{"id":"F2005L02415","name":"AD/EC 120/12 Amdt 1 - Collective Torque Tube Assembly","slug":"ad-ec-120-12-amdt-1-collective-torque-tube-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":36920,"registerId":"commonwealth-F2005L02415-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Eurocopter EC 120 Series Helicopters","sectionType":"division","heading":"Eurocopter EC 120 Series Helicopters","content":"### Eurocopter EC 120 Series Helicopters\n\n| AD/EC 120/12 Amdt 1 | Collective Torque Tube Assembly | 10/2005 |\n| ------------------- | ------------------------------- | ------- |\n\n| Applicability: | Model EC 120 B helicopters (RH or LH pilot configuration), equipped with a RH collective lever-to-torque tube connecting part (identified in following text of this Directive as “connecting part”), part number C671C4101202, C671C4101203, or C671C4101204.Helicopters with serial number 1383 and subsequent are not affected by this Directive.                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | 1. In accordance with the instructions described in paragraph 2.B.2 of Eurocopter EC 120 Alert Service Bulletin (ASB) No. 67A014, check:- the tightening torque load of the connecting part attachment bolts; and,- the connecting part for cracks.If the tightening torque load of the connecting part attachment bolts is above the set limit (8 Nm) or if a crack is detected in the connecting part, before further flight, replace the affected connecting part in accordance with paragraph 2.B.3.a. and 2.B.3.b. of ASB No. 67A014.2. Remove from service, part number C671C4101202, C671C4101203, and C671C4101204 connecting parts.Accomplishment of Service Bulletin No. 67-017 constitutes terminating action for the requirements of this Directive.Note: DGAC AD F-2005-086 refers. |\n| Compliance:    | 1. Within 10 flight hours after 3 March 2004.2. Before 1 May 2006.The compliance time for Requirement 1 remains unchanged by this issue.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n|                | This Amendment becomes effective on 29 September 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n\n| Background: | The manufacturer received a report of failure of the right hand collective lever-to-torque tube connecting part, which was detected on the ground, with the rotor stopped.Amendment 1 is issued in response to new DGAC AD, which introduces an alert service bulletin to replace the alert telex of the same number, extends applicability to an additional part number connecting part, introduces optional terminating action, and requires the removal from service of the affected collective lever-to-torque tube connecting parts. |\n| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n9 August 2005","sortOrder":0},{"sectionNumber":"AD/EC 120/12 Amdt 1","sectionType":"part","heading":"AD/EC 120/12 Amdt 1","content":"## AD/EC 120/12 Amdt 1","sortOrder":1},{"sectionNumber":"Collective Torque Tube Assembly","sectionType":"part","heading":"Collective Torque Tube Assembly","content":"## Collective Torque Tube Assembly","sortOrder":2},{"sectionNumber":"10/2005","sectionType":"part","heading":"10/2005","content":"## 10/2005","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"Amendment 1 expands the Directive’s scope by adding an additional affected part number, replacing the earlier alert telex with an Alert Service Bulletin for procedural detail, introducing Service Bulletin No. 67‑017 as an optional terminating action, and requiring removal from service of the specified connecting parts (Background; Requirement; Applicability)."},"complexity_factors":["Technical inspection requirement with a numeric torque threshold (8 Nm) and crack detection — requires workshop capability and measuring tools (Requirement: check tightening torque load; 8 Nm limit).","Multiple specific part numbers and a serial‑number exemption (PNs C671C4101202, C671C4101203, C671C4101204; S/N 1383 and subsequent excluded) — increases tracking and compliance checks (Applicability).","Short, staged compliance deadlines (within 10 flight hours after 3 March 2004; complete removal before 1 May 2006) — operational scheduling pressure for operators (Compliance).","Cross‑references to manufacturer documents (Eurocopter ASB No. 67A014 and Service Bulletin No. 67‑017) for inspection, replacement procedures and terminating action — creates dependency on external technical documents (Requirement/Background).","Mandatory removal from service of affected parts and optional terminating action via a separate service bulletin — creates a choice between recurring inspections and one‑off modification/repair (Requirement: remove from service; Service Bulletin No. 67‑017 as terminating action).","Regulatory enforcement and effective dates set by CASA (Delegate signature, effective 29 September 2005) — administrative compliance and recordkeeping obligations for operators (document header/effective date).","Historical layering of directives and alerts (DGAC AD, alert telex replaced by ASB, amendment issued) — requires reading multiple instrument versions to confirm current obligations (Background)."],"plain_english_summary":"Requires operators of Eurocopter EC120B helicopters fitted with specific right‑hand collective lever‑to‑torque tube connecting parts (PN C671C4101202/03/04; excludes S/N 1383 and later) to inspect bolt tightening (limit 8 Nm) and check for cracks, and to replace or remove affected parts within set timeframes. Operators pay for inspections and replacements; the Civil Aviation Safety Authority enforces the directive. The action follows a reported part failure and cross‑references Eurocopter service instructions."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Amendment 1 remains tightly focused on the original safety issue (collective torque tube connecting part failures). The amendment expands applicability slightly (adding one part number) and adds terminating action options, but does not represent scope creep beyond the original safety purpose of preventing collective control system failures."},"complexity_factors":["Short, single-purpose directive with only 2 main requirements","Clear applicability criteria (specific helicopter model, specific part numbers, serial number cutoff)","References to external technical documents (Eurocopter Alert Service Bulletin No. 67A014) without reproducing their full content","Simple conditional logic: 'If X or Y, then replace before flight'","Two distinct compliance deadlines with clear dates","Minimal defined terms (only 'connecting part' is explicitly defined in context)","No nested exceptions or complex cross-referencing within the instrument itself"],"plain_english_summary":"This CASA Airworthiness Directive mandates owners/operators of Eurocopter EC120B helicopters (except S/N 1383 and later) inspect and, if necessary, replace a specific right‑hand collective lever‑to‑torque tube connecting part (P/Ns C671C4101202/1203/1204). Inspections for over‑tight bolts and cracks must be done promptly and defective parts removed from service by the specified deadline; compliance can be terminated by installing the Service Bulletin 67‑017 modification. It prevents loss of collective pitch control."},"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-ec-120-12-amdt-1-collective-torque-tube-assembly","history":"/api/acts/ad-ec-120-12-amdt-1-collective-torque-tube-assembly/history","analysis":"/api/acts/ad-ec-120-12-amdt-1-collective-torque-tube-assembly/analysis","conflicts":"/api/acts/ad-ec-120-12-amdt-1-collective-torque-tube-assembly/conflicts","importantCases":"/api/acts/ad-ec-120-12-amdt-1-collective-torque-tube-assembly/important-cases","documents":"/api/acts/ad-ec-120-12-amdt-1-collective-torque-tube-assembly/documents"}}