{"id":"F2006B10705","name":"AD/HU 369/43 - Main Rotor Blade Root Fitting Assemblies and Lead-Lag Assemblies - Inspection","slug":"ad-hu-369-43-main-rotor-blade-root-fitting-assemblies-and-lead-lag-assemblies-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116673,"registerId":"commonwealth-F2006B10705-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HU 369/43 - Main Rotor Blade Root Fitting Assemblies and Lead-Lag Assemblies - 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)  McDonnell Douglas (Hughes) and Kawasaki 369 Series Helicopters\n\n \n\nAD/HU 369/43 Main Rotor Blade Root Fitting Assemblies\n\nand Lead-Lag Assemblies - Inspection\n\n\n2/80\n\n \n\nApplicability: All model 369H with component S/Nos. as listed in the requirement document. Document:               Hughes SIN No. HN-140.\n\nCompliance: Part 1 - Initial Inspection - within 25 hours time in service after 3 January 1980.\n\n \n\nPart 2 - Periodic Inspection - as detailed in requirement document.\n\n \n\nBackground: Cracking of the main rotor hub lead-lag link attach lugs has been reported 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","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 specific mechanical defect in a specific helicopter model. It has not expanded beyond its original purpose of mandating inspections for cracked rotor components."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 2 defined compliance requirements (initial and periodic inspection)","Single cross-reference to external technical document (Hughes SIN HN-140)","No nested exceptions or conditional logic","Clear applicability criteria (specific model and serial numbers)","Straightforward temporal trigger (25 hours time in service after fixed date)"],"plain_english_summary":"This is an **Airworthiness Directive** (a mandatory safety order) issued by Australia's Civil Aviation Safety Authority for certain Hughes and Kawasaki helicopters.\n\n**What it does:**\n- Requires owners and operators of specific **McDonnell Douglas (Hughes) 369H model helicopters** to inspect the main rotor blade root fittings and lead-lag assemblies (parts that connect the rotor blades to the hub and allow them to move).\n\n**Why it matters:**\n- **Cracks have been found** in the lead-lag link attach lugs (connection points) during normal helicopter operations. If these cracks aren't caught, the rotor assembly could fail catastrophically.\n\n**Who must comply:**\n- Anyone operating a **369H model helicopter** with specific serial numbers listed in Hughes Service Information Notice HN-140.\n\n**What must be done:**\n- **First inspection:** Within 25 flight hours after 3 January 1980\n- **Ongoing inspections:** Repeated periodically as specified in the technical document (HN-140)\n\nThis is a **safety-critical maintenance requirement** — non-compliance means the helicopter cannot legally fly."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The source text does not indicate any change in scope from an original instrument. It plainly applies to all model 369H helicopters that have the listed component serial numbers and sets the initial and periodic inspection requirements, with procedural detail delegated to Hughes SIN No. HN‑140."},"complexity_factors":["Narrow technical scope limited to model 369H helicopters and specific component serial numbers (Applicability).","Short initial compliance window (25 hours TIS after 3 January 1980) increases logistical complexity for operators (Compliance: Part 1).","Key procedural and interval details are delegated to an external document (Hughes SIN No. HN‑140), requiring operators to obtain and apply that separate material (Document: HN‑140; Compliance: Part 2).","The AD itself does not list corrective actions or procedural steps in the text provided, so implementers must reconcile the AD with the requirement document to determine exact tasks and potential repairs (Compliance; Document).","Technical inspection work requires qualified maintenance personnel and part identification, adding practical and record‑keeping burdens (Applicability; Compliance)."],"plain_english_summary":"# What this instrument changes mechanically\n\n- It requires inspections of the main rotor blade root fitting assemblies and the lead‑lag assemblies on McDonnell Douglas (Hughes) and Kawasaki 369 series helicopters that have certain component serial numbers. (Applicability)\n- Operators must carry out an initial inspection within 25 hours time in service after 3 January 1980. (Compliance: Part 1)\n- Operators must carry out ongoing periodic inspections