{"id":"F2008L04407","name":"AD/JBK 117/6 Amdt 6 - Main Rotor Blade","slug":"ad-jbk-117-6-amdt-6-main-rotor-blade","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":76383,"registerId":"commonwealth-F2008L04407-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 117/6 Amdt 6 | Main Rotor Blade | 13/2008 |\n| ------------------- | ---------------- | ------- |\n\n| Applicability: | Model BK117, BK117A-3, BK117A-4, BK117B-1, BK117B-2, and BK117C-1 helicopters; equipped with main rotor blade part numbers 117-150041, 117-150051, 117-150071, 117-150081, 117-151311, 117-151331, 117-151371, and117-151371V001.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Revise the KHI-BK117 Maintenance Manual to Revision No. 14 (or later approved revision) for Models KHI-BK117, BK117A-3, BK117A-4, BK117B-1, BK117B-2, and Revision No. 2 (or later approved revision) for ModelKHI-BK117C-1.2. Perform an inspection for bulging on the upper and lower surfaces of the main rotor blades in the area of the outboard lead balance weight in accordance with the KHI-BK117 Maintenance Manual, revised by Requirement 1. Inspect at the intervals 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-117-115A-1 dated 11 September 2008, refers.Note 2: JCAB AD TCD-4114A-1-2008 refers. |\n| Compliance:    | Unless Requirement 1 is already accomplished, before further flight after18 December 2008. Thereafter, inspect as specified in Requirement 2.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n|                | This Amendment becomes effective on 18 December 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n| Background:    | In response to incidents, the manufacturer recommended an immediate inspection for bulging on the upper and lower surfaces of the main rotor blades in the area of the outboard lead balance weight.Amendment 1 referenced the JCAB AD and the Kawasaki service bulletin rather than the LBA AD and the MBB service bulletin of the initial issue.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n\n|     | Amendment 2 introduced an additional blade part number to applicability.Amendment 3 was issued in response to a new JCAB AD, which expanded applicability to all main rotor blade part numbers.Amendment 4 was issued in response to a new JCAB AD, which transferred the inspection requirements of this Directive to the KHI-BK117 Maintenance Manual. This also introduced an additional inspection.Amendment 5 excluded certain Main Rotor Blade part numbers from inspection, with no change to the requirements or compliance.Amendment 6 is issued in response to a revision of the related JCAB AD, which specifies the part numbers of affected main rotor blades.The original issue of this Airworthiness Directive became effective on13 October 1994. |\n| --- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n28 October 2008","sortOrder":0},{"sectionNumber":"AD/JBK 117/6 Amdt 6","sectionType":"part","heading":"AD/JBK 117/6 Amdt 6","content":"## AD/JBK 117/6 Amdt 6","sortOrder":1},{"sectionNumber":"Main Rotor Blade","sectionType":"part","heading":"Main Rotor Blade","content":"## Main Rotor Blade","sortOrder":2},{"sectionNumber":"13/2008","sectionType":"part","heading":"13/2008","content":"## 13/2008","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"The Directive has changed in scope since the original 1994 issue. Across successive amendments the applicability and compliance mechanism were altered: at one point applicability was expanded to all main rotor blade part numbers (Amendment 3), later inspections were transferred into the manufacturer’s maintenance manual (Amendment 4), some part numbers were subsequently excluded (Amendment 5), and Amendment 6 refines the applicability to a specific list of part numbers in response to a revised JCAB AD. These changes mean the regulatory footprint and the way compliance is achieved (direct AD prescriptive text versus reliance on the approved maintenance manual) have both shifted from the original instrument, resulting in a materially different compliance and oversight approach from the original issue."},"complexity_factors":["Applicability lists 8 distinct main rotor blade part numbers.","Cross‑reference to an external document: KHI‑BK117 Maintenance Manual (specified revision numbers or later approved revision).","Inspection intervals and allowable limits are set in the revised maintenance manual (i.e. material is located outside the AD text).","Conditionals in compliance timing: immediate pre‑flight compliance if manual not already revised, then ongoing inspections per manual.","References to multiple external service/airworthiness documents (Kawasaki Service Bulletin and JCAB AD) and prior amendment history.","Operational discretion: requirement to contact the manufacturer for technical advice if limits exceeded (delegates technical remediation to KHI)."],"plain_english_summary":"**What this directive does (mechanically)**\n\n- Requires operators of certain Kawasaki BK117 helicopter models to update their maintenance documentation and to inspect specific main rotor blades for bulging in the area of the outboard lead balance weight. (See \"Requirement 1\" and \"Requirement 2\".)\n- The required maintenance manual revisions are to be to KHI‑BK117 Maintenance Manual Revision No. 14 (or a later approved revision) for most BK117 models and Revision No. 2 (or later approved revision) for the BK117C‑1 model. After the manual is revised, inspections for bulging must be performed at the intervals the revised manual specifies. If an inspection finds bulging beyond the allowable limit in the manual, the helicopter must not fly further until the operator contacts Kawasaki Heavy Industries (KHI) Customer Service for technical advice. (Requirements 1–2; Compliance.)\n- The Directive took effect on 18 December 2008; if the manual had not already been revised, the revision had to be done before the next flight after that date. Thereafter, inspections follow the intervals in the revised manual. (Compliance.)\n\n**Who this affects**\n\n- Owners and operators of Kawasaki BK117, BK117A‑3, BK117A‑4, BK117B‑1, BK117B‑2 and BK117C‑1 helicopters that are fitted with any of the listed main rotor blade part numbers: 117‑150041, 117‑150051, 117‑150071, 117‑150081, 117‑151311, 117‑151331, 117‑151371, and 117‑151371V001. (Applicability.)