AD/EC 135/10 Amdt 1 - Main Rotor - Sliding Sleeve

The AD is structured around a small set of operational safety controls and regulatory cross-references. The core safety concept is prevention by detection: discover movement of the plain journal bearings in the sliding sleeve through pre-flight visual inspection, thereby preventing a mechanical condition that could limit collective control movement and could lead to loss of control (Background).

Key technical concepts named in the AD:

• Plain journal bearing and sliding sleeve: the AD identifies both the upper and lower plain journal bearings within the main rotor sliding sleeve as the components of concern (Requirement).
• Visual inspection procedures: the AD requires inspections carried out in accordance with ASB EC135-62A-021 dated 23 June 2005, for both upper (visual inspection in situ) and lower (visual inspection after opening the gear cover) bearings (Requirement).
• Flight Manual amendment: the AD commands insertion of a flight manual page supplied with the ASB into the helicopter Flight Manual (Requirement).
• Delegated inspection certification: trained pilots may perform and certify the inspection, provided they complete an approved training program (Requirement).
• Conditional flight prohibition: where mis-positioned bushings are found, further flight is limited, specifically only permitted under CASR 21.197 (Requirement).

The regulatory concepts and linkages:

• The AD is issued under the Civil Aviation Safety Authority (CASA) regime in Australia; it refers to a foreign authority directive, Luftfahrt-Bundesamt AD D-2005-233, demonstrating international regulatory alignment on this safety issue (Note).
• The AD corrects a prior regulatory reference in Requirement 2 and restates that prior compliance with AD/EC 135/10 satisfies this amendment (Background). The AD thus functions as both a corrective amendment and an operative restatement of compliance obligations.

Operationally important wording includes "before the next flight, and thereafter at each pre-flight check" for the two bearing inspections, which establishes recurring, per-flight or per-pre-flight obligations depending on operator practices. The AD also specifies that inspections are visual and references an ASB for the inspection method, which anchors the practical inspection content to the manufacturer’s procedure (Requirement).

Mechanically the AD replaces investigative discretion with a binary protocol: inspect per ASB; if bearings are out of position, further flight is restricted to the pathway established in CASR 21.197; otherwise continue with routine pre-flight checks. The AD therefore converts a reported rare mechanical failure mode into an ongoing operational inspection and procedural requirement tied to documentation (the Flight Manual) and to a specified remedial pathway.

The AD applies to all Eurocopter EC 135 helicopters, as stated under Applicability. That application is categorical, not limited by serial number or configuration in the AD text provided; therefore the regulatory requirement attaches to any operator, owner, lessor or maintenance organisation responsible for an EC 135 in Australian operations (Applicability). In practical terms the following actor categories are affected:

• Registered aircraft operators: the legal operators must ensure that the specified inspections are completed before the next flight after the AD’s effective date and at each subsequent pre-flight check (Compliance). Operators are responsible for integrating the ASB inspection steps into their standard pre-flight procedures and ensuring the Flight Manual is updated as required.
• Pilots who conduct pre-flight checks: the AD allows a pilot to carry out and certify the inspections provided the pilot has completed an approved training program. That provision assigns an operational inspection and certification role to pilots, subject to training completion (Requirement). The AD therefore affects pilot training providers and roster planners because pilots will need to be trained and qualified to carry out and certify these inspections.
• Maintenance organisations and engineers: although the AD permits pilot-performed inspections, the requirement to open the gear cover and visually inspect the lower plain journal bearing (Requirement 2) will impose practical implications on maintenance personnel and may require co-ordination between flight crew and maintenance if access or technical action is necessary. If a bushing is discovered out of position, removal, repair or technical intervention will be necessary before returning to normal flight operations; the AD funnels such situations into the CASR 21.197 process (Requirement).
• Owners/lessors and flight planners: the requirement to insert a Flight Manual page derived from the ASB into the Flight Manual before the next flight imposes a documentation change which owners and lessors must manage; flight planners must account for the potential for immediate grounding under the AD if a mispositioned bushing is found (Requirement; Compliance).
• Regulatory/compliance staff: CASA and delegated personnel will be responsible for oversight of compliance, including confirming that operators have implemented the inspections and Flight Manual amendment, and that pilots who certify inspections have appropriate approved training.

