{"id":"F2006B10687","name":"AD/HU 369/23 - Main Rotor Hub Lead Lag Link - Inspection","slug":"ad-hu-369-23-main-rotor-hub-lead-lag-link-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116638,"registerId":"commonwealth-F2006B10687-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HU 369/23 - Main Rotor Hub Lead Lag Link - 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 369/23 Main Rotor Hub Lead Lag Link - Inspection 3/77\n\nApplicability: All 500 model 369H with lead lag links P/Nos. 369A1234, 369A1234-7, 80-369H1234 and lead lag link assembly P/No. 369H1203.\n\n \n\nDocument: Hughes SIN No. HN-109.\n\n \n\nCompliance: Within 100 hours time in service after 31 March 1977 and thereafter 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\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 focused on a specific mechanical component on a specific aircraft model. It has not expanded beyond its original purpose of ensuring lead lag link integrity through periodic inspection."},"complexity_factors":["Very short document (approximately 150 words)","Only 4 specific part numbers identified","Single compliance requirement with clear time intervals","No defined terms section","No cross-references to other legislation beyond the enabling Civil Aviation Regulations 1998","Simple conditional structure: applicability → requirement → compliance timeframe","No exceptions or exemptions listed"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of specific Hughes/Kawasaki 369 series helicopters to inspect a critical part called the **\"lead lag link\"** in the main rotor hub.\n\n**What it does:**\n- Mandates visual or physical inspection of lead lag links (part numbers 369A1234, 369A1234-7, 80-369H1234, and assembly 369H1203) on Model 369H helicopters\n- Requires the first inspection within 100 flight hours after 31 March 1977\n- Requires repeat inspections every 100 flight hours thereafter\n\n**Who it affects:**\n- Operators of Hughes 500 model 369H helicopters with the specified part numbers\n- Maintenance organisations servicing these aircraft\n\n**Why it matters:**\nLead lag links are crucial components that allow helicopter rotor blades to move back and forth (lead and lag) during rotation. Failure of these links can cause catastrophic rotor system failure and loss of the aircraft. This AD was issued following Hughes Service Information Notice HN-109, suggesting a known defect or wear pattern requiring proactive monitoring."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument itself sets a limited, specific requirement: mandatory inspections for specified lead–lag link part numbers on 500 model 369H helicopters, using Hughes SIN No. HN-109, with a 100‑hour recurring interval (Applicability; Document; Compliance). The text does not indicate any expansion or narrowing of scope from a prior instrument or an amendment; it states the current applicability and compliance schedule without reference to a changed scope."},"complexity_factors":["Narrow, specific applicability to one airframe model (500 model 369H) and a short list of part numbers (Applicability)","Single, recurring action specified with a fixed time interval (inspect within 100 hours after date, then every 100 hours) (Compliance)","Reliance on an external manufacturer document for inspection procedure (Hughes SIN No. HN-109) which requires operators to obtain and follow that material (Document)","Operational compliance tasks: identification of parts on each helicopter, scheduling inspections, tracking hours in service, and performing inspections—administrative and maintenance workload","Temporal reference to a historical date (31 March 1977) that may require interpreting service-hour records for legacy aircraft"],"plain_english_summary":"This AD mandates recurring inspections of the main rotor hub lead–lag link on 500‑model Hughes/Kawasaki 369H helicopters fitted with specified part numbers, to be done per Hughes SIN No. HN‑109 within 100 hours after 31 Mar 1977 and every 100 hours thereafter. It affects owners/operators and maintenance organisations, imposing a mandatory, recurring inspection burden (and associated costs) to preserve airworthiness."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hu-369-23-main-rotor-hub-lead-lag-link-inspection","history":"/api/acts/ad-hu-369-23-main-rotor-hub-lead-lag-link-inspection/history","analysis":"/api/acts/ad-hu-369-23-main-rotor-hub-lead-lag-link-inspection/analysis","conflicts":"/api/acts/ad-hu-369-23-main-rotor-hub-lead-lag-link-inspection/conflicts","importantCases":"/api/acts/ad-hu-369-23-main-rotor-hub-lead-lag-link-inspection/important-cases","documents":"/api/acts/ad-hu-369-23-main-rotor-hub-lead-lag-link-inspection/documents"}}