AD/BELL 222/44 - Disc Assemblies - Tail Rotor Driveshaft

Applicability and population control

• The directive uses narrow applicability to limit the affected fleet: "Model 230 helicopters S/N up to 23038" and only when fitted with the specified part numbers (P/N 36300-1, 37855-1 and C048354-1). That determines the universe of airframes and parts that must proceed through the AD’s steps (Applicability).

Manufacturer ASB as the technical standard

• The AD delegates detailed inspection procedures to BHTC Alert Service Bulletin ASB-230-07-37 (dated 28 March 2007), allowing "later approved revisions." The ASB is the operative technical reference for how to verify manufacturing date, thickness and indexing; the AD does not reproduce procedural steps but makes compliance to the ASB mandatory (Requirement 1).

Measurement tolerances as pass/fail criteria

• For thickness the AD sets pass/fail numeric limits per P/N in a table. The table lists minimum and maximum total thicknesses for each P/N:
  • 36300-1: 0.174 inch (4.42 mm) minimum; 0.186 inch (4.75 mm) maximum.
  • 37855-1: 0.126 inch (3.20 mm) minimum; 0.138 inch (3.50 mm) maximum.
  • C048354-1: 0.046 inch (1.16 mm) minimum; 0.051 inch (1.29 mm) maximum. These numeric tolerances convert an inferred design or manufacturing defect concern into a discrete measurement test (Requirement 2, table).

Indexing as a discrete conformity attribute

• The AD requires removal of any disc assembly "which is not properly indexed" (Requirement 3). The text does not define "properly indexed" beyond referencing the ASB, so the ASB supplies the operative method/definition for indexing checks (Requirement 1).

Timing and staged remediation

• The compliance schedule staggers remediation based on operational priorities:
  • Verification (Requirement 1): within 25 flight hours or 30 days from the effective date.
  • Removal for thickness out-of-tolerance (Requirement 2): within 10 flight hours after completion of Requirement 1.
  • Removal for incorrect indexing (Requirement 3): within 300 flight hours or at next scheduled inspection after completion of Requirement 1.
  • Prohibition on installs (Requirement 4): applies "After the effective date of this Airworthiness Directive." This staging delineates urgent measurement checks and faster removal for some defects, while permitting later correction for other defects (Compliance).

Record-keeping obligation

• If, after verification, assemblies "do not require any further action, or if the manufacturing date is not between 01 November 2005 and 30 November 2006," the directive requires "an appropriate log book entry to this effect. No further action is required." That makes a logbook declaration the formal record of compliance or a finding that no action is required (Requirement 1).

Cross-reference to foreign regulator

• The AD expressly notes "Transport Canada Airworthiness Directive CF-2007-15 dated 24 August 2007 refers." The AD is therefore issued in apparent response to findings identified by Transport Canada and aligns CASA action with that foreign regulator’s advisory (Note; Background).

Delegation and effective date

• The instrument is an Airworthiness Directive signed by "David Villiers, Delegate of the Civil Aviation Safety Authority" and "becomes effective on 3 October 2007." The document is therefore an administrative instrument with an explicit effective date (signature and effective date lines).

Technical fix prohibition

• The AD contains a continuing prohibition: "Do not install any of the disc assemblies P/N 36300-1, 37855-1 and C048354-1 into any helicopter unless it is compliant to the ASB-230-07-37 dated 28 March 2007 or later approved revisions." This restricts the future fitment of parts unless they have been rendered compliant per the ASB (Requirement 4).

Operators of affected helicopters

• The primary burden falls on operators who have Bell BHTC Model 230 helicopters with serial numbers up to 23038 and which are fitted with disc assemblies with P/N 36300-1, 37855-1 or C048354-1. These operators must verify manufacturing dates and physical conformity and then carry out removal or corrective action according to the AD’s schedule (Applicability; Requirements 1-4; Compliance).

