AD/S-92/5 - Tail Rotor Pitch Change Bearing Assembly

The AD revolves around a narrow technical hazard and a prescriptive remedial regime. The hazard is a failure mode of a tail rotor pitch change shaft and bearing assembly, and an associated servo clevis shaft failure which in an incident caused loss of tail rotor control. The AD frames the problem and prescribes primary responses conforming to standard airworthiness practice: immediate inspection, follow the manufacturer’s Alert Service Bulletin procedures for inspection, and replacement of failed components.

Key technical concepts spelled out by the AD text are:

• Applicability: The AD applies only to Model S-92A helicopters that have the tail rotor pitch change shaft and bearing assembly part-number 92358-06303-041 installed. The AD therefore targets a defined piece of hardware, not all S-92As generally.
• Borescope inspection: The AD mandates borescope inspection as the inspection technique, with two access points. The tail rotor side inspection is to follow the ASB Accomplishment Instructions paragraphs 3.A.(1)-(7) and Figure 4. The servo side inspection is to be performed through the oil filler cap following ASB paragraphs B.(1)-(9) and Figures 2 and 3. The AD does not reproduce the inspection acceptance/rejection criteria; it directs the operator to the ASB for detailed procedures and figures.
• Replacement on failure: Requirement 3 instructs that if the shaft bearing fails the inspection detailed in Requirement 1, the shaft and bearing assembly must be replaced. The AD does not specify a replacement part number explicitly for the replacing unit; it states “replace the shaft and bearing assembly” but the applicability and context identify the implicated assembly as part number 92358-06303-041.
• Procedural references: The AD cross-references the Sikorsky ASB No. 92-64-002 dated 3 August 2007 and Maintenance Manual SA S92A-ANM-000. It also refers to FAA AD 2007-17-05 as a related document.
• Timing: The AD sets multiple, brief time windows for compliance measured in hours time-in-service (TIS): primary inspection within 20 hours TIS after the effective date; inspection between 10 and 15 hours TIS after installing a shaft and bearing assembly; and a listed direction “Before further flight after the effective date of this AD.” The AD places immediate short-term operational constraints on aircraft scheduling and component installation.

These concepts combine to make the AD a targeted, time-sensitive maintenance mandate. The AD replaces open-ended monitoring with specific inspection procedures and a clear remedial action (replacement) when inspection criteria are not met. The instrument does not itself set out acceptance/rejection criteria in its text; the operator must consult the ASB paragraphs and figures that the AD specifically cites.

The AD identifies the population affected precisely: Model S-92A helicopters with a tail rotor pitch change shaft and bearing assembly part number 92358-06303-041 installed. That is the single technical precondition for applicability stated in the AD’s Applicability box. The following actors are therefore within scope:

• Operators and owners of Model S-92A helicopters that have the specified assembly installed. The AD’s Requirements and Compliance entries place obligations on the operator to perform inspections and replacements within the stated timeframes.
• Licensed maintenance personnel and organisations who perform borescope inspection and component replacement. The AD directs compliance with specific ASB accomplishment instructions and figures (ASB No. 92-64-002), which requires maintenance organisations to follow those manufacturer procedures when performing the mandated borescope inspections.
• Engineers and maintenance planners responsible for component installation scheduling. The compliance windows apply both to existing installations (within 20 hours TIS after the effective date) and to future installations (inspect between 10-15 hours TIS after installing a shaft and bearing assembly). That creates obligations whenever the relevant assembly is installed or already present.
• Aircraft managers and continuing airworthiness managers who must ensure the inspections are incorporated into maintenance records and that replacements are effected where required. The AD references Maintenance Manual SA S92A-ANM-000 as pertaining to the subject of this AD, signalling that continuing airworthiness documentation and procedures will need to incorporate the AD and associated ASB instructions.
• Regulatory personnel and delegated authorities. The AD is issued by CASA and signed by a Delegate of the Civil Aviation Safety Authority, denoting regulatory oversight and the instrument’s mandatory character within Australian civil aviation.

The AD does not explicitly name passengers, lessors, insurers, or third parties. It does not allocate cost responsibility in express terms. However, because the Requirements create maintenance obligations applying to operators and owners of affected helicopters, those entities will carry the direct functional responsibility for arranging, funding and documenting the borescope inspections and any replacements. The AD also makes no provision in its text for exemptions, alternative methods of compliance (AMOCs), or waivers; none are stated in the supplied text.

