AD/OH-58/5 - Main Rotor Trunnion

The directive rests on a small set of operational and technical concepts stated in the text.

• Applicability by part number and model: The AD applies only to Model OH-58A (Bell 206A-1) series helicopters "with main rotor trunnions part number 206-010-104-3, 206-011-113-001, or 206-011-120-001, installed" (Applicability). This creates a threshold that requires checking the installed trunnion part number before the AD's substantive requirements flow.

• Inspection method and standard: The mandated inspection is a magnetic particle inspection "in accordance with Bell Helicopter Alert Service Bulletin 206-80-7 Rev. A, or later FAA approved revision" (Requirements 1-4). The AD therefore makes the manufacturer technical procedure the normative inspection technique; practitioners must use the specified service bulletin text (or a later FAA‑approved revision) to meet the AD.

• TIS‑driven schedules: The AD divides affected trunnions into four TIS categories (less than 1,100 hours; >1,100 and <1,700; ≥1,700; and time unknown) and links each to specific timing for the initial inspection and repeating intervals (Requirements; Compliance). The Compliance cells use both absolute and relative triggers: "Before accumulating 1,200 hours", "Within the next 100 hours time in service", and repeating intervals "not to exceed 600 hours".

• Immediate action on defect detection: The directive requires that if a crack is detected "during any inspection, before further flight, replace the cracked trunnion with a serviceable trunnion" (Requirement). That imposes a strict no‑flight‑with‑defect rule: discovery of cracking halts flight until replacement.

• Reassembly and maintenance documentation: If no cracking is detected, reassembly and installation of the main rotor hub must be performed "in accordance with the applicable Model 206 Maintenance and Overhaul Manual" (Requirement). The AD therefore binds not only the inspection method but also the reassembly practice to the manufacturer's maintenance manual.

• Terminating action via a specified part: The AD explicitly provides a terminating action: installation of trunnion part number 206-011-113-103 ends the AD's recurring inspection requirements ("Installation of trunnion part number 206-011-113-103 constitutes terminating action to the requirements of this Directive" , Requirement/Note).

• Referential link to FAA AD: The AD records “Note: FAA AD 80-18-04 R1 Amdt 39-3954 refers.” This indicates that the CASA AD is cross‑referenced to an FAA AD and therefore likely aligns with the FAA's safety determination and prior regulatory action (Note).

Those are the principal legal and technical levers in the instrument as published. The AD therefore combines prescriptive technical direction (use the named service bulletin and maintenance manual), temporal triggers tied to component TIS, and a path to permanent compliance relief by installing the specified replacement part.

The document names a clearly bounded set of stakeholders.

• Aircraft operators and owners of Model OH-58A (Bell 206A-1) series helicopters that have installed one of the three specified trunnion part numbers. The Applicability clause limits the AD to helicopters "including all certificated versions; with main rotor trunnions part number 206-010-104-3, 206-011-113-001, or 206-011-120-001, installed." Operators will therefore need to check logbooks and physical parts to establish whether the AD applies to their aircraft.

• Maintenance organisations and engineers charged with performing magnetic particle inspections and reassembly work. The AD requires compliance "in accordance with Bell Helicopter Alert Service Bulletin 206-80-7 Rev. A, or later FAA approved revision" and reassembly per the Model 206 Maintenance and Overhaul Manual. Those procedural references mean maintenance personnel must have access to and follow the specified technical documentation.

• Parts suppliers and component manufacturers for the specified trunnion numbers. The terminating action is an installation of trunnion part number 206-011-113-103; suppliers or manufacturers of that part are directly implicated because that part offers a route to terminate recurring inspections under this AD. The AD does not identify who supplies that part, only that its installation constitutes terminating action.

• Regulatory bodies and delegated officials. The AD is signed by "David Villiers, Delegate of the Civil Aviation Safety Authority" and becomes effective 28 August 2008. While the document itself does not list enforcement mechanisms, the issuer is explicit: CASA (via its delegate) is the issuing authority.

