AD/PW200/2 - Compressor Turbine Disk Retaining Nut

The AD contains a small number of technical and regulatory concepts that together create the action required of operators and maintainers.

• Applicability by model and serial number. The AD lists specific PW200-series engine models and serial number cutoffs to define the affected population (Applicability). That list includes, among others, PW206A up to Serial No. PCE-BA0031, PW206B up to PCE-BB00126, PW206B2 up to PCE-BJ0369, PW206C up to PCE-BC0605, PW206E up to PCE-BE0048, PW207C up to PCE-BH0054, PW207D up to PCE-BF0135, PW207E up to PCE-BG0106, and PW207K up to PCE-BK0032 (Applicability). The serial-number-based applicability is the instrument’s primary delimiting mechanism.

• Inspection locus and trigger. The focal airworthiness hazard is damage to the compressor turbine disk bore area arising from impacts related to the retaining nut castellations. The AD requires inspection of the CT disk bore area for damage (Requirement; Background). The inspection is to be carried out in accordance with P&WC SB PW200-72-A28280 R4 (Requirement).

• Immediate action on damage. If any damage is noticed during inspection, the AD requires replacement of the CT disk before the next flight (Requirement). The “before next flight” timing creates an immediate operational constraint where discovery of damage causes an aircraft to be grounded pending parts and maintenance.

• Mandatory replacement of retaining nut and associated hardware. Irrespective of whether damage is observed, the AD requires replacement of the existing CT disk retaining nut and associated hardware (Requirement). The AD references an “improved design nut” in its background as the remedial design change the SB implements (Background).

• Normative linkage to manufacturer service bulletin and regulator approvals. The AD makes a particular SB revision normative: PW200-72-A28280 Revision 4 is cited as the required procedure. It also allows for later revisions but only if those later revisions are approved by Transport Canada (Requirement).

• Timing rules expressed in cycles and hours. Compliance is expressed as a mixture of CT-cycle thresholds and engine operating hours since a specific date (28 April 2006) tied to the SB original issue date (Compliance). The AD provides three compliance pathways depending on shop-visit history and accumulated CT cycles (Compliance 1-3).

• Cross-reference to another regulator. The AD explicitly references Transport Canada AD CF-2007-24R1 (Requirement; Note), indicating interaction with actions taken by another national regulator.

The AD therefore combines a technical inspection/replacement requirement with a regulatory framing that makes P&WC SB PW200-72-A28280 R4 the operative procedure. The AD’s main levers are model/serial-number applicability, cycle- and time-based compliance triggers, an immediate replacement obligation where damage is present, and a mandated hardware change to an “improved design” retaining nut (Background; Requirement; Compliance).

The AD names the primary affected parties by engine model and serial-number cutoffs. The applicability list in the instrument reads (exactly as in the AD):

• PW206A Serial No. PCE-BA0031 and earlier
• PW206B Serial No. PCE-BB00126 and earlier
• PW206B2 Serial No. PCE-BJ0369 and earlier
• PW206C Serial No. PCE-BC0605 and earlier
• PW206E Serial No. PCE-BE0048 and earlier
• PW207C Serial No. PCE-BH0054 and earlier
• PW207D Serial No. PCE-BF0135 and earlier
• PW207E Serial No. PCE-BG0106 and earlier
• PW207K Serial No. PCE-BK0032 and earlier

(Applicability). The AD therefore directly affects the owners and operators of aircraft equipped with those engines within the serial-number ranges set out. It also affects maintenance organisations, repair stations and personnel responsible for engine inspections and component replacement, because they must perform the inspection and the hardware replacement in accordance with the cited service bulletin (Requirement).

Because the requirement includes replacement “before next flight” if damage is found (Requirement), operators must be prepared for the operational consequences: aircraft may be taken out of service pending parts acquisition and maintenance. The AD’s compliance timing tied to CT cycles and shop-visit history means that fleet managers must compare an engine’s maintenance records and cycle accumulation against the AD’s thresholds (Compliance 1-3). The AD draws a distinction between engines that have or have not had a shop visit; therefore maintenance record-keepers and lessors who track shop-visit history are implicated.

P&WC as the manufacturer is affected insofar as the AD references its Service Bulletin PW200-72-A28280 R4 as the required procedure for inspection and replacement, and the AD notes that P&WC had issued the alert SB prior to the AD (Background; Requirement). Transport Canada is referenced as the approval authority for later service-bulletin revisions and as the issuer of a related AD (Note). The Civil Aviation Safety Authority (CASA) via its delegate David Punshon is the Australian regulator that issued the AD (signature and date).