Geographic and jurisdictional effects: the AD is an Australian CASA directive but references Luftfahrt-Bundesamt AD D-2005-233 and EU Regulation 1592/2002 Article 10.1. The AD therefore locates the safety issue in an international airworthiness context but, as stated, the AD’s operative obligations apply to EC 135 helicopters operating under Australian regulation (Note).

Finally, the Background identifies the causal trigger,two reports of the plain journal bearings moving out within the sliding sleeve discovered during pre-flight checks. That factual predicate underscores that the immediate affected parties are operators who will need to alter routine pre-flight procedures and bear the operational consequences of discovering mis-positioned bearings.

Duties imposed by the AD are precise and limited to those listed requirements and timing in the AD document.

Mandatory duties:

• Conduct upper plain journal bearing visual inspection in accordance with ASB EC135-62A-021 dated 23 June 2005. Timing: before the next flight after the effective date and thereafter at each pre-flight check (Requirement 1; Compliance).
• Open the gear cover and visually inspect the lower plain journal bearing in the sliding sleeve in accordance with the same ASB. Timing: before the next flight after the effective date and thereafter at each pre-flight check (Requirement 2; Compliance).
• Insert the flight manual page attached to ASB EC135-62A-021 into the Flight Manual. Timing: before the next flight after the effective date (Requirement 3; Compliance).

Conditional duty:

• If either or both bushings are not in the correct position, further flight is only permitted under CASR 21.197. The AD makes continued flight conditional on satisfying the requirements of CASR 21.197 (Requirement). The AD does not itself detail the content of CASR 21.197; it establishes that compliance with CASR 21.197 is the exclusive pathway to permit further flight in the event of mispositioned bushings.

Delegation and certification rights:

• The AD expressly permits the inspection to be carried out and certified by a pilot provided the pilot has completed an approved training program (Requirement). This provision grants pilots the right to perform and certify these checks subject to completion of the "approved training program." The AD does not specify which authority approves the training program in the text supplied; it simply requires the program be "approved" (Requirement).

Documentation duty:

• The Flight Manual must be amended by inserting the page supplied with the ASB before the next flight (Requirement 3; Compliance). The AD thereby creates an immediate documentation obligation tied to the manufacturer’s ASB.

Rights and remedial pathways:

• Operators who already complied with the original AD/EC 135/10 are treated as compliant with this amendment for the same requirements (Background). This retrospective recognition is a practical right for operators who implemented the original AD.

Issuer and decision authority:

• The AD is issued by the Civil Aviation Safety Authority, here shown signed by a delegate, Mike Higgins (signature block). That identifies CASA as the issuing authority and locates the regulatory decision in the administrative process of issuing airworthiness directives.

What the AD does not state (limits on duties):

• The AD does not specify repair instructions, part replacement procedures, or an explicit maintenance schedule beyond the inspection frequency. It refers inspection technique to the ASB and channels further action to CASR 21.197 if the bearings are out of position. The AD therefore allocates technical remediation and permission to fly to the regime in CASR 21.197 and the ASB, rather than specifying them in the AD text.

In sum, the AD imposes per-flight pre-flight inspection duties tied to a manufacturer ASB, an immediate Flight Manual amendment, a conditional prohibition on further flight where mispositioned bearings are found except under CASR 21.197, and permits pilots with approved training to perform and certify the inspections.

The AD text supplied sets out mandatory compliance actions and restrictions but does not list specific monetary penalties, criminal sanctions, or administrative fines. Enforcement mechanisms and consequences are implicit rather than explicitly enumerated in the AD text.

Express enforcement provisions in the AD:

• The AD makes further flight conditional: "If either or both of the bushings is not in the correct position, further flight is only permitted under CASR 21.197" (Requirement). That statement is the operative enforcement hook within the AD; it creates a regulatory constraint on flight operations pending satisfaction of the CASR 21.197 pathway.
• The AD sets definitive compliance timing: inspections "before the next flight, and thereafter at each pre-flight check" (Compliance). A failure to adhere to those prescribed timings would constitute non-compliance with the AD.