For organisations that operate mixed fleets, the AD’s narrow applicability limits the affected fleet subset to S-92As with that specific part number installed. Operators therefore must identify which individual airframes have the part number 92358-06303-041 and assess compliance obligations per airframe. The AD also references an FAA AD, which could matter for operators who operate international fleets and must align differing authorities’ directives; the AD notes the FAA AD only as a reference (Note 2), it does not, within the supplied text, incorporate or vary the FAA requirements.

The AD imposes prescriptive duties on operators and maintenance personnel for the affected helicopters. The duties, as set out verbatim and by reference in the AD, are:

• Duty to inspect (Requirement 1 and 2): Operators must borescope inspect each affected shaft and bearing assembly. Two distinct inspections are required: (a) inspect the shaft and bearing assembly at the tail rotor side by following the Accomplishment Instructions, paragraphs 3.A.(1) through (7), and Figure 4 of Sikorsky ASB No. 92-64-002 dated 3 August 2007; and (b) inspect each shaft and bearing assembly on the servo side through the oil filler cap by following the Accomplishment Instructions paragraphs B.(1) through (9) and Figures 2 and 3 of the same ASB. Requirement 2 restates the obligation to carry out the inspections detailed in Requirement 1.
• Duty to replace on failure (Requirement 3): If the shaft bearing fails the inspection as detailed in Requirement 1, operators must replace the shaft and bearing assembly. The AD states “replace the shaft and bearing assembly” but does not specify an exact replacement part number or a supplier in the AD’s own text; the implicated assembly and context indicate the subject part number but the AD does not spell out replacement part procurement or traceability requirements.
• Duty to comply with timing windows (Compliance box): The AD sets three compliance timeframes: perform the primary inspection within 20 hours TIS after the effective date of the AD unless previously accomplished; perform the inspection between 10 and 15 hours TIS after installing a shaft and bearing assembly; and a further entry in the Compliance box reads “Before further flight after the effective date of this AD.” The AD therefore imposes time-limited duties that must be met as part of the aircraft’s continuing airworthiness regime.

Rights: The AD text as supplied does not enumerate rights such as an express right to an alternative method of compliance or a right to appeal in the document itself. The AD does, however, incorporate manufacturer procedures by reference (the Sikorsky ASB and the Maintenance Manual SA S92A-ANM-000), which gives operators a clear pathway to follow. The AD also refers to the FAA AD, which operators may consult to ensure consistency across jurisdictions. The absence of an explicit AMOC or appeals clause in the supplied AD text means that any administrative or legal remedies, discretionary exemptions, or alternative compliance pathways (if available) would be governed by broader regulatory practice or separate CASA processes not recited in the provided text.

Operationally the duties create obligations for identification of affected airframes, scheduling of borescope inspections by appropriately qualified personnel, and replacement of components found non-compliant. Because the AD embeds the ASB’s inspection procedures rather than reproducing them, the duties include an implied duty to obtain and apply the ASB and the relevant maintenance manual pages. The AD does not allocate funding or state who pays; that absence leaves the operator or owner as the practical payer responsible for performing the work and procuring replacement parts, although this allocation is an implication from the AD’s requirements rather than an express term in the AD.

The supplied AD text does not itself state civil or criminal penalties, nor does it detail the enforcement process that will follow non-compliance. The instrument is formatted as an Airworthiness Directive and is signed by a delegate of the Civil Aviation Safety Authority, which indicates it is a regulatory instrument issued by a regulator. However, within the text provided there are no explicit penalty clauses, infringement notices, or administrative sanction mechanisms set out.

The AD does show formal characteristics of a mandatory airworthiness measure: it names the affected equipment, sets mandatory inspections and replacement requirements, prescribes compliance timeframes, and references the manufacturer’s ASB and maintenance manual for the accomplishment instructions. These features typically mean the AD creates compliance obligations that air operators and maintenance organisations must meet under the regulatory system, but the AD itself does not specify the enforcement steps or penalties that CASA may apply for non-compliance.

Because the AD is issued by a regulatory authority (CASA), it should be read in the regulatory context in which such directives sit. The supplied text identifies the issuing authority (Delegate of the Civil Aviation Safety Authority) and the effective date (30 August 2007), but enforcement mechanisms such as notices, suspension of certificates, fines, or orders are not recorded in the AD document as provided. Likewise, the document does not state whether continuing flights with non-compliant components are immediately prohibited or subject to flight-termination instructions beyond the compliance timeframes already set out in the table. One entry in the Compliance box reads “Before further flight after the effective date of this AD,” which implies a pre-flight compliance requirement for at least some element of the AD, but the AD does not expand on enforcement modalities in the text supplied.