• Record‑keepers and auditors. Because the AD prescribes inspections at fixed intervals and requires replacement before flight if cracking is found, those who maintain maintenance records and demonstrate regulatory compliance will be implicated by the AD’s temporal schedule and the terminating action status tied to a specific part number.

Notably absent from the text are provisions for subsidies, cost sharing, or explicit enforcement penalties. The AD therefore imposes technical and timing obligations on the named operators and maintenance providers without setting compensatory measures or enumerating sanctions in the instrument itself. Practitioners should treat the AD as binding on the identified aircraft and trunnions, and plan to allocate inspection, maintenance, and parts procurement responsibilities accordingly.

Duties imposed by the AD are concrete and prescriptive. The instrument does not set out statutory rights or remedies; it prescribes what must be done to remain compliant.

Primary duties

• Conduct magnetic particle inspections. For affected trunnions, the AD requires "accomplish a magnetic particle inspection in accordance with Bell Helicopter Alert Service Bulletin 206-80-7 Rev. A, or later FAA approved revision" (Requirements 1-4). The inspection duty is specified identically across the four trunnion TIS categories, but the timing differs by category.

• Observe the prescribed inspection schedule. The Compliance text sets initial and repeat inspection timings:

  • For trunnions with less than 1,100 hours TIS: "Before accumulating 1,200 hours and repeat before accumulating 2,400 hours, and thereafter at intervals not to exceed 600 hours" (Compliance item 1).
  • For trunnions with more than 1,100 hours and less than 1,700 hours TIS: "Within the next 100 hours time in service and repeat before accumulating 2,400 hours, and thereafter at intervals not to exceed 600 hours" (Compliance item 2).
  • For trunnions with 1,700 hours or more TIS: "Within the next 100 hours time in service, and thereafter at intervals not to exceed 600 hours" (Compliance item 3).
  • For trunnions with time unknown: "Within the next 100 hours time in service, and thereafter at intervals not to exceed 600 hours" (Compliance item 4).

• Replace cracked trunnions before further flight. The AD instructs: "If a crack is detected during any inspection, before further flight, replace the cracked trunnion with a serviceable trunnion" (Requirement). This is an unequivocal grounding duty: discovery of a crack requires immediate corrective parts action prior to resumption of flight operations.

• Reassemble per the maintenance manual when no cracking is found. The AD requires that if inspection is clear, "reassemble and install the main rotor hub on the helicopter in accordance with the applicable Model 206 Maintenance and Overhaul Manual" (Requirement). This binds reassembly practice to the manufacturer's maintenance manual.

• Record and apply the terminating action if chosen. The AD states that "Installation of trunnion part number 206-011-113-103 constitutes terminating action to the requirements of this Directive" (Requirement/Note). If an operator elects to install that part, they must document the installation because it removes the recurring inspection obligation under this AD.

Rights and procedural implications

• The AD does not set out explicit administrative appeal rights, variance procedures, or exemptions within the text. It does, however, reference the specific service bulletin and FAA AD, which may provide technical means to demonstrate equivalent compliance where an FAA‑approved revision is used. The AD’s direction to follow "Bell Helicopter Alert Service Bulletin 206-80-7 Rev. A, or later FAA approved revision" implicitly permits reliance on later FAA‑approved revisions of the service bulletin, but the document does not otherwise state how to seek alternative means of compliance.

• Operators have the practical choice between repeated inspections and installing the terminating part. The AD creates a de facto compliance option: continue with the prescribed inspection cycle, or install trunnion part number 206-011-113-103 to terminate the directive’s requirements. The text does not require immediate installation of the terminating part, but it does make that installation a way to end the recurring inspection duty.

Administrative and operational implications

• Timing obligations are specified in hours TIS rather than calendar time; aircraft operators must therefore track flight hours for the relevant component or otherwise determine "time in service" to trigger the inspection obligations.

• The AD does not itself provide a schedule for re-inspection triggered by repair or replacement beyond the stated repeating intervals; practitioners must apply the Compliance intervals after any reassembly or replacement in the same way they apply after prior inspections.

