{"id":"F2006B10604","name":"AD/HU 269/37 - Main Rotor Lead - Lag and Flapping Hinge Bolts P/N HS1446-10-68 Vendo Identification (BM) - Inspection","slug":"ad-hu-269-37-main-rotor-lead-lag-and-flapping-hinge-bolts-p-n-hs1446-10-68-vendo-identification-bm-i","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116471,"registerId":"commonwealth-F2006B10604-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HU 269/37 - Main Rotor Lead - Lag and Flapping Hinge Bolts P/N HS1446-10-68 Vendo Identification (BM) - 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)  Schweizer (Hughes) 269 Series Helicopters\n\n \n\nAD/HU 269/37 Main Rotor Lead - Lag and Flapping\n\nHinge Bolts P/N HS1446-10-68 Vendo Identification (BM) - Inspection\n\nApplicability: Models 269A, 269A-1, 269B and 269C delivered prior to 1 August 1970. Document:  1. Hughes SIN No. N-78; or\n\n2. FAA AD 70-17-3.\n\n \n\nCompliance: In accordance with the requirement documents.\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\n10/70\n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive's scope is defined in the AD text: it applies only to Models 269A, 269A-1, 269B and 269C delivered prior to 1 August 1970 and to the specified part number. There is no indication in the AD text that this scope has been altered from its stated intent."},"complexity_factors":["Narrow scope limited to specific helicopter models and a single part number (HS1446-10-68)","Directive delegates procedural specifics to two external documents (Hughes SIN N-78 and FAA AD 70-17-3) rather than containing them","No procedural detail, intervals, or corrective actions in the AD text increases reliance on referenced documents","Simple, single-action requirement (inspection) with clear applicability date cut-off (delivered prior to 1 August 1970)"],"plain_english_summary":"### What this directive does\n\nThis airworthiness directive orders operators to inspect specific main rotor hinge bolts on certain Schweizer (Hughes) 269-series helicopters. The directive identifies the affected part as main rotor lead–lag and flapping hinge bolts, part number HS1446-10-68, with Vendo identification (BM). (See: \"AD/HU 269/37 Main Rotor Lead - Lag and Flapping Hinge Bolts P/N HS1446-10-68 Vendo Identification (BM) - Inspection\")\n\n### Which aircraft are affected\n\n- Models 269A, 269A-1, 269B and 269C delivered before 1 August 1970. (See: \"Applicability\")\n\n### What operators must do\n\n- Comply with the inspection steps and requirements set out in the referenced documents: either Hughes Service Instruction Notice No. N-78 or FAA AD 70-17-3. The AD requires compliance \"in accordance with the requirement documents.\" (See: \"Document\" and \"Compliance\")\n\n### Who decides and who pays\n\n- The Civil Aviation Safety Authority (Commonwealth of Australia) issues the directive and requires compliance through the Schedule of Airworthiness Directives. Operators/owners of the affected helicopters are responsible for carrying out the inspection and any subsequent corrective work. (See header identifying the authority and the \"Compliance\" statement.)\n\n### Practical effects, incentives and costs\n\n- Behaviour change: Maintenance personnel must inspect the specified hinge bolts on each affected helicopter and follow the inspection procedure in the referenced documents; if defects are found, follow-up maintenance or replacement will be required. (See: \"Compliance\" and referenced documents.)\n- Who pays: Costs fall on aircraft owners/operators (inspection labour, parts, and any downtime). The directive does not specify funding or compensation. (Inferred from the directive placing the compliance obligation on operators.)\n- Where the directive delegates technical detail: The AD points to external technical documents (Hughes SIN N-78 or FAA AD 70-17-3) for the specific inspection procedures and any corrective actions. That delegation means the precise tasks, intervals, and acceptance criteria are in those documents rather than in the AD text itself. (See: \"Document\" and \"Compliance\")\n- Implementation risk and compliance burden: Operators must obtain and follow the referenced documents; failure to do so risks non-compliance. Time needed for inspections creates aircraft downtime and maintenance scheduling costs. The AD does not quantify frequency, time, or parts costs. (See: \"Compliance\" and the absence of procedural detail in the AD text.)