AD/PW100/12 - Propeller Shaft

The AD builds on four core enforcement concepts: mandatory destruction of identified hardware, mandated inspections using specific service bulletin instructions, time-limited remediation deadlines, and an explicit prohibition on alternative compliance. Those concepts operate together to eliminate the specific risk identified in the background.

Mandatory destruction: The AD directs operators to “destroy/discard” propeller shafts listed in Tables 1-3 immediately (Requirement 1) and to remove and destroy those listed in Table 4 by 31 December 2007 (Requirement 4). The wording requires physical removal from service and disposal rather than repair or return-to-service of the listed shafts where they are designated for destruction.

Prescriptive inspection procedures: For Table 4 items the AD references specific parts (A, B and C) of P&WC SB 21714R2, dated 20 May 2005, and allows Transport Canada approved later revisions. The visual inspection procedure is prescribed by Part A, the internal inspection by Part B, and the replacement/installation procedure by Part C. Where an external oil leak is observed, the AD directs operators to use the Engine Maintenance Manual , Corresponding Fault Isolation Chart for “Oil leak from propeller shaft area” before further actions are taken.

Time-bound compliance: The AD sets discrete deadlines. Visual inspections for certain shafts must be done within five days of the effective date and then repeated weekly until removal; internal inspections within 250 hours air time or three months; and final removal and destruction of Table 4 shafts by 31 December 2007. The AD’s effective date is given as 27 October 2005.

Restriction on alternatives: The directive states “No extensions or alternate means of compliance are permitted.” That clause removes the typical regulatory discretion that might otherwise allow operators to propose alternate inspection techniques, reprioritise schedule, or seek relief for operational constraints.

Cross-reference and equivalence clause: Note 2 states that compliance using inspection methods contained in previous versions of P&WC SB 21714 prior to the AD’s effective date satisfy the requirements of SB 21714 Revision 2, mandated by the directive. That creates limited backwards equivalence: older SB inspection methods remain acceptable for the inspections mandated.

Applicability scope: The AD lists a broad set of PW100-series engines by model number and explicitly notes that those engines are installed on, but not limited to, several specific aircraft types (Aerospatiale ATR 42 and ATR 72, Bombardier DHC-8-100/200/300, Dornier 328-120, Embraer EMB120, and Fokker 50). That phrasing signals potential applicability beyond the listed airframes; the actual list of affected propeller shafts is determined by the Tables in Transport Canada AD CF-2005-29 referenced by the directive.

Stated root cause and trigger: The background links two reported instances of through-going cracks at the no. 19 bearing area to hydrogen embrittlement produced by an improper nickel-plating repair process at two overhaul facilities, specifically excessive immersion time in the nickel-plating tank. Both events were discovered after persistent external oil leaks, indicating that the defects may not be externally visible until the crack has migrated past the seal runner.

Enforcement authority and provenance: The AD is issued by the Civil Aviation Safety Authority (delegate signature) and references Transport Canada service and regulatory material. The AD makes mandatory service bulletin procedures and Transport Canada AD tables within the CASA regulatory framework for Australian operators.

Collectively, these concepts convert a reported repair-process-specific failure mode into fleet-wide mandatory mitigations with prescriptive methods, set timing, and limited flexibility for operators.

The AD affects operators, maintenance organisations and owners of aircraft powered by specified Pratt & Whitney Canada PW100-series engines whose propeller shafts appear in Tables 1-4 of Transport Canada AD CF-2005-29. The AD lists specific engine models: PW118, PW118A, PW118B, PW119C, PW120, PW120A, PW121, PW121A, PW123, PW123B, PW123C, PW123D, PW123E, PW124B, PW125B, PW127 and PW127E. The AD further notes those engines are installed on, but not limited to, Aerospatiale ATR 42 and ATR 72, Bombardier DHC-8-100/200/300, Dornier 328-120, Embraer EMB120, and Fokker 50 aircraft. The “not limited to” language means other airframes that use the listed engines may also be affected; the definitive list of affected propeller shafts is contained in the Tables of Transport Canada AD CF-2005-29, which the directive incorporates by reference.

