{"id":"F2007L01505","name":"AD/ECUREUIL/127 - Main & Tail Rotors Servo Controls","slug":"ad-ecureuil-127-main-tail-rotors-servo-controls","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":65956,"registerId":"commonwealth-F2007L01505-current","compilationNumber":null,"startDate":"2026-04-02","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/127 | Main & Tail Rotors Servo Controls | 7/2007 TX |\n| --------------- | --------------------------------- | --------- |\n\n| Applicability: | EUROCOPTER helicopters models AS 350 B, BA, BB, B1, B2, B3 and D equipped with GOODRICH main rotor servo-controls and tail rotor servo-controls with no letter “C” marked in the inspection box of the servo-control identification plate, and with the following Part Numbers (P/N) and Serial Numbers (S/N):- Main rotor servo-controlsP/N SC5083 with S/N 270M, 272M, 409M, 423M, 452M or 1573P/N SC5083-1 with S/N from 2902 to 2921, inclusiveP/N SC5084 with S/N 30, 84, 104, 186, 438, 575 or 695P/N SC5084-1 with S/N from 1462 to 1481 inclusive.And- Tail rotor servo-controls:P/N SC5072 with serial number 222M, 306M or 309.                                                                                                                                                                                                                             |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Verify the P/N and S/N of the main rotor and tail rotor servo-controls in accordance with paragraph 1.E.2. of EUROCOPTER Alert Service Bulletin (ASB) No. 01.00.58 Revision 1 or later NAA approved revision.Instead of inspecting the rotorcraft, a review of the helicopter maintenance records along with any other applicable data (rotorcraft logbook, Components list, etc...) is acceptable if each P/N and S/N can be positively determined from that review.2. When a servo-control whose P/N and S/N are listed in the applicability section of this AD, is identified:a. Check thoroughly that no “hard point” exists in the flight controls.b. If any “hard point” is detected in the flight controls, replace the defective servo-control(s) as instructed in paragraph 2.B. of EUROCOPTER ASBNo. 01.00.58 Revision 1 or later NAA approved revision. |\n\n|             | c. Replace all servo-controls that are identified in the applicability section of this AD, as instructed in paragraph 2.B. of EUROCOPTER ASBNo. 01.00.58 Revision 1 or later NAA approved revision.3. Do not install rotors servocontrols whose P/N and S/N are listed in the applicability section of this AD, on any EUROCOPTER AS 350 helicopter unless they have been previously returned to conformity by the equipment manufacturer as indicated in paragraph 2. of EUROCOPTER ASB No. 01.00.58 Revision 1 or later NAA approved revision.Note: EASA Emergency AD 2007-0141-E dated 21May 2007 refers.                                                                                             |\n| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | 1. Before further flight, after the effective date of this AD.2. a. During each pre-flight test (see Rotorcraft Flight Manual section 4) and until accomplishment of requirement 2c of this AD is completed.b. Before further flight, after the effective date of this AD.c. Within the next 50 Flight Hours or 4 months after the effective date of this AD, whichever occurs first.3. After the effective date of this AD.                                                                                                                                                                                                                                                                             |\n|             | This Airworthiness Directive becomes effective on 25 May 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n| Background: | An internal review revealed that some main and tail rotor servo-controls do not conform to the approved design. This results in a greater play in the input lever bearing which could lead to off-centered lever/distributor slide valve. If not corrected, this condition could jam the distributor slide valve in its sleeve contributing to reduced controllability of the rotors. Such a jamming would be detected during the pre-flight hydraulic check by a “hard point” in the flight controls. This Airworthiness Directive requires identification of the affected main and tail rotor servo-controls and mandates additional attention during the pre flight check and subsequent replacement. |\n\n![](image.001.png)  \nCharles Lenarcic  \nDelegate of the Civil Aviation Safety Authority\n\n22 May 2007","sortOrder":0},{"sectionNumber":"AD/ECUREUIL/127","sectionType":"part","heading":"AD/ECUREUIL/127","content":"## AD/ECUREUIL/127","sortOrder":1},{"sectionNumber":"Main & Tail Rotors Servo Controls","sectionType":"part","heading":"Main & Tail Rotors Servo Controls","content":"## Main & Tail Rotors Servo Controls","sortOrder":2},{"sectionNumber":"7/2007 TX","sectionType":"part","heading":"7/2007 TX","content":"## 7/2007 TX","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The AD’s measures—identify affected servo-controls, require more vigilant pre‑flight checks, and mandate replacement or return‑to‑conformity—are consistent with the stated safety objective. The instrument does not add unrelated obligations beyond addressing the identified non‑conforming servo‑controls; it uses standard AD mechanisms (inspection, replacement, prohibition on installation) and delegates technical repair steps to the manufacturer via the ASB."