For parties required to comply, the practical enforcement environment will therefore be determined by the applicable statutory and regulatory framework for civil aviation safety in Australia as administered by CASA outside the AD text itself. Any detailed enforcement response, remedial notices, or penalties for breach would be applied by the regulator under its broader statutory powers, but those powers, procedures and penalty amounts are not described in the AD text supplied.

Within the confines of the provided AD text, interaction with other instruments is shown principally by cross-reference. The AD explicitly cites and interacts with the following documents:

• Sikorsky Aircraft Corporation Alert Service Bulletin No. 92-64-002, dated 3 August 2007. The AD requires operators to follow specific paragraphs and figures in this ASB for the required borescope inspections (Accomplishment Instructions paragraphs 3.A.(1)-(7) and Figure 4 for tail rotor side inspection; paragraphs B.(1)-(9) and Figures 2 and 3 for servo side inspection). By doing so the AD incorporates the ASB’s methods and figures into the regulatory requirement, effectively giving the ASB an operational, normative role in achieving compliance with the AD.
• Maintenance Manual SA S92A-ANM-000. The AD contains Note 1 stating that the maintenance manual pertains to the subject of the AD. This reference links the AD to aircraft maintenance documentation and suggests that the maintenance manual’s procedures and references should be used in the context of accomplishing the AD.
• FAA AD 2007-17-05 Amdt 39-15163 dated 9 August 2007. The AD includes Note 2 referencing the FAA AD. That reference indicates alignment or correspondence between CASA’s AD and the FAA’s AD on the same matter. The AD does not adopt or reproduce text from the FAA AD in the supplied document; it merely records the FAA action as a related instrument.

The AD’s interaction with other laws beyond these operational documents is not described in the supplied text. There is no express cross-reference to Australian statutory provisions, civil aircraft regulations, or enforcement statutes within the AD itself. The absence of such explicit cross-references in the AD text means that any legal effect beyond the immediate maintenance requirement,such as how the AD modifies continuing airworthiness obligations under broader CASA regulations or how non-compliance triggers regulatory sanctions,must be located in the wider legislative and regulatory framework administered by CASA and is not set out within this AD.

For operators with obligations under multiple jurisdictions, the explicit citation of the FAA AD provides a point of comparison. Operators that must comply with both FAA and CASA directives can consult both ADs for consistency; the CASA AD’s reliance on the Sikorsky ASB and the FAA AD reference suggests the same technical corrective action was promoted across jurisdictions contemporaneously. The AD does not, in the supplied text, reconcile any differences between jurisdictions or provide guidance on precedence where instruments diverge.

In short, the AD interacts directly with manufacturer documentation (the ASB and maintenance manual) by reference and notes a related FAA AD, but does not, within the supplied text, set out how it fits into the suite of statutory enforcement powers or cross-border regulatory obligations beyond those references.

The supplied AD text does not include an explicit amendment history for AD/S-92/5 itself beyond its issuance details: the document is captioned “AD/S-92/5 Tail Rotor Pitch Change Bearing Assembly 11/2007 TX,” signed by Charles Lenarcic as Delegate of the Civil Aviation Safety Authority on 27 August 2007, and states that the AD becomes effective on 30 August 2007. The AD also contains a cross-reference (Note 2) to the FAA AD 2007-17-05 Amdt 39-15163 dated 9 August 2007, and cites Sikorsky ASB No. 92-64-002 dated 3 August 2007.

There are no subsequent variations, supersessions, or amending entries recorded within the text supplied. The document’s header contains duplicative labelling lines (AD/S-92/5 appears several times in the provided source), but no later amendment numbers, revision dates, or replacement AD references are present. The AD’s internal notes reference other documents but do not describe corrective amendments to the AD itself.

Because the AD relies on an external manufacturer ASB for the detailed steps, any subsequent changes to the ASB or issuance of later service bulletins might be relevant to operators. However, the AD text as provided does not record any formal amendment mechanism such as an update to incorporate later ASB revisions or a stated shelf-life for the referenced ASB. Any later amendment history of the AD , for example, if CASA later issued a superseding AD, revised compliance windows, or withdrew the AD , is not contained in the supplied text.

Where a practitioner needs to know whether this AD has been amended or superseded, the supplied AD does not provide that information and a search of CASA’s AD registry or current airworthiness directives database would be required. The supplied text only records the AD’s original issue and effective date and its references to contemporaneous documents (Sikorsky ASB dated 3 August 2007 and FAA AD dated 9 August 2007).