Overall, duties are technical and time-linked: perform specified inspections per the named service bulletin, replace cracked parts before flight, reassemble per the maintenance manual, and optionally install the terminating trunnion part to end recurring obligations.

The published text of this AD does not specify penalty provisions or enforcement mechanisms within its content. The document records the issuing authority and effective date, which situates the AD within the Civil Aviation Safety Authority’s regulatory function, but it does not spell out sanctions, infringement processes, or administrative penalties in the AD itself.

What the instrument does state about issuance

• The AD is signed by "David Villiers, Delegate of the Civil Aviation Safety Authority" and notes an effective date of 28 August 2008 (signature block; Effective date). That locates the instrument’s origin and the date from which its obligations apply.

Absence of explicit sanctions

• The AD text contains no clause that prescribes fines, suspension, grounding powers, or criminal penalties. It likewise does not reference the compliance reporting form, logbook entry format, or CASA enforcement policy. Because the AD is an operational requirement issued by CASA, compliance is mandatory for the listed aircraft and trunnions, but the AD as printed here does not describe the enforcement tools CASA may use for non‑compliance.

Practical enforcement considerations for practitioners

• Even though the AD itself does not enumerate penalties, practitioners should plan on treating the AD as a mandatory regulatory instrument. The AD procedures and effective date create binding technical obligations; operators should therefore expect that CASA will regard failure to comply as a regulatory breach for purposes of CASA’s separate enforcement framework. The AD’s text does not specify the enforcement approach, so those seeking precise information on sanctions must consult CASA’s general enforcement instruments, statutory provisions, or seek direct guidance from CASA.

• The AD references and links to FAA AD 80-18-04 R1 Amdt 39-3954. That cross reference may be informative for technical consistency and for determining whether FAA enforcement history or FAA‑approved revision pathways exist, but the Australian AD does not itself transfer FAA penalty provisions.

In short, the AD sets mandatory maintenance and inspection duties but does not articulate penalties within its own text. The responsible regulatory enforcement mechanism and the possible sanctions for non‑compliance are not specified in the document as published and must be determined from CASA’s broader regulatory and enforcement instruments.

The AD explicitly cross‑references manufacturer guidance and a US FAA airworthiness directive. It does not cite domestic statutory provisions or administrative rules in the text provided, so interaction statements are limited to the documents and materials named.

Directly referenced materials

• Bell Helicopter Alert Service Bulletin 206-80-7 Rev. A, or later FAA‑approved revision. The AD makes the service bulletin the operational standard for the inspection methodology (Requirements 1-4). By doing so, the AD imports the technical content of the service bulletin by reference: the AD compliance path requires adherence to that manufacturer document or an FAA‑approved subsequent revision.

• Model 206 Maintenance and Overhaul Manual. The AD requires reassembly and installation of the main rotor hub "in accordance with the applicable Model 206 Maintenance and Overhaul Manual" if no cracking is detected (Requirement). That binds reassembly practice to the manufacturer's maintenance manual and thereby aligns the regulatory duty with the manufacturer's maintenance standards.

• FAA AD 80-18-04 R1 Amdt 39-3954. The AD includes a note that this FAA AD "refers." That establishes a normative relationship with the FAA action for the same technical issue and suggests that the CASA AD tracks, or is informed by, an FAA safety determination. It also means operators may look to the FAA AD for additional context or subsequent FAA‑approved revisions of the referenced service bulletin.

Implications for compliance and equivalence

• The AD permits "later FAA approved revision" of the Bell service bulletin as an acceptable standard. That creates a path for incorporating FAA‑approved changes to the inspection procedure into Australian compliance practice without the need for immediate amendment of the CASA AD. It therefore sets up an interaction in which FAA technical approvals can update the practical inspection standard relied upon by the CASA AD.

• By requiring reassembly "in accordance with the applicable Model 206 Maintenance and Overhaul Manual," the AD situates compliance within the manufacturer's document set. Where the manufacturer’s manual or the referenced service bulletin contain procedures, limitations, or inspection acceptance criteria, they will be effective means to satisfy the AD. The AD does not supersede those documents; rather, it makes compliance with them a regulatory duty for the affected trunnions.