Maintenance organisations and technical personnel

• Individuals and organisations authorised to carry out inspections and maintenance will be required to follow BHTC ASB-230-07-37 instructions for verification of manufacturing date, thickness and indexing. The AD delegates the inspection method to the ASB and therefore places technical compliance responsibility on maintenance personnel to interpret and execute the ASB procedures correctly (Requirement 1).

Parts suppliers and installers

• Suppliers and installers of the listed P/N assemblies are affected because, after the effective date, no such assembly "shall be installed" unless it "is compliant to the ASB-230-07-37 dated 28 March 2007 or later approved revisions." That affects parts distribution and fitment practices, requiring sellers and installers to be able to demonstrate ASB compliance before fitment (Requirement 4).

Aircraft owners and operators responsible for records

• The directive requires "an appropriate log book entry" where no further action is required after verification. This creates an express record-keeping duty for owners/operators or their delegated maintenance organisations to document the outcome of verification activities (Requirement 1).

Regulatory and oversight functionaries

• The instrument is issued by the Civil Aviation Safety Authority (CASA) delegate and references Transport Canada AD CF-2007-15. While the AD text does not describe enforcement mechanisms or penalties, it places the CASA delegate as the issuer of the directive and links the action to a Transport Canada determination (signature; Background; Note).

Non-affected parties

• Helicopters not of Model 230 or those Model 230s without the specified P/N disc assemblies, or those whose serial numbers exceed S/N 23038, lie outside the AD’s specified applicability and therefore are not subject to the AD’s mandatory actions as set out in the text (Applicability).

Stakeholder interactions

• Manufacturers, maintenance organisations and operators must coordinate: verification must follow the ASB, removals must occur within prescribed flight‑hour windows after verification, and logbook entries must be made where appropriate. The directive thereby requires coordination among operators, maintenance providers and parts suppliers to meet the specified deadlines and to ensure only ASB-compliant parts are installed (Requirements; Compliance).

Duties imposed by the directive

• Verify: A duty to "Verify disc assemblies P/N 36300-1, 37855-1 and C048354-1 for manufacturing date, proper thickness and indexing, in accordance with the instructions provided in BHTC Alert Service Bulletin (ASB) ASB-230-07-37 dated 28 March 2007 or later approved revisions" (Requirement 1). This is a mandatory inspection duty, and the ASB is the operative technical standard.
• Record: Where verification shows either no further action is necessary or the manufacturing date lies outside the implicated window, the operator must "make an appropriate log book entry to this effect" (Requirement 1).
• Remove for thickness beyond limits: A duty to "Remove any disc assembly which is not within the required thickness as per table below" (Requirement 2), with explicit numeric thickness limits provided per P/N.
• Remove for indexing: A duty to "Remove any disc assembly which is not properly indexed" (Requirement 3).
• Do not install unless ASB-compliant: A continuing duty not to install any of the listed P/N assemblies "unless it is compliant to the ASB-230-07-37 dated 28 March 2007 or later approved revisions" (Requirement 4).

Timing duties

• Verification must be completed "no later than 25 flight hours or 30 days from the effective date of this directive, whichever comes first" (Compliance for Requirement 1).
• Removal for thickness problems must occur "Within 10 flight hours, after the completion of requirement 1." That ties the removal deadline to completion of the verification step (Compliance for Requirement 2).
• Removal for indexing problems is deferred to allow scheduled maintenance planning: "Within 300 flight hours or at next scheduled inspection, whichever comes first, after the completion of requirement 1." (Compliance for Requirement 3).
• The installation prohibition applies from the effective date onwards (Compliance for Requirement 4).

Rights implicit in the directive’s structure

• Operators retain the right to document the verification outcome: the AD expressly allows a logbook entry to be made where no further action is required, and that entry is the formal record of compliance for those units (Requirement 1).
• Operators and maintenance organisations retain the right to comply using the ASB "or later approved revisions," which permits use of an updated ASB revision if it has been approved (Requirement 1). The AD therefore allows later, approved technical changes to supersede the original ASB procedures.

