AD/PW4000/16 - Front Pylon Mount Bolts

The AD is structured around a narrow set of technical and procedural concepts extracted from US and manufacturer materials and applied by CASA. Core concepts are:

• Applicability by engine model and bolt part numbers. The AD identifies the affected engines (PW4164, PW4168, PW4168A) and the relevant front pylon mount bolts P/N 54T670 or 51U615 (Applicability). It notes these engines are installed on, but not limited to, Airbus A330 series aeroplanes, which signals installation-based applicability rather than aircraft-type limitation (Applicability).

• Inspection regime tied to a referenced FAA AD. The substantive inspection and torque-check obligations are to be performed “in accordance with the technical requirements of FAA AD 2006-16-05 Amendment 39-14705.” The AD therefore imports the technical inspection intervals, methods and criteria from that FAA AD rather than reproducing them in full (Requirement).

• Terminating action by hardware replacement. The AD identifies a specific physical modification that, when performed per a specified manufacturer SB, terminates the inspection regime: replacement of the forward engine mount bearing housing (P/N 59T794 or 54T659) with P/N 52U420 using SB PW4G-100-71-22 dated 15 January 2002, or later FAA approved revision (Requirement).

• AMOC and acceptable alternative documents. The AD accepts later revisions of specified Pratt & Whitney ASBs (PW4G-100-A71-9 Revision 1 dated 24 Nov 1997; PW4G-100-A71-18 Revision 2 dated 15 Jan 2002; PW4G-100-A71-32 dated 15 Apr 2005) as acceptable for compliance where they are approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance to the FAA AD (Requirement). This establishes a cross-jurisdictional reliance on FAA approvals for alternate compliance paths.

• Safety finding underpinning the AD. The manufacturer’s analysis identified that MP159 material pylon bolts did not meet the “full life cycle torque check interval requirement, in a bolt-out condition,” and the AD was issued to prevent front pylon mount bolt and primary mount thrust load path failure, which could cause engine separation (Background).

• Temporal effect. The AD takes legal effect from a stated date , 13 September 2010 , and references that compliance is “as specified in the Requirement Document with a revised effective date of 13 September 2010” (Compliance).

These concepts combine prescriptive technical provenance (the FAA AD and PW SBs), a hardware remedy option that terminates inspection burden, and an explicit cross-reference to FAA-approved revisions and AMOCs. The AD therefore sets out a compliance choice architecture for operators: follow the inspection regime indefinitely, or adopt the specified modification to end the requirement.

The AD identifies affected parts and engine models and provides installation guidance that determines the population of impacted operators and maintenance organisations.

• Operators of PW4164, PW4168 and PW4168A series turbofan engines fitted with front pylon mount bolts P/N 54T670 or 51U615 are directly affected (Applicability). The AD specifically notes these engines are installed on, but not limited to, Airbus A330 series aeroplanes, indicating that any airframe type with the specified engine and bolt configuration falls within the AD’s scope (Applicability).

• Owners, operators, and maintenance providers responsible for continued airworthiness of aeroplanes with those engines will face the duty to perform the initial torque checks and inspections as required by the referenced FAA AD, and to repeat those checks at the intervals set out in that FAA AD (Requirement).

• Maintenance and overhaul facilities that carry out structural or engine mount work on affected engines will be concerned with the terminating action: they must be capable of performing the forward engine mount bearing housing replacement in accordance with SB PW4G-100-71-22 dated 15 January 2002 or later FAA-approved revisions, if the operator chooses to adopt that option (Requirement).

• Supply chains for parts and logistics are implicated: the AD names specific part numbers both for the problematic bolts (54T670 and 51U615) and for the bearing housings (59T794, 54T659 and the terminating action P/N 52U420). Those managing spares inventories, procurement and conforming part installations must verify P/Ns to determine if the AD applies to a given installation (Applicability; Requirement).

• Regulatory decision-makers and certifying authorities have an operational role in accepting AMOCs. The AD ties acceptance of alternate service bulletin revisions to FAA approval as an AMOC to FAA AD 2006-16-05, which means that regulators and operators must track FAA approvals to confirm whether a later SB revision is acceptable for compliance with this AD (Requirement).

