{"id":"F2007L00326","name":"AD/GBK 117/16 - Tail Rotor Control Lever with Weights","slug":"ad-gbk-117-16-tail-rotor-control-lever-with-weights","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":68716,"registerId":"commonwealth-F2007L00326-current","compilationNumber":null,"startDate":"2026-04-02","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 117/16 | Tail Rotor Control Lever with Weights | 3/2007 |\n| ------------- | ------------------------------------- | ------ |\n\n| Applicability: | Model BK117 C2 helicopters, serial number 9075 and subsequent, and those helicopters with serial numbers 9004 through 9074, on which Eurocopter Deutschland Service Bulletin No. MBB BK117 C-2-67-006 has been accomplished; and with a tail rotor control lever B642M1009103 installed.                                                                                                                                                                                                                                                                                                                                                               |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | 1. Perform a visual inspection of the tail rotor control lever in accordance with the Accomplishment Instructions of Eurocopter Deutschland Alert Service Bulletin No. MBB BK117 C-2-64A-002 original issue, or later EASA approved revision.2. If no score marks, notching, scratches, or cracking is detected during the initial inspection, repeat the Requirement 1 inspection.If, during any inspection, score marks, notching, or scratches are detected that exceed the maintenance manual limits, or cracking is detected, before further flight, replace the control lever with a serviceable control lever.Note: EASA AD 2006-0379-E refers. |\n| Compliance:    | 1. Unless already accomplished, before further flight after 15 March 2007.2. Within 10 flight hours after the initial inspection, and thereafter at intervals not to exceed 25 flight hours.                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n|                | This Airworthiness Directive becomes effective on 15 March 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n| Background:    | The EASA received a report of an in-flight incident in which a dynamic weight broke off the tail rotor control lever, resulting in considerable vibrations. Inspection revealed that the threaded bolt of the control lever had broken off. Such damage can lead to severe vibration and reduced controllability of the helicopter.                                                                                                                                                                                                                                                                                                                    |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n1 February 2007","sortOrder":0},{"sectionNumber":"AD/GBK 117/16","sectionType":"part","heading":"AD/GBK 117/16","content":"## AD/GBK 117/16","sortOrder":1},{"sectionNumber":"Tail Rotor Control Lever with Weights","sectionType":"part","heading":"Tail Rotor Control Lever with Weights","content":"## Tail Rotor Control Lever with Weights","sortOrder":2},{"sectionNumber":"3/2007","sectionType":"part","heading":"3/2007","content":"## 3/2007","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive targets a specific identified hazard (dynamic weight/bolt failure) on a defined set of BK117 C2 helicopters and prescribes inspections and replacement where defects exceed maintenance manual limits. It does not broaden applicability beyond the listed serial numbers and part installation, nor add additional operational restrictions beyond inspection/replacement requirements as described in the source."},"complexity_factors":["Applicability limited to specific BK117 C2 serial numbers and to helicopters with the identified tail rotor control lever part (source: 'Applicability').","Inspections are visual and recurring, with short compliance intervals (initial before further flight after 15 March 2007; repeat within 10 flight hours and then every 25 flight hours) (source: 'Compliance').","Outcome-based replacement requirement: replace before further flight if score marks/notching/scratches exceed maintenance manual limits or if cracking is detected — requires maintenance judgement against manual limits (source: 'Requirement').","References to external technical documents: compliance requires following Eurocopter Deutschland Alert Service Bulletin and may rely on later EASA-approved revisions; EASA AD cross-reference noted (source: 'Requirement', 'Note').","Operational impact risk: potential grounding until replacement part is obtained if damage exceeds limits (implicit from replacement-before-flight mandate).","Enforcement and authority are prescriptive (CASA delegate issuance dated 1 February 2007), so compliance timing and method are tightly specified (source: header and signature)."],"plain_english_summary":"This Airworthiness Directive requires visual inspections of the tail-rotor control lever (with weights) on specified Eurocopter BK117 C2 helicopters and replacement of the lever before further flight if damage exceeds maintenance limits. It applies to operators of the listed serial-number helicopters with the identified part; operators bear the cost and must perform checks before the first flight after 15 March 2007 and at short flight‑hour intervals thereafter. The measure follows a reported in-flight failure where a weight/bolt broke off and caused severe vibration."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive addressing a specific safety-critical mechanical defect in a defined aircraft population. The scope remains tightly focused on the tail rotor control lever issue as originally identified."},"complexity_factors":["Single, specific mechanical issue addressed","Clear applicability criteria (specific helicopter model, serial number range, and part number)","Straightforward two-step requirement: inspect, then replace if damaged","Simple compliance timeline (initial deadline + recurring 25-hour intervals)","No nested exceptions or conditional logic","Only 1 defined term implicitly used (serviceable control lever)","No cross-references to other legislation (only references to manufacturer service bulletins and EASA AD for technical context)"],"plain_english_summary":"This AD requires owners/operators of Eurocopter BK117 C2 helicopters (serials 9075+ and certain 9004–9074 with a specific SB) fitted with tail rotor control lever P/N B642M1009103 to inspect the lever for cracks, deep scratches or score marks and replace it if damaged. It follows an in‑flight failure where a weight detached from the lever, causing severe vibration and loss of control; the measures catch damage early to prevent similar accidents."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-gbk-117-16-tail-rotor-control-lever-with-weights","history":"/api/acts/ad-gbk-117-16-tail-rotor-control-lever-with-weights/history","analysis":"/api/acts/ad-gbk-117-16-tail-rotor-control-lever-with-weights/analysis","conflicts":"/api/acts/ad-gbk-117-16-tail-rotor-control-lever-with-weights/conflicts","importantCases":"/api/acts/ad-gbk-117-16-tail-rotor-control-lever-with-weights/important-cases","documents":"/api/acts/ad-gbk-117-16-tail-rotor-control-lever-with-weights/documents"}}