What the AD does not specify:

• The AD does not specify fines, licence suspensions, or direct penalty amounts in its text. The AD similarly does not explicate the procedural enforcement steps CASA will take beyond issuing the directive itself. The AD also does not specify the content of CASR 21.197, which it references as the only permitted pathway for further flight if mispositioned bushings are found. Therefore the exact administrative process for granting permission to fly under those circumstances is not detailed in the AD text supplied.

Implied enforcement and oversight:

• Because ADs are regulatory instruments issued by CASA, operators should expect CASA to enforce compliance under the broader civil aviation regulatory framework. The AD itself is a mandatory safety requirement and, where operators fail to comply, CASA enforcement and remedial powers under the Civil Aviation Safety Regulations and associated administrative frameworks could be triggered. The AD’s signature by a CASA delegate (Mike Higgins) locates formal responsibility with CASA (signature block).

Record and certification enforcement:

• The AD allows a pilot to perform and certify the inspections provided the pilot has completed approved training. This creates a compliance record that may be inspected by CASA or auditors: inspection certification by a named, trained pilot is part of compliance evidence. The AD does not state what form that certification must take, but the phrase "carried out and certified by a pilot" implies that operators must maintain a record of who performed and certified the inspection and that pilots hold the stated training.

Practical enforcement risks for operators:

• Non-compliance with the inspection schedule or Flight Manual insertion, or failure to observe the further-flight restriction where bushings are out of position, would represent contravention of the AD’s mandatory elements. The AD’s cross-references to ASB procedures and CASR 21.197 mean that enforcement action could be grounded in failure to follow the ASB inspection technique or failure to obtain the required permission to fly after a non-conforming inspection.

In short, the AD sets mandatory actions and a conditional grounding regime but leaves specific penalty mechanisms to the general CASA regulatory enforcement framework rather than spelling them out in the AD text itself. The only explicit operational prohibition in the AD is that further flight is only permitted under CASR 21.197 when bushings are not correctly positioned.

The AD explicitly cross-references both manufacturer material and external regulatory instruments, thereby creating legal and procedural interactions rather than standalone technical requirements.

References to manufacturer documentation:

• The AD requires inspections "in accordance with Alert Service Bulletin (ASB) EC135-62A-021, dated 23 June 2005" and requires insertion of a flight manual page attached to that ASB (Requirement). The ASB is the technical source for the inspection methods and the Flight Manual content. The AD therefore binds operator compliance to the content of the ASB; operators will need to have the ASB accessible and integrated into maintenance and operational procedures to demonstrate compliance.

Interaction with Australian regulatory framework:

• The AD is issued by CASA and explicitly references CASR 21.197 as the regulatory pathway allowing further flight when bushings are out of position (Requirement). The AD itself does not reproduce or summarise CASR 21.197; it makes compliance with that regulation a condition for continued flight in specific circumstances. This creates a procedural interaction: the AD prescribes detection obligations; CASR 21.197 governs the exceptional permission to fly. Operators must therefore consult CASR 21.197 to understand the conditions and approvals required to continue flight in those circumstances.

International regulatory interactions:

• The AD includes a note stating "Luftfahrt-Bundesamt Airworthiness Directive D-2005-233 (issued in accordance with Article 10.1 of European Union Regulation 1592/2002) refers." That places this Australian AD in an international context, indicating that the LBA issued an AD on the same matter under EU law. The AD thus aligns Australian action with at least one foreign authority’s airworthiness directive. Practically, this signals that operators who comply with the LBA AD (D-2005-233) may already meet the technical requirements, subject to the AD’s applicability in Australia.

Retrospective compliance recognition:

• The AD expressly states that "Prior compliance with requirements of AD/EC 135/10 constitutes compliance with the same requirement of this amendment" (Background). That shows an interaction across AD versions: compliance history under the original AD is recognised, avoiding duplication. It therefore affects compliance obligations through time and prevents double-dipping on enforcement where prior compliance occurred.

Limits on AD scope relative to other law:

• The AD does not purport to amend or replace other statutes or regulations outside the airworthiness domain. It instead integrates with the CASA regulatory framework and with manufacturer technical guidance. Where the operator is subject to other contractual obligations (for instance, lease agreements requiring maintenance standards, or operating certificates), those may require steps beyond those in the AD, but such interactions are not addressed in the AD text.

