AD/DHC-8/125 - Main Landing Gear Shock Strut Piston

The AD is organised around three main corrective concepts: (1) a physical modification to the shock strut assembly to remove the anti-rotation needle roller; (2) an operational change to maintenance programmes by adding a specific servicing task to the approved maintenance schedule; and (3) a parts exclusion and mandatory replacement regime for repair and overhaul of shock struts, with special provision for reworked oversize cylinder bores.

The physical modification (requirement 1) is the removal of the anti-rotation needle roller from the upper bearing of the main landing gear shock strut. The AD mandates incorporation of Modsum 8/3331 by following Bombardier Service Bulletin 8-32-144 Revision A (29 April 2002) or later Transport Canada approved revisions. The AD explicitly accepts prior incorporation of Modsum 8/3331 in accordance with the original issue of the Service Bulletin dated 10 August 1998 as meeting the requirement. Mechanistically, the document states that removal of the needle roller addresses damage that can occur to the upper bearing and seal carrier when internal damping is lost. The removal is therefore presented as an engineering fix to interrupt the causal chain that led to over-extension events.

The maintenance-programme amendment (requirement 2) requires operators to amend the Transport Canada approved maintenance schedule by incorporating MLG Shock Strut Servicing task number 3210/15 into Part 1 of the DHC-8 Maintenance Program Manual. The AD lists the specific PSM numbers and revision numbers for aircraft Series 100, 200 and 300. This requirement converts a discrete technical fix into a recurring, scheduled maintenance obligation that must be reflected in the operator’s approved maintenance documentation. The wording connects to the operator’s regulatory framework by referencing the Transport Canada approved maintenance schedule and the DHC-8 Maintenance Program Manual.

The parts regime (requirement 3) establishes negative and positive lists of part numbers to prevent reintroduction of components that are implicated in the failure mechanism, and to mandate use of specific replacement components. It forbids certain legacy Upper Bearing and Damper Ring P/Ns and prescribes their replacements. For MLG units with reworked oversize cylinder bores, the AD requires conforming to the Component Maintenance Manual and lists the CRS85-167 series parts as required. This creates a supply-side specification: maintenance and overhaul shops must have or obtain the prescribed part numbers to continue overhauls lawfully on affected struts.

The AD references Transport Canada AD CF-2006-14 and calls for use of Bombardier service documentation and the Component Maintenance Manual. The document is therefore a cross-referenced, regulatoryly-binding set of engineering, procedural and parts-specification mandates that require changes at the level of component assembly, documented maintenance practices, and parts sourcing.

The AD identifies affected parties by model, aircraft serial number ranges, and shock strut serial numbers. It thus directly affects aircraft owners and operators of Bombardier DHC-8 models listed and whose aircraft and components fall within the specified serial-number ranges. Specifically:

• Requirement 1: Directly affects operators of DHC-8 Models 311, 314 and 315 with aircraft serial numbers 202 through 516 where the main landing gear shock struts installed have serial numbers in the range DCL3501/90 to DCL3768/97. The AD also extends that requirement to all spare MLG shock struts having serial numbers in the same DCL range. This places responsibilities on both operators for in-service aircraft and on maintenance organisations, parts depots and spares managers who hold or plan to install spare MLG shock struts within that serial-number bracket.

• Requirement 2: Affects operators of DHC-8 Models 101, 102, 103, 106, 201, 202, 301, 311, 314 and 315 with aircraft serial numbers 003 to 614. Those operators must amend their Transport Canada approved maintenance schedule by incorporating MLG Shock Strut Servicing task 3210/15 into Part 1 of the DHC-8 Maintenance Program Manual for their aircraft series and PSM numbers as specified.

• Requirement 3: Affects operators and any repair or overhaul organisations servicing DHC-8 Models 101, 102, 103, 106, 201, 202, 301, 311, 314 and 315 with aircraft serial numbers 003 to 618. It restricts the parts that may be used during repair or overhaul of any shock strut assembly for these aircraft, forbidding specific legacy Upper Bearing and Damper Ring part numbers and prescribing particular replacement part numbers. It also imposes parts requirements for units with reworked oversize cylinder bores, directing compliance with the applicable Component Maintenance Manual.

