AD/ECUREUIL/127 - Main & Tail Rotors Servo Controls

The AD rests on several discrete concepts that structure the obligations it imposes:

• Targeted applicability by P/N and S/N. The AD specifies exact part and serial numbers for main rotor servo-controls (P/Ns SC5083, SC5083-1, SC5084, SC5084-1 with enumerated S/N ranges and discrete S/Ns) and tail rotor servo-controls (P/N SC5072 with discrete S/Ns) (Applicability). It also excludes servo-controls marked with a letter “C” in the inspection box of the identification plate. This creates a narrow, enumerated universe of affected components that carries implications for identification work and for parts inventory control.

• Verification by inspection or records. The AD instructs operators to verify P/N and S/N in accordance with ASB paragraph 1.E.2 or, alternatively, by review of maintenance records and other applicable data (rotorcraft logbook, component lists) provided that each P/N and S/N can be positively determined from those reviews (Requirement para 1). This provides two routes to compliance: physical inspection of the aircraft, or documentary verification.

• Enhanced pre-flight testing and interim mitigations. Until all affected servo-controls are replaced, the AD requires that during each pre-flight test (see Rotorcraft Flight Manual section 4) operators check for a “hard point” and, if one is detected, replace defective servo-controls before further flight (Requirement para 2a-b; Compliance para 2a-b). This makes the pre-flight hydraulic check an on-going operational control measure that continues until permanent corrective action is completed.

• Mandatory replacement of identified items. Where a servo-control with a listed P/N/S/N is identified, the AD mandates replacement of that servo-control as instructed in ASB paragraph 2.B.; it further mandates replacement of all servo-controls identified in the applicability section in accordance with the ASB (Requirement para 2b-c). This is not limited to the defective unit alone but extends to all units identified by the applicability clause.

• Installation prohibition pending conformity return. The AD prohibits installation of any listed servo-controls on any AS 350 helicopter unless the component has been returned to conformity by the equipment manufacturer as indicated in paragraph 2 of the ASB (Requirement para 3). That is, listed spares cannot be fitted unless the manufacturer has issued a conformity return.

• Delegation and cross-reference to manufacturer AMM/ASB. The AD delegates the detailed inspection and replacement techniques to an industry service bulletin (EUROCOPTER ASB No. 01.00.58 Rev 1 or later NAA approved revision) and references an EASA Emergency AD (Background, Requirement). The AD itself contains high-level statutory obligations and defers procedural specifics to the ASB.

• Temporal obligations. The Compliance section sets varying timeframes: some actions must be accomplished “before further flight” after the effective date (i.e. immediate), certain inspections must be carried out during each pre-flight test until replacements are installed, replacement must occur “within the next 50 flight hours or 4 months after the effective date, whichever occurs first”, and the prohibition on installation applies after the effective date (Compliance).

Collectively, these concepts structure a targeted technical mitigation strategy: identify the narrow set of suspect units; step up operational checks pending remediation; replace suspect units on a defined schedule; and prevent re-introduction of suspect units without manufacturer-conducted rectification. The regulatory mechanism relies on a combination of operator-level checks, manufacturer rectification, and an industry ASB to provide the technical steps.

The AD affects a specific, delimited set of stakeholders:

• Operators and owners of EUROCOPTER AS 350 models B, BA, BB, B1, B2, B3 and D that are fitted with GOODRICH main and tail rotor servo-controls within the enumerated P/N and S/N ranges, and that do not have the letter “C” marked in the inspection box of the servo-control identification plate (Applicability). This includes commercial and private operators, maintenance organisations who service those airframes, and owners who control spares inventories.

• Maintenance personnel and organisations. The AD requires verification of P/N and S/N through inspection or maintenance records review, and mandates replacements according to procedures in EUROCOPTER ASB No. 01.00.58 Rev 1 or later (Requirement). This places operational responsibility on maintenance staff or contracted maintenance organisations to carry out the checks and remedial work, and to follow the ASB’s procedural steps (including ASB paragraph 1.E.2 for identification and paragraph 2.B. for replacement technique).