The AD does not limit applicability to a single aircraft type and therefore affects a dispersed set of operators that have the specified combinations of engine model and bolt P/N fitted. The AD assigns responsibilities to those who control the aircraft’s maintenance and airworthiness compliance to identify affected equipment, perform the mandated inspections or adopt the terminating modification, and to rely on the FAA for acceptance of later service bulletin revisions as AMOCs when applicable.

The AD prescribes specific duties and specifies one explicit right or option , to terminate the inspection obligation by performing the specified modification.

Duties:

• Initial and repeated inspections and torque checks. Operators must perform initial torque checks and inspections, and repeat them in accordance with the technical requirements of FAA AD 2006-16-05 Amendment 39-14705 (Requirement). The AD does not reproduce those technical steps but mandates adherence to them; therefore, the content of the duty is to follow the FAA AD’s inspection and torque-check procedures and intervals.

• Applicability verification. Operators and maintainers must verify whether their engines are the PW4164, PW4168, or PW4168A models and whether front pylon mount bolts with P/N 54T670 or 51U615 are installed, because the AD’s duties apply only where those conditions are met (Applicability).

• Compliance timing. The AD’s compliance is governed by the Requirement Document with a revised effective date of 13 September 2010; the AD itself becomes effective on 13 September 2010 (Compliance). This imposes an obligation to ensure inspections or modifications are scheduled and performed in line with that effective date and the intervals in the FAA AD.

Rights and options:

• Terminating action via specified modification. The AD grants a specific option: replacement of forward engine mount bearing housing P/N 59T794 or P/N 54T659 with P/N 52U420, carried out using SB PW4G-100-71-22 dated 15 January 2002 or a later FAA-approved revision, constitutes terminating action to the inspection requirements (Requirement). This gives operators a discrete compliance pathway: continue the inspection loop or perform the hardware change to stop it.

• Use of FAA-approved AMOCs. The AD recognises that later revisions to specified PW ASBs, if approved by the FAA as an AMOC to FAA AD 2006-16-05, are acceptable for compliance with the equivalent requirements of this AD (Requirement). This creates a right to use FAA-approved alternate methods of compliance rather than being limited strictly to the service documents specified in the AD.

What the AD does not state as a duty:

• The AD does not specify who must pay for the inspections or the modifications, nor does it include penalty provisions, enforcement steps or record-keeping specifics in the text provided. The AD also does not reproduce the technical inspection methodology or intervals but imports them by reference to the FAA AD (Requirement; Compliance).

In practical terms, duties fall on the persons and organisations responsible for maintaining the affected aeroplanes and engines. The primary explicit choice point is between an ongoing inspection regime and the one-time hardware replacement that terminates the inspection obligation.

The AD text provided does not include express penalty provisions or procedural enforcement mechanisms. The document records that it is an Airworthiness Directive issued by the Civil Aviation Safety Authority (CASA) delegate and states the effective date, but it does not set out sanctions, monetary penalties, administrative procedures, or criminal consequences within the text supplied (Compliance; signature block).

What the AD does state relevant to enforcement context:

• Effective date. The AD becomes effective on 13 September 2010 and specifies that compliance is “as specified in the Requirement Document with a revised effective date of 13 September 2010” (Compliance). The effective date marks when the obligations and options described become operative.

• Source of technical requirements. The AD requires adherence to the technical requirements of FAA AD 2006-16-05 Amendment 39-14705 for inspections and torque checks (Requirement). Because the AD imports those technical requirements by reference, any technical conformity assessment would necessarily examine whether an operator followed the FAA AD’s procedures.

• Termination via specified SB. The AD specifies a terminating modification that, when accomplished using SB PW4G-100-71-22 dated 15 January 2002, or a later FAA approved revision, relieves the operator from the inspection obligations in paragraph (h) of FAA AD 2006-16-05 Amendment 39-14705 (Requirement). Compliance verification therefore may involve confirming that the replacement occurred per the specified SB revision.

• Use of AMOCs. Later revisions to certain PW ASBs are accepted only if the FAA has approved them as an AMOC to the FAA AD; thus, compliance checks might inspect FAA AMOC approvals to determine whether a later ASB revision can be relied upon for compliance with this AD (Requirement).

The AD does not itself state enforcement actions that CASA will take for non-compliance nor does it list civil or criminal penalties. It also does not specify how compliance records must be kept or produced. Any enforcement practice, certification actions, or sanctions that might follow non-compliance are not articulated in the text provided and are therefore outside the scope of this AD as supplied.