Other affected parties include maintenance organisations and engineers, spares suppliers, and maintenance-programme approval authorities. The AD explicitly refers to the Transport Canada approved maintenance schedule and to the DHC-8 Maintenance Program Manual, thereby creating work that must be reflected in regulator-approved maintenance documentation. Where an operator’s Maintenance Program Manual is Transport Canada approved, the operator will need to ensure the amendment is made in a manner consistent with Transport Canada approval processes. The AD also references Bombardier Service Bulletin 8-32-144 and the Component Maintenance Manual, so authorised maintenance organisations that follow Bombardier’s documentation will be required to use those documents in implementing Modsum 8/3331 and parts changes.

The AD’s application to spare shock struts extends obligations to parts inventories and to organisations that manage rotation of spares across fleets. Any party that installs a spare shock strut from the prohibited serial range onto an affected aeroplane will need to ensure Modsum 8/3331 has been incorporated or that other parts requirements are satisfied as specified.

Duties

• Incorporate Modsum 8/3331: For applicable DHC-8 Models 311, 314 and 315 with specified shock strut serial numbers (DCL3501/90 to DCL3768/97), operators must remove the anti-rotation needle roller from the upper bearing of the MLG shock strut by incorporating Modsum 8/3331 in accordance with Bombardier Service Bulletin 8-32-144 Revision A dated 29 April 2002, or later Transport Canada approved revisions. The duty extends to spare shock struts in the same serial-number range. The AD states that prior incorporation according to the original Service Bulletin dated 10 August 1998 also satisfies this duty (Note 1).

• Amend approved maintenance schedule: Operators of specified DHC-8 models and serial numbers must amend their Transport Canada approved maintenance schedule by incorporating MLG Shock Strut Servicing task 3210/15 into Part 1 of the DHC-8 Maintenance Program Manual. The AD provides specific PSM numbers and revision numbers for each aircraft series. This is a duty to update approved documentation and thereby embed the servicing task into prospective maintenance cycles.

• Prohibit and mandate parts: Maintenance and overhaul organisations must not use specified legacy parts (Upper Bearing P/Ns 10130-3 and 10130-551; Damper Ring P/Ns 10129-3 and 10129-551) as replacements during repair or overhaul of any shock strut assembly for affected models and serial numbers. Instead, they must use the prescriptive replacement parts (Upper Bearing P/N 10130-5; Damper Ring P/Ns 10129-5 and 10129-553). For shock struts with a reworked oversize cylinder bore, specified CRS85-167 series parts are to be used in accordance with the applicable Component Maintenance Manual.

• Timely compliance: The AD imposes specific timeframes: requirement 1 within 3000 flight hours after the AD’s effective date, requirement 2 within 30 days after the AD’s effective date, and requirement 3 is effective immediately on the AD’s effective date.

Rights

• Recognition of prior compliance: The AD recognises that previous incorporation of Modsum 8/3331 in accordance with the original Service Bulletin (10 August 1998) meets requirement 1. This provides a right to treat prior properly-documented work as compliance without repeat action.

• Use of later regulator-approved revisions: Where Bombardier Service Bulletin 8-32-144 is later revised and approved by Transport Canada, operators may follow the later approved revision to meet the Modsum incorporation requirement. The AD therefore permits use of Transport Canada approved revisions in place of the specific 29 April 2002 revision.

• Use of CMM for oversize bores: For MLGs with reworked oversize cylinder bore, operators have the right to use the parts identified in the Component Maintenance Manual as the required parts (CRS85-167 series), i.e., the AD defers to CMM instructions for such configurations.

Operational implications of duties

• Documentation and record-keeping: Operators must record Modsum incorporation and maintenance manual amendments in maintenance records and, where applicable, satisfy Transport Canada approval processes for maintenance programme amendments.

