{"id":"F2005L00005","name":"AD/ECUREUIL/108 - Tail Servo-Control","slug":"ad-ecureuil-108-tail-servo-control","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":33292,"registerId":"commonwealth-F2005L00005-current","compilationNumber":null,"startDate":"2026-04-01","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/108 | Tail Servo-Control | 2/2005 TX |\n| --------------- | ------------------ | --------- |\n\n| Applicability: | AS 350 B3 helicopters fitted with a GOODRICH tail servo-control part number (P/N) SC5071-XX or SC5072, except:- tail rotor servo-controls P/N SC5072 with a serial number equal to or above 1372,- tail rotor servo-controls overhauled or repaired in compliance with Service Bulletin GOODRICH No. SC507X-67-39-01-3, and- tail rotor servo-controls having never been removed since the delivery of a new rotorcraft. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement: | 1. Intentional auto-rotation flight is prohibited until the check of the tail servo-control is accomplished in accordance with paragraph 2.B.2 of Alert Telex (AT) Eurocopter AS 350 No 67.00.30. or later DGAC approved revision. |\n| | 2. Carry out the following in accordance with AT AS 350 No 67.00.30. or later DGAC approved revision: |\n| | a. For helicopters not fitted with Automatic Flight Control System -comply with paragraph 2.B.2.a. |\n| | b. For helicopters fitted with Automatic Flight Control System -comply with paragraph 2.B.2.b |\n| | 3. Remove from service any servo-control that is found to be non-compliant as a result of the bench check carried out in accordance with paragraph 2.B.6. of the AT and install a compliant tail servo-control in accordance with paragraph 2.B.2 of the AT. |\n| | 4. Check spare tail servo-controls in accordance with paragraph 2.B.6. of the AT. |\n| | Note: DGAC AF UF-2004-196 (EASA approval 2004-12557) refers. |\n| Compliance: | For Requirement 1 - As of the effective date of this Directive. |\n\n| | For Requirement 2 - Within 50 hours time in service from the effective date of this Directive. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | For Requirement 3 - Before further flight after accomplishing Requirement 2. |\n| | For Requirement 4 - Before installation on a rotorcraft. |\n| | This Airworthiness Directive becomes effective on 7 January 2005. |\n| Background: | The Direction Générale de l’Aviation Civile of France has advised that servos fitted with the incorrect servo piston could cause loss of tail rotor control authority during certain phases of autorotative flight.This Directive prohibits intentional autorotation flight until tail rotor servo-control systems are inspected and, if necessary, replaced. |\n\n![](image.001.png) \nDavid Punshon \nDelegate of the Civil Aviation Safety Authority\n\n6 January 2005","sortOrder":0},{"sectionNumber":"AD/ECUREUIL/108","sectionType":"part","heading":"AD/ECUREUIL/108","content":"## AD/ECUREUIL/108","sortOrder":1},{"sectionNumber":"Tail Servo-Control","sectionType":"part","heading":"Tail Servo-Control","content":"## Tail Servo-Control","sortOrder":2},{"sectionNumber":"2/2005 TX","sectionType":"part","heading":"2/2005 TX","content":"## 2/2005 TX","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive's scope aligns with the stated safety objective: it targets AS350 B3 helicopters fitted with the identified GOODRICH servo P/Ns (Applicability) and mandates inspection/replacement to mitigate the risk of losing tail‑rotor control during autorotation (Background; Requirement). It does not broaden applicability beyond those part numbers, serial‑number exceptions, or the specified inspection/replacement actions."},"complexity_factors":["Narrow applicability defined by specific Goodrich part numbers and serial‑number exceptions (Applicability).","Mandatory reference to external technical instructions (Eurocopter Alert Telex) for inspection and bench‑check procedures (Requirement 2; Requirement 3).","Different procedural paths depending on whether the helicopter has an Automatic Flight Control System (Requirement 2.a–b).","Immediate operational prohibition (no intentional autorotation) until checks are done, creating urgent compliance pressure (Requirement 1; Compliance).","Time‑limited compliance windows and before‑flight constraints for removals/replacements and spare installation (Compliance; Requirement 3–4).","Reliance on foreign regulator and EASA approvals noted (Background; Note), creating inter‑jurisdictional reference points for conformity.","Technical bench‑check standard referenced by paragraph numbers (2.B.6), requiring access to and understanding of the AT's detailed test procedures."],"plain_english_summary":"Mechanically, this directive forbids intentional autorotation on AS350 B3 helicopters fitted with specified GOODRICH tail servo-controls until those servos are bench‑checked and any non‑compliant units are removed and replaced according to the Eurocopter Alert Telex (Requirement 1–3; Applicability). It also requires spare servos to be checked before installation. Operators/owners must carry out inspections and bear any replacement cost and aircraft downtime; CASA issued the directive based on DGAC/EASA advice about possible loss of tail‑rotor control in autorotation (Background; Compliance)."},"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"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with a focused, narrow scope addressing a specific safety defect in specific helicopter models. It has not expanded beyond its original purpose of addressing the identified servo-control piston defect."},"complexity_factors":["Multiple nested exemption conditions in the Applicability section (3 separate exceptions to the general rule)","Cross-references to external technical documents (Alert Telex Eurocopter AS 350 No 67.00.30, Service Bulletin GOODRICH No. SC507X-67-39-01-3, DGAC AF UF-2004-196) that are not reproduced in the directive itself","Different compliance requirements for helicopters with and without Automatic Flight Control Systems (conditional logic)","Staggered compliance deadlines (immediate, 50 hours, before next flight, before installation)","Mixture of regulatory language and technical aviation terminology (part numbers, serial number thresholds, time-in-service calculations)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's aviation regulator (CASA) for specific helicopters.\n\n**What it does:**\nIt grounds certain Eurocopter AS 350 B3 helicopters from performing intentional auto-rotation flights (a manoeuvre where the engine is disengaged and the helicopter glides using rotor momentum) until a critical safety check is done.\n\n**Who it affects:**\n- Owners and operators of **AS 350 B3 helicopters** fitted with specific **Goodrich tail servo-controls** (part numbers SC5071-XX or SC5072)\n- **Exemptions apply** to:\n - Servo-controls with serial numbers 1372 or higher\n - Units already overhauled/repaired using a specific service bulletin\n - Units that have never been removed since the helicopter was new\n\n**Why it matters:**\nFrench aviation authorities discovered that some servo-controls were fitted with **incorrect servo pistons**. During auto-rotation (when the tail rotor is crucial for maintaining control), this defect could cause **complete loss of tail rotor control** — potentially leading to a crash.\n\n**What must be done:**\n1. **Immediately:** Stop intentional auto-rotation flights\n2. **Within 50 flight hours:** Inspect the tail servo-control following specific technical instructions (Alert Telex AS 350 No 67.00.30)\n3. **If faulty:** Replace the servo-control before flying again\n4. **Spare parts:** Check any spare servo-controls before installing them\n\n**The bottom line:** This is an emergency safety measure to prevent catastrophic loss of control in a specific helicopter model during a specific flight manoeuvre."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ecureuil-108-tail-servo-control","history":"/api/acts/ad-ecureuil-108-tail-servo-control/history","analysis":"/api/acts/ad-ecureuil-108-tail-servo-control/analysis","conflicts":"/api/acts/ad-ecureuil-108-tail-servo-control/conflicts","importantCases":"/api/acts/ad-ecureuil-108-tail-servo-control/important-cases","documents":"/api/acts/ad-ecureuil-108-tail-servo-control/documents"}}