The AD explicitly cross-references US Federal Aviation Administration material and Pratt & Whitney service documentation, creating interaction points across regulatory and manufacturer documents.

• Incorporation of FAA AD requirements. The AD imports the technical inspection and torque-check requirements from FAA AD 2006-16-05 Amendment 39-14705 (Requirement). That means the substantive inspection method, intervals and criteria are governed by the FAA AD and apply for the purposes of satisfying this CASA AD. The AD thereby creates an operational dependency on the content and interpretation of that FAA AD.

• Reliance on FAA approval for AMOCs. The AD accepts later revisions of specified PW ASBs (PW4G-100-A71-9 Rev 1, PW4G-100-A71-18 Rev 2, and PW4G-100-A71-32) as acceptable for compliance only where they are approved by the FAA as an Alternate Method of Compliance to FAA AD 2006-16-05 (Requirement). This makes FAA AMOC approvals a point of regulatory interface: an operator relying on a later ASB revision must confirm FAA approval to rely on that document for compliance with this AD.

• Manufacturer service bulletin as terminating action. The AD specifies that SB PW4G-100-71-22 dated 15 January 2002, or later FAA approved revision, provides the terminating action by replacing the bearing housing with P/N 52U420 (Requirement). That SB is a manufacturer document; the AD requires that the SB be followed as specified and that later revisions be FAA-approved to serve as the terminating action. Thus, this AD creates a chain where CASA’s regulatory requirement refers to manufacturer documentation, which in turn is subject to FAA approval for certain revisions.

• Non-exclusivity of aircraft platform. The AD says the engines are installed on, but not limited to Airbus A330 series aeroplanes (Applicability). This wording means that the AD is engine- and part-based rather than aircraft-model limited, so any other national or international rules that derive airworthiness obligations from engine configuration will interact with this AD in the sense that the presence of the identified engine and parts triggers these obligations irrespective of aircraft type.

• Absence of domestic enforcement detail. The AD does not state domestic enforcement procedures or penalties within its text (Penalties and enforcement). That leaves room for interaction with the broader domestic regulatory enforcement framework, but the AD itself does not define that interaction.

In short, the AD anchors compliance obligations to a US FAA AD and to Pratt & Whitney service documents and requires FAA approval for use of later ASB revisions as AMOCs. The AD thus explicitly ties CASA’s directive to decisions and approvals made by the FAA and to manufacturer-issued SBs.

The AD text supplied includes references to specific external documents and dates that constitute its amendment and revision references, but the AD itself contains only a single effective-date modification.

• Effective date. The AD states that it becomes effective on 13 September 2010 and that compliance is “as specified in the Requirement Document with a revised effective date of 13 September 2010” (Compliance).

• References to FAA AD amendment. The AD requires compliance with the technical requirements of FAA AD 2006-16-05 Amendment 39-14705 (Requirement). The AD therefore relies on that FAA AD and its cited amendment as the operative technical source.

• References to manufacturer service bulletins and ASBs. The AD identifies SB PW4G-100-71-22 dated 15 January 2002, as the service bulletin that provides terminating action when used to replace the forward engine mount bearing housing with P/N 52U420, or a later FAA approved revision (Requirement). It also lists PW Alert Service Bulletins PW4G-100-A71-9 Revision 1 dated 24 November 1997, PW4G-100-A71-18 Revision 2 dated 15 January 2002, and PW4G-100-A71-32 dated 15 April 2005, stating that later revisions to those ASBs, when approved by the FAA as an AMOC to the FAA AD, are acceptable for compliance with the equivalent requirements of this AD (Requirement).

• No domestic amendment log. The text of the AD supplied does not include a serial amendment history of prior revisions to this AD itself, nor does it show amendment numbers attributed to CASA beyond the single AD identifier AD/PW4000/16, and the date line 18/2010 (header). The document does not record any superseding ADs or prior versions of this particular CASA AD within the supplied text.

• Cross-jurisdictional amendment path. The AD’s allowance for later PW ASB revisions to be acceptable only when the FAA approves them as AMOCs means that amendment to the ASB or SB that are FAA-approved effectively amend acceptable compliance methods for this AD. In other words, evolution of the FAA’s AMOC approvals will change the set of acceptable documents for compliance with this AD without requiring this AD to be re-issued for each such FAA approval.