according to the inspection intervals and procedures set out in the referenced requirement document. (Compliance: Part 2)\n- The directive points operators to Hughes Service Information Notice No. HN‑140 for the list of affected component serial numbers and the detailed inspection instructions. (Document: Hughes SIN No. HN-140)\n\n# Who this affects\n\n- Owners and operators of model 369H helicopters that contain the component serial numbers listed in the requirement document. (Applicability; Document: HN‑140)\n- Maintenance organisations or technicians who must perform the inspections and record compliance. (Compliance)\n- The Civil Aviation Safety Authority is the issuing authority that requires compliance with the directive (COMMONWEALTH OF AUSTRALIA; Civil Aviation Safety Authority). \n\n# Why the directive exists (source description)\n\n- The directive states it was issued because cracking of the main rotor hub lead‑lag link attach lugs has been reported in service. (Background)\n\n# Practical implications, costs and implementation mechanics\n\n- Who pays: operators/owners bear the direct cost of performing the initial and periodic inspections and any associated downtime. (Compliance)\n- What must be done: operators must identify whether their helicopter contains the listed component serial numbers by consulting Hughes SIN No. HN‑140 and then perform the inspections in the timeframes specified. (Applicability; Document: HN‑140; Compliance)\n- Timing constraint: the initial inspection deadline is short — within 25 hours time in service after 3 January 1980 — which can force near‑term rescheduling of flights or maintenance slots. (Compliance: Part 1)\n- Ongoing burden and uncertainty: the AD delegates procedural and interval detail to the external Hughes SIN (HN‑140). The AD itself does not reproduce the step‑by‑step procedures or the corrective actions; operators must obtain and follow that separate document for specifics. (Document: HN‑140; Compliance: Part 2)\n- Operational effect: performing inspections may reduce aircraft availability while inspections are carried out. The AD does not, in its text, set out corrective actions or specified dispensations; those details are in the referenced requirement document. (Compliance; Document: HN‑140)\n- Administrative/compliance actions: operators must track compliance with the initial and periodic inspection requirements and keep records as required by aviation safety rules and the AD. (Compliance)\n\n# Incentives, trade‑offs and risks (source‑grounded)\n\n- Incentives: by requiring inspections, the AD shifts the immediate risk‑management and cost burden to operators, who are incentivised to locate affected components and remediate any faults found. (Applicability; Compliance)\n- Trade‑offs: the AD reduces the risk of in‑service failure (the stated aim) at the cost of maintenance time and expense for operators. (Background; Compliance)\n- Implementation risk and administrative friction: because the AD relies on a separate Hughes Service Information Notice (HN‑140) for the list of serial numbers and inspection detail, compliance requires access to and correct interpretation of that document; misidentification of parts or failure to follow the external document could create compliance gaps. (Document: HN‑140)\n\n# Source citations\n\n- Applicability: \"All model 369H with component S/Nos. as listed in the requirement document.\" (Applicability)\n- Requirement document: \"Hughes SIN No. HN‑140.\" (Document)\n- Compliance deadlines: \"Part 1 - Initial Inspection - within 25 hours time in service after 3 January 1980.\"; \"Part 2 - Periodic Inspection - as detailed in requirement document.\" (Compliance)\n- Stated reason: \"Cracking of the main rotor hub lead‑lag link attach lugs has been reported in service.\" (Background)\n"}},"importantCases":[],"_links":{"self":"/api/acts/ad-hu-369-43-main-rotor-blade-root-fitting-assemblies-and-lead-lag-assemblies-inspection","history":"/api/acts/ad-hu-369-43-main-rotor-blade-root-fitting-assemblies-and-lead-lag-assemblies-inspection/history","analysis":"/api/acts/ad-hu-369-43-main-rotor-blade-root-fitting-assemblies-and-lead-lag-assemblies-inspection/analysis","conflicts":"/api/acts/ad-hu-369-43-main-rotor-blade-root-fitting-assemblies-and-lead-lag-assemblies-inspection/conflicts","importantCases":"/api/acts/ad-hu-369-43-main-rotor-blade-root-fitting-assemblies-and-lead-lag-assemblies-inspection/important-cases","documents":"/api/acts/ad-hu-369-43-main-rotor-blade-root-fitting-assemblies-and-lead-lag-assemblies-inspection/documents"}}