AD/PC-6/51 Amdt 1 - Stabiliser-Trim Attachment Components - Inspection/Replacement

The AD rests on a small set of interlocking technical and regulatory concepts, each expressed in the text of the instrument.

• Inspection requirement tied to a service document. The AD makes the conduct of a crack inspection contingent on following Pilatus Aircraft Service Bulletin No. 53‑001 Revision 1 (dated 1 June 2005). The AD therefore imports the SB’s inspection scope, methods and affected items as the mandatory inspection procedure.

• Immediate replacement of unsafe parts. The AD imposes a hard rule: any crack‑damaged component discovered under the required inspection must be replaced before further flight. That converts an inspection finding into an immediate operational constraint (no further flight until replacement).

• Mandatory unconditional replacements. The directive requires, without inspection, the replacement of all Fairchild connecting pieces with Pilatus connecting pieces for Configuration 2 aircraft (part number 6232.0026.xx) and the replacement of fittings that bear part number 116.40.06.033 without an index with either the indexed version of the same part number or with part 116.40.06.112. Those replacements are mandated irrespective of the components’ observed condition.

• Termination of repetitive inspections. The text states that the mandated replacement of certain fittings "provides terminating action for the repetitive inspections required by HB‑86‑042." In other words, replacing those fittings ends the need to continue the repetitive inspection regime established by the earlier AD identified as HB‑86‑042 (AD/PC‑6/40).

• Technical correction to fitment tolerance. Revision 1 of the Requirement document (the SB revision) corrects the tolerance of the actuator attachment hole diameters in fitting 116.40.06.033 for Configuration 1 aircraft. The AD therefore not only mandates inspection and replacement but also introduces a corrected dimensional tolerance in the SB that forms part of the compliance standard.

• Scope and applicability. The AD delineates exact applicability by serial numbers: all PC‑6 series aircraft with serial numbers up to and including MSN 946, and all PC‑6 series aircraft manufactured by Fairchild Industries with MSN 2001 through MSN 2092. It also refers to configurations (Config. 1 and Config. 2) when specifying which parts are to be replaced without inspection.

• Compliance timing. The AD sets a concrete compliance timeframe: at the next 100‑hour inspection or within three months after 4 August 2005, whichever occurs first within that schedule. The AD itself became effective 4 August 2005, and was issued in response to a FOCA AD that superseded prior ADs.

These concepts together convert a safety incident , failure of a lower stabiliser attachment bracket , into a prescriptive maintenance regimen: inspect per a specific SB, immediately remove cracked items, unconditionally replace certain parts, and realise that certain replacements remove the need for previously required repetitive inspections. The AD thus defines both an operational prohibition (no further flight with crack‑damaged parts) and a replacement pathway that, if followed for specified parts, ends prior recurring inspection obligations.

The AD names a limited, identifiable set of affected persons and entities. Primary affected parties are owners and operators of Pilatus PC‑6 series aeroplanes that fall within the serial‑number ranges stated in the AD: all Model PC‑6 Series aircraft up to and including Manufacturer Serial Number (MSN) 946, and all Model PC‑6 Series aircraft manufactured by Fairchild Industries with MSN 2001 through MSN 2092. Those owners/operators are the parties with immediate compliance duties.

Secondary affected parties include maintainers, licensed aircraft maintenance engineers and organisations whose work includes the stabiliser‑trim attachment systems and those parts specified by the AD. The AD requires inspections in accordance with a Pilatus service bulletin and replacement of specified part numbers, so organisations responsible for supply chains (procurement of parts 6232.0026.xx, 116.40.06.033 and 116.40.06.112) and for installation work will be involved. Configuration distinctions are salient: the AD singles out Config. 2 aircraft for mandatory replacement of Fairchild connecting pieces (6232.0026.xx), and it refers to Config. 1 in respect of a tolerance correction for fitting 116.40.06.033. Maintenance providers therefore must be able to determine an aircraft’s configuration and select the correct replacement components and fitment.