},"complexity_factors":["56 distinct serial numbers or serial-number ranges listed across the affected P/Ns (multiple discrete items to check)","Cross-reference to EUROCOPTER Alert Service Bulletin No. 01.00.58 Revision 1 or later NAA-approved revision for procedural details","Prohibition on installation unless parts are ‘returned to conformity by the equipment manufacturer’ (requires manufacturer action and documentation)","Multiple, different compliance timeframes (before further flight; on every pre-flight until replacement; immediately if a hard point is detected; within 50 flight hours or 4 months)","Allowance for alternative methods of identification (records review in lieu of physical inspection), which creates branching compliance paths","Operational detection requirement ('hard point' in pre-flight hydraulic check) that depends on human performance of procedural check","Reference to an external EASA Emergency AD and manufacturer ASB increases cross-referencing and dependence on other instruments"],"plain_english_summary":"**What this directive requires (mechanics)\n\n- Identifies specific Eurocopter AS350 (Ecureuil) helicopters equipped with certain GOODRICH main-rotor and tail-rotor servo-controls by part number (P/N) and serial number (S/N), and only those servo-controls that do not have the letter “C” marked in the inspection box of the servo-control identification plate. (See Applicability.)\n\n- Requires operators or maintainers to verify the P/N and S/N of each main and tail rotor servo-control by either inspecting the helicopter or by reviewing maintenance records so the P/N and S/N can be positively determined (Requirement 1).\n\n- If a listed servo-control is found, requires:\n  - an immediate, careful check for any \"hard point\" (a detectable jam or abrupt stop) in the flight controls during the pre-flight hydraulic control check (Requirement 2.a); and\n  - if a hard point is detected, replacement of the defective servo-control(s) as directed in Eurocopter Alert Service Bulletin (ASB) No. 01.00.58 Rev 1 (Requirement 2.b);\n  - in all cases, replacement of every servo-control that falls within the applicability list, as directed in the ASB (Requirement 2.c).\n\n- Prohibits installing any of the listed servo-controls on an AS350 helicopter unless the servo-control has been returned to conformity by the equipment manufacturer as described in the ASB (Requirement 3).\n\n- Cross-references Eurocopter ASB No. 01.00.58 Revision 1 (or later NAA‑approved revision) for the detailed replacement and conformity procedures; the AD also cites an EASA emergency AD for background.\n\n- Sets compliance timing: verification and any required pre-flight checks before further flight; a) pre-flight hydraulic checks on each flight until the listed servo-controls are replaced, b) immediate replacement where a hard point is detected, and c) replacement of listed servo-controls within 50 flight hours or 4 months (whichever occurs first) after the AD’s effective date.\n\n\nWho this affects\n\n- Aircraft owners/operators of Eurocopter AS350 B/BA/BB/B1/B2/B3 and D helicopters that have the listed GOODRICH servo-controls.\n- Maintenance organisations and engineers who perform inspections, run pre‑flight hydraulic checks, and carry out part replacement and paperwork.\n- The servo-control manufacturer, insofar as the AD requires parts to be \"returned to conformity by the equipment manufacturer\" before re‑installation.\n\n\nWhy the rule exists (stated purpose) and how that squares with costs and incentives\n\n- Stated purpose: an internal review found certain servo-controls may have excessive play in the input lever bearing. That can lead to an off‑centred lever or distributor slide valve which may jam in its sleeve, reducing rotor controllability. A hard point during the pre‑flight hydraulic check is expected to reveal such a jam. The AD’s measures (identification, extra pre‑flight attention, and replacement) are intended to remove non‑conforming units from service (Background).\n\n- Costs and who pays: operators/owners bear inspection and replacement costs and operational downtime unless the manufacturer provides repairs or replacements under warranty. The AD directs parts to be \"returned to conformity by the equipment manufacturer,\" which places the technical repair responsibility on the manufacturer but not explicitly the financial one.