The AD does not list operators, airworthiness authorities beyond Transport Canada, or third parties, but the practical effect is to impose obligations on any Australian operator or maintenance organisation with an engine that falls within the listed applicability. The AD text does not itself state who bears the cost of inspection or replacement; however the AD’s instructions create maintenance, parts and downtime obligations that will be borne by the engine owner/operator and the maintenance provider required to carry out the work under the SB (Requirement; Compliance).

Duties established by the AD

• Inspect the CT disk bore area for damage. The AD requires operators or their maintenance organisations to perform an inspection of the compressor turbine disk bore area for damage in accordance with P&WC SB PW200-72-A28280 R4 or later revisions approved by Transport Canada (Requirement).

• Replace the CT disk before next flight if damage is noticed. If the inspection finds any damage, the AD requires replacement of the CT disk before the next flight, using the procedures set out in the P&WC SB (Requirement).

• Replace the CT disk retaining nut and associated hardware. The AD requires replacement of the existing CT disk retaining nut and associated hardware, reflecting a mandated hardware change intended to prevent future castellations-related impact damage (Requirement; Background).

• Meet the timing requirements. The AD sets concrete time- and cycle-based deadlines. For engines in higher accumulated-cycle categories the required inspection and nut replacement must be done within 1150 engine operating hours since 28 April 2006 but not later than 10 June 2008. For other engines, action is required before they exceed specified cycle counts or not later than 10 June 2008, whichever is later (Compliance 1-3).

• Use the specified SB revision or approved later revisions. Operators must use P&WC SB PW200-72-A28280 Revision 4, or later revisions only if those are approved by Transport Canada (Requirement). This makes the SB R4 the normative technical standard unless Transport Canada has approved a later revision.

Rights and options preserved in the AD text

• Acceptable prior compliance. The AD explicitly permits that compliance with earlier versions of P&WC SB PW200-72-A28280, if performed prior to the AD effective date, satisfies the AD’s corrective-action requirement (Requirement). That preserves the validity of earlier conforming actions already performed.

• Use of later SB revisions subject to Transport Canada approval. The AD allows later revisions of the SB to be used, but only with Transport Canada approval (Requirement). That gives operators the option to follow later technical instructions once a foreign airworthiness authority has approved those revisions.

Decision-making and allocation of responsibilities

• Regulatory decision. The AD is an instrument issued by CASA, as evidenced by the signature of the CASA delegate, and the AD prescribes mandatory actions. The AD does not itself provide an administrative appeals or exemption pathway in the text. It does however point operators to the SB and to Transport Canada as the approval authority for later revisions (Requirement).

• Operational decision. The immediate operational decision point for operators is the inspection result: where damage is found the operator must not release the engine to flight until the CT disk has been replaced (Requirement). That is a clear safety-based prohibition embedded in the AD.

Record-keeping implication

• The AD’s cycle- and shop-visit-based compliance triggers require accurate maintenance records for CT cycles, dates of last shop visit, last CT disk inspection, and incorporation of service bulletins. The AD’s text implicitly makes those records material to determining when the inspection and replacement must occur (Compliance 1-3).

The instrument therefore creates direct duties of inspection, immediate remedial action when damage is found, and hardware replacement, while preserving the validity of earlier SB compliance and allowing later SB revisions with Transport Canada approval.

The AD text itself does not specify civil penalties, criminal sanctions or explicit enforcement remedies within its paragraphs. The AD sets mandatory maintenance and inspection requirements, and it is issued by the Civil Aviation Safety Authority with the delegate’s signature, which establishes it as a regulatory instrument requiring compliance (signature: David Punshon, Delegate of the Civil Aviation Safety Authority; date 26 February 2008). The AD states its effective date as 10 April 2008 (Compliance).

Because the AD does not list specific penalties in the text, the document leaves unspecified in this instrument the enforcement mechanisms, penalty amounts or administrative processes that might apply for non-compliance. The AD does, however, impose immediate operational constraints where damage is discovered, by requiring CT disk replacement “before next flight” if damage is noticed during inspection (Requirement). That clause creates an operational enforcement point: discovery of damage under the AD’s inspection procedure prevents further flight until remedial action has been taken.

The AD links to a manufacturer service bulletin as the technical standard to be followed (Requirement). In practice, regulators typically enforce ADs by means available to them under the broader aviation safety regulatory framework. The AD does not reproduce those enforcement provisions, and it does not refer to any particular enforcement section or penalties in the Civil Aviation Act or Regulations within the text provided. Similarly, the AD cross-references Transport Canada AD CF-2007-24R1 but does not detail enforcement actions arising from that instrument (Requirement; Note).