\n\n### Trade-offs and effects on private choice\n\n- The directive increases mandatory maintenance obligations for a narrowly defined set of older helicopters (delivered prior to 1 Aug 1970), which reduces operator discretion over when and how to inspect those parts because the AD requires adherence to the referenced technical documents. (See: \"Applicability\" and \"Document\")\n- Concentration of effect: The cost and administrative burden are concentrated on owners/operators of the listed models delivered before the specified date. Any safety or reliability benefits that result from the inspections are not quantified in the AD text. (See: \"Applicability\" and lack of quantified benefits in the AD.)\n\n### Source citations\n\n- Authority and scheme: \"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - ... SCHEDULE OF AIRWORTHINESS DIRECTIVES\" (header)\n- Affected part and action: Title line \"Main Rotor Lead - Lag and Flapping Hinge Bolts P/N HS1446-10-68 Vendo Identification (BM) - Inspection\"\n- Applicability: \"Applicability: Models 269A, 269A-1, 269B and 269C delivered prior to 1 August 1970.\"\n- Requirement documents: \"Document: 1. Hughes SIN No. N-78; or 2. FAA AD 70-17-3.\"\n- Compliance instruction: \"Compliance: In accordance with the requirement documents.\"\n"},"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 defect in a narrow cohort of aircraft. It has not expanded beyond its original purpose of addressing identified bolt failures in pre-1970 Hughes/Schweizer helicopters."},"complexity_factors":["Very short document (approximately 150 words)","Only 4 defined applicability criteria (specific model numbers and delivery date)","No nested conditional logic or exceptions","Single compliance pathway with two alternative reference documents","No interpretation section or defined terms","Straightforward imperative structure: identify aircraft → inspect bolts → follow referenced manual"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA) for specific helicopters.\n\n**What it does:**\nOrders owners and operators of certain older Schweizer (formerly Hughes) 269 series helicopters to inspect specific bolts on the main rotor system. These bolts (part number HS1446-10-68 with \"BM\" vendor marking) are found in the lead-lag and flapping hinges — critical components that allow the rotor blades to move properly during flight.\n\n**Who it affects:**\n- **Aircraft models:** Schweizer (Hughes) 269A, 269A-1, 269B, and 269C\n- **Specific group:** Only those helicopters delivered **before 1 August 1970**\n\n**Why it matters:**\nThese bolts are under enormous stress during flight. If they fail, the main rotor could separate or malfunction, leading to catastrophic loss of control. This AD mandates inspection to catch potential defects before they cause accidents.\n\n**What must be done:**\nOperators must follow the inspection procedures in either:\n- Hughes Service Information Notice No. N-78, **or**\n- FAA Airworthiness Directive 70-17-3 (the equivalent US safety notice)\n\n**In short:** If you own one of these old helicopters, you must check these specific rotor bolts for cracks or damage — and you must do it exactly as the manufacturer or FAA has prescribed."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hu-269-37-main-rotor-lead-lag-and-flapping-hinge-bolts-p-n-hs1446-10-68-vendo-identification-bm-i","history":"/api/acts/ad-hu-269-37-main-rotor-lead-lag-and-flapping-hinge-bolts-p-n-hs1446-10-68-vendo-identification-bm-i/history","analysis":"/api/acts/ad-hu-269-37-main-rotor-lead-lag-and-flapping-hinge-bolts-p-n-hs1446-10-68-vendo-identification-bm-i/analysis","conflicts":"/api/acts/ad-hu-269-37-main-rotor-lead-lag-and-flapping-hinge-bolts-p-n-hs1446-10-68-vendo-identification-bm-i/conflicts","importantCases":"/api/acts/ad-hu-269-37-main-rotor-lead-lag-and-flapping-hinge-bolts-p-n-hs1446-10-68-vendo-identification-bm-i/important-cases","documents":"/api/acts/ad-hu-269-37-main-rotor-lead-lag-and-flapping-hinge-bolts-p-n-hs1446-10-68-vendo-identification-bm-i/documents"}}