• Pilots and flight crews. The AD requires pre-flight testing (Rotorcraft Flight Manual section 4) to check for “hard points” during each pre-flight test until the replacement requirement is completed (Requirement para 2a, Compliance para 2a). Pilots and crews must be aware of the AD and the obligation for heightened pre-flight checks while the aircraft remains fitted with listed servo-controls.

• Component manufacturers and suppliers. GOODRICH as the servo-control manufacturer, and EUROCOPTER as the aircraft manufacturer issuing the ASB, have roles: the AD requires that listed servo-controls not be installed unless “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” (Requirement para 3). This imposes an obligation on the manufacturer to provide a conformity return process for affected units.

• National aviation authority and its delegate. The AD was issued by the Delegate of the Civil Aviation Safety Authority (CASA) and became effective on 25 May 2007 (signature block). The regulator is the issuing authority whose delegate set the AD’s mandates.

• Parts inventory managers and logistics. The prohibition on installing listed servo-controls unless returned to conformity affects spare parts management, procurement decisions, and logistics planning , organisations holding listed stock must either take them out of service, return them to the manufacturer for conformity actions, or otherwise ensure they are not installed.

Geographically, the AD is framed as an instrument of the Civil Aviation Safety Authority, effective in the jurisdiction to which CASA’s delegate issues ADs. The AD also references EASA Emergency AD 2007-0141-E, indicating parallel or related action in another jurisdiction and suggesting cross-border relevance for operators who operate in or move equipment between jurisdictions. The text does not list enforcement agencies or penalties; responsibilities are framed as express technical and operational duties (Applicability, Requirement, Compliance).

Key duties imposed by the AD are specific and procedural:

• Duty to identify affected servo-controls. Operators must verify P/N and S/N of main and tail rotor servo-controls in accordance with ASB paragraph 1.E.2 or by review of maintenance records and other applicable data, provided that each P/N and S/N can be positively determined (Requirement para 1). This duty establishes an affirmative obligation to establish whether the listed servo-controls are present.

• Duty to inspect for a “hard point” during pre-flight tests. When a servo-control whose P/N and S/N are listed is identified, the operator must "check thoroughly that no ‘hard point’ exists in the flight controls" (Requirement para 2a). The Compliance section specifies this is required "during each pre-flight test (see Rotorcraft Flight Manual section 4) and until accomplishment of requirement 2c is completed" (Compliance para 2a). This imposes a recurrent operational duty on crews and maintenance personnel.

• Duty to replace defective units and listed units. If a hard point is detected, operators must replace the defective servo-control(s) as instructed in ASB paragraph 2.B. (Requirement para 2b; Compliance para 2b , "Before further flight"). Additionally, the AD requires replacement of all servo-controls that are identified in the applicability section, as instructed in ASB paragraph 2.B. (Requirement para 2c) within a finite period (Compliance para 2c , "Within the next 50 Flight Hours or 4 months... whichever occurs first"). These replace-and-rectify duties convert detection into mandated physical interventions.

• Duty not to install non-conforming units. The AD states: "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." (Requirement para 3). This is a preventive duty affecting installation decisions and spare parts usage.

• Duty to follow the EUROCOPTER ASB for procedural steps. The AD explicitly requires verification and replacement "in accordance with paragraph 1.E.2." and paragraph 2.B. of the EUROCOPTER ASB No. 01.00.58 Rev 1 or later NAA approved revision (Requirement paras 1-3). The ASB is thus incorporated by reference as the technical method.

Rights and administrative features present in the text are limited, but the AD does make certain allowances:

• Right to use records in lieu of physical inspection. The AD permits operators to satisfy the identification duty by review of maintenance records and other applicable data if each P/N and S/N can be positively determined from the records (Requirement para 1). This reduces operational cost where records are clear.

• Right to rely on the manufacturer's conformity return. The prohibition on installing listed servo-controls is conditional: components that have been "returned to conformity by the equipment manufacturer as indicated in paragraph 2. of EUROCOPTER ASB No. 01.00.58" may be installed. This gives operators a clear compliance pathway through manufacturer action.