Operational consequence:

• Because the AD ties the permissibility of flight after detecting mispositioned bushings to CASR 21.197, there is an operational dependency: compliance with the AD requires coordination between the operator and the CASA regulatory process defined in CASR 21.197. The AD’s correction of a regulatory reference in Requirement 2 (stated in the Background) reduces the risk of mismatch between the AD and other regulations and clarifies the precise regulatory interaction required.

In summary, the AD operates by incorporating manufacturer technical requirements (ASB), by delegating exceptional permission to another Australian regulation (CASR 21.197), and by aligning itself with an LBA/EU AD. Operators must therefore read the AD together with ASB EC135-62A-021 and CASR 21.197, and may rely on prior compliance with AD/EC 135/10 for this amendment’s obligations.

The AD provided is titled AD/EC 135/10 Amdt 1 and dated as Amendment 24/2012. The document records an amendment purpose and a brief timeline of prior action.

Key historical points in the AD text:

• The original issue of this Airworthiness Directive (AD/EC 135/10) became effective on 30 June 2005 (Background).
• This instrument is an amendment issued to correct a regulatory reference in Requirement 2 (Background). The AD therefore operates as a corrective amendment rather than introducing a new technical obligation beyond re-stating inspection and documentation requirements.
• The amendment itself becomes effective on 6 December 2012 (Compliance). The AD is dated 29 November 2012 and signed by Mike Higgins, Delegate of CASA (signature block).
• The AD includes the explicit statement that "Prior compliance with requirements of AD/EC 135/10 constitutes compliance with the same requirement of this amendment" (Background). That provision recognises and preserves the legal effect of earlier compliance, removing the need for re-performance where the original AD had already been complied with.

Cross-jurisdictional linkage in the history:

• The AD includes a note referencing Luftfahrt-Bundesamt Airworthiness Directive D-2005-233, which was issued under Article 10.1 of European Union Regulation 1592/2002 (Note). That suggests the original issue dated 2005 had been linked to a contemporaneous LBA/EU directive and that CASA’s amendment continues to reflect that international lineage.

Administrative signature and authority:

• The AD is signed by "Mike Higgins, Delegate of the Civil Aviation Safety Authority" with a date of 29 November 2012. The 6 December 2012 effective date indicates a short interval between signature and legal effect, which is typical for ADs that require urgent operational compliance.

Nature of the amendment:

• The AD states that the amendment "is issued to correct a regulatory reference in Requirement 2" (Background). There is no indication in the text supplied that the amendment changed the technical inspection method, inspection frequency, or the substantive safety measures from the original AD. The compliance statement that prior compliance suffices confirms that the amendment is primarily an administrative correction of a regulatory citation.

What the history does not include:

• The AD does not include a legislative history beyond the 2005 original AD and the 2012 amendment. It does not set out consultation records, alternative options considered, cost estimates, or stakeholder submissions. It also does not include any subsequent amendments after 2012 in the text supplied.

For operators and auditors, the practical consequence is that compliance records showing adherence to AD/EC 135/10 (2005) will satisfy the requirements of AD/EC 135/10 Amdt 1 (2012), and that the 2012 action adjusted a regulatory cross-reference rather than imposing new inspection techniques or frequencies.

The AD text supplied contains no references to litigation, appeals, judicial review, or legal disputes arising from AD/EC 135/10 or this amendment. The document does not record any court decisions, administrative appeals, or legal challenges either to the original AD or to the amendment. It contains the standard administrative material: applicability, requirements, compliance timing, background factual basis, and signatures.

Consequences of the absence of litigation references in the AD text:

• The lack of litigation history in the document indicates that, at least as of the date of this AD (29 November 2012) and in the text supplied, CASA did not record or announce ongoing or concluded court proceedings related to the AD. It does not preclude that litigation occurred elsewhere or later, but such events are not reflected in this document.
• For practitioners seeking precedential or interpretative guidance, there is no case law or adjudicative history within the AD text to consult. Any interpretive disputes about scope, the meaning of "approved training program," or the application of CASR 21.197 would therefore not be resolved by this AD text and would require reference to external legal decisions or regulatory guidance not supplied here.

Practical note for counsel and compliance officers:

• Where operators require legal certainty on how CASA will apply or enforce the AD, or want to challenge a CASA enforcement action or interpretation, the absence of litigation markers in the AD text means that counsel will need to search CASA records, administrative decisions, or court databases for any subsequent cases. The AD itself does not provide litigated interpretation.

