{"id":"F2006L00139","name":"AD/EC 120/13 Amdt 1 - Pilot's Cyclic Stick Friction Washers","slug":"ad-ec-120-13-amdt-1-pilot-s-cyclic-stick-friction-washers","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":58021,"registerId":"commonwealth-F2006L00139-current","compilationNumber":null,"startDate":"2026-04-02","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 120/13 Amdt 1 | Pilot's Cyclic Stick Friction Washers | 2/2006 |\n| ------------------- | ------------------------------------- | ------ |\n\n| Applicability: | Model EC 120 B helicopters, with serial numbers up to and including 1385, and fitted with:- thrust washer part number C671A1006201, of the pilot’s cyclic stick friction device,- pilot’s cyclic sticks, part numbers C671A1007101, C671A1007102, and C671A1003102.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | 1. For helicopters equipped with pilot cyclic stick part numbers C671A1007101 or C671A1007102:a. Flights without friction applied to the pilot’s cyclic stick are prohibited.b. Remove the pilot’s cyclic stick and replace the thrust washers in accordance with paragraph 2 of Eurocopter EC 120 Alert Service Bulletin (ASB) No. 67A011.Note 1: DGAC AD F-2004-059 refers.2. For helicopters equipped with pilot cyclic stick part number C671A1003102:a. Flights without friction applied to the pilot’s cyclic stick are prohibited.b. Action in accordance with paragraphs 2.B. and 2.C. of ASB 67A011 Revision 1.Before installing a cyclic stick held as spares, replace the stock of thrust washers held in store, and modify the pilot cyclic sticks in accordance with paragraph 2.B.5. of ASB No. 67A011 Revision 1.Note 2: DGAC AD F-2005-175 refers. |\n\n| Compliance: | 1.a. During each flight after 5 May 2004 until Requirement 1.b. is accomplished.1.b. Within 550 flight hours or 6 months after 5 May 2004, whichever occurs first.2.a. During each flight after 16 February 2006 until Requirement 2.b. is accomplished.2.b. Before 28 February 2006, unless already accomplished.The compliance times for Requirement 1 remain unchanged by this issue. |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|             | This Amendment becomes effective on 16 February 2006.                                                                                                                                                                                                                                                                                                                                    |\n| Background: | A report was received of sudden restriction of cyclic stick travel on an EC 120 B helicopter during a flight when the cyclic stick was moved back to neutral.Amendment 1 is issued in response to a new DGAC AD, which introduces a revision of the Requirement document, and a new cyclic stick part number.                                                                            |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n21 December 2005","sortOrder":0},{"sectionNumber":"AD/EC 120/13 Amdt 1","sectionType":"part","heading":"AD/EC 120/13 Amdt 1","content":"## AD/EC 120/13 Amdt 1","sortOrder":1},{"sectionNumber":"Pilot's Cyclic Stick Friction Washers","sectionType":"part","heading":"Pilot's Cyclic Stick Friction Washers","content":"## Pilot's Cyclic Stick Friction Washers","sortOrder":2},{"sectionNumber":"2/2006","sectionType":"part","heading":"2/2006","content":"## 2/2006","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"This amendment extended the instrument's scope compared with the earlier requirement by introducing an additional pilot cyclic stick part number (C671A1003102) and by adopting the ASB Revision 1 remedy. It adds new, earlier compliance timing for helicopters fitted with the new part number and imposes explicit action on spare stocks (replace thrust washers held in store and modify spare cyclic sticks before installation). Mechanically, the change broadened the population of affected components and tightened immediate operational restrictions (prohibiting flight without friction) for that newly-identified subset."},"complexity_factors":["Applicability limited by serial number range and by multiple specific part numbers (several part numbers listed: C671A1006201, C671A1007101, C671A1007102, C671A1003102)","Cross-references to external technical documents (Eurocopter ASB No. 67A011 and Revision 1) for the detailed corrective actions","Different requirements and staggered compliance deadlines depending on which part number is fitted (nested conditional obligations)","Incorporation of requirements extending to spares and store stock (pre-installation modification of spares)","References to related foreign regulator directives (DGAC ADs) rather than containing all technical detail in the AD itself"],"plain_english_summary":"**What this instrument does (mechanically)\n\n- Applies to: Eurocopter EC 120 B helicopters with serial numbers up to and including 1385 that are fitted with specific pilot cyclic stick and thrust washer part numbers (see \"Applicability\").\n- Prohibits flight without friction applied to the pilot’s cyclic stick for affected helicopters (Requirement 1.a and 2.a).\n- Requires replacement or modification of the thrust washer(s) and, in some cases, modification of the pilot’s cyclic stick(s) in accordance with the Eurocopter EC 120 Alert Service Bulletin (ASB) No. 67A011 (or its Revision 1) (Requirement 1.b and 2.b and 2.B/C references).\n- For spare cyclic sticks, requires replacing the stock of thrust washers held in store and modifying the spare sticks before installation (Requirement 2, ASB paragraph 2.B.5).\n- Sets staged compliance deadlines depending on which cyclic stick part number is fitted (Compliance):\n  - For sticks with part numbers C671A1007101 or C671A1007102: do not fly without friction applied from 5 May 2004 until washers are replaced; washers must be replaced within 550 flight hours or 6 months after 5 May 2004 (whichever is earlier) (Requirement 1, Compliance 1.a/1.b).\n  - For sticks with part number C671A1003102: do not fly without friction applied from 16 February 2006 until modification/replacement is done; modification must be done before 28 February 2006 (Requirement 2, Compliance 2.a/2.b).\n- Effective date of this amendment: 16 February 2006.