AD/OH-58/2 - Pylon Support Link Assemblies

The Directive operates through a narrow set of technical concepts and terms that control applicability and the required maintenance response. The key elements are:

• Applicability by model and part number. The AD applies to "Model OH-58A (Bell 206A-1) series helicopters, including all certificated versions, with pylon support links part number 206-031-508-5 or -7, installed" (Applicability). That creates a targeted population defined by airframe model and installed part number.

• Two inspection pathways. The inspection regime is split into inspections described in Part II and Part III of Bell Helicopter Service Bulletin No. 206-01-73-2 Revision A (Requirement 1; Requirement 2). The AD does not contain the inspection steps; it makes compliance conditional on following those specific parts of the service bulletin or any later FAA-approved revision. The language "or later FAA approved revision" ties the required method to a version approved by the FAA rather than leaving permissive interpretation to other authorities.

• Quantitative defect threshold. The Directive sets a quantitative acceptance criterion: "If the bearing inner race measures more than 1.255-inches in diameter ... replace the link assembly" (Requirement 1). The presence of any crack in the link is also an immediate reject criterion ("or there is any crack in the link, before further flight, replace the link assembly" , Requirement 1). For the Part III inspections, cracking likewise requires replacement before further flight (Requirement 2).

• Immediate flight prohibition pending remediation. Where an inspection discloses the cited defects, the directive uses the phrase "before further flight" to require replacement prior to operating the helicopter (Requirement 1; Requirement 2). That creates an operational stoppage until the required maintenance is completed.

• Terminating action by parts replacement. The Directive designates installation of pylon support links part number 206-031-589 as a terminating action to the AD's requirements (Requirement 2). That provides an alternative to repeated inspections and replacements that otherwise would recur at the specified 25-hour interval.

• Compliance schedule. Timing obligations are explicit. Requirement 1 must be done "within 10 hours time in service after the effective date of this Directive" unless already accomplished. Requirement 2 initial inspection is "within 25 hours time in service after compliance with Requirement 1, and thereafter at intervals not to exceed 25 hours time in service" (Compliance). The Directive also sets an effective date (becomes effective on 28 August 2008).

• External reference note. The AD includes a note that "FAA AD 73-08-03 Amdt 39-1622 refers" (Note). The AD therefore situates itself in part against an FAA action, but does not reproduce or restate the FAA AD’s content beyond referencing it.

These concepts narrow the AD’s scope to a specific technical risk (pylon support link failure) and prescribe precise inspection criteria, timing, and a hardware-based terminating remedy.

The Directive explicitly affects operators and owners of Bell OH-58A (206A-1) series helicopters that have pylon support link assemblies with part numbers 206-031-508-5 or 206-031-508-7 installed (Applicability). That group includes:

• Registered operators and owners of the specified model and configuration. The applicability language limits the regulatory obligation to those helicopters with the identified part numbers installed. Where those part numbers are not present, the Directive’s requirements do not apply.

• Maintenance organisations and certificated maintenance personnel who perform inspections and replacements. Compliance requires following Parts II and III of the Bell Helicopter Service Bulletin No. 206-01-73-2 Revision A or a later FAA-approved revision. Those procedures will normally be executed by qualified maintenance technicians or organisations authorised to perform the work, who must obtain and follow the referenced service bulletin to satisfy the Directive.

• Parts suppliers and installers. The terminating action requires installing pylon support links part number 206-031-589. Suppliers of that part and organisations that procure or fit them will be implicated where operators elect the terminating action. The AD creates a demand for the terminating part among the affected helicopter population.

• Flight operations and schedulers. Because the Directive includes a "before further flight" prohibition if certain defects are found, flight operations personnel must arrange for non-operational time and grounding for helicopters undergoing remedial replacement. The compliance schedule , an initial inspection within 10 hours TIS and recurrent intervals of 25 hours TIS after the initial Part III inspection , will affect maintenance scheduling, particularly for aircraft with frequent flight hours.

• Regulatory personnel and certificating authorities. The Directive is issued by the Civil Aviation Safety Authority (CASA) as an Airworthiness Directive (signed by David Villiers, Delegate of CASA). It establishes an enforceable requirement applicable to the listed aircraft in the issuing jurisdiction.