Absent statutory cross‑reference

• The AD text itself does not cite the enabling statute, CASA’s regulatory powers, or any domestic aviation regulation clause. It therefore does not directly discuss how it interacts with statutes or regulations that govern sanctions, delegation, or appeals. Practitioners wanting to understand the AD’s place in the broader legislative scheme must consult CASA’s statutory instruments and administrative law sources outside this AD text.

In summary, the AD imports and binds to compliance two manufacturer documents (the Bell service bulletin and the Model 206 maintenance manual) and acknowledges the corresponding FAA AD. It allows subsequent FAA‑approved revisions of the service bulletin to form part of the compliance path, but it does not itself set out how this AD interfaces with domestic enforcement statutes or appeal processes.

The AD as presented includes an effective date and a cross‑reference to FAA documentation, but contains no internal record of amendment history beyond that effective date and its references.

• Effective date and signature: The AD "becomes effective on 28 August 2008" and carries the signature block "David Villiers, Delegate of the Civil Aviation Safety Authority" dated 14 July 2008 (Effective date; signature). Those are the only dated entries in the text.

• Revision of referenced documents: The AD requires compliance with "Bell Helicopter Alert Service Bulletin 206-80-7 Rev. A, or later FAA approved revision." That language admits future technical revisions of the service bulletin approved by the FAA into the CASA AD’s compliance pathway without the AD itself being formally amended in this text. The AD therefore contemplates that the procedural standard may be updated by FAA‑approved revisions of the service bulletin; those updates are not logged as amendments to the AD itself within this document.

• FAA cross‑reference: The AD notes "FAA AD 80-18-04 R1 Amdt 39-3954 refers." That indicates a corresponding FAA action and may be a source of later technical changes, but the AD does not list any subsequent CASA amendments or revisions.

What is not present

• There is no schedule of past amendments, supersessions, or revocations included in the AD text provided here. No amendment numbers, amendment dates, or modification history of the CASA AD are recorded in the document text.

Practical implication

• For operators and maintenance organisations, the lack of amendment history in the AD text means they must treat the AD as published effective 28 August 2008 and must track any separate CASA notices, bulletins, or formal amendment instruments to learn of changes to the AD after that date. The AD’s express allowance for "later FAA approved revision" of the service bulletin provides a mechanism by which the substantive inspection procedure may change without CASA issuing a fresh AD, but any change to the AD’s own legal force would require an amendment instrument outside the text presented.

The AD contains no litigation history, court citations, administrative appeals, or references to legal challenges. The text is a single regulatory instrument that records its issuance, effective date, technical requirements, and the signature of a CASA delegate, but it does not recount any legal proceedings, contested decisions, or judicial interpretations.

What the document shows

• The instrument includes a single "Note: FAA AD 80-18-04 R1 Amdt 39-3954 refers." No case names, no litigation outcomes, and no references to tribunal decisions appear in the text.

Implication for practitioners

• There is no record in the AD text of past or pending litigation relating to its substance. If a practitioner requires information about court decisions or administrative law challenges to this AD or to the corresponding FAA AD, that information is not in the AD and must be sought from case law repositories, administrative records, or CASA’s public records.

• Because the AD is an operational safety instrument rather than a statute or general regulation, it is common for ADs to be challenged on procedural grounds or issues of technical sufficiency in particular circumstances. No such litigation is recorded in the instrument itself.

In sum, the AD as presented contains no litigation history. Users needing to know whether the AD or the FAA AD it references has been the subject of legal challenge should consult separate legal resources or CASA and FAA public records.

This section highlights potential points of confusion, implementation traps, and details that require attention when applying the AD text as published.

1. Part‑numbered applicability

   • The AD applies only to helicopters with trunnions having part numbers 206-010-104-3, 206-011-113-001, or 206-011-120-001 (Applicability). Practitioners must verify the installed trunnion part number physically and in the component records. Failure to check part numbers carefully may lead to mistakenly applying the AD to unaffected aircraft or missing affected ones.