• Right to detailed technical procedure in ASB. The AD delegates detailed technical steps to a EUROCOPTER ASB; operators have the right to rely on that ASB's procedures (Requirement). The AD also permits later NAA-approved revisions of that ASB to be used.

The AD does not state rights to appeal, exception processes, or alternative methods of compliance within its text. It also does not specify penalties or enforcement mechanisms in the document itself. The effective date and issuing delegate are stated, but no administrative review or waiver process is included in the AD text provided.

The AD text provided does not set out penalties, sanctions, or enforcement mechanisms. It prescribes mandatory actions and sets compliance timelines (Compliance; Requirement), but it contains no express provision addressing consequences for non-compliance, financial penalties, or criminal sanctions within its text. The document does specify an effective date (25 May 2007) and is issued by the Delegate of the Civil Aviation Safety Authority (signature block), indicating the issuing authority, but it does not describe the enforcement powers or penalties that CASA might apply for breach of the AD in this document itself.

Because the AD references compliance obligations with a service bulletin (EUROCOPTER ASB No. 01.00.58 Rev 1 or later NAA approved revision) and refers to an EASA Emergency AD (EASA Emergency AD 2007-0141-E dated 21 May 2007), there are cross-references to other safety instruments. The AD does not, however, incorporate or reproduce enforcement language from those referenced instruments. Any enforcement action or penalties that may follow from failing to comply with an AD would be outside the text of this AD and would need to be determined from the regulator’s enforcement policies or enabling aviation safety law, neither of which are included in the supplied text.

Practical enforcement implications that the AD implies, without explicit penalty language, are:

• Immediate operational constraints. Certain actions are required “before further flight” where a hard point is detected or where a listed servo-control is identified and the AD requires replacement prior to further flight in some circumstances (Compliance paras 1 and 2b). This creates an operational enforcement mechanism: failure to carry out the mandated replacement prior to flight can be recognised and acted upon by the operator’s maintenance control, the responsible pilot-in-command, or aviation authorities during oversight inspections.

• Regulatory provenance. The AD is issued by the CASA delegate, and it cross-references an EASA emergency AD. The presence of an official signature and effective date means the AD is a formal regulatory instrument within the issuing authority’s toolkit; regulatory oversight bodies typically treat ADs as mandatory safety directives.

• Manufacturer conformity process. The prohibition on installation unless the equipment manufacturer has returned the part to conformity (Requirement para 3) creates an administrative control point. If a part is installed without the manufacturer’s conformity return, that can be documented and used as the basis for regulatory action.

In short, while the AD itself does not provide explicit sentences about penalties or enforcement measures, it imposes clear technical and operational obligations with immediate compliance deadlines. Any enforcement or penalty regime applicable for breach is not present in the text provided and would need to be sourced from the regulator’s legal framework or enforcement policy documents outside this AD.

Within the text, this AD interacts explicitly with technical service literature and a referenced foreign regulator AD:

• Incorporation by reference to EUROCOPTER ASB No. 01.00.58 Rev 1 (or later NAA approved revision). The AD requires that identification and replacement activities be carried out "in accordance with paragraph 1.E.2." and "as instructed in paragraph 2.B." of EUROCOPTER ASB No. 01.00.58 Revision 1 or later NAA approved revision (Requirement paras 1-3). This means the AD uses the ASB as the operative technical method, and any obligations set in the ASB become the procedural norm for compliance under the AD. The AD therefore functions together with the ASB: the AD sets mandatory high-level requirements, and the ASB supplies step-by-step technical procedures.

• Reference to EASA Emergency AD 2007-0141-E. The AD includes the note "EASA Emergency AD 2007-0141-E dated 21 May 2007 refers" (Requirement Note). That cross-reference signals alignment with an emergency directive issued by the European Aviation Safety Agency. Read together, the AD and the EASA emergency AD are likely addressing the same underlying safety occurrence. The AD does not reproduce the content of the EASA AD, but the reference indicates that regulators in other jurisdictions have issued related mandates.