The AD therefore establishes its effective date and then delegates acceptance of certain later-revision service documents to FAA approvals. The text does not record prior CASA amendments to this AD or later CASA revisions; it captures amendment activity only by reference to FAA amendment and manufacturer SB revision dates.

The document supplied contains no information about litigation, appeals, judicial review, or disputes arising from this AD. The AD does not record any legal challenges, court decisions, or administrative appeals in its text.

What the AD does record that is relevant to potential dispute points, without stating any litigation history, are:

• A technical finding by the manufacturer that underpins the safety concern: MP159 material pylon bolts did not meet the full life cycle torque check interval requirement in a bolt-out condition (Background). Such a technical finding is commonly the factual basis for an AD, but no litigation arising from that analysis is recorded here.

• Cross-references to FAA and manufacturer approvals. The AD conditions acceptance of later service bulletin revisions to FAA approval as an AMOC. If a dispute were to arise about whether a later ASB revision is acceptable, the relevant approval authority would be the FAA as stated; however no litigation or challenges to such approvals are recorded in the supplied text.

• No record of enforcement proceedings. The supplied AD does not include any record of enforcement actions or proceedings related to its requirements (Penalties and enforcement).

Because the supplied text contains no litigation history, practitioners seeking information about any legal challenges, enforcement proceedings, or judicial consideration of this AD would need to consult external judicial or administrative records. None of those external records are included in or cited by the AD text provided.

The AD contains several precise, technical items and cross-reference traps that can cause compliance failures if overlooked.

• Applicability is part-number specific. The AD applies only when front pylon mount bolts with P/N 54T670 or 51U615 are installed on PW4164, PW4168 or PW4168A engines (Applicability). Failure to verify bolt P/Ns on affected engines can lead to misclassification of whether the AD applies.

• Applicability not limited to Airbus A330. While the AD notes the engines are installed on, but not limited to, Airbus A330 series aeroplanes, the “not limited to” phrase means operators cannot assume that only A330s are affected; any aircraft type with the specified engine and bolts is in scope (Applicability).

• The AD imports technical requirements by reference. The AD does not reproduce the inspection procedures, torque values, or intervals. It requires compliance “in accordance with the technical requirements of FAA AD 2006-16-05 Amendment 39-14705” (Requirement). Operators must obtain and follow that FAA AD to understand the full technical obligations. Missing or misreading the FAA AD’s technical content is a compliance risk.

• Terminating action linked to specific SB revision and FAA-approved later revisions. The AD specifies SB PW4G-100-71-22 dated 15 January 2002 as the terminating-action procedure and allows later FAA-approved revisions to serve the same function (Requirement). Operators must ensure that the SB revision they use is either the dated SB or a later FAA approved revision. Using an unapproved company revision without FAA approval would not meet the AD’s explicit terminating-action requirement.

• AMOC acceptance depends on FAA approval. The AD accepts later revisions to certain PW ASBs only if the FAA has approved them as an AMOC to FAA AD 2006-16-05 (Requirement). Therefore, operators wishing to rely on later ASB revisions must confirm FAA AMOC approval status; assuming acceptance without FAA approval is a compliance risk.

• The AD references a specific paragraph of the FAA AD. The terminating action is described as relieving the inspection requirements of “paragraph (h) of the requirement document, FAA AD 2006-16-05 Amendment 39-14705” (Requirement). Compliance checks will need to map the CASA AD’s paragraph references to the FAA AD’s paragraphing to confirm the scope of relief.

• No penalties or enforcement procedures included in AD text. Because the AD does not specify penalties or enforcement mechanisms in the supplied text, operators may assume there is flexibility. That assumption would be risky: the AD sets mandatory airworthiness obligations as issued by CASA, and the absence of explicit penalties in the AD document does not mean non-enforcement in practice. The supplied AD text, however, does not provide procedural guidance or timelines for demonstrating compliance.

• Timing and record-keeping expectations are not spelled out. The AD specifies the effective date and that compliance is “as specified in the Requirement Document with a revised effective date of 13 September 2010” (Compliance), but it does not include a detailed compliance timeline or record-keeping requirements. Operators must therefore rely on the FAA AD and SBs for timing and recording detail; failing to maintain records may create difficulty demonstrating compliance.