Primary accountable parties:

• Aircraft operators/owners: Responsible for ensuring the mandated inspections, removals and destruction are completed within the specified timeframes. The AD’s compliance schedule imposes immediate and short-term operational tasks (for example, visual inspections within five days and weekly repeats) and longer-term hardware replacement obligations.
• Maintenance organisations and overhaul facilities: Responsible for performing the visual and internal inspections as prescribed by Parts A and B of P&WC SB 21714R2, applying the Engine Maintenance Manual fault isolation chart when an oil leak is present, and carrying out removal and installation per Part C of the SB where required. If a crack is detected, the maintenance organisation must remove and discard the shaft and install a new propeller shaft in accordance with the SB.
• Civil Aviation Safety Authority (CASA) as regulator: The AD is issued under CASA authority (signed by a CASA delegate), setting the mandatory obligations and enforcement position for the Australian jurisdiction. CASA, via the AD, imposes the requirement and also states that no extensions or alternate means of compliance are permitted.

Secondary affected parties:

• Parts suppliers and engine manufacturers: Where the AD requires removal and replacement of propeller shafts, suppliers and manufacturers will supply replacement shafts; the AD specifies installation per Part C of SB 21714R2. The AD also references P&WC SB 21714R2 and prior versions as the authoritative technical instructions.
• Overhaul facilities whose nickel-plating processes were implicated: The background identifies two overhaul facilities whose nickel-plating repair processes were the root cause in two events. Those facilities are directly relevant to the causation narrative, though the AD applies to shafts across the fleet rather than targeting particular facilities.
• Aircraft operators with scheduling constraints: The AD’s short lead times and, for some inspections, repeated weekly checks until removal, will affect scheduling and may require aircraft to be grounded for inspection or removal actions.

Geographic and fleet reach:

• The AD is an Australian Civil Aviation Safety Authority instrument but it explicitly relies on and incorporates information from Transport Canada AD CF-2005-29 and Transport Canada Service Difficulty Alert AL-2005-05. Any Australian-registered aircraft using affected engine and shaft combinations are subject to the AD’s requirements. The cross-reference to Transport Canada’s listings means operators must consult that external AD to determine which specific propeller shafts in their fleet are named in Tables 1-4.

Information obligations not specified in the AD:

• The AD does not specify recordkeeping or reporting procedures in the text supplied, beyond directing compliance with the SB and the EMM fault isolation chart where applicable. Any reporting or documentation duties would arise from the broader regulatory framework or from the referenced service bulletin, but such duties are not set out in the AD text provided.

In short, the AD places mandatory, time-sensitive obligations on operators and maintenance organisations handling the listed P&WC PW100-series engine propeller shafts, with the precise universe of affected components defined by Transport Canada AD CF-2005-29’s tables.

Duties imposed by the AD are precise and prescriptive. The AD sets out duties for operators and maintainers and limits discretionary relief.

Primary duties

• Removal and destruction (Requirement 1 and 4): Operators must destroy/discard propeller shafts identified in Tables 1-3 of Transport Canada AD CF-2005-29 immediately (Requirement 1). For propeller shafts in Table 4, operators must remove and destroy them no later than 31 December 2007 (Requirement 4).
• Visual inspection for oil leaks (Requirement 2): For Table 4 propeller shafts, operators must perform a visual inspection for oil leaks according to Part A of P&WC SB 21714R2 (or later Transport Canada approved revisions). If an oil leak is found, they must follow the Oil Leak fault isolation chart in the Engine Maintenance Manual and decide whether the engine can be returned to service or whether propeller removal and an internal inspection (Requirement 3) is needed.
• Internal inspection (Requirement 3): For Table 4 propeller shafts, an internal inspection per Part B of the SB is required. If a crack is found on internal inspection, remove and discard the shaft and install a new shaft per Part C of the SB; if no crack is found, the engine may be returned to service.
• Use of specified service instructions: The AD mandates adherence to Parts A, B and C of P&WC SB 21714R2 dated 20 May 2005, or to Transport Canada approved later revisions. The AD also allows, for visual and internal inspections, prior versions of P&WC SB 21714 to satisfy the requirement, per Note 2.

Timing duties

• Immediate short-term inspections: Some inspections must be done within five days after the effective date (Compliance notes). Visual inspections for Table 4 shafts must be done within five days and repeated weekly until the shaft is removed from service.
• Internal inspection deadline: The internal inspection must be completed within 250 hours air time or not more than three months after the AD’s effective date, whichever occurs first.
• Final removal deadline: Table 4 propeller shafts must be removed and destroyed by 31 December 2007.
• The AD becomes effective on 27 October 2005.