Regulatory and oversight actors are also implicated to the extent that the AD is issued by a CASA delegate; the instrument cross‑references a FOCA AD (HB‑2005‑263) and notes that the FOCA action supersedes earlier ADs. Any person responsible for continuing airworthiness records (operators, maintenance organisations) will be required to record compliance with the AD and any component replacements or inspections performed in accordance with service bulletin No. 53‑001 Rev 1.

Finally, supply sources for replacement parts are materially affected. The AD requires unconditional replacement of some parts, which creates immediate demand for Pilatus connecting pieces and indexed fittings or alternate part 116.40.06.112. The AD does not itself specify suppliers or availability, but by mandating immediate replacement and linking compliance to an SB, it places burden and cost on operators and maintainers to source the required components and execute downtime for replacement within the stated compliance window.

Duties

• Perform inspection per Pilatus SB No. 53‑001 Revision 1. The AD requires a crack inspection "in accordance with Pilatus Aircraft Service Bulletin No. 53‑001 Revision 1, dated 1 June 2005." The obligation to follow that specific SB makes its procedures the operative standard for the inspection.

• Replace any crack‑damaged component before further flight. The AD states that if cracks are found during the required inspection, "before further flight, replace any crack damaged components." That imposes an immediate grounding obligation until replacement is carried out and recorded.

• Replace certain parts without inspection. The AD mandates replacement without inspection of Fairchild connecting pieces part number 6232.0026.xx installed in Config. 2 aircraft with Pilatus type connecting pieces. It likewise mandates replacement without inspection of fittings part number 116.40.06.033 where the part number has no index, with either an indexed 116.40.06.033 or with part number 116.40.06.112. These replacements are unconditional and not contingent on observed damage.

• Comply within a set time window. Compliance must occur "at the next 100 hour inspection or 3 months after 4 August 2005." The AD therefore sets a concrete scheduling duty and an effective date (4 August 2005).

• Follow amended SB tolerances where applicable. The AD introduces Revision 1 of the requirement document, which corrects a tolerance for actuator attachment hole diameters in fitting 116.40.06.033 for Config. 1 aircraft. The duty to comply with the SB revision includes adherence to that corrected tolerance.

Rights / Operational effects that function as benefits or regulatory consequences

• Terminating action for repetitive inspections. The AD records that the mandated replacement of certain part number fittings "provides terminating action for the repetitive inspections required by HB‑86‑042 (AD/PC‑6/40)." That creates a regulatory benefit for operators who undertake the mandated replacement: once the specified fittings are replaced, they may cease carrying out the repetitive inspections previously required under HB‑86‑042, according to the AD’s statement.

• Clear compliance pathway. By tying the inspection method and tolerances to Pilatus SB No. 53‑001 Rev 1, the AD effectively grants operators and maintainers a prescriptive compliance standard. Following the SB and making the mandated replacements provides a clear route to meet the AD’s requirements.

• No inspection required before replacement for specified parts. For parts singled out for unconditional replacement, operators do not need to arrange or pay for an inspection to justify the replacement; the AD requires replacement outright, which simplifies procedural decision‑making though it imposes immediate parts cost and downtime.

Who pays and who decides (procedural rights and responsibilities)

• The operator or owner is responsible for ensuring the inspection is performed and for arranging and funding any replacements. The AD locates implementation responsibilities with those who operate and maintain the affected aircraft, and with those who are responsible for continuing airworthiness and maintenance scheduling.

• Maintenance organisations decide how to implement the SB procedures, determine configuration (Config. 1 or Config. 2), select the required replacement parts (indexed versus unindexed part numbers), and perform the installations and record compliance.

The AD does not state administrative appeal rights, alternative means of compliance, or exemptions in the text supplied. The AD also does not enumerate penalties or enforcement procedures; it sets operative duties, compliance windows and the technical steps required to meet them. Operators are therefore required to implement the inspection and replacement steps described in the AD and the SB to discharge their obligations.

