{"id":"F2005L00926","name":"AD/GBK 117/15 - Main Rotor Blades with Bolted Lead Inner Weights","slug":"ad-gbk-117-15-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":34375,"registerId":"commonwealth-F2005L00926-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Eurocopter BK 117 Series Helicopters","sectionType":"division","heading":"Eurocopter BK 117 Series Helicopters","content":"### Eurocopter BK 117 Series Helicopters\n\n| AD/GBK 117/15 | Main Rotor Blades with BoltedLead Inner Weights | 6/2005 DM |\n| ------------- | ----------------------------------------------- | --------- |\n\n| Applicability: | Models BK117 A-1 through C-1, all serial numbers.                                                                                                                                                                                                                                                                                                                                                                             |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with Eurocopter Deutschland Alert Service Bulletin No. ASB-MBB-BK117-10-125, dated 14 February 2005, or later EASA approved revision.Note: LBA AD D-2005-115 refers.                                                                                                                                                                                                                                     |\n| Compliance:    | As specified in the Requirement document. Unless it has already been accomplished, the 4 week period for the log check begins on 20 April 2005.                                                                                                                                                                                                                                                                               |\n|                | This Airworthiness Directive becomes effective on 20 April 2005.                                                                                                                                                                                                                                                                                                                                                              |\n| Background:    | The LBA received a report of severe vibrations in-flight on a BK117 helicopter. The pilot immediately performed a safe landing, and 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\n14 April 2005","sortOrder":0},{"sectionNumber":"AD/GBK 117/15","sectionType":"part","heading":"AD/GBK 117/15","content":"## AD/GBK 117/15","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":"6/2005 DM","sectionType":"part","heading":"6/2005 DM","content":"## 6/2005 DM","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The directive introduces a new operational constraint—a life limit—specifically for main rotor blades fitted with bolted lead inner weights where none was previously specified. It applies to all BK117 A‑1 through C‑1 serial numbers and converts a reactive safety finding (a cracked blade caused by a loose weight) into a recurring maintenance and replacement obligation enforced by CASA, with required action per the manufacturer's ASB and a four‑week logbook check window starting 20 April 2005."},"complexity_factors":["Technical specificity: requires inspection and a new life limit for a specific blade component (bolted lead inner weights).","Dependence on external document: mandatory compliance references a manufacturer Alert Service Bulletin (ASB‑MBB‑BK117‑10‑125) or later EASA‑approved revision.","Regulatory cross‑references: cites a related LBA AD (D‑2005‑115) and relies on EASA approval for revisions.","Applicability breadth: applies to all serial numbers of multiple BK117 models (A‑1 through C‑1), increasing operational reach.","Operational timing: imposes a short compliance window (log check begins 20 April 2005) creating scheduling pressure for operators.","Enforcement and cost allocation: places inspection, maintenance and replacement costs on operators while CASA enforces the directive."],"plain_english_summary":"This Airworthiness Directive requires operators of Eurocopter BK117 A‑1 through C‑1 helicopters to follow Eurocopter Deutschland Alert Service Bulletin ASB‑MBB‑BK117‑10‑125 (or a later EASA‑approved revision) to address a risk from bolted lead inner weights on main rotor blades. It introduces a life limit for blades with those weights after an in‑flight vibration incident caused a weight to come loose.\n\nOperators must perform a logbook check starting 20 April 2005 and carry out the inspections and corrective actions in the service bulletin; operators bear the inspection and replacement costs and the regulator (CASA) enforces compliance."},"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":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific mechanical failure mode in specific helicopter models. The scope remains precisely limited to rotor blade weight inspection and life limits, consistent with the original safety concern."},"complexity_factors":["Very short document (under 300 words)","Only 1 defined applicability criterion (specific helicopter models)","Single requirement referencing an external technical document (Eurocopter service bulletin)","No nested exceptions or conditional logic","Straightforward compliance deadline structure","Minimal cross-referencing (only to German aviation authority LBA and EASA)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's aviation regulator (CASA). It applies to specific Eurocopter BK 117 helicopter models (A-1 through C-1).\n\n**What it does:**\n- Requires owners/operators to inspect their main rotor blades if those blades have **bolted lead inner weights** installed\n- Introduces a **life limit** (maximum flying hours/cycles) for these specific blades\n- Mandates compliance with a Eurocopter service bulletin that details the inspection and replacement requirements\n\n**Why it matters:**\nA bolted weight inside a rotor blade came loose on one helicopter, causing severe vibrations and cracking the blade. This could have led to catastrophic rotor failure. The AD prevents this by forcing operators to check their records and replace blades before they reach unsafe limits.\n\n**Who must act:**\n- Anyone operating BK 117 A-1 through C-1 helicopters with these specific rotor blades\n- Compliance was required by specific deadlines starting 20 April 2005"}},"importantCases":[],"_links":{"self":"/api/acts/ad-gbk-117-15-main-rotor-blades-with-bolted-lead-inner-weights","history":"/api/acts/ad-gbk-117-15-main-rotor-blades-with-bolted-lead-inner-weights/history","analysis":"/api/acts/ad-gbk-117-15-main-rotor-blades-with-bolted-lead-inner-weights/analysis","conflicts":"/api/acts/ad-gbk-117-15-main-rotor-blades-with-bolted-lead-inner-weights/conflicts","importantCases":"/api/acts/ad-gbk-117-15-main-rotor-blades-with-bolted-lead-inner-weights/important-cases","documents":"/api/acts/ad-gbk-117-15-main-rotor-blades-with-bolted-lead-inner-weights/documents"}}