The AD text supplied contains no litigation history, case citations, court decisions, or references to litigation arising from the AD. There are no judicial proceedings, appeals, or tribunal outcomes recorded within the AD document as given. The AD is a technical regulatory instrument whose immediate focus is the mandated inspection and replacement procedure, and the supplied text does not mention any past or ongoing litigation connected to the subject matter.

Absent any litigation references in the supplied AD, no source-supported statements about legal challenges, judicial review, or enforcement proceedings can be made from the document itself. If a user requires information on whether this AD has been the subject of litigation, an external search of administrative law and aviation case law databases, or CASA enforcement records, would be necessary; that material is not present in the provided text and therefore cannot be summarised here.

The AD’s narrow scope and short compliance windows create several practical implementation points that operators and maintenance organisations must observe carefully. These are matters of timing, documentation, access method, and reliance on external procedural material. Each of these is stated or clearly implied in the AD text:

• Narrow applicability requires accurate parts traceability. The AD applies only to Model S-92A helicopters with shaft and bearing assembly part number 92358-06303-041 installed. Operators must be able to identify, on each airframe, whether that exact part number is fitted. If their parts records are incomplete, they risk either failing to comply (if an affected part is present but not identified) or expending unnecessary effort (if parts are misidentified). The AD places the onus on the operator to determine applicability; the AD itself does not provide alternative identification criteria.
• Reliance on external documents for inspection criteria. The AD requires inspections “by following” specified paragraphs and figures of Sikorsky ASB No. 92-64-002. The AD does not reproduce the acceptance/rejection criteria or the precise steps; operators must obtain and apply the ASB’s Accomplishment Instructions paragraphs 3.A.(1)-(7), B.(1)-(9) and the referenced figures. That means practitioners must ensure they have the correct ASB revision and interpret the ASB’s steps correctly. Similarly, Note 1 points to Maintenance Manual SA S92A-ANM-000 as pertaining; any inconsistency between the ASB and the maintenance manual must be identified and resolved by the operator in line with normal maintenance governance.
• Limited inspection access may complicate logistics. The AD requires borescope inspection of the shaft and bearing assembly at two locations: the tail rotor side and the servo side through the oil filler cap. Borescoping through an oil filler cap implies limited visual access and requires appropriate borescope equipment and personnel skilled in borescope inspection techniques. If operators are not equipped or certified for that work, they will need to outsource to suitably qualified facilities, potentially at short notice given the AD’s tight time windows.
• Short compliance windows. The AD requires inspection “within 20 hours TIS after the effective date of this AD” unless previously accomplished, and an inspection “between 10 and 15 hours TIS after installing a shaft and bearing assembly.” Those are short timeframes in operational terms; scheduling inspections within 20 hours TIS may require maintenance to be prioritised immediately following the AD’s effective date. The AD became effective on 30 August 2007 with the delegate signing on 27 August 2007, indicating a short lead time between issue and effect which increases scheduling pressure.
• Consequence of failed inspections. Requirement 3 requires replacement if the shaft bearing fails the inspection. The AD does not specify replacement part procurement, whether particular part numbers or approved parts must be used, nor whether ferry flights or special flight permits are permitted for repositioning to effect the replacement. The Compliance box contains “Before further flight after the effective date of this AD” which suggests some actions must be taken prior to further flight, but the AD text does not delineate whether replacement must in all cases occur before any next flight or whether a temporary limitation could be authorised under separate regulatory processes. Operators must assume replacement is required on a failed inspection and plan to remove the helicopter from service until the requirement is met.
• Lack of stated enforcement and administrative relief in the AD text. The AD does not list an alternative method of compliance (AMOC) process or an explicit appeal mechanism in the supplied text. If an operator seeks to use an alternative inspection method, procedure or timing, the AD as provided does not set out the pathway; operators will need to rely on CASA processes outside the AD to obtain relief.
• Cross-jurisdictional reference without harmonisation detail. The AD notes the FAA AD but does not indicate whether any differences in compliance approach exist; operators who must satisfy multiple authorities should verify cross-acceptance rather than assume equivalence.

Each of these points is supported by the AD’s text: the Applicability box identifies the exact part number; the Requirement box specifies the ASB paragraphs and figures for inspections; the Compliance box gives the short time windows; Note 1 and Note 2 cross-reference the maintenance manual and FAA AD. The AD therefore requires that operators act quickly, confirm parts identity, obtain ASB and maintenance manual instructions, schedule borescope-capable technicians, and be prepared to replace components found to be non-compliant.

