{"id":"F2005L01083","name":"AD/JBK 117/23 - Main Rotor Blades with Bolted Lead Inner Weights","slug":"ad-jbk-117-23-main-rotor-blades-with-bolted-lead-inner-weights","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":34708,"registerId":"commonwealth-F2005L01083-current","compilationNumber":null,"startDate":"2026-04-01","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 117/23 | Main Rotor Blades with BoltedLead Inner Weights | 7/2005 DM |\n| ------------- | ----------------------------------------------- | --------- |\n\n| Applicability: | Model BK117, BK117 A-3, BK117 A-4, BK117 B-1, BK117 B-2, and BK117 C-1 helicopters.                                                                                                                                                                                                                                                                                                                                                     |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with Kawasaki Service Bulletins KSB-117-248 and KSB-117-248-1, or later JCAB approved revisions.Note: JCAB AD No. TCD-6590-2005 refers.                                                                                                                                                                                                                                                                            |\n| Compliance:    | As specified in the Requirement documents. Unless it has already been accomplished, the 4 week period for the log check begins on 6 May 2005.                                                                                                                                                                                                                                                                                           |\n|                | This Airworthiness Directive becomes effective on 6 May 2005.                                                                                                                                                                                                                                                                                                                                                                           |\n| Background:    | A report was received of the in-flight occurrence of severe vibrations on a BK117 helicopter. The pilot immediately performed a safe landing. The initial inspection revealed a cracked-open main rotor blade trailing edge. A subsequent inspection by the manufacturer revealed that a part of a bolted lead inner weight had come loose. This Directive introduces a life limit for blades with bolted lead inner weights installed. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n4 May 2005","sortOrder":0},{"sectionNumber":"AD/JBK 117/23","sectionType":"part","heading":"AD/JBK 117/23","content":"## AD/JBK 117/23","sortOrder":1},{"sectionNumber":"Main Rotor Blades with BoltedLead Inner ","sectionType":"part","heading":"Main Rotor Blades with BoltedLead Inner Weights","content":"## Main Rotor Blades with Bolted  \nLead Inner Weights","sortOrder":2},{"sectionNumber":"7/2005 DM","sectionType":"part","heading":"7/2005 DM","content":"## 7/2005 DM","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive addressing a specific safety defect in specific helicopter models. It has not expanded beyond its original purpose of addressing the loose bolted weight issue."},"complexity_factors":["Very short document (approximately 200 words of substantive content)","Only 2 operative requirements: comply with referenced service bulletins, and meet the specified timeframe","No defined terms section — all terminology is standard aviation maintenance language","No nested exceptions or conditional logic — single straightforward compliance pathway","Cross-references are minimal: two service bulletins and one Japanese regulator reference (JCAB AD)","Single applicability criterion (specific helicopter models)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's aviation regulator (CASA) that requires specific maintenance actions on certain helicopters.\n\n**What it does:**\nOrders owners and operators of specific Kawasaki BK117 helicopter models to inspect and replace main rotor blades that have \"bolted lead inner weights\" — heavy metal weights bolted inside the rotor blades to balance them.\n\n**Why it matters:**\nA bolted weight came loose during flight on one helicopter, causing severe vibrations and cracking the rotor blade. This could have led to catastrophic rotor failure. The directive prevents this by:\n- Setting a **life limit** (maximum flying hours/cycles) for these specific blades\n- Requiring compliance with two Kawasaki Service Bulletins (KSB-117-248 and KSB-117-248-1)\n\n**Who it affects:**\nOwners and operators of BK117, A-3, A-4, B-1, B-2, and C-1 model helicopters with these specific rotor blades.\n\n**When:**\nThe 4-week inspection period started 6 May 2005, and the directive took effect the same day.\n\n**Key point:** This is not optional — it's legally enforceable. Non-compliance means the aircraft cannot fly legally in Australia."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD stays within the original, stated purpose: to address the specific safety hazard of bolted lead inner weights loosening and to introduce a life limit for blades with that configuration. It does not broaden the directive beyond that safety problem; it primarily mandates inspections, a log check, and a life limit, with technical particulars left to the Kawasaki service bulletins and JCAB-approved revisions."},"complexity_factors":["Short, single-issue AD focused on one blade configuration","Applicability limited to six BK117 model variants","Delegates technical detail to two external Kawasaki Service Bulletins (KSB-117-248 and KSB-117-248-1) and any later JCAB-approved revisions","One conditional timing provision: 4-week log check window starting 6 May 2005 unless already done","Introduces a life limit whose precise value and implementation depend on the referenced service bulletins (cross-document dependency)"],"plain_english_summary":"This AD requires owners/operators of specified Kawasaki BK117 models to follow Kawasaki Service Bulletins (and JCAB‑approved revisions) to inspect logbooks, perform inspections, and adopt a new life limit for main rotor blades fitted with bolted lead inner weights. It responds to an in‑flight severe vibration from a cracked blade and loose inner weight.\n\nIt affects BK117 operators and maintenance providers, shifting inspection, replacement and downtime costs to operators while reducing the safety risk of weight separation."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-jbk-117-23-main-rotor-blades-with-bolted-lead-inner-weights","history":"/api/acts/ad-jbk-117-23-main-rotor-blades-with-bolted-lead-inner-weights/history","analysis":"/api/acts/ad-jbk-117-23-main-rotor-blades-with-bolted-lead-inner-weights/analysis","conflicts":"/api/acts/ad-jbk-117-23-main-rotor-blades-with-bolted-lead-inner-weights/conflicts","importantCases":"/api/acts/ad-jbk-117-23-main-rotor-blades-with-bolted-lead-inner-weights/important-cases","documents":"/api/acts/ad-jbk-117-23-main-rotor-blades-with-bolted-lead-inner-weights/documents"}}