{"id":"F2006B04675","name":"AD/BELL 412/41 - Tailboom Attachment Cap Angle","slug":"ad-bell-412-41-tailboom-attachment-cap-angle","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44427,"registerId":"commonwealth-F2006B04675-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.","sortOrder":0},{"sectionNumber":"AD/BELL 412/41 Tailboom Attachment Cap A","sectionType":"part","heading":"AD/BELL 412/41 Tailboom Attachment Cap Angle 12/2000","content":"# AD/BELL 412/41 Tailboom Attachment Cap Angle 12/2000\n\nDM\n\nApplicability: Model 412, 412EP, and 412CF helicopters, with upper left hand cap angle part number 212-030-191-001 installed.\n\nRequirement: Inspect the cap angle and adjacent structure in accordance with Bell Alert Service Bulletin 412-00-100.\n\nNote: FAA AD 2000-18-09 Amendment 39-11894 refers.\n\nCompliance: Initially, within 25 hours time in service after 11 October 2000, unless already accomplished; thereafter at intervals not to exceed 100 hours time in service.\n\nThis Airworthiness Directive becomes effective on 11 October 2000.\n\nBackground: The FAA received a report of a fatigue crack in a tailboom attachment cap angle.\n\n![](image.003.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 5 October 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 11 October 2000.","sortOrder":1}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1622},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD remains precisely targeted at the original unsafe condition (fatigue cracking in the tailboom attachment cap angle) and has not expanded beyond the specific helicopter models and part number initially identified."},"complexity_factors":["Single, unambiguous part number determines applicability","Only one required action (inspection per external service bulletin)","Straightforward compliance schedule with just two time thresholds (initial 25 hours, recurring 100 hours)","No defined terms, interpretation clauses, or legislative cross-references beyond the enabling regulation","Minimal conditional logic (only an exception for pre-existing compliance)"],"plain_english_summary":"**What this is:** A mandatory safety order requiring owners of specific Bell helicopters to check a critical tail component for dangerous cracks.\n\n**Who it affects:** Operators of Bell 412, 412EP, or 412CF helicopters that have a specific part installed—the upper left-hand \"cap angle\" (part number 212-030-191-001) that helps hold the tailboom to the fuselage.\n\n**What you must do:** Inspect the cap angle and surrounding structure following the exact steps in \"Bell Alert Service Bulletin 412-00-100.\" This is legally binding—you cannot skip it.\n\n**When:** First inspection within 25 hours of flying time after 11 October 2000 (unless already done). Then re-inspect every 100 hours of flying time thereafter.\n\n**Why it matters:** The US aviation safety regulator found a fatigue crack in this part. If the tailboom attachment fails during flight, the helicopter could lose its tail section—with potentially fatal consequences. This rule catches cracks before they cause catastrophe."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-412-41-tailboom-attachment-cap-angle","history":"/api/acts/ad-bell-412-41-tailboom-attachment-cap-angle/history","analysis":"/api/acts/ad-bell-412-41-tailboom-attachment-cap-angle/analysis","conflicts":"/api/acts/ad-bell-412-41-tailboom-attachment-cap-angle/conflicts","importantCases":"/api/acts/ad-bell-412-41-tailboom-attachment-cap-angle/important-cases","documents":"/api/acts/ad-bell-412-41-tailboom-attachment-cap-angle/documents"}}