Operationally, non-compliance with the AD’s required inspection and hardware replacement would likely have immediate safety implications for the aircraft’s airworthiness status, because the AD ties remedial action to flight continuation when damage is found (Requirement). In this AD the immediate, direct enforcement lever visible in the text is therefore the grounding effect: an engine with a damaged CT disk bore area must have the CT disk replaced before next flight, which prevents continued operations until the issue is remedied (Requirement).

Readers should therefore note two points from the AD text: first, the AD prescribes mandatory technical actions and timeframes; second, the AD does not itself specify monetary penalties or particular enforcement processes within its text. Any questions about enforcement procedures, administrative penalties or appeals would require reference to CASA’s broader regulatory instruments and enforcement policies not reproduced in this AD.

The AD explicitly interfaces with at least one foreign regulator’s directive and with manufacturer service bulletins. The AD refers to Transport Canada AD CF-2007-24R1 dated 21 December 2007 (Requirement; Note). It also makes Transport Canada the approval authority for any later revisions of P&WC SB PW200-72-A28280; the AD requires compliance with SB PW200-72-A28280 Revision 4 or later revisions only if those later revisions are approved by Transport Canada (Requirement). This establishes a cross-jurisdictional linkage where a later SB revision will be usable in Australia only with Transport Canada’s approval as referenced in the AD.

The AD makes a manufacturer’s service bulletin the operative technical document. By referencing P&WC SB PW200-72-A28280 R4 as the normative procedure for inspection and replacement, the AD converts a manufacturer-issued alert SB into a regulatory norm to be complied with under CASA’s AD (Requirement). The AD also states that compliance with earlier versions of the SB, if performed prior to the AD effective date, is acceptable and satisfies the AD’s corrective-action requirements (Requirement). This creates temporal interaction between private maintenance actions taken under manufacturer guidance and subsequent regulatory mandates.

The AD’s operability relies on accurate maintenance records, which interact indirectly with regulatory record-keeping obligations under broader aviation rules. The compliance paths in the AD depend on CT-cycle counts since new, since last shop visit, since last CT disk inspection, and since SB incorporation (Compliance). Therefore an operator’s ability to determine compliance timing is contingent on maintenance history and record-keeping practices.

The AD does not explicitly refer to or modify other Australian legislative instruments in its text. It does not name specific sections of the Civil Aviation Regulations, nor does it set out exemptions or appeals procedures that are available under other laws. The AD’s signature by a CASA delegate and its stated effective date indicate it is issued under CASA’s regulatory powers, but the AD text does not reproduce those enabling provisions.

Finally, the AD’s cross-reference to Transport Canada indicates that Australian compliance may be influenced by the actions of a foreign airworthiness authority and by manufacturer revisions approved by that authority. The AD thus creates a conditional interaction: a later SB revision becomes acceptable in Australian regulated practice only if approved by Transport Canada, as stated in the AD (Requirement).

The AD text itself contains a concise history of the relevant service bulletin and regulator actions referenced in the instrument.

• P&WC SB chronology. The AD cites P&WC Alert Service Bulletin PW200-72-A28280 and references its original issue date as 28 April 2006 when setting the 1150-hour compliance window for some engine groups (Compliance 1). The AD specifically requires compliance in accordance with P&WC SB PW200-72-A28280 Revision 4 (Requirement). The text also refers to PW200-72-28287 in the compliance criteria, which appears in the AD’s compliance wording; that reference should be noted for clarity when matching records (Compliance).

• Transport Canada action. The AD notes Transport Canada AD CF-2007-24R1 dated 21 December 2007 (Requirement; Note). That indicates Transport Canada had issued its own AD addressing the same or similar condition prior to the Australian AD.

• AD issuance and effective dates. The AD is presented as AD/PW200/2 with an identifier 4/2008. The instrument bears the delegate signature of David Punshon, dated 26 February 2008 (signature block). The AD states that it becomes effective on 10 April 2008 (Compliance; Effective date).

• Acceptance of prior SB compliance. The AD explicitly states that compliance with earlier versions of SB PW200-72-A28280, if performed prior to the effective date of the AD, satisfies the corrective-action requirements of this AD (Requirement). That provision functions as a retrospective acceptance for prior conforming work.

• Revision control. The AD requires adherence to SB PW200-72-A28280 Revision 4 as the baseline and allows later revisions only if approved by Transport Canada (Requirement). This sets a point-in-time normative revision for Australian compliance and delegates approval of subsequent changes to the foreign authority named.