The Directive does not name specific lessees, insurers, or third-party service providers, but the obligations and timelines are such that owners, operators and certificated maintenance organisations will carry direct operational impact. The Directive does not address helicopters without the specified pylon support link part numbers, and it does not create obligations for other aircraft types.

The Directive creates a set of enforceable duties for operators and maintenance organisations that fall within its applicability, and it provides a single explicit operational option that functions as a "right" to terminate ongoing obligations.

Duties

• Identify applicability. Operators must determine whether their aircraft are within scope by checking if the pylon support links installed are part number 206-031-508-5 or -7 (Applicability). This identification is a precondition to the other duties.

• Perform inspection required by Part II. Unless already accomplished, the operator must inspect the pylon support link assemblies "in accordance with Part II of Bell Helicopter Service Bulletin No. 206-01-73-2 Revision A, or later FAA approved revision" within 10 hours time-in-service after the Directive’s effective date (Requirement 1; Compliance). That inspection must establish whether the bearing inner race measures more than 1.255 inches in diameter or whether there is any crack in the link.

• Replace defective links before further flight. If the bearing inner race measures more than 1.255 inches, or if any crack is present in the link, the operator must "before further flight, replace the link assembly" (Requirement 1). The text frames replacement as mandatory and immediate with respect to flight operations.

• Perform inspections required by Part III and recurrent inspections. The operator must "inspect the pylon support link assemblies in accordance with Part III of Bell Helicopter Service Bulletin No. 206-01-73-2 Revision A, or later FAA approved revision" initially within 25 hours time-in-service after compliance with Requirement 1, and thereafter at intervals not to exceed 25 hours time-in-service (Requirement 2; Compliance). Any cracking detected requires replacement "before further flight" (Requirement 2).

• Use FAA-approved revisions of the Service Bulletin. Inspections must follow either Revision A of the specified service bulletin or a later revision that has FAA approval (Requirement 1; Requirement 2). That implies maintaining access to and following the correct revision of the manufacturer’s service documentation as approved by the FAA.

Rights / Options

• Terminating action by installing P/N 206-031-589. The Directive explicitly provides that "Installation of pylon support links part number 206-031-589 constitutes terminating action to the requirements of this Directive" (Requirement 2). Operators therefore have the option to install the specified part to cease the recurring inspection regime and the ongoing replacement risk for the inspected part numbers. This functions as an elective compliance pathway: continuing inspections and replacements is one path; retrofitting the designated part number is an alternative that removes the AD's recurring burdens.

Procedural implications

• Timing constraints. The duties include precise timing obligations: 10 hours TIS for the initial Part II inspection (unless already done), and initial and recurrent 25-hour TIS windows for the Part III inspections. Those constraints require operators to track time-in-service carefully and schedule maintenance accordingly.

• "Before further flight" threshold. The Directive uses "before further flight" to describe when replacements must occur after defect discovery, which imposes an immediate operational constraint on aircraft found to have the specified defects.

The Directive does not enumerate rights beyond the terminating action, and it does not provide for alternatives to the specified inspections or other means of compliance in the text. It also does not specify record-keeping requirements or who must certify the completion of the inspection or replacement in the AD text itself.

The AD text supplied does not specify criminal, civil, or administrative penalties, nor does it set out enforcement mechanisms in detail. The document is presented and signed as an Airworthiness Directive by a CASA delegate (signed "David Villiers, Delegate of the Civil Aviation Safety Authority" and dated 14 July 2008). The AD indicates an effective date ("This Airworthiness Directive becomes effective on 28 August 2008") but contains no explicit penalty clause or enforcement procedure in its body.

From the content of the Directive itself, the following points about enforcement and practical legal effect can be drawn strictly from the text:

• Issuing authority. The Directive is issued under the authority of the Civil Aviation Safety Authority, as evidenced by the signature and the heading style identifying it as an AD (header AD/OH-58/2; signature). The text identifies the instrument as an Airworthiness Directive, which by form is a regulatory maintenance requirement.

• Command-and-control style requirement. The AD imposes mandatory actions (inspections and replacements) and fixed compliance windows (10 hours; 25 hours) with the explicit phrase "before further flight" for remedial replacement. Those directives are prescriptive rather than advisory.

• No penalties stated. The AD does not, within the supplied text, state the consequences of non‑compliance or describe a prosecution or administrative enforcement pathway. Nor does it attach monetary fines, suspension terms, or other sanctions in the body provided.

