{"id":"F2006B11083","name":"AD/LA-4/9 - Rudder Bellcrank - Inspection","slug":"ad-la-4-9-rudder-bellcrank-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56740,"registerId":"commonwealth-F2006B11083-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LA-4/9 - Rudder Bellcrank - 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 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Consolidated Aeronautics, Colonial and LA-4 Series Aeroplanes\n\n \n\nAD/LA-4/9 Rudder Bellcrank - Inspection 3/74\n\nApplicability: All models.\n\n \n\nDocument: Consolidated Aeronautics SL L-50.\n\n \n\nCompliance: Within 100 hours time in service after 30 April 1974, and there- after at intervals not exceeding 1 year or at anytime rudder pedals are subjected to abnormal loads.\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\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive, as written, sets an inspection requirement for the rudder bellcrank for all models of the specified aircraft series and specifies timing and conditional triggers for inspection. The text contains no explicit statement that it expands or narrows a prior requirement, and no comparison to an earlier instrument is provided in this document. Therefore there is no indication in this text that the scope has changed from any original intent."},"complexity_factors":["Narrow technical focus limited to one component (rudder bellcrank) — reduces complexity.","Clear, simple timing requirements (within 100 hours after 30 April 1974; thereafter ≤1 year; after abnormal loads) — straightforward compliance schedule.","Broad applicability to all models in the series increases number of affected operators.","Technical inspection procedure is referenced to an external document (Consolidated Aeronautics SL L-50) — requires locating and following that document, adding practical complexity.","Directive text does not specify enforcement, recordkeeping, or who formally certifies compliance — leaves administrative details to other rules or practice."],"plain_english_summary":"Applies to all Consolidated Aeronautics Colonial and LA‑4 series aeroplanes: this AD mandates inspection of the rudder bellcrank (per Consolidated Aeronautics SL L‑50) within 100 hours TIS after 30 Apr 1974, thereafter at intervals not exceeding one year, and after any event imposing abnormal rudder‑pedal loads. Owners/operators must arrange and pay for inspections and any repairs. It matters because it creates a recurring safety check and predictable maintenance cost, and requires access to the referenced inspection procedure."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a historical Airworthiness Directive from 1974 (as indicated by '3/74' in the reference number). It has not expanded beyond its original narrow purpose: mandating inspection of a specific mechanical part on specific aircraft models. The scope remains precisely targeted at the rudder bellcrank safety issue identified in the manufacturer's service letter."},"complexity_factors":["Extremely short document (approximately 150 words)","Only 1 defined term implicitly referenced ('time in service' — standard aviation term)","No cross-references to other legislation beyond the parent Civil Aviation Regulations 1998","Simple conditional logic: one initial deadline + recurring annual requirement + trigger condition","Single mechanical component scope (rudder bellcrank only)","No exceptions, exemptions, or nested conditions"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to all models of **Consolidated Aeronautics Colonial and LA-4 series aeroplanes** (small aircraft).\n\n**What it requires:**\nOwners and operators must **inspect the rudder bellcrank** — a mechanical component that connects the rudder pedals to the rudder itself, allowing the pilot to steer the aircraft on the ground and in the air.\n\n**When to do it:**\n- **First inspection:** Within 100 hours of flying time after 30 April 1974\n- **Repeat inspections:** At least once every year, **or** immediately if the rudder pedals experience abnormal force (like a hard landing or someone stepping on them too hard)\n\n**Why it matters:**\nThis directive addresses a specific safety risk identified by the manufacturer (Consolidated Aeronautics) in their Service Letter L-50. Without this inspection, a faulty rudder bellcrank could fail in flight, causing loss of directional control and potentially a crash.\n\n**Who must comply:**\nAnyone operating these specific aircraft in Australia — private owners, flying schools, charter operators. Non-compliance is illegal and can ground an aircraft."}},"importantCases":[],"_links":{"self":"/api/acts/ad-la-4-9-rudder-bellcrank-inspection","history":"/api/acts/ad-la-4-9-rudder-bellcrank-inspection/history","analysis":"/api/acts/ad-la-4-9-rudder-bellcrank-inspection/analysis","conflicts":"/api/acts/ad-la-4-9-rudder-bellcrank-inspection/conflicts","importantCases":"/api/acts/ad-la-4-9-rudder-bellcrank-inspection/important-cases","documents":"/api/acts/ad-la-4-9-rudder-bellcrank-inspection/documents"}}