"}}