Rights and limitations

• Limited methodological choice: The AD confers limited choice about inspection methodology. It requires specific service bulletin instructions (SB 21714R2 Parts A-C) but, via Note 2, allows previous SB versions for the visual/internal inspections. It does not authorise alternate means of compliance.
• No relief measured in the AD: The AD explicitly states “No extensions or alternate means of compliance are permitted.” That is a restriction on an operator’s right to seek regulatory relief or to implement a different, operator-proposed inspection or repair regime in place of the mandated SB methods.
• Return-to-service conditionality: The AD permits returning the engine to service in specific, conditional circumstances , for example, where a visual inspection finds no oil leak (Requirement 2(b)), or where an oil leak is fixed without propeller removal (Requirement 2(a)(ii)), or where internal inspection reveals no crack (Requirement 3(b)). Those are conditional rights to return an engine to service without removal or replacement.
• Cross-jurisdictional reference: The AD obliges compliance with content that originates from Transport Canada AD CF-2005-29 and P&WC SB 21714R2. Operators’ rights to choose different service material are constrained to what the AD permits; Transport Canada approved later revisions are allowed, and earlier SB versions are accepted for inspections per Note 2, but otherwise the AD prescribes the exact technical route.

Operational duties when oil leak is present

• If visual inspection reveals an oil leak, the operator must inspect the propeller shaft seal area for leaks using the Engine Maintenance Manual Corresponding Fault Isolation Chart for the fault “Oil leak from propeller shaft area” (Requirement 2(a)(i)).
• If the oil leak can be fixed without removing the propeller, the engine may be put back into service (Requirement 2(a)(ii)).
• If the propeller needs to be removed to fix the oil leak, the operator must perform the internal inspection of the propeller shaft as per Requirement 3 (Requirement 2(a)(iii)).

Documentation and compliance evidence

• The AD itself does not specify documentation or reporting formats in the provided text, but the duty to follow SB procedures implies standard maintenance records and installation records consistent with the referenced SB Parts and engine maintenance instructions. The AD’s prohibition on alternative compliance means operators cannot rely on different procedures unless captured within the AD’s allowed exceptions (older SB versions or later TC-approved revisions).

Enforcement consequence implicit in duties

• The AD imposes mandatory technical duties with tight time constraints and an explicit prohibition on alternate compliance. This creates an enforcement regime where regulatory non-compliance would be measured by whether the mandated inspections, removals and destructions occurred within the prescribed timelines and in accordance with the SB and referenced manuals.

In short, the AD sets precise, time-bound duties for inspection, removal, destruction and replacement that limit operator discretion and restrict alternative compliance options.

The supplied text of the Airworthiness Directive does not specify monetary penalties, sanctioning procedures, or explicit enforcement mechanisms within the AD’s text. What the AD does provide about enforcement, implicitly and explicitly, can be drawn from the document’s mandatory language and the regulatory context it signals.

Mandatory instructions and prohibitions

• The AD contains unqualified commands: “Destroy/Discard propeller shafts,” “perform a visual inspection,” “remove and discard the propeller shaft, and install a new propeller shaft,” and deadlines for completion. The AD also states “No extensions or alternate means of compliance are permitted.” Those formulations indicate mandatory regulatory obligations that are enforceable under the broader statutory authority that allows CASA to issue ADs. The AD itself does not set the penalty quantum or administrative process; it prescribes technical non-discretionary requirements.

Regulatory authority and signature

• The AD is signed by a CASA delegate , James Coyne , dated 16 September 2005. The signature line indicates that the directive is an instrument of the Civil Aviation Safety Authority and therefore sits within CASA’s enforcement framework. Enforcement in practice would be executed by CASA under its statutory powers, but specific sanctioning procedures and penalty amounts are not included in the AD text provided.

Compliance deadlines as enforcement levers

• The AD uses time-limited compliance (five days, weekly repeats until removal, 250 hours/three months, and removal by 31 December 2007) to create immediate obligations. Failure to comply with those timescales would, in normal regulatory practice, constitute non-compliance and expose operators to enforcement action by CASA , for example, prohibition notices, grounding, or administrative enforcement , though those mechanisms and outcomes are not detailed in the AD text supplied.