In short, the supplied AD contains no litigation history. Any inquiry about legal disputes arising from this AD must proceed to external sources beyond this AD document.

This AD contains several features that may create operational or compliance pitfalls if not carefully managed. The AD text itself is concise, but its precise wording produces a number of practical risks for operators.

1. Per-flight inspection frequency language

• The AD requires the two bearing inspections "before the next flight, and thereafter at each pre-flight check" (Compliance). Operators must translate "each pre-flight check" into their operational context. For multi-leg daily operations, that may mean inspecting before every flight leg. Failure to incorporate this into checklists risks non-compliance.

2. Lower bearing inspection requires opening the gear cover

• Requirement 2 instructs opening the gear cover to inspect the lower plain journal bearing. In some operating environments, opening that cover may have implications for maintenance personnel, jacking or safety precautions, tools, or access panels. Operators who assume the lower bearing check is trivial visual inspection without any procedural safeguards may expose themselves to safety and compliance risk.

3. Pilot certification is permitted but tied to unspecified "approved training program"

• The AD permits a pilot to "carry out and certify" the inspections provided the pilot has completed an "approved training program" (Requirement). The AD does not specify who approves the training program, the content or standard of the training, or the evidentiary form of the approval. Operators relying on pilot-performed inspections must confirm what constitutes an "approved" training program under CASA or otherwise, and ensure documentation of the approval. Absent clarity, relying on pilot certification without explicit training approvals risks non-compliance on audit.

4. Further flight only permitted under CASR 21.197 , procedural uncertainty

• If bushings are not in the correct position, the AD states further flight is only permitted under CASR 21.197 (Requirement). The AD does not summarise CASR 21.197’s requirements or process. Operators that find bearings out of position must consult CASR 21.197 to understand the approval pathway, documentation, maintenance action or conditions for return to service. Assuming informal permission or a stop-gap remedy without invoking CASR 21.197 could breach the AD.

5. Flight Manual insertion timing and control

• Requirement 3 requires insertion of a flight manual page attached to the ASB into the Flight Manual before the next flight (Requirement; Compliance). Depending on an operator’s Flight Manual change control procedures, this may require formal approval steps, documenting the change in the log, revising distributed copies, or otherwise controlling revision status. Failure to ensure the Flight Manual insertion is captured in the operator’s revision control system may render the operator non-compliant.

6. Amendment corrected a regulatory reference

• The Background states the amendment "is issued to correct a regulatory reference in Requirement 2" (Background). Operators who complied with the original AD should verify whether their compliance actions referenced the old regulatory citation. Although the AD recognises prior compliance, operators should confirm records to ensure the correction does not create ambiguity in audits.

7. Limited technical detail in the AD

• The AD relies on ASB EC135-62A-021 for inspection methodology and the attached Flight Manual page for procedural information. Operators need to possess and review the ASB. Relying on a paraphrase of the AD without the ASB content risks missing key inspection steps or criteria for "correct position" of the bushings.

8. Evidence and record-keeping expectations are not explicit

• The AD does not state precisely what records are required, how long to retain them, or who should hold them. However, the AD requires certification of inspections and Flight Manual amendment insertion. Operators must decide on an auditable record process for inspection certifications, training approvals, and Flight Manual changes to show compliance.

9. Potential immediate operational disruption if mispositioning is detected

• The Background reports that a shifted plain journal bearing can cause limited collective controls and potential loss of helicopter control. The AD’s instruction to restrict further flight unless CASR 21.197 is satisfied can result in immediate removal of the aircraft from service pending remediation and approval. Operators should be prepared for the logistical and financial consequences of such a stoppage.

10. International alignment but local legal effect

• The AD notes the Luftfahrt-Bundesamt AD reference and the EU regulation context. Operators that operate internationally must reconcile the Australian AD requirements with any foreign airworthiness directives and with any bilateral or local requirements. Aligning documentation across jurisdictions can be a source of error if not synchronised.

Each of these "gotchas" can be managed by explicit operational controls, but the AD text itself provides limited procedural detail beyond the reference to the ASB and CASR 21.197. Operators should therefore avoid assuming implicit permissions and should document how they interpret and implement each AD requirement.