• Delegation and national authority. The AD is issued by the Delegate of the Civil Aviation Safety Authority and includes an effective date. This embeds the AD within the national regulator’s instrument set; the AD thus sits within the broader legal and regulatory framework the regulator administers, though the AD text itself does not quote enabling legislation or enforcement provisions. The AD’s legal force, acceptance across regulatory processes, and interaction with other aviation safety instruments (for example, continued airworthiness requirements, operator maintenance programmes, and certification directives) are implied by it being a regulator-issued AD.

• Interface with rotorcraft flight manuals and maintenance records. The AD directs that pre-flight tests be carried out "see Rotorcraft Flight Manual section 4" and allows identification via maintenance records, rotorcraft logbook and component lists (Requirement para 1; Requirement para 2a; Compliance para 2a). These references bind the AD practically to operator flight manuals and maintenance documentation frameworks, so the AD interacts functionally with those operational instruments.

• Manufacturer conformity return process. The AD conditions the permissibility of installing a listed servo-control on it being "previously returned to conformity by the equipment manufacturer as indicated in paragraph 2. of EUROCOPTER ASB No. 01.00.58" (Requirement para 3). Thus, the AD creates a dependency between the regulator's directive and the manufacturer’s corrective action procedure, making the manufacturer’s output part of the compliance chain.

What the AD does not do within its text is to cite or amend specific statutes, criminal provisions, or administrative penalty regimes. It does not specify processes for alternative methods of compliance within its text, nor does it state how conflicts between the ASB and operator procedures should be resolved. Therefore, interaction with other laws or instruments beyond the ASB and the EASA AD is implicit (regulatory setting, flight manual obligations) but not articulated in the document’s text.

The AD text provides only limited material relevant to amendment history:

• Effective date. The AD "becomes effective on 25 May 2007", and it is signed by the Delegate of the Civil Aviation Safety Authority on 22 May 2007 (signature block). This establishes the date the AD took legal effect.

• Cross-reference to ASB revisioning. The AD repeatedly conditions compliance on "EUROCOPTER Alert Service Bulletin (ASB) No. 01.00.58 Revision 1 or later NAA approved revision" (Requirement). This language allows compliance to be based on that ASB Rev 1, or later revisions that are approved by the national aviation authority, effectively permitting subsequent NAA-approved revisions of the ASB to be used for compliance without further amendment of the AD. In practice, that provides a mechanism for the technical procedures to be updated via the ASB and NAA approval process without needing to amend the AD itself.

• Reference to EASA Emergency AD 2007-0141-E. The AD notes that the EASA emergency AD dated 21 May 2007 refers. This indicates contemporaneous regulatory activity in another jurisdiction, but it is not an amendment history for this instrument.

The AD document includes no recorded amendments, no historical versions of the AD itself, and no amendment dates beyond the listed effective date. It does not state that the AD supersedes previous ADs or that it is an amendment to a prior AD. It also does not document any subsequent amendments, revocations, or extensions within the provided text. The AD does, however, incorporate a tolerance for later NAA-approved revisions of the EUROCOPTER ASB, which functions as a limited amendment mechanism for the technical procedures.

If changes to the AD itself were required, the text supplied does not show any further versions, nor does it include a mechanism for administrative variances, waivers, or formal amendments within its own body. Any formal amendment history beyond the effective date is not recorded in the supplied text.

The AD text contains no litigation history. There are no references to judicial proceedings, appeals, challenges to the AD, or precedent cases in the document. The document also does not describe any disputes between manufacturers, operators, or regulators arising from this AD. The only references included are to technical service literature (EUROCOPTER ASB No. 01.00.58 Rev 1 or later NAA approved revision) and to a related EASA Emergency AD (EASA Emergency AD 2007-0141-E dated 21 May 2007).

Therefore, based solely on the supplied instrument, there is no litigation history to report. Any legal proceedings concerning this AD, challenges to its content, or enforcement actions that may have occurred would not be visible in the AD text itself and would need to be sourced from court records, tribunal files, regulator enforcement logs, or other external records that are not contained in the provided text.

