{"id":"F2006B06144","name":"AD/PC-6/4 - Aileron Balance Weight Arm - Inspection","slug":"ad-pc-6-4-aileron-balance-weight-arm-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46937,"registerId":"commonwealth-F2006B06144-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PC-6/4 - Aileron Balance Weight Arm - 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)  Pilatus Porter PC-6 Series Aeroplanes\n\n \n\nAD/PC-6/4 Aileron Balance Weight Arm - Inspection 3/66\n\nApplicability: All models with S/Nos. 338, 341, 344, 345, 349, 350, 516 to 518, 521, 522, 524, 525,\n\n526, 528, 531, 532, 535 to 538, 543 to 551 and 554.\n\n \n\nDocument: Pilatus SB No. 25.\n\n \n\nCompliance: At intervals not exceeding 100 hours time in service after 15 April 1966.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive from 1966 addressing a specific mechanical issue in specific aircraft. It has not expanded beyond its original purpose of mandating inspections for aileron balance weight arms on affected PC-6 serial numbers."},"complexity_factors":["Extremely short document (single page directive)","Only 4 operative provisions: applicability list, document reference, compliance deadline, and recurring interval","No defined terms section — uses plain aviation terminology","No cross-references to other legislation beyond the enabling regulation (CAR 1998 Part 39)","Simple conditional logic: 'If your aircraft serial number is in this list, do this inspection every 100 hours'","No exceptions, exemptions, or nested conditions"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** issued by Australia's Civil Aviation Safety Authority (CASA). It mandates a safety inspection for specific Pilatus Porter PC-6 aircraft.\n\n**What it does:**\n- Requires owners/operators of certain Pilatus Porter PC-6 aeroplanes to inspect the **aileron balance weight arm** — a component that helps keep the aircraft's control surfaces stable during flight.\n- The inspection must be carried out every **100 hours of flight time** after 15 April 1966.\n\n**Who it affects:**\n- Owners and operators of Pilatus PC-6 aircraft with specific serial numbers listed (ranging from #338 to #554, with gaps).\n\n**Why it matters:**\n- Airworthiness Directives are legally binding safety orders. If you don't comply, you cannot legally fly the aircraft. This particular directive addresses a potential structural or mechanical defect in the aileron system that could affect flight safety.\n- The reference to \"Pilatus SB No. 25\" means this directive implements a Service Bulletin from the manufacturer (Pilatus), essentially making the manufacturer's recommended fix mandatory under Australian law.\n\n**Key point:** This is a recurring maintenance requirement — not a one-off fix. The 100-hour interval means it becomes part of the regular maintenance schedule for these aircraft."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The text provided sets out a narrowly tailored inspection requirement for specified serial-numbered PC-6 aeroplanes and a fixed interval (100 hours TIS after 15 April 1966). Nothing in the supplied instrument indicates a change of scope from that stated applicability and interval."},"complexity_factors":["Narrow and specific applicability: applies only to Pilatus PC-6 aircraft with a defined list of serial numbers (Applicability).","Single, simple mandated action: periodic inspection of one component (aileron balance weight arm) rather than multiple conditional measures (Compliance).","Fixed and straightforward compliance interval: every 100 hours time in service after a stated date (Compliance).","Reliance on an external technical document for procedure: Pilatus SB No. 25 contains the inspection technique and likely acceptance/corrective criteria (Document).","No discretionary or alternative-compliance pathways included in the provided text, reducing procedural complexity but shifting detail to the referenced service bulletin (Document)."],"plain_english_summary":"This Airworthiness Directive (AD/PC‑6/4) requires owners/operators of the specified Pilatus PC‑6 serial numbers to carry out recurring inspections of the aileron balance weight arm, at intervals no greater than 100 hours time-in-service (counting from 15 April 1966), using Pilatus Service Bulletin No. 25 for the technical procedure. Compliance is mandatory under the Commonwealth Civil Aviation Regulations Part 39 and creates recurrent maintenance costs and scheduling impacts for affected operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pc-6-4-aileron-balance-weight-arm-inspection","history":"/api/acts/ad-pc-6-4-aileron-balance-weight-arm-inspection/history","analysis":"/api/acts/ad-pc-6-4-aileron-balance-weight-arm-inspection/analysis","conflicts":"/api/acts/ad-pc-6-4-aileron-balance-weight-arm-inspection/conflicts","importantCases":"/api/acts/ad-pc-6-4-aileron-balance-weight-arm-inspection/important-cases","documents":"/api/acts/ad-pc-6-4-aileron-balance-weight-arm-inspection/documents"}}