• Internal text duplication. The AD document repeats its header material and title lines multiple times and contains formatting that reproduces the AD identifier in several places (for example, lines reading “AD/PW200/2 AD/PW200/2”, “AD/PW200/2”, and “Compressor Turbine Disk Retaining Nut” repeated). Those repetitions appear to be formatting artefacts of the printed AD rather than substantive amendments, but they are present in the instrument as given.

The AD does not list later Australian amendments to itself in the supplied text. The supplied material records the original AD issuance elements, the original SB issue date referenced for timing calculations, and the related Transport Canada AD. It does not specify any subsequent amendments to the Australian AD beyond what is quoted.

The AD text supplied contains no references to litigation, legal challenges, court proceedings, or judicial review relating to this directive. The document is administrative in nature and records the regulatory action, the technical service bulletin it mandates, who signed it, and the dates. It does not recite any litigation history, nor does it reference cases, appeals, or legal decisions.

Because the AD does not include any litigation material, readers seeking information about legal challenges or judicial interpretation of this AD will need to consult court records or legal reporting sources outside the text provided. The AD itself records only the regulatory action and technical instructions, without any account of disputes, enforcement proceedings, or judicial outcomes.

The AD contains several textual and implementation elements that create practical risks or require careful reading by operators and maintenance organisations.

• Mixed or potentially inconsistent SB references. The AD uses P&WC SB PW200-72-A28280 R4 as the controlling procedure (Requirement). However, the compliance section refers to incorporation of SB PW200-72-28287 as one of the cycle-count triggers (Compliance 1-3). This could create ambiguity when maintenance records refer to slightly different SB identifiers. Operators must explicitly confirm which SB revision or identifier is being referenced in their records to determine timing and compliance status.

• Serial-number applicability presented in a single line. The applicability list is presented in the AD as a long, run-together string of model and serial-number cutoffs (Applicability). Care is required to ensure correct parsing of those serial-number ranges against an operator’s maintenance records to determine whether a particular engine is within scope.

• Undefined operational terms. The AD distinguishes engines that “have never had a shop visit” versus those with a “last shop visit” or “last CT disc inspection,” and it bases compliance timing on CT cycles since those events (Compliance 1-3). The AD does not define “shop visit” or describe what constitutes a qualifying CT disc inspection for the purpose of measuring cycles. Operators must therefore rely on their maintenance records and possibly seek regulator clarification if there is uncertainty about whether a prior activity constitutes a shop visit or a qualifying inspection.

• Mixed units and conversion needs. One compliance pathway requires action “within 1150 hrs of engine operating time since 28 April 2006, but not later than 10 June 2008” (Compliance 1). The AD elsewhere uses CT cycles as the threshold. Where operators track hours differently from cycles, determining exact deadlines will require conversion and accurate record-keeping. The AD does not provide conversion factors between CT cycles and operating hours.

• Immediate grounding effect if damage is found. The AD requires replacement of the CT disk if any damage is noticed, and specifies “before next flight” (Requirement). That creates an immediate operational interruption if an inspection reveals damage. Operators must plan for potential AOG scenarios, parts availability and shop capacity.

• Mandatory nut replacement irrespective of damage? The AD requires inspection and replacement of the nut and associated hardware (Requirement). The operative language requires both the inspection and the hardware replacement; however some readers might misread the sequence. The AD’s background explains that P&WC’s SB requires inspection and replacement of the existing disk retaining nut with an improved design nut (Background). Practically, the AD requires replacement of the retaining nut and associated hardware as a corrective action; operators should not assume nut replacement is optional where no damage is found.

• Deadlines close to effective date. The AD becomes effective on 10 April 2008 but sets a latest compliance date of 10 June 2008 for some categories (Compliance). That short window between effective date and latest compliance date could create logistical pressure for parts and maintenance scheduling.

• Acceptance of prior SB compliance limited to actions before the effective date. The AD accepts earlier SB compliance only if performed prior to the AD effective date (Requirement). Any work performed after the effective date must conform to the AD’s specified SB revision or to a later revision approved by Transport Canada.

• Inter-regulatory approval dependency. The AD allows later SB revisions to be used only if approved by Transport Canada (Requirement). If a later revision exists but Transport Canada approval has not been obtained, Australian operators are constrained to SB R4 or must seek specific approval. That approval dependency may delay adoption of subsequent procedural clarifications from the manufacturer.