The AD contains several discrete technical and procedural features that can create compliance pitfalls if overlooked:

• Narrow applicability requires exact P/N and S/N matching. The AD lists specific P/Ns and S/Ns across several groupings for both main rotor (SC5083, SC5083-1, SC5084, SC5084-1) and tail rotor (SC5072) servo-controls (Applicability). Compliance demands positive identification of part and serial numbers. Operators who perform cursory checks that only verify P/N but not S/N risk missing affected units. Conversely, parts with a letter "C" marked in the inspection box are excluded; operators must note that marking. The AD allows records review in lieu of physical inspection only where each P/N and S/N can be positively determined from the records (Requirement para 1), so poor records can force a physical inspection.

• Records review is allowed but conditional. The AD expressly permits a review of the helicopter maintenance records and other applicable data “instead of inspecting the rotorcraft” only if “each P/N and S/N can be positively determined from that review” (Requirement para 1). If records are incomplete or ambiguous, the operator will have to schedule a physical inspection, possibly resulting in unexpected downtime.

• Different time-driven and condition-driven triggers. The AD imposes multiple overlapping obligations: a recurrent pre-flight test obligation (each pre-flight) until replacement is complete; “before further flight” replacement when a hard point is detected; and a mandatory replacement timeline for listed units generally (within 50 flight hours or 4 months). Operators must track all three pathways; failure to comply with the correct timeline for a specific scenario (e.g. thinking the 50-flight-hours timeline applies to a detected hard point when in fact replacement is required before further flight) could lead to non-compliance.

• “Hard point” detection triggers immediate grounding until replaced. The AD states that if any “hard point” is detected in the flight controls, the defective servo-control(s) must be replaced as instructed in the ASB (Requirement para 2b) and Compliance para 2b requires replacement "Before further flight". For operators this means that a hard-point detection on pre-flight could result in immediate non-fly status for that helicopter until replacement is completed, which has operational and logistical knock-on effects.

• All listed servo-controls must be replaced, not just the defective one. The AD requires replacement of "all servo-controls that are identified in the applicability section of this AD" as instructed in the ASB (Requirement para 2c). This obligation is broader than replacing only those showing failed tests and therefore may increase parts and labour costs compared with a simple remedial replacement of only observed defects.

• Installation prohibition affects spare parts management. The AD forbids installing any listed servo-controls unless they have been returned to conformity by the equipment manufacturer as indicated in the ASB (Requirement para 3). Operators holding stocks of listed spare servo-controls must either return them to the manufacturer for conformity work or ensure they are marked and segregated to prevent unintended installation.

• Reliance on the ASB for technical detail. The AD defers to EUROCOPTER ASB No. 01.00.58 Rev 1 (or later NAA approved revision) for procedural steps (Requirement). Operators must obtain and follow that ASB to carry out the AD’s technical requirements; failure to follow the ASB’s specific instructions could lead to ineffective or non-compliant repair.

• Effective date vs issuance date. The AD is signed on 22 May 2007 but becomes effective on 25 May 2007. Operators must be attentive to the effective date, as compliance deadlines (such as the 4-month window) are measured from the effective date (Compliance).

• Inter-jurisdictional references. The AD references an EASA Emergency AD dated 21 May 2007. Operators working across jurisdictions should verify the corresponding measures required under other regulators and ensure consistency with national requirements, noting that the AD itself does not reproduce or summarise the EASA AD.

• Terminology and definitions not defined in the AD. Terms such as “returned to conformity” are used but defined procedures are in the ASB rather than in this AD text. Operators should consult the ASB for any definitions and for the manufacturer’s conformity procedures to avoid misunderstanding what “returned to conformity” requires.

These gotchas underline the need to (a) cross-check records and plate markings closely, (b) maintain strict parts segregation and inventory controls, (c) plan for potential immediate grounding in the event of a hard-point detection, and (d) obtain and act on the ASB’s detailed instructions.

The AD sets out a clear sequence of compliance actions and timelines. The following steps restate the AD’s mandated actions in practical form; operators should follow the EUROCOPTER ASB No. 01.00.58 Rev 1 (or later NAA approved revision) for the detailed technical method referenced in the AD.