Delegated technical discretion

• The AD delegates detailed technical inspection methods and acceptance criteria for indexing and measurement to the manufacturer’s ASB, rather than setting procedural steps in the AD text itself. That gives maintenance personnel discretion to follow the ASB methodology, while making compliance to those procedures mandatory (Requirement 1).

No penalties specified in text

• The directive includes an effective date and a signature by a CASA delegate but the text supplied does not set out penalty provisions, enforcement procedures or appeal rights. The AD does, however, create specific operational obligations and time limits, the breach of which would, in practice, engage regulatory compliance scrutiny by the issuing authority , but the AD text itself does not describe sanctioning mechanisms or rights of review (signature; effective date; Compliance).

Record of foreign regulator action

• The directive explicitly records that "Transport Canada Airworthiness Directive CF-2007-15 dated 24 August 2007 refers." That provides operators with a cross-reference and, practically, the right to consult the referenced foreign regulator guidance for context or technical detail (Note).

Direct statements in the source

• The text of the Airworthiness Directive provided does not include explicit penalty provisions, monetary fines, or a step-by-step enforcement procedure. It sets mandatory actions and effective dates but does not itself state sanctions for non-compliance within the printed text (Compliance; effective date).

Issuer and legal status signalled

• The AD is issued by a named delegate ("David Villiers, Delegate of the Civil Aviation Safety Authority") and contains an explicit effective date ("This Airworthiness Directive becomes effective on 3 October 2007"). This identifies the issuing authority and establishes when the AD’s duties became operative (signature; effective date). An AD of this form is an administrative regulatory instrument; however, the provided text does not state the particular statutory provisions that empower the delegate to issue sanctions or criminal/civil penalties, and it does not record how CASA will enforce compliance in practice.

Implied enforcement mechanisms (text-bound)

• Although the document does not set out sanctions, the AD imposes concrete compliance windows and record-keeping requirements. The presence of those mandatory deadlines and the signature of a CASA delegate imply the instrument is intended to be a regulatory requirement rather than mere guidance, and that compliance will be expected by the regulator. The directive’s cross-reference to Transport Canada AD CF-2007-15 indicates coordination with a foreign regulator’s equivalent mandatory instrument (Compliance; Note; Background). The AD itself, as supplied, stops short of describing the mechanisms CASA will use to verify compliance (e.g. audits, inspections, notices) or the penalties for non‑compliance.

What the AD does require for evidentiary purposes

• The AD requires a logbook entry where no further action is needed after verification, which creates a document trail that can be used to demonstrate compliance. That is the document‑level obligation explicitly stated in the AD (Requirement 1). The AD’s timing requirements also create an evidentiary trail if the documented verification timestamps and subsequent removals are retained.

Practical enforcement considerations not specified in text

• The AD does not state whether CASA will accept compliance records from the operator, require separate inspection by the regulator, or impose specific remedial directions for non‑compliant operators. Nor does it specify appeal or review procedures relating to the AD’s technical judgments. Those matters would depend on broader regulatory frameworks and CASA’s administrative practice, but they are not set out in the supplied AD text and therefore cannot be asserted as requirements or procedures from the AD itself.

Delegation to manufacturer technical material

• The AD binds operators to a manufacturer document: "verify ... in accordance with the instructions provided in BHTC Alert Service Bulletin (ASB) ASB-230-07-37 dated 28 March 2007 or later approved revisions." That creates an interaction where regulatory compliance is achieved by following a private-sector technical document that the regulator has adopted as the technical standard (Requirement 1). The AD thereby converts the ASB into an enforceable compliance benchmark for the specified parts and helicopters.

Reference to foreign regulator action

• The AD expressly notes that "Transport Canada Airworthiness Directive CF-2007-15 dated 24 August 2007 refers." This is a cross-reference to another regulator’s AD, indicating that CASA’s action aligns with or responds to findings recorded by Transport Canada. The text thus links Australian regulatory action to an analogous foreign regulatory instrument (Note; Background).

No direct repeal or amendment of statutes in text

• The supplied AD does not amend or repeal any primary legislation. It is an administrative directive with mandatory inspection and maintenance requirements; the text does not attempt to modify statutory law. Interactions with broader aviation law, licensing or penal frameworks are not specified in the AD text.