• Parts management: Maintenance providers must ensure legacy prohibited parts are not used and that inventory and procurement processes supply the mandatory replacement parts and CRS85 parts where relevant.

The AD does not itself set out a permissive exemption procedure in the text provided; it instead establishes required actions, timelines and approved references (Bombardier Service Bulletin, CMM, Transport Canada approvals) through which compliance can be demonstrated.

The AD text provided does not set out specific penalties or enforcement mechanisms within its body. It is presented as an Airworthiness Directive issued by the Civil Aviation Safety Authority delegate and becomes effective on a stated date (3 August 2006). The directive prescribes mandatory actions and compliance timeframes: for example, removal of the anti-rotation needle roller within 3000 flight hours for certain struts, amendment of maintenance schedules within 30 days, and an immediate prohibition on specified parts as of the effective date.

What the AD does show is the regulator-level issuance mechanism and effective date, and it cross-references Transport Canada approvals and a Transport Canada AD (CF-2006-14). The absence of explicit penalty language in the text means that the AD itself does not specify monetary fines, licence sanctions or criminal penalties; however, the AD is issued by a national aviation safety authority and therefore functions as a mandatory regulatory instrument. Compliance obligations flow to operators, maintenance organisations and parts suppliers as set out in the AD.

In practice, enforcement of an AD of this kind typically occurs through routine surveillance, continuing airworthiness oversight, airworthiness inspections, and certification processes, and non-compliance can be identified during those activities. The AD’s text does not detail enforcement procedures, nor does it specify appeal, exemption or rectification processes in the event an operator cannot comply by the stated times. The AD does, however, provide a clear effective date and compliance windows that set the expected timeline for action.

Because the AD refers to Transport Canada approved revisions and a Transport Canada AD, it also ties Australian regulatory action to Transport Canada’s regulatory and approval frameworks for the particular service documentation and the accepted technical solution. That cross-reference may influence how compliance documentation is prepared and assessed by regulators, particularly where maintenance schedule amendments require approval by the relevant competent authority.

Readers of this AD should therefore note two points from the instrument itself. First, the AD prescribes mandatory action and dates without specifying penalties in its text. Second, it references regulator-approved service documentation and another national regulator’s AD, which means that the practical enforcement and acceptance of the corrective measures will be evaluated against those approved technical references and the operator’s approved maintenance programme.

The AD expressly cross-references Transport Canada material and Bombardier/De Havilland technical documentation, creating interaction lines between this CASA-issued directive and foreign regulator approvals and manufacturer instructions. The AD requires incorporation of Modsum 8/3331 in accordance with Bombardier Service Bulletin 8-32-144 Revision A dated 29 April 2002, or later Transport Canada approved revisions. It also requires amendment of the Transport Canada approved maintenance schedule and notes Transport Canada AD CF-2006-14 dated 14 June 2006. The AD therefore operates in a network of regulatory and manufacturer-controlled documents.

Interaction with maintenance programme approvals. The AD requires amendment of the “Transport Canada approved maintenance schedule” by adding the specified task 3210/15 into Part 1 of the DHC-8 Maintenance Program Manual for the relevant PSM numbers and rev numbers. This creates an interaction with maintenance programme approval regimes: operators must ensure that the required change is incorporated into their approved documentation. In jurisdictions where an operator’s maintenance programme is approved by a national regulator, that approval process and the procedures for submission of amendments will be implicated. The AD’s wording refers specifically to the Transport Canada approved maintenance schedule, which indicates a prescriptive alignment with the documentation approved by that authority. Where the operator’s maintenance programme is overseen under a different national authority, the operator will still need to reflect the AD’s requirements in its own approved documentation consistent with domestic approval procedures.

Interaction with manufacturer documentation. The AD mandates compliance with Bombardier Service Bulletin 8-32-144 and with the Component Maintenance Manual for oversize bore configurations. That means work must be performed in accordance with the manufacturer’s specified accomplishment instructions or the parts and procedures described in the CMM. The AD accepts later Transport Canada approved revisions of the Service Bulletin, which makes Transport Canada’s approvals a determinative reference point for acceptable technical variants.