1. Determine applicability

• Verify whether the helicopter is one of the EUROCOPTER AS 350 models listed (B, BA, BB, B1, B2, B3 and D) and whether it is equipped with GOODRICH main and tail rotor servo-controls lacking the letter “C” in the inspection box of their identification plate (Applicability).
• Verify the P/N and S/N of the main and tail rotor servo-controls. Do this either by physical inspection in accordance with ASB paragraph 1.E.2 or, if reliable, by a thorough review of maintenance records, rotorcraft logbook, component lists or other applicable documentation, provided that each P/N and S/N can be positively determined from the records (Requirement para 1).

2. If a listed servo-control is found

• Perform a thorough check for any “hard point” in the flight controls during the pre-flight hydraulic check (Requirement para 2a; Compliance para 2a).
• If a hard point is detected, replace the defective servo-control(s) before further flight, following the replacement procedure specified in EUROCOPTER ASB paragraph 2.B. (Requirement para 2b; Compliance para 2b).
• Regardless of whether a hard point is detected, ensure that all servo-controls identified in the applicability section of the AD are replaced as instructed in ASB paragraph 2.B. The AD sets a deadline for replacement: within the next 50 flight hours or 4 months after the effective date of the AD, whichever occurs first (Requirement para 2c; Compliance para 2c).

3. Interim operational control

• While any listed servo-control remains installed, continue to perform the pre-flight hydraulic check and specifically test for hard points during each pre-flight test (see Rotorcraft Flight Manual section 4). Continue these checks until all required replacements are accomplished (Requirement para 2a; Compliance para 2a).

4. Spares and installation control

• Do not install any servo-control with a P/N and S/N listed in the applicability section on any EUROCOPTER AS 350 helicopter unless the servo-control has been returned to conformity by the equipment manufacturer as indicated in paragraph 2 of the EUROCOPTER ASB (Requirement para 3). Ensure spares inventories are managed to prevent inadvertent installation (segregate and tag listed parts until conformity return is obtained).

5. Documentation

• Record the identification activity (inspection or records review), pre-flight checks, detected hard points, and any replacements in the helicopter’s maintenance records and rotorcraft logbook, in line with standard maintenance record-keeping practice and as required by the AD’s procedural chain (Requirement para 1; Requirement para 2).
• Retain documentation of any conformity return from the equipment manufacturer for installed or installed-after-repair servo-controls to demonstrate compliance with the installation prohibition (Requirement para 3).

6. Follow the ASB

• Obtain EUROCOPTER ASB No. 01.00.58 Revision 1 or a later NAA-approved revision, and follow the specific instructions set out in paragraph 1.E.2 (identification) and paragraph 2.B. (replacement technique). The AD conditions identification and replacement actions on compliance with those ASB paragraphs (Requirement).

7. Operational planning

• Plan maintenance windows to accommodate replacement of multiple servo-controls within the 50 flight hours / 4 months timeline where applicable. Anticipate potential for immediate groundings if a hard point is detected during a pre-flight check and ensure spare-conformity channels are in place to minimise downtime.

8. Liaise with the manufacturer and regulator

• Where servo-controls are listed in inventories, arrange for the equipment manufacturer to perform the conformity return process as described in the ASB (Requirement para 3). Keep the national aviation authority informed where applicable, and rely on the ASB’s provisions for interaction with the manufacturer.

9. Note the effective date

• All compliance timing is measured from the AD effective date (25 May 2007), which is relevant for the 4-month window and other time-based obligations (Compliance).

10. Cross-jurisdictional checks

• The AD notes EASA Emergency AD 2007-0141-E dated 21 May 2007 refers. Operators with international operations should confirm whether corresponding obligations apply under other applicable national regulations and ensure consistent compliance across jurisdictions.

By following these steps , identification via records or inspection, operational mitigation via recurrent pre-flight checks, timely replacement per the ASB, and strict control over spares installation pending manufacturer conformity , operators will align their actions with the AD’s mandatory requirements. Keep all records proving identification, inspection and replacement actions, and retain evidence of any manufacturer-issued conformity returns to support compliance verification.