Record-keeping and compliance evidence

• By requiring a logbook entry where no further action is required, the AD interacts with the operators’ statutory or regulatory duties to maintain maintenance records. The AD creates an explicit record duty for the actions it prescribes (Requirement 1). Any wider obligations on records under civil aviation law are not reproduced here but operators should treat the AD’s logbook entry requirement as part of their maintenance- and airworthiness‑related records.

Installation prohibition and parts commerce

• The AD’s installation prohibition constrains the commercial use and fitment of the specified P/N assemblies: "Do not install any of the disc assemblies ... unless it is compliant to the ASB." That condition interacts with supply-chain practices for spare parts and with the obligations of certificated maintenance organisations to ensure parts meet regulatory requirements prior to fitment. The AD does not, however, set import/export or trade controls, nor does it specify obligations of parts suppliers beyond the installation prohibition itself (Requirement 4).

Interaction through "later approved revisions"

• The AD allows compliance via "later approved revisions" of the ASB. That creates a dynamic interaction where subsequent technical updates approved by the relevant authority become the operative standard without needing immediate amendment of the AD text. It therefore interfaces with any approval process for ASB revisions (Requirement 1).

No direct mention of certificates, insurance or operational authorisations

• The AD does not reference air operator certificates, airworthiness certificates, insurance or other authorisations, nor does it specify consequences for those instruments if the AD is not complied with. The AD’s mandatory actions are clear, but the supplied text does not describe how non-compliance would affect those other legal instruments.

What the document records

• The supplied Airworthiness Directive itself provides a single effective date and a signature: it "becomes effective on 3 October 2007" and is signed by "David Villiers, Delegate of the Civil Aviation Safety Authority" (effective date; signature). There are no internal amendments, revision histories, or subsequent amendments recorded in the supplied text.

Allowance for later ASB revisions

• The AD expressly permits compliance using "ASB-230-07-37 dated 28 March 2007 or later approved revisions." That clause creates a mechanism by which future, approved ASB revisions may be used to satisfy the AD without reissuing the AD itself. The AD therefore recognises an external amendment channel (the ASB revision and approval process) for technical procedures and tolerances (Requirement 1).

References to external directives (Transport Canada)

• The AD references Transport Canada AD CF-2007-15 dated 24 August 2007, but it does not state whether that foreign AD has been amended or superseded. The supplied text does not include any change history to either the CASA AD or the referenced Transport Canada AD (Note; Background).

No recorded consolidations or supersessions in the supplied text

• The supplied AD does not identify any earlier CASA AD that it replaces or any later CASA AD that supersedes it. It stands as a single document with the stated effective date. If an operator requires the instrument’s amendment history beyond what is shown here, the AD text itself directs the operator to rely on "later approved revisions" of the ASB for updated technical requirements, but the AD contains no log of instrument-level amendments (entire document).

Implication for practitioners

• Practitioners should note that while the AD itself is a static instrument with one effective date in the supplied text, the operative technical standard it mandates (the ASB) is expressly allowed to change by "later approved revisions." Any subsequent ASB revision that is "approved" would thereby alter the technical method by which the AD’s duties are satisfied without an explicit update to the AD text in this document (Requirement 1).

Documentary record

• The supplied Airworthiness Directive contains no litigation history. There are no cases, appeals, or disputes referenced in the text. The AD records the administrative facts: background finding by Transport Canada, the specific mandatory actions, compliance timing, and the effective date and signature, but it does not include or summarise any court or tribunal decisions (Background; Compliance; signature).

Absence of judicial outcomes or challenges in text

• Because the AD itself does not include or reference any litigation, the supplied text provides no basis to report judicial or tribunal outcomes, challenges to the AD’s legality, or case law interpreting these requirements. The AD simply establishes technical and timing obligations without indicating whether those obligations were contested in court or administrative review (entire document).