• Material condition and life-cycle language. The background identifies the issue as related to “MP159 material pylon bolts” and their inability to meet “the full life cycle torque check interval requirement, in a bolt-out condition” (Background). Operators must be able to identify material types and life-cycle status of bolts to determine whether the identified issue applies to installed components.

Taken together, these “gotchas” are primarily issues of cross-referencing, part-number precision, and reliance on FAA approvals for AMOCs and later service-document revisions. Ensuring access to and understanding of the FAA AD and the specified PW SBs, confirming part numbers and SB revision approvals, and mapping the FAA document references precisely are necessary steps to avoid non-compliance.

The AD sets out two alternative compliance paths: follow the inspection and torque-check regime as specified by the FAA AD, or perform the specified bearing housing replacement as a terminating action. The following steps describe the compliance actions the AD requires or permits, based directly on the AD text.

1. Confirm applicability.

   • Verify that the engine is a Pratt & Whitney PW4164, PW4168 or PW4168A series turbofan engine.
   • Confirm whether front pylon mount bolts installed are P/N 54T670 or P/N 51U615 (Applicability). If both conditions are met, the AD applies to that engine installation.

2. Obtain the referenced documents.

   • Acquire FAA AD 2006-16-05 Amendment 39-14705 and identify the technical requirements for initial and repetitive torque checks and inspections. The CASA AD requires compliance in accordance with the technical requirements of that FAA AD (Requirement).
   • Obtain SB PW4G-100-71-22 dated 15 January 2002 for the terminating-action procedure. If relying on a later revision, confirm FAA approval of that later revision for use as the terminating action (Requirement).
   • If considering alternate PW ASB revisions, obtain the relevant ASB revisions and confirm whether the FAA has approved them as an AMOC to FAA AD 2006-16-05 (Requirement).

3. Execute the inspection route (if chosen).

   • Perform the initial torque checks and inspections exactly as specified in FAA AD 2006-16-05 Amendment 39-14705. The CASA AD imports these technical steps and intervals by reference (Requirement).
   • Schedule and perform repeat torque checks and inspections at the intervals specified by the FAA AD. Record the inspections, findings, and any corrective action taken as required by the FAA AD and by any applicable maintenance record requirements.

4. Execute the terminating-action route (if chosen).

   • Procure approved parts: the replacement forward engine mount bearing housing must be P/N 52U420, replacing P/N 59T794 or P/N 54T659 (Requirement).
   • Perform the bearing housing replacement in accordance with SB PW4G-100-71-22 dated 15 January 2002, or use a later revision only if that revision is FAA approved (Requirement). After completion, document that the terminating action has been accomplished per the SB and note that the inspection obligations identified in paragraph (h) of FAA AD 2006-16-05 are thereby terminated for that engine installation, as described in the AD (Requirement).

5. Use of AMOCs or later ASB revisions.

   • If relying on later revisions to the named PW ASBs (PW4G-100-A71-9 Rev 1; PW4G-100-A71-18 Rev 2; PW4G-100-A71-32) for compliance, confirm FAA approval of the later revision as an AMOC to FAA AD 2006-16-05. Only FAA-approved AMOCs to the FAA AD are acceptable for compliance with this AD (Requirement).

6. Timing and effective date.

   • Note that this AD became effective on 13 September 2010 and compliance is “as specified in the Requirement Document with a revised effective date of 13 September 2010” (Compliance). Ensure initial actions and any staged scheduling are undertaken in line with that effective date and the intervals in the referenced FAA AD.

7. Record evidence of compliance.

   • Maintain records that show part numbers inspected, dates and results of torque checks and inspections, SB revision numbers and dates where terminating action was performed, and any FAA AMOC approvals relied upon. The AD text does not define record-keeping standards; therefore, operators should retain documentation adequate to demonstrate to an airworthiness authority that the AD’s prescribed procedures have been followed.

8. Coordinate approvals where necessary.

   • If uncertain whether a later SB revision or ASB revision is acceptable, obtain written confirmation of FAA approval as an AMOC to FAA AD 2006-16-05 before relying on that revision to comply with this AD (Requirement).

These steps implement the obligations and options specified in the AD: either ongoing inspection per the FAA AD or replacement in accordance with SB PW4G-100-71-22 to terminate that inspection obligation. The AD’s operative references are the FAA AD and the named PW SBs and ASBs; compliance depends on following those documents and on confirming FAA approvals where the AD conditions them.