Reference to service instructions and prohibition on alternatives

• The AD’s mandate that inspections and corrective actions be performed per specific parts of P&WC SB 21714R2 (or Transport Canada approved later revisions), together with the prohibition on alternate means of compliance, narrows acceptable methods of remediation. Non-use of the referenced instructions would constitute non-compliance with the AD and, again, subject the operator to CASA enforcement discretion.

Interaction with Transport Canada ADs and alerts

• The AD refers explicitly to Transport Canada AD CF-2005-29 and Transport Canada Service Difficulty Alert AL-2005-05. That cross-reference does not itself create a separate enforcement regime under Australian law, but it does indicate the safety rationale and the source material CASA is mandating for Australian operators. Transport Canada’s parallel regulatory action suggests international coordinated oversight, which in enforcement terms may affect expectations about reporting and compliance within the intergovernmental safety framework.

What the AD does not specify

• The AD does not state penalty amounts, infringement notice mechanisms, or the administrative process for CASA enforcement. It does not specify a process for requesting relief, and indeed it explicitly bars extensions or alternate means of compliance. The AD also does not mention who bears the cost of replacement shafts, or whether CASA will permit phased compliance for operational reasons; those are either outside the AD or governed by separate CASA processes or commercial arrangements.

Practical implication for operators

• Given the AD’s mandatory wording and time constraints, operators must treat the AD as an enforceable regulatory instrument and complete the required inspections, removals and destructions in accordance with the SB and the timelines. Where compliance cannot be achieved without grounding aircraft, operators would need to manage operations to meet the AD’s duties, aware that CASA’s enforcement options could be applied for non-compliance. The AD’s explicit prohibition on alternative compliance removes a common avenue for negotiated remedial strategies.

In summary, while the AD does not list penalties or enforcement procedures in the text provided, it creates clear mandatory obligations with strict timing and prescriptive technical methods; enforcement and penalties would be administered under the broader CASA statutory enforcement framework that sits outside the AD’s specific text.

The AD expressly cross-references Transport Canada regulatory and service-material documents and incorporates P&WC service bulletin instructions as technical mandates. The interaction is therefore primarily a requirement to implement external service material within the CASA regulatory framework.

Incorporation by reference

• The AD makes Transport Canada AD CF-2005-29 the determinant of which specific propeller shafts are affected, referring to its Tables 1-4 for the lists of propeller shafts. Operators must consult Transport Canada AD CF-2005-29 to identify whether the propeller shafts on their aircraft are listed in Tables 1-4; the CASA AD does not replicate those tables in the text provided but instead points to the Transport Canada AD as the authoritative source.
• The AD mandates compliance with P&WC SB 21714R2 dated 20 May 2005, Parts A, B and C, or later Transport Canada approved revisions. Where the SB instructs inspection procedures, internal checks or installation procedures, the AD converts those instructions into mandatory requirements under CASA jurisdiction.

Cross-jurisdictional coordination

• The AD references Transport Canada Service Difficulty Alert AL-2005-05 as part of its background material, demonstrating cross-jurisdictional information sharing and coordination regarding the safety issue (hydrogen embrittlement linked to nickel plating).
• For operators with fleets registered in multiple jurisdictions, the CASA AD aligns Australian regulatory obligations with actions taken by Transport Canada and service instructions from Pratt & Whitney Canada. That means operators may need to implement harmonised actions across registrations to meet varying but substantially overlapping regulatory mandates.

Constraints on regulatory relief

• The AD explicitly states “No extensions or alternate means of compliance are permitted.” That removes the option , at least under this AD text , for operators to use CASA’s administrative flexibility to seek alternative compliance methods or different deadlines. Any interaction with other legislative relief regimes (such as seeking exemptions or emergency permissions) is not provided for in the AD text supplied and would require separate regulatory processes not addressed here.

Relationship to maintenance manuals

• The AD points to the Engine Maintenance Manual , Corresponding Fault Isolation Chart (for “Oil leak from propeller shaft area”) as the diagnostic procedure when an oil leak is found. That links the AD directly to the operator’s engine maintenance documentation and diagnostic regimes. Compliance therefore requires following the EMM chart in addition to the SB instructions.