What practitioners should do if seeking litigation history

• The AD cross-references Transport Canada AD CF-2007-15. If a practitioner needs to establish whether litigation, judicial review, or administrative challenges have arisen either in Australia or abroad in relation to these facts, they must consult external databases, regulatory records and case law sources; none of those sources or outcomes are contained in the text supplied here.

Strict applicability criteria

• The AD applies only to "Model 230 helicopters S/N up to 23038 fitted with disc assemblies P/N 36300-1, 37855-1 and C048354-1." Operators who assume the AD applies to all Bell 222/230 family helicopters or to parts with different P/Ns risk either over‑ or under‑compliance. The serial number and exact P/N combination are decisive: absence of the listed P/Ns or a serial number above the stated cap places the helicopter outside the AD’s stated applicability (Applicability).

Manufacturing date window triggers different outcomes

• The Background flags assemblies "manufactured between 1 November 2005 and 30 November 2006" as potentially defective. Requirement 1 instructs verification of manufacturing date and requires an "appropriate log book entry" if "the manufacturing date is not between 01 November 2005 and 30 November 2006." Thus a part with a manufacturing date outside that window (even if the part has the listed P/N) may require no further action beyond documentation; conversely, parts within that date window must be measured and checked (Background; Requirement 1). Failure to check the manufacturing date precisely may lead to unnecessary removals or missed defects.

Tight timing for removal after verification for thickness

• The AD requires verification within 25 flight hours or 30 days, whichever comes first, but requires removal of any discs out of thickness tolerance "Within 10 flight hours, after the completion of requirement 1." That means an operator who delays verification to the last permissible day must still effect removal within a short subsequent window. Practitioners must plan maintenance slots accordingly (Compliance for Requirements 1 and 2).

Different deadlines for different defects

• Indexing defects have a much longer remediation window ("Within 300 flight hours or at next scheduled inspection, whichever comes first") compared with thickness problems. Maintenance planners might misread the AD and treat both defects as equally urgent; the AD does not , it differentiates urgency and permits deferred correction for indexing defects (Requirement 3; Compliance).

ASB is the operative technical procedure but not reproduced

• The AD mandates adherence to ASB-230-07-37 for the verification method and for what constitutes "proper indexing," but the AD text does not reproduce the technical steps or the definition of indexing. Maintenance staff must obtain and apply the ASB. Failing to follow the exact ASB steps may result in non‑compliant verification even if measurements are recorded (Requirement 1).

Numeric measurement tolerances require calibrated measurement

• The thickness limits are narrow (for example, 0.174-0.186 inch for P/N 36300-1). Accurate measurement equipment and measurement technique as defined by the ASB will be essential. The AD does not provide alternative acceptance tests or measurement tolerances beyond the table; the specifics are binding. The AD therefore implicitly requires access to suitable metrology capability but does not specify it (Requirement 2, table).

Logbook entry is the formal record when no action is required

• If Verification shows no further action or the manufacturing date is outside the implicated window, the required compliance evidence is a logbook entry. Operators should ensure the logbook entry is "appropriate" in content so it will serve as demonstrable compliance in audit or oversight settings. The AD does not prescribe the precise wording of the entry (Requirement 1).

Prohibition on installation is unconditional after effective date

• From the effective date, the AD forbids installing the listed P/N assemblies unless they are ASB‑compliant. That affects spare-parts fitment practice and means that, even if an operator acquires a used spare after the AD’s effective date, it must verify ASB compliance before installation (Requirement 4; Compliance).

Cross-jurisdictional references may cause confusion

• The AD references Transport Canada AD CF-2007-15. Operators may want to rely on or consult that foreign AD; however, technical differences between the ASB and foreign AD or differences in how each regulator treats "approved revisions" could create confusion. The AD does not reconcile those documents within the text; operators must consult each document and the ASB to determine the exact steps (Note; Background).

No penalties or enforcement steps stated

• Because the AD text does not set out enforcement mechanisms, operators who fail to comply will not find the specific sanction or enforcement procedure within the AD itself. Practitioners should not assume absence of enforcement; rather they should treat the AD as a mandatory regulatory instrument and obtain external guidance from CASA on enforcement practice if needed (effective date; signature; Compliance).