• Reference to external documents for technical compliance. The AD requires compliance with specific parts of a manufacturer’s Service Bulletin and with "later FAA approved revision[s]" if present. Where compliance requires following such external documents, enforcement of the AD would logically depend on demonstrating whether the requisite inspections and replacements were made in accordance with those documents and within the timeframes specified, but the Directive text itself does not set out how conformity is to be evidenced.

Given the text’s silence on penalties, recipients needing certainty about enforcement or sanctions must seek authoritative regulatory guidance outside the AD text , for example, CASA regulatory instruments or national aviation regulations , because the AD as provided does not state enforcement mechanisms or consequences of non-compliance. The document does, however, set definitive operational constraints ("before further flight") which create mandatory action points for operators once defects are discovered.

Within the supplied text, the only cross-reference to another jurisdictional instrument is the Note stating "FAA AD 73-08-03 Amdt 39-1622 refers" (Note). The Directive therefore acknowledges an FAA airworthiness action addressing related subject matter but does not reproduce or restate that FAA AD’s content. The AD requires compliance with manufacturer service bulletin revisions "or later FAA approved revision" (Requirement 1; Requirement 2), which binds the required inspection procedures to FAA approval for any revision beyond Revision A. These two references indicate two interaction points:

• Link to FAA approvals and FAA ADs. The AD ties procedural compliance to the Bell Helicopter Service Bulletin only "Revision A, or later FAA approved revision", making the FAA the approving authority for any later revision that would be acceptable for compliance. The Note that the FAA AD "refers" indicates that an FAA AD has addressed, or is related to, the same technical issue. The Directive therefore establishes a path of technical alignment with FAA-determined methods and standards: operators must use a revision that has FAA approval if it is later than Revision A.

• No other legislative or regulatory cross-references are provided. The Directive does not cite Australian Civil Aviation Regulations, criminal or civil enforcement provisions, or other national instruments in the supplied text. It also does not reference international agreements beyond the single FAA link.

Because the AD itself lacks explicit language about how it is to be implemented relative to other Australian laws or regulations, the text alone does not describe whether operators' obligations under the AD modify, supersede, or sit alongside other statutory maintenance or airworthiness requirements. The AD's ties to FAA approval and the FAA AD suggest a technical harmonisation with FAA measures, but the Directive does not state the legal mechanics of that harmonisation within Australian law.

Operators needing a legal determination of how compliance with this AD interacts with their broader statutory obligations should consult the CASA regulatory framework and guidance outside the AD text, since the AD as supplied neither provides nor disclaims interactions beyond the explicit reference to FAA materials.

The supplied document contains limited material relevant to amendment history. The AD header and dates provide the following data points:

• AD identification. The AD is identified as AD/OH-58/2 and is dated 9/2008 in the header rows that repeat the AD identifier and subject heading.

• Service Bulletin reference and revision. The AD requires inspections "in accordance with Part II of Bell Helicopter Service Bulletin No. 206-01-73-2 Revision A, or later FAA approved revision" and similarly for Part III. The reference to "Revision A, or later FAA approved revision" implies that later revisions may exist and may be acceptable for compliance, provided they are FAA approved. The AD therefore permits amendment to the technical inspection method by relying on later FAA-approved revisions of the stated Service Bulletin.

• Issue and effective dates. The Directive signature block shows the date 14 July 2008 (signed by David Villiers). The compliance block states, "This Airworthiness Directive becomes effective on 28 August 2008." The header labels the document 9/2008, which is consistent with an AD issuance in the 2008 series.

• No recorded amendments in the supplied text. The AD text as provided does not show any amendments, rescissions, supersessions, or replacement ADs. It does not include a history table showing prior or subsequent amendment actions. The only temporal qualifiers included are the Service Bulletin revision clause and the effective date details.

• Terminating action as a change path. The provision that installing pylon support links part number 206-031-589 "constitutes terminating action to the requirements of this Directive" provides an internal pathway to terminate the AD’s inspection and replacement obligations for a given aircraft, but it is not itself an amendment to the AD text. It is a substantive provision within the AD that changes an aircraft’s compliance regime upon installation of the specified part.

Because the document is a snapshot of the AD as issued, anyone needing an authoritative amendment history should consult CASA’s official records or AD amendment logs. The AD text supplied does not contain an explicit amendment history beyond the initial issuance and the allowance for later FAA-approved service bulletin revisions.

