{"id":"F2006L00913","name":"AD/JBK 117/10 Amdt 3 - Tail Boom Vertical Fin Spar","slug":"ad-jbk-117-10-amdt-3-tail-boom-vertical-fin-spar","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":58209,"registerId":"commonwealth-F2006L00913-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Kawasaki BK 117 Series Helicopters","sectionType":"division","heading":"Kawasaki BK 117 Series Helicopters","content":"### Kawasaki BK 117 Series Helicopters\n\n| AD/JBK 117/10 Amdt 3 | Tail Boom Vertical Fin Spar | 5/2006 DM |\n| -------------------- | --------------------------- | --------- |\n\n| Applicability: | Model BK 117, BK117A-3, BK117A-4, BK117B-1, BK117B-2, and BK117C-1 helicopters.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Revise the KHI-BK117 Maintenance Manual to Revision No. 14 (or later approved revision) for Models KHI-BK 117, BK117A-3, BK117A-4, BK117B-1, BK117B-2, and Revision No. 2 (or later approved revision) for ModelKHI-BK117C-1.2. Perform the inspections detailed in KSB-117-129C in accordance with the inspection interval and method specified in the KHI-BK117 Maintenance Manual, revised by Requirement 1.If the inspection results exceed the allowable limit specified in the KHI-BK117 Maintenance Manual, before further flight, contact KHI Customer Service for technical advice.Note 1: Kawasaki Service Bulletin No. KSB-117-129C refers.Note 2: JCAB AD TCD-4605B-2006 refers. |\n| Compliance:    | Initially, before further flight after 28 March 2006. Thereafter as specified in Requirement 2.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n|                | This Amendment becomes effective on 28 March 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n| Background:    | A report was received of a fatal accident overseas where investigation revealed that the tail boom vertical fin had failed as a result of a fatigue crack that initiated on the left side of the vertical fin spar cap, and propagated across the cap and the web.Amendment 1 required a reinforcement modification, while still requiring a repetitive inspection at increased periodicity.Amendment 2 introduced the latest revision of the Requirement document which revised the modification procedures.                                                                                                                                                                                   |\n\n|     | Amendment 3 is issued in response to a new JCAB AD, which transfers the inspection requirements of this Directive to the KHI-BK117 Maintenance Manual.The original issue of this Airworthiness Directive became effective on 9 May 1997. |\n| --- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n23 March 2006","sortOrder":0},{"sectionNumber":"AD/JBK 117/10 Amdt 3","sectionType":"part","heading":"AD/JBK 117/10 Amdt 3","content":"## AD/JBK 117/10 Amdt 3","sortOrder":1},{"sectionNumber":"Tail Boom Vertical Fin Spar","sectionType":"part","heading":"Tail Boom Vertical Fin Spar","content":"## Tail Boom Vertical Fin Spar","sortOrder":2},{"sectionNumber":"5/2006 DM","sectionType":"part","heading":"5/2006 DM","content":"## 5/2006 DM","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"The legislation maintains its original scope. This amendment continues to address the same safety defect (tail boom vertical fin spar fatigue) that prompted the original 1997 directive. The change from Amendment 3 merely transfers inspection procedures from the AD itself into the maintenance manual — an administrative streamlining that doesn't expand the directive's reach to new aircraft, parts, or operators."},"complexity_factors":["Short, single-purpose directive with clear applicability table","Only 2 main requirements with straightforward conditional logic (if cracks found, contact manufacturer)","Minimal defined terms (relies on external documents: KSB-117-129C, JCAB AD TCD-4605B-2006, KHI-BK117 Maintenance Manual)","No nested exceptions or complex cross-referencing within the document itself","Simple compliance structure: one-time manual update + recurring inspections","Document formatting issues (repeated headers, image references) suggest poor digitisation but don't affect legal complexity"],"plain_english_summary":"This AD requires operators of specified Kawasaki BK117 helicopter models to update their maintenance manuals to the approved revisions and carry out repetitive inspections of the tail boom vertical fin spar, per Kawasaki Service Bulletin KSB-117-129C. \n\nIt responds to a fatal overseas accident revealing fatigue cracking that can cause in‑flight fin failure; if cracks exceed limits the helicopter must be grounded and Kawasaki contacted. First inspection: before any flight after 28 March 2006."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 3 transfers the AD’s inspection requirements into the KHI‑BK117 Maintenance Manual rather than leaving them solely in the AD text, while retaining the same applicability to BK 117 variants (Amendment 3; Applicability). Earlier amendments had added a reinforcement modification and increased inspection periodicity; this amendment consolidates inspection control into the manufacturer's manual and the referenced service bulletin rather than changing the set of affected helicopters or the safety objective (Background; Requirement 1–2)."},"complexity_factors":["Multiple helicopter models listed in applicability increases administrative coverage (Applicability).","Mandate to revise the manufacturer's maintenance manual to specific revision numbers creates procedural and approval steps (Requirement 1).","Inspections are defined by an external service bulletin (KSB‑117‑129C), creating cross‑document dependencies (Requirement 2).","Initial immediate compliance (before further flight after 28 March 2006) plus ongoing repetitive inspection intervals imposes recurring operational burden (Compliance).","Requirement to contact KHI for technical advice if inspection exceeds allowable limits introduces manufacturer discretion and case‑by‑case decision points (Requirement 2).","References to prior amendments and a foreign authority (JCAB AD) require tracing historical changes to confirm current obligations (Background)."],"plain_english_summary":"This amendment requires operators of Kawasaki BK 117 series helicopters to update their KHI‑BK117 Maintenance Manual to the specified revisions and to carry out the inspections set out in Kawasaki Service Bulletin KSB‑117‑129C, with an initial inspection required before further flight after 28 March 2006 and then at the manual’s intervals. It was issued in response to a fatal accident attributed to fatigue cracking of the tail‑boom vertical fin spar (Background). Operators pay the cost and labour of the manual revision and recurring inspections; if an inspection exceeds allowable limits they must obtain KHI technical advice before further flight (Requirement 1–2; Compliance)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jbk-117-10-amdt-3-tail-boom-vertical-fin-spar","history":"/api/acts/ad-jbk-117-10-amdt-3-tail-boom-vertical-fin-spar/history","analysis":"/api/acts/ad-jbk-117-10-amdt-3-tail-boom-vertical-fin-spar/analysis","conflicts":"/api/acts/ad-jbk-117-10-amdt-3-tail-boom-vertical-fin-spar/conflicts","importantCases":"/api/acts/ad-jbk-117-10-amdt-3-tail-boom-vertical-fin-spar/important-cases","documents":"/api/acts/ad-jbk-117-10-amdt-3-tail-boom-vertical-fin-spar/documents"}}