Implications for contractual and commercial arrangements

• While not explicitly legal in the AD text, the mandatory destruction and replacement of propeller shafts will interact with commercial contracts between operators, maintenance facilities and parts suppliers. The AD’s requirement to install new propeller shafts “as per Part C of the Accomplishment Instructions of P&WC SB 21714R2” indicates that installation must follow manufacturer-prescribed procedures, which may affect warranties, supplier obligations and parts procurement. Those contractual implications fall outside the AD text but will be activated by the AD’s technical mandates.

Absence of other statute references

• The AD does not reference specific Australian aviation statutes, general civil penalties, or specific enforcement regulations in its text. The regulatory effect is nonetheless clear: CASA has issued a mandatory directive that imposes obligations on Australian-registered operators. Any enforcement action arising from non-compliance would be executed under CASA’s statutory powers, but the AD itself does not articulate those statutory enforcement mechanisms.

Practical compliance interaction

• Operators must therefore treat three sources as interacting obligations: the CASA AD (this instrument), Transport Canada AD CF-2005-29 (for the lists of affected shafts and as an allowed approval path for SB revisions), and P&WC SB 21714R2 (Parts A-C) and prior versions (permitted for inspections per Note 2) for the technical steps. The AD also embeds the EMM fault isolation chart as a diagnostic reference when oil leaks are present. Compliance requires coherent implementation of all four documents.

In short, the AD integrates and elevates external service instructions and a foreign regulator’s AD into enforceable Australian obligations, narrows the scope for procedural deviation, and anchors required technical steps to the manufacturer’s service bulletin and the engine maintenance manual.

The AD text supplied contains limited explicit amendment-history material but does indicate the versions of technical material that are relevant and acceptable for compliance.

Service bulletin versions and acceptance

• The AD mandates P&WC SB 21714R2 dated 20 May 2005 for Parts A (visual inspection), B (internal inspection) and C (installation/replacement instructions) and permits “later Transport Canada approved revisions.” That language allows for subsequent Transport Canada approvals of later SB revisions to be acceptable in lieu of SB 21714R2. The AD thus anticipates, and formally allows, future Transport Canada-approved SB revisions as compliant alternatives.
• Note 2 explicitly states that compliance using inspection methods contained in any previous versions of P&WC SB 21714 prior to the effective date of the directive satisfy the requirements mandated by SB 21714 Revision 2. That creates a backward-compatibility acceptance: older SB versions that existed before the AD’s effective date are accepted for the inspection obligations set by the AD.

References to Transport Canada ADs and alerts

• The AD repeatedly refers to Transport Canada AD CF-2005-29. This AD is used as the repository for the Tables (1-4) identifying specific propeller shafts; the CASA AD therefore relies on Transport Canada’s listing rather than reproducing it. Any amendment to Transport Canada AD CF-2005-29 that changes those Tables could therefore affect which propeller shafts are covered, subject to whether CASA later revises its own AD.
• Transport Canada Service Difficulty Alert AL-2005-05 (issued March 2005) is cited in the background as part of the sequence of notifications and planned corrective actions that preceded the CASA AD. The AD does not catalog revisions to the Service Difficulty Alert; rather, it refers to it as part of the factual context.

Effective date and signing

• The AD states it “becomes effective on 27 October 2005” and is signed by a CASA delegate on 16 September 2005. The effective date is the formal date by which the compliance timelines are measured (for example, five days after the effective date). The signature date and effective date are both recorded in the supplied text, which establishes the AD’s timing baseline.

No subsequent CASA amendments recorded in the text

• The supplied AD contains no text indicating it has itself been revised or amended subsequent to its initial issuance. The AD does, however, provide for Transport Canada approved later revisions of SB 21714R2 to be acceptable, which introduces a mechanism for technical updating without changing the CASA AD itself.

Practical consequence for operators

• Operators must track revisions to P&WC SB 21714 and any Transport Canada approvals of later revisions because the AD allows those later Transport Canada approved revisions to satisfy its requirements. Likewise, operators must monitor Transport Canada AD CF-2005-29 for any changes to the listing of propeller shafts (Tables 1-4) because that listing determines which shafts are mandated for destruction or inspection under the CASA AD.

Summary

• The AD itself contains no amendment log documenting changes to the AD text after issuance. It does, however, embed a dynamic interaction with P&WC SB 21714 versioning and Transport Canada approvals, by mandating a specific SB revision but accepting both older SB inspection methods (Note 2) and later Transport Canada approved revisions. Any formal amendment to the CASA AD would have to be tracked through CASA publications; such amendments are not present in the text supplied.