Interaction across national regulators. The AD references Transport Canada AD CF-2006-14; it therefore aligns CASA’s directive with Transport Canada actions addressing the same or similar problem. This is an example of multinational regulatory cross-recognition of technical corrective measures on a specific aircraft type. Operators that operate or register aircraft across jurisdictions should note that compliance documentation may need to show conformity to both CASA’s directive and Transport Canada’s referenced AD or approvals.

Limitations in the AD text. The AD itself does not set out explicit legal mechanisms for seeking exemptions or extensions, nor does it recite domestic aviation statute or regulation sections under which non-compliance would attract sanctions. It also does not prescribe steps for how maintenance programme amendments are to be submitted to the approving authority. The AD therefore functions primarily as a technical and operational directive; its interaction with broader regulatory processes will be mediated through the usual maintenance programme approval and continuing airworthiness oversight channels in the operator’s jurisdiction.

Overall, the AD links manufacturer service instructions, parts lists and the maintenance programme approval regime together. Compliance therefore requires coordination among those responsible for airworthiness management, and documentary proof that the specified Modsum, maintenance task and parts usage requirements have been embedded into approved maintenance documentation and executed on affected aircraft and spare parts.

The AD itself contains internal cross-references and acceptance of prior amendments and revisions of manufacturer documentation. The key amendment and document-revision touchpoints the AD records are:

• Bombardier Service Bulletin 8-32-144: The AD requires incorporation of Modsum 8/3331 in accordance with Bombardier Service Bulletin 8-32-144 Revision A dated 29 April 2002. The AD also acknowledges that incorporation carried out in accordance with the original issue of Bombardier Service Bulletin 8-32-144 dated 10 August 1998 meets the requirement (Note 1). Thus the AD accepts work done pursuant to either the original issue or Rev A.

• Modsum 8/3331: The AD prescribes incorporation of Modsum 8/3331 as the engineering change required to remove the anti-rotation needle roller from the upper bearing of the MLG shock strut.

• Transport Canada AD CF-2006-14: The AD explicitly references Transport Canada AD CF-2006-14 dated 14 June 2006 (Note 2). That Transport Canada AD is a parallel regulator action addressing the same technical concern. The CASA AD thus cross-references and harmonises with the contemporaneous Transport Canada measure.

• Effective dates and issuance: The AD is signed by James Coyne, Delegate of the Civil Aviation Safety Authority, dated 21 June 2006 and states that the AD becomes effective on 3 August 2006. The AD contains three compliance timeframes tied to that effective date: within 3000 flight hours for Modsum incorporation where applicable, within 30 days for maintenance schedule amendment, and immediate effect for parts prohibitions.

The AD does not itself set out subsequent amendments to the AD; there is no text in the provided document that records later revisions of the AD instrument. The amendment history captured in the AD therefore pertains to incorporated or referenced manufacturing and regulatory documents, rather than changes to the AD’s own text. The AD’s approach is to require incorporation of a specific Modsum and to allow compliance via certain prior or later Transport Canada approved revisions of the Bombardier Service Bulletin. The prescriptive parts lists include legacy parts to be removed from use and the required replacement P/Ns, and they include CRS85 series parts for oversize bore configurations, again tying to the Component Maintenance Manual.

Operators should note that the AD accepts prior compliance if Modsum 8/3331 was incorporated under the original SB issued 10 August 1998, and that it expressly allows later Transport Canada approved revisions of the Bombardier Service Bulletin to be relied upon. Any further amendments to the AD or to the referenced service documentation would have to be consulted separately; the AD text as provided does not record any subsequent AD amendments.

The AD text provided contains no record of litigation, appeals, or judicial or administrative adjudication relating to the directive. The document records the safety background (six reported cases over 10 years of shock strut piston over-extension and related damage), the technical corrective measures demanded, the effective date and the signatory delegate of the Civil Aviation Safety Authority. It also cross-references Transport Canada AD CF-2006-14 and Bombardier technical publications. There is no mention in the AD text of legal challenges, contested factual findings, requests for extension or exemption, or related case law.