The supplied AD text does not disclose any litigation history. There are no references to court proceedings, disputes, appeals, stays, or administrative review decisions attached to this Directive within the text provided. The document presents the Directive as a regulatory instrument signed and dated by a CASA delegate, with no notation of legal challenge or subsequent judicial or administrative action.

If recipients or stakeholders require information about litigation or challenges to this AD, they will need to search external sources such as CASA public records, tribunal or court databases, or industry bulletins. The AD itself does not contain or reference any such materials. The absence of litigation history in the AD text means the document should not be read as asserting there have been no legal challenges; it simply does not report them.

This Directive contains precise technical and procedural elements that create potential compliance traps if misread or incompletely followed. The following points are drawn directly from the text and identify practical risks of non-compliance or misunderstanding:

• Narrow applicability by part number. The AD applies only where pylon support links part number 206-031-508-5 or -7 are installed (Applicability). Operators who assume the AD applies to other pylon support link part numbers risk unnecessary action; conversely, operators who fail to check exact part numbers risk non-compliance if their aircraft have the listed parts.

• Reliance on the specific parts of the Service Bulletin. The inspections are mandated "in accordance with Part II" and "in accordance with Part III" of Bell Helicopter Service Bulletin No. 206-01-73-2 Revision A, or a later FAA-approved revision (Requirement 1; Requirement 2). The AD does not reproduce the inspection steps; therefore, compliance requires access to and faithful execution of the specified parts of the service bulletin. Failing to follow the correct part of the service bulletin , for example, using a different part or a non-FAA-approved revision , would not meet the Directive’s textual requirements.

• Dimensional threshold expressed in imperial units. The rejection criterion for the bearing inner race is an absolute dimension: "more than 1.255-inches in diameter" (Requirement 1). Maintenance and inspection personnel must measure in those units or appropriately convert and document equivalent tolerances. Misinterpreting the measurement or tolerance could lead to incorrect acceptance or rejection decisions.

• "Any crack" threshold. The Directive uses an absolute standard for cracking: any crack requires replacement (Requirement 1; Requirement 2). That minimal tolerance for crack presence increases the likelihood of replacement where small cracks might otherwise be judged acceptable in other contexts, and it creates low ambiguity: any crack reported triggers the "before further flight" replacement requirement.

• Immediate grounding if defects found. The phrase "before further flight, replace the link assembly" appears twice (Requirement 1; Requirement 2). Practically, that wording requires the aircraft to be taken out of service until the replacement is completed. That may not be obvious to flight crews or schedulers unfamiliar with the legal phrasing; misinterpretation could lead to unairworthy operations.

• Short initial compliance window. The initial inspection per Requirement 1 must be completed "within 10 hours time in service after the effective date of this Directive" unless already done (Compliance). For operators with frequent flight hours, 10 hours TIS can elapse rapidly; failure to track TIS relative to the AD effective date may lead to late inspections.

• Recurring inspection interval. Part III inspections must begin within 25 hours TIS after compliance with Requirement 1 and recur at intervals not to exceed 25 hours TIS (Compliance). The relatively short recurrence interval means operators must plan maintenance cycles to accommodate inspections that may interrupt operations at frequent intervals unless they elect the terminating action.

• Terminating action requires specific part number installation. The AD provides a terminating action only if pylon support links P/N 206-031-589 are installed (Requirement 2). Operators who install different replacement parts, even if claimed by some suppliers to be equivalent, will not achieve the AD’s terminating action unless the installed part matches the exact part number. The AD text contains no approval mechanism for alternative terminating parts.

• Dependence on FAA approval for later service bulletin revisions. The AD permits later revisions of the service bulletin only if FAA-approved. If Bell issues a later revision that is not FAA-approved, it would not be acceptable for AD compliance under the supplied text. Operators must verify FAA approval status for any revision they intend to use.

• No enforcement or penalty details contained. The Directive itself does not state penalties or enforcement procedures (Penalties and enforcement). Operators expecting to find explicit sanctioning language in the AD will not find it here; legal consequences of non-compliance must be sought in the broader regulatory framework because the AD does not set them out.

• Potential supply constraint for terminating parts. The AD requires installation of P/N 206-031-589 for terminating action. If supply of that part is limited, operators who want the terminating action may face delays or higher replacement costs; the AD text does not address availability or alternative paths while awaiting parts.