The supplied AD text does not include or reference any litigation history, court decisions, determinations, or judicial interpretations related to the AD, the underlying failure events, or the implicated overhaul facilities. The document contains background factual statements about two reported instances of through-going cracks and identifies the root cause as hydrogen embrittlement due to improper nickel-plating repair processes, but it does not cite any legal proceedings arising from those events.

Material explicitly present and relevant to potential disputes

• The AD documents the factual basis for regulatory action: two reported instances of propeller shafts found with through-going cracks at the no. 19 bearing area and identification of hydrogen embrittlement caused by improper nickel-plating repair processes at two overhaul facilities. It further refers to Transport Canada’s Service Difficulty Alert AL-2005-05 and Transport Canada AD CF-2005-29. These items could feature as factual material in any dispute over the AD’s necessity or scope, but no litigation is referenced in the AD text.

Absence of judicial record in the AD

• Because the AD itself is an administrative safety instrument, the document would normally be the subject of regulatory compliance processes rather than litigation, unless an affected party sought judicial review or challenged enforcement action. The AD text supplied does not indicate any such challenges, appeals, or court rulings.

Operational implications of absent litigation signals

• From the AD alone, practitioners cannot infer whether trade disputes, warranty claims, tort actions, or administrative appeals were pursued in relation to the events or to the overhaul facilities. The AD’s background supplies the causation narrative and the safety rationale, but it does not indicate that that narrative was litigated or contested in court.

What to do if litigation history is required

• If a practitioner requires litigation history, they must consult external sources: CASA enforcement records, court databases, or public records of any proceedings involving the overhaul facilities, Pratt & Whitney Canada, Transport Canada, or operators affected by the AD. The AD itself does not provide that information.

In short, the AD contains factual background and regulatory action but no litigation history or case citations in the text supplied.

The AD contains numerous operational and compliance traps that operators and maintenance organisations must be alert to; these arise from prescriptive language, short timeframes and cross-references to external documents. The following are specific “gotchas” grounded in the AD’s text.

1. Applicability is determined by Transport Canada Tables, not the AD’s engine list alone

• The AD lists numerous PW100 engine models and notes common aircraft installations, but the actual propeller shafts that are subject to destruction, inspection or removal are those listed in Tables 1-4 of Transport Canada AD CF-2005-29. Operators who rely only on the engine model list without checking the Transport Canada AD’s tables may misidentify affected components. The AD therefore requires consultation of an external document to determine exact applicability.

2. “Not limited to” language expands the potential fleet

• The AD states the listed engines are “installed on, but not limited to” certain aircraft types. This “not limited to” phrasing means affected shafts may be present on other airframes. Operators should not assume that absence from the listed aircraft types equals non-applicability.

3. Immediate and recurring inspection timing for Table 4

• The visual inspection for oil leaks required by Requirement 2 must be completed within five days of the AD’s effective date and then repeated every week until the propeller shaft is removed from service. That creates a recurring weekly operational burden; failing to maintain the weekly repeat inspections is a compliance breach.

4. Tight deadline for internal inspection

• The internal inspection for Table 4 propeller shafts must be completed within 250 hours air time or not more than three months after the AD’s effective date, whichever occurs first. Operators with high utilisation aircraft must calculate the 250-hour window carefully; the shorter of the two limits governs.

5. No alternate means or extensions allowed

• The AD explicitly prohibits extensions or alternate means of compliance. That prevents operators from proposing alternate inspection technologies, phased implementation, or deadline extensions without separate regulatory action. Where operational constraints would otherwise justify variation, the AD’s text does not permit it.

6. “Destroy/Discard” requires permanent removal

• For Table 1-3 shafts, Requirement 1 mandates destruction/discard. That language does not permit repair, refurbishment or re-plating for those specific listed shafts. For Table 4 shafts the AD also mandates removal and destruction by a date (Requirement 4). Operators must arrange for replacement parts and manage the supply chain; failure to acquire replacements cannot be used as a justification to retain an affected shaft in service.

7. Conditional return-to-service traps

• The AD allows returning an engine to service in certain conditions: if no oil leak is found on visual inspection (Requirement 2(b)), if an oil leak can be fixed without propeller removal (Requirement 2(a)(ii)), or if internal inspection reveals no crack (Requirement 3(b)). Those returns-to-service are conditional; operators must ensure the conditions are strictly satisfied and documented in the maintenance records consistent with the SB and EMM procedures.