\n- Maintenance organisations and engineers who hold responsibility for the operators’ approved maintenance manuals and for performing the blade inspections. They must implement the revised inspection procedures and intervals set out in the approved manual. (Requirement 1.)\n\n**Why it matters (stated purpose and operational effect)**\n\n- The action responds to reported incidents involving bulging of main rotor blades in the area of the outboard lead balance weight. The manufacturer and the Japanese Civil Aviation Bureau (JCAB) recommended inspections; this Directive makes the inspection requirement mandatory for affected Australian‑registered aircraft by enforcing the required manual revision and inspection regime. (Background; Note references to Kawasaki Service Bulletin and JCAB AD.)\n\n**Costs, incentives and trade‑offs (practical implications)**\n\n- Who pays: aircraft owners/operators pay for updating the maintenance manual (administrative and approval cost), the physical inspections (labour and downtime), and any corrective action (repairs or blade replacement) resulting from inspections. If an inspection reveals bulging above the allowable limit, the helicopter is grounded until Kawasaki provides technical advice and the indicated remedial action is taken — this can cause additional direct costs and opportunity costs from lost flight time. (Requirements; Compliance.)\n- Where discretion lies: the Directive requires operators to follow the revised KHI maintenance manual. The manufacturer (KHI) is the technical contact when limits are exceeded and provides the technical advice; regulatory approval is required for the manual revisions (\"or later approved revision\"). This concentrates technical decisioning with the manufacturer and the regulator for the approved manual content. (Requirement 1.)\n- Compliance burden: the inspection interval itself is not specified in the AD text; it is set in the revised maintenance manual. That means ongoing inspection frequency and any operational constraints are set by the manufacturer’s approved procedures rather than by the AD text. This reduces ambiguity in the AD but makes operators dependent on the manufacturer’s maintenance policy. (Requirement 2; Compliance.)\n- Possible substitution effects: operators could, in principle, fit different blade part numbers that are not on the applicability list to avoid this inspection regime, subject to airworthiness approval and compatibility. The Directive does not prescribe replacements — it enforces inspection and directs operators to the manufacturer for remedies. (Applicability; Requirement 2.)\n- Implementation risk: timely approval of manual revisions and consistent adoption by maintenance organisations is required for uniform compliance. Independent maintenance organisations must work to the operator’s approved manual; if multiple operators or MROs interpret the manual differently, inspection practice could vary. (Requirement 1.)\n\n**Concrete behavioural changes required**\n\n- Update the operator’s approved maintenance manual to the specified (or later approved) revision.\n- Perform the specific bulging inspections on the listed rotor blades at the intervals the revised manual prescribes.\n- If bulging exceeds the allowable limit in the manual, do not fly and contact KHI Customer Service for technical advice before further flight. (Requirement 1–2; Compliance.)\n\n**Key cross‑references and notes**\n\n- The Directive refers to Kawasaki Service Bulletin KSB‑117‑115A‑1 (11 September 2008) and JCAB AD TCD‑4114A‑1‑2008 for background and technical context. (Notes.)"},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"The original 1994 directive has grown significantly through 6 amendments. Amendment 3 expanded applicability to 'all main rotor blade part numbers' (broadening scope), then Amendment 5 excluded certain part numbers (narrowing), and Amendment 6 refined the part number list again based on Japanese regulatory updates. The inspection requirements have also shifted from being specified directly in the AD to being incorporated by reference to the manufacturer's maintenance manual (Amendment 4), effectively outsourcing the technical detail to a private document while maintaining regulatory enforceability."},"complexity_factors":["Multiple amendment history (6 amendments since 1994) with cross-references to previous versions","Dual compliance paths: one-time manual revision plus recurring inspections","Conditional logic: 'Unless Requirement 1 is already accomplished' creates an exception to the compliance date","Model-specific requirements (different revision numbers for different helicopter models)","Cross-references to external documents: JCAB AD (Japanese regulator), Kawasaki Service Bulletin, KHI Maintenance Manual","Specific part number applicability list (8 distinct part numbers)","Nested action requirement: inspection must be performed 'in accordance with' the revised manual, creating a dependency chain"],"plain_english_summary":"This Airworthiness Directive requires operators of specified Kawasaki BK117 helicopters to update their maintenance manuals and carry out recurring inspections of main rotor blades for bulging near the outboard lead balance weight, grounding any helicopter that exceeds allowable limits and contacting Kawasaki Heavy Industries for technical advice. It applies to the listed BK117 models and specific blade part numbers.\n\nBulging can indicate internal structural damage that could lead to catastrophic blade failure; the AD (6th amendment) mandates checks to catch defects before flight."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jbk-117-6-amdt-6-main-rotor-blade","history":"/api/acts/ad-jbk-117-6-amdt-6-main-rotor-blade/history","analysis":"/api/acts/ad-jbk-117-6-amdt-6-main-rotor-blade/analysis","conflicts":"/api/acts/ad-jbk-117-6-amdt-6-main-rotor-blade/conflicts","importantCases":"/api/acts/ad-jbk-117-6-amdt-6-main-rotor-blade/important-cases","documents":"/api/acts/ad-jbk-117-6-amdt-6-main-rotor-blade/documents"}}