\n\n- Behavioural effects: operators must either inspect/confirm serial numbers or ground the helicopter until that is done; they must perform additional attention to pre‑flight hydraulic checks; they must replace affected servo-controls within a short window or after detection of a hard point; and they cannot re‑fit affected parts unless the manufacturer has certified they are restored to conformity.\n\n\nImplementation, trade-offs and risks (practical assessment)\n\n- Compliance burden: moderate. The AD requires paperwork review or physical inspection to identify parts (records review is explicitly allowed), repeated vigilance during pre‑flight checks until parts are replaced, and a fleet‑wide replacement action for affected parts within a defined short period (50 flight hours / 4 months).\n\n- Operational impact and opportunity cost: replacing servo-controls can cause helicopter downtime and parts/maintenance expense; the 50‑flight‑hour / 4‑month deadline compresses scheduling and may force out‑of-turn maintenance.\n\n- Supply and market effects: the prohibition on installing listed servo-controls unless returned to conformity limits the pool of usable spare parts until the manufacturer has restored them. Operators will either need conforming spares or to wait for manufacturer rework.\n\n- Implementation risk and discretion: the AD relies on the EUROCOPTER ASB No. 01.00.58 Revision 1 (or later NAA‑approved revision) for the technical remedy; allowing \"or later NAA approved revision\" gives national aviation authorities and the manufacturer some discretion about the precise repair steps and acceptable documentation.\n\n- Detection likelihood: the AD notes that a jamming would be detected during the pre‑flight hydraulic check by a \"hard point,\" which creates a practical on‑aircraft detection step but also relies on correct performance of that check every flight.\n\n\nWho decides and when\n\n- Civil Aviation Safety Authority delegates the AD; national aviation authorities approve the ASB revision that specifies the repair procedures.\n- Operators and their maintenance organisations decide how to schedule inspections and replacements, subject to the AD timing constraints.\n\n\nKey reference steps to follow (practical checklist)\n\n- Verify P/N and S/N for main and tail servo-controls (records or physical inspection).\n- If an affected part is present: increase attention to the pre‑flight hydraulic check on every flight until the part is replaced; replace immediately if a hard point is detected; replace all listed parts within 50 flight hours or 4 months.\n- Do not install listed servo-controls unless the manufacturer has returned them to conformity as per the ASB.\n\n(References: Applicability; Requirements 1–3; Compliance timing; Background; EUROCOPTER ASB No. 01.00.58 Rev 1.)"},"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 targeted emergency airworthiness directive addressing a specific manufacturing defect in identified servo-controls. The scope remains precisely limited to the safety issue identified — faulty bearings in specific part/serial number combinations — and has not expanded beyond this original safety purpose."},"complexity_factors":["Multiple specific part numbers and serial number ranges to cross-reference (6 main rotor P/N variants with specific S/Ns, 3 tail rotor S/Ns)","Conditional logic: different compliance timelines for different requirements (immediate vs. 50 hours/4 months)","Alternative compliance method permitted (maintenance records review instead of physical inspection)","Reference to external technical document (Eurocopter Alert Service Bulletin 01.00.58 Rev 1) for detailed procedures","Nested conditions in Requirement 2: detection of hard point triggers immediate replacement, but all affected parts must be replaced regardless within timeframe","Specific marking exemption ('no letter C') creates additional identification step"],"plain_english_summary":"This emergency Airworthiness Directive requires owners/operators of Eurocopter AS350 (B/BA/BB/B1/B2/B3/D) helicopters to identify and remove certain Goodrich main- and tail-rotor servo-controls that lack a \"C\" mark, because bearing play can cause control “hard points” (jamming).  \n\nUntil replacement (within 50 flight hours or 4 months), pilots must perform preflight hard-point checks and affected parts may not be reinstalled unless repaired by the manufacturer — a safety action to prevent loss of control in flight."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ecureuil-127-main-tail-rotors-servo-controls","history":"/api/acts/ad-ecureuil-127-main-tail-rotors-servo-controls/history","analysis":"/api/acts/ad-ecureuil-127-main-tail-rotors-servo-controls/analysis","conflicts":"/api/acts/ad-ecureuil-127-main-tail-rotors-servo-controls/conflicts","importantCases":"/api/acts/ad-ecureuil-127-main-tail-rotors-servo-controls/important-cases","documents":"/api/acts/ad-ecureuil-127-main-tail-rotors-servo-controls/documents"}}