{"id":"F2006L00674","name":"AD/ECUREUIL/117 - Main Servo-Controls","slug":"ad-ecureuil-117-main-servo-controls","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":136676,"registerId":"commonwealth-F2006L00674-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Eurocopter AS 350 (Ecureuil) Series Heli","sectionType":"division","heading":"Eurocopter AS 350 (Ecureuil) Series Helicopters","content":"### Eurocopter AS 350 (Ecureuil) Series Helicopters\n\n| AD/ECUREUIL/117 | Main Servo-Controls | 4/2006 TX |\n| --------------- | ------------------- | --------- |\n\n| Applicability: | Models AS 350 B, BA, BB, B1, B2, B3, and D helicopters, equipped with main servo-controls, all part numbers, not modified per MOD 073343, and on which the tightening torque of the nut that secures the upper ball-end has been increased following:- embodiment of MOD 073191; or,- compliance with MET Work Card 67.30.00.402 since MET Revision 04-06.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | For main servo-controls installed on helicopters:1. Check the tapered housings of the main servo-controls for cracks, in accordance with paragraph 2.B.2.of Eurocopter AS 350 Alert Service Bulletin (ASB) No. 05.00.51.a. If no crack is evident, comply once with paragraph 2.B.3. of ASB No. 05.00.51, then resume flights.b. If there is a vertical crack (along the servo-control axis) that is less than 20 mm long:(i) Comply once with paragraph 2.B.3. of ASB No. 05.00.51, and identify the end of the crack using an indelible ink marker and resume flights.(ii) Comply with paragraph 2.B.4. of ASB No. 05.00.51.2. Replace the servo-control in accordance with paragraph 2.A. of ASB No. 05.00.51, in the following cases if:- a vertical crack is found (along the servo-control axis) that is 20 mm long or longer,- the crack has grown by more than 5mm,- there is an oblique or a horizontal crack,- there are several cracks. |\n\n|             | For main servo-controls held as spares:3. Accomplish paragraph 2.B.2.b. of ASB No. 05.00.51.If no crack is evident, comply once with paragraph 2.B.3. of ASB No. 05.00.51.If a crack is evident, return the servo-control for repair.Note: EASA AD 2006-0055-E refers.                                                                                                                                                                                                                            |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | 1. Within 10 flight hours or 10 days after 6 March 2006, whichever occurs first.1.b.(ii) During the check after the last flight of the day, without exceeding 10 flight hours between two inspections, pending replacement of the servo-control (in accordance with paragraph 2.A. of ASB No. 05.00.51) no later than within 150 flight hours without exceeding 3 months.2. Before further flight.3. Within 10 days after 6 March 2006, or before installing a main servo-control held as spares. |\n|             | This Airworthiness Directive becomes effective on 6 March 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n| Background: | The European Aviation Safety Agency received reports of cracks discovered in the tapered housings of main servo-controls during scheduled inspections. Undetected cracking in the tapered housing of a main servo-control could lead to the loss of attachment of the affected servo-control to the non-rotating swashplate, and consequent loss of control of the helicopter.                                                                                                                    |\n\n![](image.001.png)  \nDavid Punshon  \nDelegate of the Civil Aviation Safety Authority\n\n3 March 2006","sortOrder":0},{"sectionNumber":"AD/ECUREUIL/117","sectionType":"part","heading":"AD/ECUREUIL/117","content":"## AD/ECUREUIL/117","sortOrder":1},{"sectionNumber":"Main Servo-Controls","sectionType":"part","heading":"Main Servo-Controls","content":"## Main Servo-Controls","sortOrder":2},{"sectionNumber":"4/2006 TX","sectionType":"part","heading":"4/2006 TX","content":"## 4/2006 TX","sortOrder":3}],"analysis":{"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"},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"The AD focuses on Eurocopter AS350 helicopters with specified modification or nut‑torque status and prescribes inspection, marking, repair or replacement of main servo‑controls per the Eurocopter ASB. The text does not indicate a change in scope from its stated safety objective; it limits application by model and modification status and sets conditional corrective actions and timeframes."},"complexity_factors":["Targeting only AS350 models with specific modification/torque status creates a narrow but technically conditional applicability (Applicability).","Different required actions for installed servo‑controls versus spares (Requirement paragraphs 1–3) increases procedural branches.","Crack‑length thresholds and growth criteria (20 mm threshold; >5 mm growth; vertical vs oblique/horizontal; multiple cracks) drive different mandatory outcomes (identify/mark, monitor, or replace).","Multiple, staggered compliance windows and limits (10 flight hours or 10 days; checks at last flight of day; replacement within 150 flight hours or 3 months) raise scheduling complexity (Compliance).","Reliance on an external Eurocopter Alert Service Bulletin for inspection and replacement procedures means operators must interpret and apply two documents together (Requirement; Note: EASA AD reference).","Safety‑critical consequence (loss of servo attachment → loss of control) requires conservative 'before further flight' actions in some scenarios, increasing operational disruption (Background; Compliance).","Marking and continued monitoring option for short cracks imposes ongoing tracking and recordkeeping burdens on operators (Requirement 1.b.(i) & 1.b.(ii))."],"plain_english_summary":"This Airworthiness Directive requires operators of specified Eurocopter AS350 helicopters (those with certain modifications or increased nut‑torque settings) to inspect main servo‑control tapered housings for cracks and to repair, mark or replace units that meet defined defect criteria. \n\nOperators/owners must follow the Eurocopter Alert Service Bulletin procedures within the AD’s time limits; they bear the inspection, repair and any grounding costs, and must act according to crack‑length thresholds to keep aircraft airworthy."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with focused scope. It addresses a specific safety-critical component failure mode on specific helicopter models. The spare parts provision is standard aviation safety practice to prevent installation of defective components, not scope creep."},"complexity_factors":["Multiple conditional pathways based on crack characteristics (vertical vs oblique/horizontal, length thresholds at 20mm, growth thresholds at 5mm)","Cross-references to external technical documents: Eurocopter ASB No. 05.00.51 (specific paragraphs 2.A, 2.B.2, 2.B.3, 2.B.4), MOD 073343, MOD 073191, and MET Work Card 67.30.00.402","Dual applicability criteria creating a narrow subset of affected aircraft (specific models PLUS specific modification history PLUS specific maintenance history)","Multiple compliance timelines with 'whichever occurs first' logic (flight hours vs calendar days)","Nested requirements: different actions for installed vs spare servo-controls","Reference to European EASA AD 2006-0055-E for additional context"],"plain_english_summary":"This AD requires owners/operators of certain Eurocopter AS350 models (and spare main servo-controls) to inspect main servo-control tapered housings for cracks and, depending on findings, either mark/monitor small cracks or replace the servo-control immediately. It targets units not modified per a specific mod and addresses a known risk: housing cracks can allow the servo to separate from the swashplate and cause total loss of helicopter control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ecureuil-117-main-servo-controls","history":"/api/acts/ad-ecureuil-117-main-servo-controls/history","analysis":"/api/acts/ad-ecureuil-117-main-servo-controls/analysis","conflicts":"/api/acts/ad-ecureuil-117-main-servo-controls/conflicts","importantCases":"/api/acts/ad-ecureuil-117-main-servo-controls/important-cases","documents":"/api/acts/ad-ecureuil-117-main-servo-controls/documents"}}