Step-by-step compliance checklist (mapped to the AD text)

1. Identify affected airframes:

   • Query fleet records to identify BHTC Model 230 helicopters with S/N up to 23038. Limit the scope to those fitted with disc assembly P/N 36300-1, 37855-1 or C048354-1 (Applicability).

2. Obtain the operative ASB and any later approved revisions:

   • Secure BHTC ASB‑230‑07‑37 dated 28 March 2007 and verify whether any "later approved revisions" exist and are applicable. The AD makes compliance contingent on following the ASB procedures (Requirement 1).

3. Schedule and perform verification within the AD time limits:

   • Complete verification (manufacturing date, total thickness, and indexing) "no later than 25 flight hours or 30 days from the effective date" (Compliance). Use the ASB procedure to conduct verification and to establish how to inspect indexing.

4. Logbook entry where verification yields no action:

   • If, after verification, assemblies do not require further action, or the manufacturing date is outside 01 November 2005 to 30 November 2006, make "an appropriate log book entry to this effect." Ensure the entry records the date, identity of the part (P/N and serial number if available), the measured manufacturing date and the identity of the person or organisation performing the verification (Requirement 1).

5. Immediate removal for thickness out-of-tolerance:

   • If verification shows the disc assembly is outside the numeric thickness ranges in the AD’s table, remove the disc assembly "Within 10 flight hours, after the completion of requirement 1." The AD provides exact minimum and maximum thicknesses by P/N which must be used as the pass/fail criteria (Requirement 2; Compliance).

6. Removal for indexing defects within deferred period:

   • If verification reveals improper indexing, plan removal "Within 300 flight hours or at next scheduled inspection, whichever comes first, after the completion of requirement 1." Schedule maintenance slots to meet this window (Requirement 3; Compliance).

7. Do not install unless ASB-compliant:

   • From the effective date forward, do not install any P/N 36300-1, 37855-1 or C048354-1 assembly unless it is compliant with ASB‑230‑07‑37 or a later approved revision. Before fitment, obtain documentation or evidence that the part has been rendered compliant per the ASB and retain that evidence (Requirement 4; Compliance).

8. Record and retain evidence of compliance:

   • Keep the verification records, measurements, logbook entries, and any work orders or parts-traceability documents that show removed parts were measured and either discarded or replaced in accordance with the AD. Where the AD requires a logbook entry, make sure the entry is sufficiently detailed to show date, person/organisation, part identity, and outcome (Requirement 1).

9. Coordinate with parts suppliers and maintenance providers:

   • If replacement parts are needed, obtain parts demonstrated to be ASB‑compliant. The AD does not specify how compliance is to be evidenced beyond the ASB requirement; obtain whatever paperwork or certification the ASB or the supplier provides and hold it with maintenance records (Requirement 4).

10. Note cross-reference to Transport Canada AD:

    • Consult Transport Canada AD CF-2007-15 for additional context or technical detail; ensure any actions taken here are consistent with the requirements of both CASA’s AD and the referenced Transport Canada AD where that is operationally relevant (Note; Background).

Tips and practical considerations drawn from the AD text

• Make verification early: because the removal deadline for thickness issues is only 10 flight hours after verification, do not leave verification to the last permitted day if the helicopter will fly again soon.
• Ensure measurement capability matches tolerances: the thickness tolerances are narrow; use calibrated measurement equipment and follow the ASB’s specified measurement technique to avoid measurement error disputes.
• Maintain a clear trail: the AD makes a logbook entry the formal record when no further action is required; ensure entries are complete and stored according to operator record-retention practice.
• Keep the ASB and its revisions on file: because the AD permits later approved revisions, maintain a record of which ASB revision was used to perform verification and corrective work.

Final note

• The AD is effective from 3 October 2007 and was issued by a CASA delegate. Compliance actions should be planned and documented according to the AD’s explicit requirements and timelines, and the ASB procedures should be followed exactly as the technical method for verification and remediation.