2. Mapping Requirements to Compliance intervals

   • The Requirements are numbered 1-4 and describe the inspection action associated with four TIS bands. The Compliance table then sets timing for items 1-4. The text alignment between Requirement numbers and Compliance lines must be followed precisely. For example, Requirement 1 (trunnions with less than 1,100 hours) corresponds to Compliance item 1 (inspection "Before accumulating 1,200 hours ... and thereafter at intervals not to exceed 600 hours"). Misalignment in practice could lead to incorrect inspection timing.

3. Interpretations of "Within the next 100 hours time in service"

   • For several categories (Requirements 2-4), the Compliance schedule uses the phrase "Within the next 100 hours time in service." The AD does not define the starting point for "next"; the typical operational interpretation is from the AD effective date or from discovery of the AD applicability, but the text here does not specify. Practitioners should note this ambiguity and treat the "next 100 hours TIS" as an urgent short‑term trigger, documenting the chosen calculation basis in maintenance records.

4. Terminating action limited to a specific part number

   • Installation of trunnion part number 206-011-113-103 is the AD's sole stated terminating action. If an operator installs that specific part and documents the installation, the recurring inspection obligations under this AD no longer apply for that trunnion. Practitioners must ensure the installed part number matches exactly; similar part numbers or modified parts are not stated as terminating unless they are exactly 206-011-113-103.

5. "Serviceable trunnion" undefined

   • The AD requires replacement of cracked trunnions with a "serviceable trunnion" (Requirement). The AD does not define "serviceable." In practice, operators should interpret "serviceable" to mean an airworthy, non‑cracked trunnion conforming to the maintenance manual and applicable parts standards, and they should rely on the Model 206 Maintenance and Overhaul Manual and parts traceability.

6. Reassembly requirements linked to maintenance manual

   • If inspections find no crack, reassembly must follow the applicable Model 206 Maintenance and Overhaul Manual. Be sure the maintenance organisation has the current revision of that manual and documents compliance with its procedures during reassembly.

7. FAA cross‑reference

   • The AD notes that FAA AD 80-18-04 R1 Amdt 39-3954 "refers." That cross‑reference may provide additional technical rationale, historical context, or further instruction. Practitioners looking for acceptance of alternative procedures or for FAA updates should consult the FAA AD and any FAA‑approved revisions of the Bell service bulletin.

8. Lack of penalties and enforcement detail in the AD text

   • The AD does not state penalties for non‑compliance. That absence does not mean non‑compliance is permitted; it simply means sanctioning mechanisms are not described here. Operators should assume CASA will treat the AD as mandatory and should consult CASA for enforcement and reporting procedures.

9. Dates and timing

   • The AD was signed 14 July 2008 and "becomes effective on 28 August 2008." The gap between signature and effective date could affect scheduling; practitioners must observe the effective date as the operative date for any "before" or "within" obligations that reference "next 100 hours" or similar triggers.

10. Paperwork and records

    • The AD implies the need to record inspection dates, results, replacements, and any terminating part installations because compliance is TIS‑driven and repetitive. While the AD does not detail recordkeeping formats, absence of explicit instruction is a gotcha: maintainers must ensure traceable records to demonstrate compliance to auditors or inspectors.

These are the concrete implementation pitfalls and attention points that the AD text itself suggests or creates by omission. Practitioners should plan work orders, parts procurement, and maintenance records with these specifics in mind.

The AD sets a clear procedural pathway; compliance requires the operator or maintenance organisation to carry out specified steps in sequence and document them.

Step 1 , Establish applicability

• Check each helicopter's maintenance records and physically verify the main rotor trunnion part number. The AD applies only where the installed trunnion is one of: 206-010-104-3, 206-011-113-001, or 206-011-120-001 (Applicability). If the installed trunnion is not one of those part numbers, the AD does not apply to that helicopter.