The AD sets prescriptive technical obligations and a firm compliance timetable, but the text supplied does not specify monetary fines, criminal sanctions, or the procedural enforcement mechanisms that CASA may use to enforce non‑compliance. The instrument records an effective date (4 August 2005) and a compliance deadline (at the next 100‑hour inspection or within three months after that date), and is signed by a delegate of CASA, which identifies the issuing authority; however, it contains no express paragraph enumerating penalties or administrative enforcement steps.

What the AD does provide that relates to enforcement is operationally significant: it converts inspection findings into mandatory operational constraints (aircraft with crack‑damaged components identified by the required inspection must have those components replaced "before further flight"). That operational prohibition functions as a direct mechanism by which safety is enforced in practice: if an operator permits further flight after detection of crack damage, they would be operating contrary to the AD’s explicit requirement. The AD also prescribes unconditional replacement of specified parts without inspection, which again creates a definitive maintenance state required by the regulator.

Because the AD is the operative prescriptive instrument, non‑compliance would be a breach of the obligation the AD imposes. The supplied text does not describe how CASA will detect non‑compliance, what notices or directions it might issue, what administrative sanctions might apply, or whether there is a formal process for approval of alternative means of compliance. The AD does reference related FOCA and prior ADs and records that its mandated replacements provide terminating action for certain earlier repetitive inspections; this interlinking affects the applicable continuing airworthiness regime for an aircraft.

Practically, enforcement relies on the broader regulatory framework and oversight processes not included in the AD text provided. The AD itself specifies what must be done and when (inspection per SB, immediate replacement if cracks are found, unconditional replacement of named parts, compliance at next 100‑hour inspection or within three months after the effective date). Parties relying on this AD should assume that failure to comply is inconsistent with the directive, and should consult their regulator or regulatory material outside this AD for particulars on penalties, notices, or remedial enforcement action.

The AD text explicitly cross‑references and interacts with other airworthiness directives and service documents. It is issued "in response to a new FOCA AD" and notes that that FOCA AD (HB‑2005‑263) supersedes existing ADs HB‑86‑042 (AD/PC‑6/40) and HB‑2005‑080. The AD itself states that the mandated replacement of certain part number fittings "provides terminating action for the repetitive inspections required by HB‑86‑042." At minimum, therefore, the AD modifies the continuing airworthiness regime created by earlier AD HB‑86‑042 by introducing a replacement‑based terminating action for at least some of the inspections that the earlier AD required.

The AD incorporates Pilatus Aircraft Service Bulletin No. 53‑001 Revision 1 (dated 1 June 2005) by reference as the inspection standard; compliance with the SB is required by the AD. Additionally, Revision 1 of that requirement document corrects a tolerance for actuator attachment hole diameters in fitting 116.40.06.033 for Configuration 1 aircraft; the AD thereby imposes the corrected tolerance standard as part of the mandatory compliance content.

Beyond those cross‑references, the AD also notes "FOCA AD HB‑2005‑263 refers." That establishes a bilateral or reciprocal regulatory link: the FOCA AD prompted this amendment, and the Australian AD adopts the FOCA AD’s remedial mechanics in the Australian regulatory context. The AD records that Amendment 1 was issued in response to that FOCA AD, which implies alignment of regulatory action in response to the same technical issue.

The AD does not, within the supplied text, explicate how it interacts with specific statutory provisions, enforcement statutes, or the administrative processes by which CASA imposes or enforces ADs. It does not specify appeals processes, alternative compliance pathways, or exemptions. It also does not set out how operators should record compliance for certification or audit purposes outside the direct requirement to perform the inspection and to replace affected parts. Therefore the interaction is described in the instrument primarily through cross‑references to the Pilatus service bulletin and to FOCA and earlier ADs, and through the statement that certain replacements provide terminating action for specific previously required inspections.

Practically, the AD replaces or amends earlier operational requirements (HB‑86‑042 and HB‑2005‑080) to the extent described, adopts the SB revision for inspection standards, and aligns with the FOCA action that prompted the amendment. Any further legal questions about enforcement mechanisms, recordkeeping obligations under Australian aviation law, or appeals should be addressed by consulting the regulator or the governing statutes and instruments that provide the legal framework for CASA’s issuance and enforcement of airworthiness directives, none of which are specified in the AD text supplied.