The AD’s compliance path is tightly specified and relies on the Sikorsky ASB and the maintenance manual for procedure detail. The following stepwise compliance roadmap restates and organises the AD’s instructions into actionable steps strictly grounded in the AD text:

1. Confirm applicability for each airframe. Verify whether the Model S-92A helicopter has a tail rotor pitch change shaft and bearing assembly with part number 92358-06303-041 installed. The Applicability box in the AD establishes this part-number condition as the trigger for the AD’s requirements.

2. Obtain the referenced documents. Acquire Sikorsky Aircraft Corporation Alert Service Bulletin No. 92-64-002, dated 3 August 2007, and ensure you are reading the Accomplishment Instructions paragraphs 3.A.(1) through (7), paragraph B.(1) through (9), and Figures 2-4 which the AD cites. Also have Maintenance Manual SA S92A-ANM-000 available, since Note 1 states it pertains to the subject of this AD. The AD does not reproduce the ASB steps, so compliance requires following the ASB as cited.

3. Schedule borescope inspections within the AD’s timeframes. The Compliance box sets three timeframes:

   • For helicopters with the affected assembly already installed, complete the inspection within 20 hours TIS after the effective date of the AD (30 August 2007), unless the inspection has already been accomplished. This is Compliance item 1.
   • For helicopters on which a shaft and bearing assembly is installed after the effective date, perform the inspection between 10 and 15 hours TIS after installing the shaft and bearing assembly. This is Compliance item 2.
   • Note Compliance item 3 reads “Before further flight after the effective date of this AD.” Operators should interpret this in conjunction with the ASB and their regulatory obligations to establish whether any detected defects or replacements must be completed before the next flight. The AD itself does not elaborate beyond this phrase.

4. Perform borescope inspections following the ASB. Specifically:

   • Inspect each affected shaft and bearing assembly at the tail rotor side using the steps in ASB Accomplishment Instructions paragraphs 3.A.(1)-(7) and Figure 4.
   • Inspect each shaft and bearing assembly on the servo side through the oil filler cap using ASB Accomplishment Instructions paragraphs B.(1)-(9) and Figures 2 and 3. Use appropriately trained maintenance personnel and borescope equipment. The AD prescribes borescope inspection technique and the ASB provides the procedural detail.

5. Evaluate inspection results against ASB criteria. The AD requires replacement if “the shaft bearing fails the inspection, as detailed in Requirement 1 of this AD.” The AD itself does not present pass/fail criteria; those criteria will be in the ASB. Operators must apply the ASB’s acceptance/rejection criteria exactly as cited by the AD.

6. Replace the shaft and bearing assembly where required. Requirement 3 mandates replacement where the ASB-based inspection is failed. The AD does not specify the replacement part details in the supplied text beyond “replace the shaft and bearing assembly,” so operators must use approved parts and procedures consistent with the maintenance manual and applicable regulatory approval processes. Confirm replacement parts meet approved part-number and airworthiness standards before installation.

7. Document compliance. The AD does not specify record-keeping procedures, but usual continuing airworthiness practice is to record AD compliance in the aircraft maintenance log or continuing airworthiness records. Note 1’s reference to the maintenance manual implies that existing maintenance record-keeping practices and manual procedures should be used.

8. Check related ADs and bulletins. The AD notes FAA AD 2007-17-05 (Amdt 39-15163 dated 9 August 2007) in Note 2. Operators should consult that FAA AD and any subsequent CASA communications to determine if there are additional or differing requirements to reconcile.

9. If seeking relief or an alternative means of compliance, engage CASA. The AD supplied does not list an AMOC or appeals process. If an operator believes an alternative inspection method, different timing, or a specific operational workaround is necessary, that must be pursued through CASA’s standard regulatory engagement processes (not set out in the AD text provided).

10. Plan logistics and supply. Given the AD’s short compliance windows and the potential need for component replacement, operators should plan for parts availability, borescope-equipped maintenance slots, and potential out-of-service time for affected airframes. The AD does not provide ferry allowances, special flight permits, or exemption clauses in the text supplied; operators must manage each helicopter’s schedule to meet the AD’s prescribed timing.

In sum, compliance requires identifying affected airframes, obtaining the cited ASB and maintenance manual, performing the specified borescope inspections within the stated TIS windows, replacing failed components, and documenting the work. The AD provides the prescriptive steps and timing but delegates procedural detail to the manufacturer’s ASB and the maintenance manual referenced.