Taken together, these points mean that operators must: confirm exact part numbers installed, obtain and follow the correct Service Bulletin parts and FAA approval status, track aircraft time-in-service against the stated windows (10 hours and 25 hours), measure the bearing inner race accurately to the stated dimension, treat any crack as mandatory replacement before further flight, and procure the exact terminating part number if they wish to end the recurring inspection regime.

The Directive prescribes a clear, stepwise compliance pathway. The following actionable procedure follows the Directive’s text precisely. Operators should document each step and retain records consistent with their own regulatory obligations outside the AD text.

1. Confirm applicability.

   • Verify the helicopter model is Model OH-58A (Bell 206A-1) series, including all certificated versions.
   • Confirm whether the pylon support link assemblies installed on the helicopter are part number 206-031-508-5 or 206-031-508-7. The AD applies only where those part numbers are present (Applicability).

2. Obtain the correct service bulletin revision.

   • Acquire Bell Helicopter Service Bulletin No. 206-01-73-2, Revision A, or verify any later revision is FAA approved. The Directive requires inspection "in accordance with Part II" and "in accordance with Part III" of that Service Bulletin, or a later FAA-approved revision (Requirement 1; Requirement 2). Ensure the version used is either Revision A or bears FAA approval if it is later.

3. Perform initial inspection per Part II.

   • Unless already accomplished, within 10 hours time-in-service after the AD’s effective date (28 August 2008), perform the inspection procedures in Part II of the Service Bulletin (Compliance; Requirement 1).
   • Measure the bearing inner race diameter accurately. If the inner race measures more than 1.255 inches in diameter, replace the link assembly before further flight (Requirement 1).
   • Inspect for any crack in the link. If any crack is present, replace the link assembly before further flight (Requirement 1).

4. Schedule and perform Part III inspections.

   • Initially perform the Part III inspection within 25 hours time-in-service after compliance with Requirement 1 (i.e., after completing the Part II inspection) (Compliance; Requirement 2).
   • Continue performing Part III inspections at intervals not to exceed 25 hours time-in-service (Compliance; Requirement 2).
   • If cracking is detected during any Part III inspection, replace the link assembly before further flight (Requirement 2).

5. Replace defective assemblies immediately.

   • Where the inspection criteria in Parts II or III indicate replacement is necessary (inner race >1.255 inches or any crack), ensure the link assembly is replaced "before further flight" (Requirement 1; Requirement 2). Do not return the aircraft to flight until replacement is completed in accordance with the Service Bulletin procedures.

6. Consider terminating action.

   • To terminate the AD’s inspection and replacement requirements for an aircraft, install pylon support links part number 206-031-589. The AD states that installation of that part number "constitutes terminating action to the requirements of this Directive" (Requirement 2). Confirm that the replacement part number is correctly installed and documented.

7. Document work and compliance timing.

   • Record the date, time-in-service, and particulars of the inspections and any replacements, including serial numbers and part numbers fitted, to demonstrate compliance with the specified time windows (10 hours for initial Part II inspection unless already done; initial Part III within 25 hours after Requirement 1 compliance; recurring Part III every ≤25 hours). The AD text requires compliance within those windows but does not specify record-keeping details; operators should keep robust records to substantiate compliance in their own regulatory context.

8. Confirm technical conformity to FAA-approved procedures.

   • If using a Service Bulletin revision later than Revision A, confirm that the revision has FAA approval. The AD limits acceptable inspection procedures to Revision A or later FAA-approved revisions (Requirement 1; Requirement 2).

9. Plan operationally for possible grounding.

   • Because replacements are mandated "before further flight" when defects are found, plan for potential aircraft grounding time and arrange parts, qualified maintenance personnel and logistical support to complete replacements promptly.

10. Liaise with parts suppliers and maintenance providers.

    • If electing the terminating action, secure genuine pylon support links part number 206-031-589 and ensure installation by appropriately qualified technicians according to the manufacturer’s instructions.

Following these steps will align operator actions with the Directive’s explicit requirements. The AD prescribes inspection procedures and replacement thresholds but not the detailed repair tasks; those are found in the specified parts of Bell Helicopter Service Bulletin No. 206-01-73-2 Revision A or a later FAA-approved revision, and adherence to those technical procedures is required for compliance.