The document supplied is Amendment 1 to AD/PC‑6/51. Key dates and change points recorded in the text are as follows:

• Service Bulletin revision date: The inspection is mandated to be carried out "in accordance with Pilatus Aircraft Service Bulletin No. 53‑001 Revision 1, dated 1 June 2005." The AD therefore depends on that SB revision as the operative inspection document.

• Effective date: The AD states "This Amendment becomes effective on 4 August 2005." The compliance window is tied to that date: compliance is required "at the next 100 hour inspection or 3 months after 4 August 2005."

• Issuance and signature: The AD is signed by David Villiers as "Delegate of the Civil Aviation Safety Authority" on 21 June 2005. The signature date precedes the effective date, indicating that the AD was issued and promulgated in June and set to be effective in August.

• Relationship to FOCA AD and prior ADs: The Amendment 1 is explicitly issued in response to a FOCA AD (HB‑2005‑263). The FOCA action superseded existing ADs HB‑86‑042 (AD/PC‑6/40) and HB‑2005‑080. Amendment 1 to AD/PC‑6/51 adopts a requirement that mandates replacement of certain fittings and connecting pieces, and the AD states that the mandated replacement "provides terminating action for the repetitive inspections required by HB‑86‑042." Thus, the amendment history recorded in this instrument links it to a process of harmonisation or follow‑up action in response to the FOCA directive and signals that earlier ADs are superseded to the extent indicated.

• Technical correction: Revision 1 of the Requirement document (the SB revision incorporated by the AD) includes "a correction of the tolerance of the actuator attachment hole diameters in fitting part number 116.40.06.033 of Config. 1 aircraft." That correction is part of the Amendment 1 package and is therefore part of the effective requirement.

• Applicability extension and specification: The Amendment "extends and specifies aircraft applicability" as part of its changes, thereby refining which serial numbers and which configurations are affected.

The supplied text does not include any earlier versions of AD/PC‑6/51 itself, beyond the references to prior FOCA and Australian ADs, nor does it supply a full amendment log beyond the narrative explanation that Amendment 1 responds to FOCA AD HB‑2005‑263 and supersedes certain inspections by providing terminating replacement action. The supplied instrument therefore records a single, concrete amendment event tied to a service bulletin revision and an effective date; it records the supersession of certain earlier AD inspection obligations through the replacement requirement and a dimensional correction in the SB.

The AD document supplied contains no record of litigation, judicial review, tribunal decisions, or court orders relating to AD/PC‑6/51 Amdt 1. There are no cases named, no appeals cited, and no judicial determinations noted in the text. The AD itself is a regulatory instrument prescribing technical maintenance actions and an effective compliance timetable; the supplied material does not include any subsequent or prior litigation history.

Where litigation is conceivable given the instrument’s content, the AD text does not supply particulars. Potential contestable points that could give rise to disputes , but about which the AD gives no procedural guidance or litigation history , include (a) the precise interpretation of part numbers and indices (for example whether a fitting "without an index" meets the textual definition), (b) the determination of aircraft configuration (Config. 1 versus Config. 2) for specific MSNs, (c) the adequacy or applicability of the referenced Pilatus Service Bulletin Revision 1 for particular installations, and (d) the sufficiency of replacement parts supplied as alternative parts (e.g., whether 116.40.06.112 is an acceptable substitute for an unindexed 116.40.06.033 in all circumstances). The AD itself does not provide a dispute resolution mechanism or any appeal process in the text supplied.

Because the AD does not identify any administrative review procedure, alternative means of compliance, or exemption process in the supplied text, operators or maintainers who disagree with the technical prescription or who face supply or scheduling difficulties would need to look elsewhere (for example, to CASA administrative procedures or to the wider regulatory framework) for dispute resolution, but none of that framework is described in the AD as supplied.

In sum, the instrument contains no litigation record. Any reader requiring information about judicial or administrative review of this AD will need to consult external sources or the regulator for records of any disputes, prosecutions, enforcement actions, or rulings related to the AD, none of which are present in the text provided.