8. Reliance on service bulletin parts and EMM fault isolation chart

• The AD mandates adherence to specific parts of P&WC SB 21714R2 and to the Engine Maintenance Manual fault isolation chart for oil leaks. Operators must have immediate access to the referenced SB and the EMM; failure to use the mandated parts or the EMM chart could be a compliance failure. Note 2 allows previous SB versions for inspections, but only prior versions, not other documents.

9. Differences in dates within the document

• The AD is signed on 16 September 2005 but states it becomes effective on 27 October 2005. Operators must use the AD’s stated effective date (27 October 2005) when calculating compliance periods (for example, “within five days after the effective date”).

10. Potentially limited visibility of affected serial numbers

• The AD delegates identification of affected shafts to the Transport Canada AD tables. If an operator’s parts records are incomplete or cross-references between engine serial numbers and shaft part numbers are missing, they may find it difficult to determine which propeller shafts require action. That creates a record-keeping risk that is not addressed by the AD text.

11. Underlying cause tied to repair process at overhaul facilities

• The AD’s background attributes the root cause to hydrogen embrittlement from an improper nickel-plating repair process at two overhaul facilities. Where operators have shafts that were reworked at those or other facilities, the AD gives a causal clue, but the directive applies across the list in Transport Canada’s Tables regardless of provenance. Operators cannot treat local provenance as a defence to compliance.

12. No guidance in the AD text on documentation or reporting

• The AD does not specify the format or recipient for compliance records or reports. Operators must therefore rely on standard maintenance record practices or seek clarification from CASA if a specific reporting requirement is necessary. The absence of specified reporting steps in the AD could create confusion during audits or enforcement actions.

13. Parts provisioning and scheduling impact

• The AD requires replacement shafts “as per Part C” where a crack is found. Because the AD mandates destruction and replacement, operators must plan for procurement and installation resources. The AD gives no grace for supply shortages.

14. Cross-border document reliance

• The AD permits “later Transport Canada approved revisions” of the SB. Operators must monitor both P&WC SB revisions and Transport Canada approvals to confirm which later versions are acceptable. Failure to use the correct, Transport Canada-approved revision could be a compliance issue.

Being alert to these specifics will reduce the risk of inadvertent non-compliance and operational disruption. The AD’s prescriptive approach, tight deadlines and reliance on external listing and SB material create a set of practical hazards that require active management.

Compliance under this AD requires following the numbered requirements, the specified timelines, and the referenced technical instructions. The steps below restate the AD’s mandatory tasks in operational sequence and cite the relevant AD requirements and compliance provisions.

Step 1 , Determine applicability

• Consult Transport Canada AD CF-2005-29 Tables 1-4 to identify whether the propeller shaft(s) fitted to your PW100-series engine(s) are listed. The CASA AD uses those Tables to determine which shafts are subject to Requirement 1, Requirement 2/3, or Requirement 4. Do not rely solely on the engine model list in the AD text; the Transport Canada AD tables contain the definitive list.

Step 2 , Immediate actions for shafts in Tables 1-3 (Requirement 1)

• If a propeller shaft on an engine is identified in Tables 1, 2 or 3 of Transport Canada AD CF-2005-29, destroy/discard the shaft as mandated by Requirement 1. The AD prescribes destruction/discard without authorising repair or continued service for those listed shafts.
• Timing: Complete this within five days after the AD’s effective date, per the Compliance section. The AD became effective on 27 October 2005; count five days from that date.

Step 3 , Visual inspection for Table 4 shafts (Requirement 2)

• For propeller shafts identified in Table 4, perform a visual inspection for oil leaks in accordance with Part A of P&WC SB 21714R2 dated 20 May 2005, or a later Transport Canada approved revision of that SB, as permitted by the AD.
• Timing: Conduct the visual inspection within five days of the AD’s effective date and repeat the visual inspection weekly until the shaft is removed from service (Compliance).
• If no oil leak is found on the visual inspection, the engine may be returned to service (Requirement 2(b)).