Step 2 , Determine trunnion time in service (TIS)

• For each affected trunnion establish its total TIS. The AD’s compliance schedule depends on whether the trunnion TIS is: less than 1,100 hours; more than 1,100 and less than 1,700 hours; 1,700 hours or more; or unknown (Requirements 1-4). If TIS is not recorded, the trunnion falls into the "time unknown" category for which the AD prescribes "Within the next 100 hours time in service, and thereafter at intervals not to exceed 600 hours" (Compliance item 4).

Step 3 , Apply the matching Compliance interval

• Use the Compliance wording that maps to the determined TIS category:
  • If TIS < 1,100 h: carry out the inspection "Before accumulating 1,200 hours and repeat before accumulating 2,400 hours, and thereafter at intervals not to exceed 600 hours" (Compliance item 1).
  • If 1,100 < TIS < 1,700 h: carry out the inspection "Within the next 100 hours time in service and repeat before accumulating 2,400 hours, and thereafter at intervals not to exceed 600 hours" (Compliance item 2).
  • If TIS ≥ 1,700 h: carry out the inspection "Within the next 100 hours time in service, and thereafter at intervals not to exceed 600 hours" (Compliance item 3).
  • If time unknown: "Within the next 100 hours time in service, and thereafter at intervals not to exceed 600 hours" (Compliance item 4).

Step 4 , Perform the inspection per the mandated standard

• Conduct a magnetic particle inspection strictly "in accordance with Bell Helicopter Alert Service Bulletin 206-80-7 Rev. A, or later FAA approved revision" (Requirements 1-4). Ensure the maintenance organisation uses the service bulletin revision that is FAA‑approved if a later revision is relied upon.

Step 5 , Act on inspection findings

• If a crack is found: replace the cracked trunnion with a serviceable trunnion "before further flight" (Requirement). Do not return the aircraft to service until replacement is completed and the replacement trunnion is verified as serviceable.
• If no crack is found: reassemble and install the main rotor hub "in accordance with the applicable Model 206 Maintenance and Overhaul Manual" (Requirement).

Step 6 , Consider the terminating action option

• Installation of trunnion part number 206-011-113-103 "constitutes terminating action to the requirements of this Directive" (Requirement/Note). If an operator elects this option, procure the specified part, install it per the maintenance manual and service bulletin as applicable, and record the installation event in the aircraft maintenance records to demonstrate that recurring inspections under this AD are no longer required for that trunnion.

Step 7 , Recordkeeping and scheduling

• Maintain clear records of:
  • the trunnion part number,
  • TIS at the time of inspection,
  • the date and results of each magnetic particle inspection,
  • any replacement parts installed (including part numbers),
  • reassembly actions and reference to the Model 206 Maintenance and Overhaul Manual procedures used,
  • any installation of the terminating part 206-011-113-103.
• Use the recorded TIS to schedule the next inspection at intervals "not to exceed 600 hours" as required by the Compliance section.

Step 8 , Use of later FAA‑approved service bulletin revisions

• If relying on a later FAA‑approved revision of Bell Helicopter Alert Service Bulletin 206-80-7, confirm FAA approval and use that revision for inspection work. The AD explicitly permits the use of "later FAA approved revision" of the service bulletin (Requirements).

Step 9 , Work with CASA or delegated authority for questions

• Where timing, interpretation of "within the next 100 hours", or definition of "serviceable" is unclear in a particular case, consult CASA or the delegated authority. The AD does not provide appeals or variances in the text; practical uncertainties should be resolved with CASA guidance, and all such correspondence should be filed with maintenance records.

Step 10 , Plan parts logistics and downtime

• Anticipate that discovery of cracking will require replacement before flight; plan procurement of serviceable trunnions and scheduling of maintenance windows accordingly. Also consider the terminating part installation as a discrete procurement and installation project if that route is chosen.

Following these steps will enable maintenance organisations and operators to translate the AD’s prescriptive requirements into an auditable compliance process. The AD’s own language prescribes the inspection method, replacement-before-flight rule, reassembly standard, compliance intervals, and the terminating part; compliance requires strict adherence to those textual directives and careful recordkeeping.