This section sets out concrete steps, strictly drawn from and consistent with the AD text, for operators to align practice with the AD’s requirements. The AD mandates three discrete actions and the timing for each. Follow these steps exactly as stated in the AD, and ensure record-keeping to demonstrate compliance.

Step 1 , Obtain the referenced ASB and Flight Manual page

• Acquire Alert Service Bulletin EC135-62A-021 dated 23 June 2005 and the flight manual page attached to that ASB. The AD requires inspections to be performed "in accordance with" that ASB and requires insertion of the attached Flight Manual page into the Flight Manual (Requirement).

Step 2 , Update Flight Manual before the next flight

• Insert the flight manual page attached to ASB EC135-62A-021 into the Flight Manual before the next flight after the AD’s effective date (Requirement 3; Compliance). Control the amendment in accordance with your operations manual and record the insertion as a Flight Manual amendment. Ensure all crew copies and distributed manuals are updated or continuous page inserts are managed.

Step 3 , Implement pre-flight inspection procedure

• Implement the upper plain journal bearing visual inspection in accordance with ASB EC135-62A-021. Conduct this inspection before the next flight after the effective date and thereafter at each pre-flight check (Requirement 1; Compliance).
• Implement the lower plain journal bearing inspection (opening the gear cover) as set out in ASB EC135-62A-021. Conduct this inspection before the next flight after the effective date and thereafter at each pre-flight check (Requirement 2; Compliance).

Step 4 , Train and approve pilots if using pilot-performed certification

• If you propose to have pilots perform and certify the inspections, ensure each pilot completes an "approved training program" as the AD requires (Requirement). The AD does not specify who approves the training program; operators should confirm the applicable approving authority (for example CASA or the operator’s internal approvals), obtain written approval, and maintain training records. Document the training content so it maps to the inspection steps required by ASB EC135-62A-021.

Step 5 , Establish inspection certification and record-keeping

• Create and maintain an auditable record that demonstrates each inspection was performed in accordance with the ASB and the AD timing. If a pilot performs the inspection and certification, record the pilot’s identity, the training approval evidence, date/time of inspection, and the result of the inspection. Retain records in accordance with your continuum-of-care documentation policy and in a manner available for CASA inspection.

Step 6 , Action on non-conforming findings

• If either or both bushings are not in the correct position on inspection, do not fly except in accordance with CASR 21.197. The AD makes further flight conditional on CASR 21.197; therefore immediately refer to CASR 21.197 to determine and follow the procedure for obtaining permission to fly or for achieving return to service. Log the non-conforming condition and initiate maintenance intervention per the ASB and applicable maintenance procedures.

Step 7 , Coordinate maintenance and operational responses

• Because the lower bearing inspection requires opening the gear cover, ensure maintenance staff or appropriately trained personnel are available where necessary, and record any maintenance actions performed. If a repair or part replacement is required, follow the ASB and applicable maintenance regulations for parts, sign-off, and return-to-service.

Step 8 , Confirm prior compliance where applicable

• If your aircraft complied previously with AD/EC 135/10, retain evidence of that compliance. The AD states that prior compliance with AD/EC 135/10 constitutes compliance with the same requirement of this amendment (Background). Maintain these records for audit purposes.

Step 9 , Update operational manuals and checklists

• Incorporate the inspection steps and Flight Manual changes into your pre-flight checklists, operations manual, and maintenance control procedures. Make sure line crews and pilots are briefed on the inspection requirements and the procedure to follow if an out-of-position bushing is detected.

Step 10 , Prepare for operational disruption

• Given the safety risk identified in the Background,that a shifted plain journal bearing can limit collective control movement and potentially result in loss of control,plan for the logistical consequences of aircraft grounding, including alternative transport, passenger/customer communication, and maintenance scheduling.

These compliance steps strictly follow the AD’s text. The AD ties both the method and the content of inspections to ASB EC135-62A-021 and makes the procedural outcome for non-conformance dependent upon CASR 21.197. Operators should not substitute alternate inspection methods or remediation pathways without explicit manufacturer instructions or regulatory approval.

If any ambiguity arises in the course of complying with the AD, especially about what constitutes an "approved training program" or the application of CASR 21.197, operators should seek clarification from CASA or the relevant approved authority, and document any guidance received.