{"id":"F2006B10753","name":"AD/HU 369/89 - Main Blade Root End","slug":"ad-hu-369-89-main-blade-root-end","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56200,"registerId":"commonwealth-F2006B10753-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HU 369/89 - Main Blade Root End","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nMcDonnell Douglas (Hughes) and Kawasaki 369 Series Helicopters\n\nAD/HU 369/89 Main Blade Root End 8/96 DM\n\nApplicability: Model 369, 369A, 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, and\n\n500N helicopters.\n\nRequirement: Inspect in accordance with Part I and Part II of McDonnell Douglas Helicopter Systems Service Information Notice HN-239, DN-188,EN-81, FN-67, or NN-008, as applicable.\n\nNote: FAA AD 96-10-09 Amdt 39-9615 refers.\n\nCompliance: For Part I: Unless the initial inspection has already been accomplished, within 10 hours time in service after 17 June 1996.\n\nFor Part II: Within 100 hours time in service after 17 June 1996, thereafter at intervals not to exceed 100 hours time in service.\n\nBackground: The FAA received a report of one accident in which a blade separated from the helicopter, as well as eight other reports of cracked blades. The actions specified in this Directive are intended to prevent failure of a blade and subsequent loss of control of the helicopter.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive issued in response to specific accident reports. It has not expanded beyond its original purpose of mandating blade root inspections for the identified helicopter models. The scope remains tightly focused on the single mechanical failure mode (blade root cracking) that prompted the AD."},"complexity_factors":["Short, single-purpose directive (approximately 200 words)","Only 4 defined structural elements (Applicability, Requirement, Note, Compliance, Background)","Simple conditional logic: 'unless already accomplished' for Part I only","Cross-reference to external technical documents (FAA AD and McDonnell Douglas service bulletins) rather than incorporating text directly","No nested exceptions or layered definitions","Straightforward time-based compliance schedule (10 hours / 100 hours)"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it as a \"recall notice\" for aircraft, but with legal force. Owners and operators must comply or the aircraft cannot fly legally.\n\n**What it does:** This AD requires urgent safety inspections of the main rotor blade \"root end\" (the part where the blade attaches to the helicopter hub) on specific McDonnell Douglas (formerly Hughes) and Kawasaki 369 series helicopters.\n\n**Who it affects:**\n- **Aircraft owners/operators** of Model 369, 369A, 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, and 500N helicopters\n- **Maintenance engineers** who must perform the inspections\n\n**The requirements:**\n- **Part I inspection:** Must be done within 10 flight hours after 17 June 1996 (unless already completed)\n- **Part II inspection:** Must be done within 100 flight hours after 17 June 1996, then repeated every 100 flight hours thereafter\n\n**Why it matters:** The US Federal Aviation Administration (FAA) investigated a fatal accident where a rotor blade completely separated from a helicopter, plus eight other cases of cracked blades. A failed rotor blade means instant, catastrophic loss of control. This AD exists to catch cracks before they cause crashes.\n\n**Key point:** The actual inspection procedures aren't written in this document — operators must follow specific McDonnell Douglas service bulletins (HN-239, DN-188, EN-81, FN-67, or NN-008 depending on the helicopter model)."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The directive's scope is limited to inspection requirements for main blade root ends on the listed 369‑series helicopters and aligns with the stated purpose in the Background (prevent blade failure after reported cracks and one separation). It does not, in this text, broaden authority to require modifications or replacements beyond following the specified service information; it instead prescribes inspection timing and intervals."},"complexity_factors":["Applicability covers a range of models (Model 369, 369A, 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, and 500N), increasing administrative tracking for operators and maintainers (Applicability).","Inspections must follow multiple model‑specific McDonnell Douglas Helicopter Systems Service Information Notices (HN-239, DN-188, EN-81, FN-67, or NN-008), requiring correct identification and use of the matching document (Requirement).","Two‑part inspection regime with different compliance urgencies: Part I within 10 hours time in service after 17 June 1996; Part II within 100 hours and recurring at 100‑hour intervals (Compliance).","Short initial compliance window (10 hours) creates operational disruption risk and immediate workload/cost for affected operators (Compliance: Part I).","Recurring inspections at fixed flight‑hour intervals impose ongoing maintenance scheduling and labor/material costs (Compliance: Part II).","Background ties the directive to reported incidents (one accident and eight cracked blades), indicating a safety‑risk trigger but no mandated parts replacement or design change within the text (Background, Requirement).","Reference to FAA AD 96-10-09 indicates cross‑jurisdictional coordination; operators may need to reconcile multiple regulatory documents (Note)."],"plain_english_summary":"This airworthiness directive requires operators of McDonnell Douglas (Hughes) and Kawasaki 369-series helicopters to carry out specified inspections of main rotor blade root ends, using the manufacturer's service information. It mandates an immediate short‑term inspection and recurring inspections at 100‑hour intervals. The stated purpose is to detect cracked blades and prevent blade separation and loss of control following reported incidents."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hu-369-89-main-blade-root-end","history":"/api/acts/ad-hu-369-89-main-blade-root-end/history","analysis":"/api/acts/ad-hu-369-89-main-blade-root-end/analysis","conflicts":"/api/acts/ad-hu-369-89-main-blade-root-end/conflicts","importantCases":"/api/acts/ad-hu-369-89-main-blade-root-end/important-cases","documents":"/api/acts/ad-hu-369-89-main-blade-root-end/documents"}}