The AD’s wording and structure create several practical pitfalls that operators and maintenance organisations should note. These items are taken directly from the AD’s requirements and surrounding text; they are not inferred from external sources.

• Mandatory replacement without inspection: The AD requires unconditional replacement "without inspection" of certain Fairchild connecting pieces (part number 6232.0026.xx) in Config. 2 aircraft with Pilatus connecting pieces, and unconditional replacement of fittings 116.40.06.033 when the part number appears "without an index" with either an indexed 116.40.06.033 or with 116.40.06.112. The phrase "without inspection" means operators cannot rely on an inspection certificate or condition assessment to avoid replacement; the parts must be replaced irrespective of apparent serviceability. That creates immediate parts procurement and downtime obligations.

• Part‑number indexing nuance: The AD distinguishes between 116.40.06.033 "without an index" and the indexed variant. Operators must correctly interpret what constitutes "with an index after the part number." Misreading or misrecording indices could lead to incorrect replacements or apparent non‑compliance. Maintenance records may list variants differently; verifying the exact part designation is essential.

• Configuration determination: The AD refers to Config. 1 and Config. 2 when specifying which parts to replace. The AD does not define in the supplied text how to determine configuration for a given MSN. If an aircraft’s configuration is unclear in maintenance records, operators must resolve configuration status before deciding whether an unconditional replacement applies.

• Compliance scheduling tied to 100‑hour inspection or calendar time: The compliance window is "at the next 100 hour inspection or 3 months after 4 August 2005." Operators must carefully schedule to ensure the inspection or replacements occur within the required window. Miscalculation of the "next 100 hour inspection" or of the three‑month calendar period could expose an operator to non‑compliance.

• Terminating action only for specified repetitive inspections: The AD states that replacing certain fittings "provides terminating action for the repetitive inspections required by HB‑86‑042," but does not state that replacement terminates all previous obligations. Operators must ensure they understand exactly which inspections under HB‑86‑042 are terminated; the supplied AD text limits this statement to "certain part number fittings" and does not provide a blanket termination for other requirements.

• Dependence on Pilatus SB Revision 1: The AD requires that the inspection be carried out in accordance with Pilatus Aircraft Service Bulletin No. 53‑001 Revision 1, dated 1 June 2005, and notes that Revision 1 corrects a tolerance for actuator attachment hole diameters for fitting 116.40.06.033 in Config. 1 aircraft. Operators must ensure they use Revision 1 (not an earlier revision) since the AD incorporates the correction. Using an earlier SB revision may not fulfil the AD requirement.

• No enforcement or dispute detail in AD text: The AD does not include enforcement mechanisms, appeals, or alternative means of compliance in the supplied text. If supply constraints or safety judgements make immediate replacement impracticable, the AD does not itself provide the administrative path; operators will need to seek regulatory guidance outside the AD text.

• Cross‑jurisdictional references: The AD was issued "in response to a FOCA AD" and notes the FOCA AD supersedes earlier ADs. Operators operating internationally should note the cross‑references, but must not assume harmonised administrative pathways; the AD in the supplied text only prescribes the Australian requirements it announces.

• No parts availability information: The AD mandates replacement of specific parts but does not address lead times, approved suppliers or interchangeability beyond the named part numbers. Operators facing shortages must manage logistical risk without guidance in the AD.

These "gotchas" derive from precise phrases in the AD: "without inspection," the part numbers listed, the reliance on SB Revision 1, the configuration references, the specified compliance time window, and the AD’s statement that replacement "provides terminating action" for certain prior inspections. Each of those items requires affirmative administrative and maintenance action to avoid inadvertent non‑compliance.

The AD sets out a concise set of compliance steps; implementing them requires coordination between operator, maintenance organisation and parts procurement. Below are concrete, source‑grounded steps that follow directly from the AD text.