Operators should treat these items as specific points of attention when planning compliance. The AD’s text supplies the obligations and timing rules, but leaves operational definitions and parts-logistics issues unaddressed; those practical details are where most implementation risk and operational cost will arise.

The AD sets out a direct compliance pathway. Follow the AD text and the cited Service Bulletin. The steps below restate the AD’s requirements with operational sequencing that corresponds to the instrument’s instructions.

1. Determine applicability. Check the engine model and serial number against the applicability list in the AD. The AD lists PW206A, PW206B, PW206B2, PW206C, PW206E, PW207C, PW207D, PW207E, and PW207K with specific serial-number cutoffs (Applicability). Confirm each engine’s serial number and whether it is “and earlier” than the cutoff shown.

2. Review maintenance history. Determine whether the engine has ever had a shop visit, the date and cycle count of the last shop visit if any, the date and cycle count of the last CT disk inspection, and whether the SB PW200-72-A28280 (or PW200-72-28287 as referenced) has been incorporated. The AD’s compliance timing depends on whether the engine has: (a) never had a shop visit and has 4000 CT cycles or more since new; (b) accumulated 2700 CT cycles or more since the last shop visit, last CT disk inspection, or incorporation of SB PW200-72-28287; or (c) accumulated fewer cycles than the threshold categories (Compliance 1-3).

3. Apply the correct timing rule. For engines in the first or second categories use the 1150 engine-operating-hour window counted from 28 April 2006, but ensure action occurs not later than 10 June 2008 (Compliance 1). For engines without a shop visit and with fewer than 4000 CT cycles since new, act before the engine reaches 4000 CT cycles or not later than 10 June 2008, whichever is later (Compliance 2). For engines with less than 2700 CT cycles since last shop visit/inspection/SB incorporation, act before reaching 2700 CT cycles or not later than 10 June 2008, whichever is later (Compliance 3).

4. Obtain and follow the technical procedure. Use P&WC SB PW200-72-A28280 Revision 4 as the inspection and replacement procedure required by the AD (Requirement). If a later SB revision is to be used, confirm Transport Canada approval for that later revision before proceeding, as the AD conditions use of later revisions on Transport Canada approval (Requirement).

5. Conduct the inspection. Perform the CT disk bore-area inspection for damage in accordance with the SB instructions (Requirement). Maintain a record of the inspection and its findings, including CT-cycle and hour counts used to determine compliance timing.

6. Act on findings. If any damage is noticed during inspection, replace the CT disk before the next flight as required by the AD and in accordance with the SB (Requirement). Ensure replacement parts meet the SB-specified improved design nut and associated hardware requirements.

7. Replace retaining nut and associated hardware. Replace the existing CT disk retaining nut and associated hardware as required by the AD (Requirement). The AD indicates replacement with an improved design nut is the corrective remedy recommended in P&WC’s SB (Background).

8. Record compliance. Document the inspection, any replacement of the CT disk, the replacement of the retaining nut and associated hardware, the SB revision used, and the dates and cycle/hour counts in the engine’s maintenance records. If the operator relied on an earlier SB performed before the AD effective date, document that the earlier action was completed prior to 10 April 2008 to rely on the AD’s acceptance of prior SB compliance (Requirement).

9. Coordinate with regulator and manufacturer as needed. If there is uncertainty about which SB identifier applies (note the AD’s internal reference to PW200-72-28287 as a compliance trigger), seek clarification from CASA or the manufacturer. If intending to use a later SB revision, obtain confirmation of Transport Canada approval for that revision as required by the AD (Requirement).

10. Plan parts and maintenance resources. Given the AD’s “before next flight” replacement requirement for damaged CT disks, ensure access to replacement disks, improved-design retaining nuts and associated hardware, and qualified maintenance facilities. Schedule inspections timely to avoid last-minute AOG work, particularly because the AD sets a latest compliance date of 10 June 2008 for many cases (Compliance).

11. Verify cross-references. Review Transport Canada AD CF-2007-24R1 as referenced by the AD to understand any related requirements or approvals (Requirement; Note).

12. Keep records for audit. Because the AD ties compliance to historical events such as shop visits and prior inspections, retain contemporaneous documentation that supports cycle counts and the dates of prior maintenance actions used to calculate compliance windows.

These steps follow the AD’s text. The operator should treat the SB as the technical instruction set; the AD makes compliance with SB PW200-72-A28280 R4 the regulatory standard unless a later revision has Transport Canada approval. Compliance planning should therefore focus on accurate record reconciliation, timely inspection scheduling, parts availability for nut and CT disk replacement, and documentation sufficient to demonstrate compliance to CASA.