\n\nWhy it was issued (official rationale)\n\n- The directive responds to a report of sudden restriction in cyclic stick travel during flight on an EC 120 B. The issuer identifies this as a safety-related defect and points to a related French DGAC airworthiness directive (DGAC AD) and Eurocopter ASB as the source of the corrective actions.\n\nWho it affects and what they must do\n\n- Affected parties: owners/operators of EC 120 B helicopters (serials up to 1385) that have the listed cyclic stick and thrust washer part numbers, maintenance organisations handling those helicopters, and holders of spare cyclic sticks and washer stock.\n- Immediate operator obligations: do not operate (fly) the helicopter without friction applied to the pilot’s cyclic stick unless and until the specified washers are replaced or the stick is modified as required by the ASB.\n- Maintenance obligations: replace thrust washers and modify cyclic sticks to the ASB standard; replace spare washer stock and modify spare sticks before installation.\n\nCosts, incentives and trade-offs (mechanical effects on behaviour, finance and markets)\n\n- Who pays: the aircraft owner/operator bears direct costs — purchasing parts (thrust washers), performing modifications, and absorbing any aircraft downtime for maintenance.\n- Who decides: the operator must decide when to schedule the work within the mandated compliance window; maintenance organisations perform the work to the referenced ASB standards; the regulator enforces compliance.\n- Direct costs and burden: parts procurement and shop-labour for washer replacement/modification, potential short-term loss of aircraft availability. Smaller operators face the same absolute tasks but proportionally higher operational impact per aircraft.\n- Market effects: increased short-run demand for the specified parts and for maintenance services qualified to perform the ASB work; maintenance providers authorised by Eurocopter are likely to capture most of the work because the service bulletin specifies the method.\n- Substitution and operational responses: operators may reschedule flights, lease replacement aircraft, or concentrate flying on unaffected airframes while compliance work is done.\n- Compliance risk and implementation: the directive incorporates and depends on the Eurocopter ASB (external technical document). Availability of parts, lead times, and capacity at approved maintenance facilities determine whether operators can meet the deadlines. The directive creates an operational prohibition (no flight without friction) that is simple to check operationally but requires physical intervention to lift.\n\nSafety claim and testing that claim against costs and incentives\n\n- The instrument’s stated purpose is to eliminate a hazard of sudden cyclic stick restriction by ensuring the correct thrust washer and/or modified stick is in place (source: \"Background\" and references to DGAC AD and ASB). Mechanically, replacing washers or modifying sticks removes the identified physical failure mode.\n- The trade-off is straightforward: one-off parts and maintenance costs and downtime for operators in exchange for reduced risk of in-flight control restriction. The directive centralises the corrective method by reference to the manufacturer ASB, which reduces variability of repairs but concentrates demand for the particular parts and approved repair procedures.\n\nConcrete implementation notes\n\n- Operators must follow the specific paragraphs of Eurocopter ASB No. 67A011 or its Revision 1 (the AD cross-references exact paragraphs). That means the quality and completeness of the ASB determine the technical steps, and compliance requires access to and adherence to that ASB.\n- The directive explicitly demands that spare washer stock be replaced and spare sticks be modified before installation, expanding the obligation beyond in-service units to spares held in stores (Requirement 2.B.5 reference).\n\nSources cited in the instrument: the Eurocopter EC 120 Alert Service Bulletin No. 67A011 (and Revision 1) and DGAC airworthiness directives F-2004-059 and F-2005-175 are incorporated by reference for the technical remediation steps.\n"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original safety purpose — addressing the specific mechanical defect in cyclic stick friction washers. Amendment 1 simply expands coverage to include an additional cyclic stick part number (C671A1003102) and corresponding new compliance deadlines in response to updated manufacturer information. The scope has not grown beyond the original safety intent of preventing cyclic stick jamming."},"complexity_factors":["Multiple overlapping applicability criteria (serial number range plus three specific part numbers)","Two distinct requirement tracks with different compliance deadlines based on part number identification","Cross-references to external manufacturer documents (Eurocopter ASB 67A011 and its Revision 1) without reproducing their content","Nested conditional logic: different actions required depending on which of three part numbers is installed","Reference to French aviation authority directives (DGAC AD F-2004-059 and F-2005-175) for context","Interim operational restriction (friction must be applied during flight) pending physical modification"],"plain_english_summary":"This CASA Airworthiness Directive orders owners/operators of Eurocopter EC120B helicopters (S/N up to 1385) fitted with cyclic stick P/Ns C671A1007101/7102 or C671A1003102 and thrust washer C671A1006201 to prevent sudden cyclic jamming from faulty thrust washers. \n\nPilots must apply friction to the cyclic in flight immediately (flying without it is prohibited) and operators must replace the defective thrust washers per Eurocopter service instructions by the specified deadlines to avoid potential loss of 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-120-13-amdt-1-pilot-s-cyclic-stick-friction-washers","history":"/api/acts/ad-ec-120-13-amdt-1-pilot-s-cyclic-stick-friction-washers/history","analysis":"/api/acts/ad-ec-120-13-amdt-1-pilot-s-cyclic-stick-friction-washers/analysis","conflicts":"/api/acts/ad-ec-120-13-amdt-1-pilot-s-cyclic-stick-friction-washers/conflicts","importantCases":"/api/acts/ad-ec-120-13-amdt-1-pilot-s-cyclic-stick-friction-washers/important-cases","documents":"/api/acts/ad-ec-120-13-amdt-1-pilot-s-cyclic-stick-friction-washers/documents"}}