Step 4 , Actions if a visual inspection reveals an oil leak (Requirement 2(a))

• If a leak is found, perform an inspection of the propeller shaft seal area using the Engine Maintenance Manual , Corresponding Fault Isolation Chart for “Oil leak from propeller shaft area” (Requirement 2(a)(i)).
• If the leak can be fixed without removing the propeller, effect the repair per the EMM and then the engine may be put back into service (Requirement 2(a)(ii)).
• If propeller removal is required to fix the leak, remove the propeller and proceed to the internal inspection procedure required by Requirement 3 (Requirement 2(a)(iii)). The internal inspection must follow Part B of P&WC SB 21714R2 or later Transport Canada approved revisions.

Step 5 , Internal inspection for Table 4 shafts (Requirement 3)

• Perform the internal inspection of the propeller shaft per Part B of P&WC SB 21714R2 (or later Transport Canada-approved revisions).
• Timing: The internal inspection must be completed within 250 hours air time or not more than three months after the AD’s effective date, whichever occurs first (Compliance). If the initial visual inspection indicated a leak necessitating propeller removal, perform the internal inspection as soon as the propeller is removed, consistent with the AD’s sequencing.
• If a crack is found during internal inspection, remove and discard the shaft and install a new propeller shaft per Part C of P&WC SB 21714R2 (Requirement 3(a)). If no crack is found, the engine may be returned to service (Requirement 3(b)).

Step 6 , Removal and destruction deadline for Table 4 (Requirement 4)

• Regardless of inspection results, propeller shafts listed in Table 4 must be removed and destroyed/discarded no later than 31 December 2007 (Requirement 4). Plan parts procurement, shop labour and scheduling to meet that date.
• The AD states no extensions or alternate means of compliance are permitted; therefore operators should assume the December 2007 deadline is mandatory without in-AD flexibility.

Step 7 , Use correct service bulletin versions

• Use P&WC SB 21714R2 dated 20 May 2005 for Parts A, B and C where required, or later Transport Canada approved revisions. For the visual and internal inspections (Requirements 2 and 3), Note 2 permits inspection methods from any previous versions of P&WC SB 21714 prior to the AD’s effective date to satisfy the AD’s inspection requirements. Confirm which SB revisions Transport Canada has approved if using a later SB revision.

Step 8 , Record the actions

• While the AD text does not specify recordkeeping formats in the supplied text, standard maintenance practice requires documenting inspections, repairs, removals and installations in the aircraft and engine maintenance records, noting the AD reference (AD/PW100/12), the SB part used (Part A, B or C of SB 21714R2 or the accepted pre-existing SB version), dates, serial numbers, findings (e.g. oil leak, crack detected), corrective actions (e.g. shaft destroyed and replaced per Part C), and signatures of certifying personnel. This documentation will be necessary to demonstrate compliance in any inspection or audit.

Step 9 , Manage parts supply and labour

• Because the AD requires destruction/discard and replacement in many cases, arrange procurement of approved replacement propeller shafts and allocation of shop time for the installations per Part C of the SB. The AD’s explicit prohibition of alternate compliance means operators cannot delay replacement by proposing alternative interim measures in place of replacement.

Step 10 , Confirm effective dates and timing calculations

• The AD becomes effective on 27 October 2005. Some documents in the AD are dated earlier (e.g. the SB dated 20 May 2005 and the signature dated 16 September 2005) but compliance timing is calculated from the AD’s effective date. Use that date as the baseline for the “within five days,” “within 250 hours or three months,” and the weekly repetition requirements.

Step 11 , Liaise with CASA if uncertain

• The AD contains strict “no extensions or alternate means of compliance” language and directs compliance to specific SB parts and Transport Canada approvals. If an operator believes exceptional operational circumstances prevent timely compliance, the AD text does not provide a route within its terms to request alternative compliance. Operators should therefore engage CASA directly to understand whether any administrative relief mechanisms exist outside the AD text, and to obtain formal clarification if necessary.

Step 12 , Monitor Transport Canada and P&WC publications

• Because the AD accepts Transport Canada approved later revisions of SB 21714R2, monitor Transport Canada approvals and P&WC SB revisions. If a later version receives Transport Canada approval, that later revision is acceptable under the AD.

By following the sequence above , identify affected shafts via Transport Canada AD tables; destroy or inspect per the AD’s requirements and timelines; perform remedial actions using the specified SB Part C installation steps where necessary; and maintain contemporaneous records , operators will implement the AD’s mandatory requirements as written. The AD’s prohibition on alternate means of compliance and its specific deadline requirements mean deviations are not permitted under the AD’s terms.