1. Determine applicability to your airframe

   • Check the aircraft’s Manufacturer Serial Number (MSN). The AD applies to "All Model PC‑6 Series aircraft ... up to and including MSN 946" and "All Model PC‑6 Series aircraft, manufactured by Fairchild Industries, MSN 2001 through MSN 2092." Confirm whether your aircraft is inside these ranges.

2. Establish aircraft configuration

   • Determine whether the aircraft is Config. 1 or Config. 2 for the purposes of part replacement obligations, since the AD prescribes different replacement rules for Config. 1 and Config. 2.

3. Schedule the inspection as required by the AD

   • Perform the inspection "in accordance with Pilatus Aircraft Service Bulletin No. 53‑001 Revision 1, dated 1 June 2005." Ensure you have and follow Revision 1 of SB No. 53‑001 (the AD incorporates that specific revision as the required inspection document). Schedule the SB inspection at the next 100‑hour inspection or within three months of 4 August 2005, as mandated.

4. Execute the inspection and log findings

   • Conduct the crack inspection following the SB procedures. Carefully document any findings in the aircraft maintenance records per usual continuing airworthiness practice.

5. If cracks are found, replace before further flight

   • The AD is explicit: "If cracks are found during the Requirement 1 inspection, before further flight, replace any crack damaged components." Do not operate the aircraft further until the crack‑damaged parts are replaced and the aircraft is returned to a serviceable condition.

6. Replace specified parts without inspection

   • For Config. 2 aircraft, replace any Fairchild type connecting pieces part number 6232.0026.xx with Pilatus connecting pieces, "without inspection" (i.e., regardless of apparent condition).
   • Replace any fittings bearing part number 116.40.06.033 that lack an index with either an indexed 116.40.06.033 or with part number 116.40.06.112, "without inspection."

7. Use corrected SB tolerances where applicable

   • For Config. 1 aircraft, apply the corrected tolerance for actuator attachment hole diameters in fitting 116.40.06.033 as set out in Pilatus SB No. 53‑001 Revision 1; ensure that installed parts meet the corrected tolerance.

8. Record compliance and replacements

   • Record the inspection, any crack findings, the replacements performed (including part numbers and serial numbers), and that replacements providing terminating action were installed (if applicable). Recording is necessary for continuing airworthiness records and for demonstrating that the AD’s requirements have been met.

9. Consider effects on prior inspections

   • If you have replaced the specified fittings that the AD identifies as providing terminating action, note that those replacements "provide terminating action for the repetitive inspections required by HB‑86‑042 (AD/PC‑6/40)" according to the AD. Ensure records reflect that terminating action has been achieved so that prior repetitive inspection entries can be updated appropriately.

10. Address logistics and parts sourcing proactively

    • Because the AD requires unconditional replacement of specified parts, procure the correct indexed fittings or the alternate part 116.40.06.112 and the Pilatus connecting pieces for Config. 2 aircraft. Verify part numbers carefully; pay attention to indices and variant designations to avoid installing incorrect parts.

11. Seek clarification if ambiguity arises

    • The AD does not include administrative appeal or alternative means of compliance within the supplied text. If there is uncertainty (for example, about configuration classification, part number indexing, or inability to source parts within the compliance window), seek formal clarification from the regulator or the Approved Maintenance Organisation responsible, and ensure any response is documented before deviating from the AD.

12. Maintain traceability to the SB and AD

    • Keep copies of Pilatus SB No. 53‑001 Revision 1 (1 June 2005) and the AD/PC‑6/51 Amdt 1 as part of the aircraft’s continuing airworthiness documentation, so future audits or inspections can verify that the AD‑mandated procedures were followed.

These steps implement the AD’s specific, source‑stated requirements: inspection per Pilatus SB No. 53‑001 Rev 1, mandatory pre‑flight replacement of cracked components, unconditional replacement of named parts for certain configurations, compliance at the next 100‑hour inspection or within three months of the effective date, and application of the correction to the actuator attachment hole tolerance for fitting 116.40.06.033 in Config. 1 aircraft. The AD supplies the part numbers and the compliance deadline; following the sequence above aligns practice with those textual commands.