Given that the AD is a technical regulatory instrument addressing an identified continuing airworthiness hazard, it is not uncommon for such directives to be implemented administratively and for compliance to be enforced through airworthiness oversight rather than by litigation. The AD itself does not describe dispute resolution procedures, appeal mechanisms against the directive, or any record of past litigation in the AD text. Therefore, based solely on the AD document provided, there is no litigation history to report.

Users seeking whether there were subsequent enforcement or judicial proceedings, or disputes arising from the AD, will need to consult regulatory enforcement records, tribunal decisions or court databases, which are outside the scope of the AD text provided. The AD does, however, reference Transport Canada action and Bombardier documentation, which may themselves have parallel administrative records in other jurisdictions.

Serial-number specificity and parts linkage. The AD’s applicability is granular and differs across the three requirements. For example, Requirement 1 applies only to Models 311, 314 and 315 serial numbers 202 through 516 and then only if the MLG shock strut(s) installed fall within a specified shock-strut serial-number range DCL3501/90 to DCL3768/97. Requirement 2 and 3 apply to a broader set of DHC-8 models but with overlapping serial-number boundaries (003 to 614 or 003 to 618). Practically, this means operators must cross-check both aircraft serial numbers and the serial numbers of the shock struts installed or in inventory. Failure to reconcile and track per-strut serial numbers could lead to inadvertent non-compliance if a spare or installed strut falls within the specified DCL range.

Spare parts treated as aircraft for requirement 1. The AD explicitly applies Requirement 1 to "all spare main landing gear shock struts in the same serial number range." That means that a spare with a DCL serial number in the affected range must be modified (Modsum 8/3331 incorporated) before installation or use. Inventory management and spares control are therefore directly implicated.

Note 1 acceptance of prior Modsum work. The AD states that previous incorporation of Modsum 8/3331 in accordance with the original issue of Bombardier Service Bulletin 8-32-144 dated 10 August 1998 meets the requirement. Operators who rely on that acceptance must be able to demonstrate documented evidence that the Modsum was incorporated in accordance with that original Service Bulletin. Absent documentation, an operator cannot rely on the Note.

Maintenance programme approvals. Requirement 2 requires amendment of the Transport Canada approved maintenance schedule by incorporating task 3210/15 into Part 1 of the DHC-8 Maintenance Program Manual. Operators must ensure that the change is reflected in the maintenance programme that is approved by the competent authority. The AD references Transport Canada approvals, which suggests that documentary conformity with the PSM numbers and revision numbers listed is required. Operators should not assume the amendment is merely an internal change; the wording contemplates formal amendment of an approved maintenance schedule.

Parts prohibition applies on overhaul/repair of any shock strut assembly. Requirement 3 forbids listed legacy parts "during the repair or overhaul of any shock strut assembly." This means that the prohibition is not limited to affected aircraft in service but applies whenever the component is repaired or overhauled. Maintenance organisations that perform overhauls must therefore ensure their parts sourcing and technical procedures conform to the AD at the point of overhaul.

Oversize bore special parts. For shock struts with a reworked oversize cylinder bore, the AD requires use of the CRS85-167 series parts "in accordance with the applicable CMM." That injects reliance upon the Component Maintenance Manual for those configurations. It also means that where a component has been reworked to an oversize cylinder bore, the standard P/N replacements listed elsewhere in Requirement 3 may not apply and maintenance must instead follow the CMM-specified P/Ns.

Divergent PSM revision numbers and records. The AD specifies particular PSM numbers and revision numbers to be amended. Operators must ensure they reference the correct PSM number/revision pairing in their Part 1 Maintenance Program Manual amendment to avoid mismatches during audit or oversight.

Timeline disparities. The AD contains differing compliance windows: within 3000 flight hours for Modsum incorporation (Req 1), within 30 days for maintenance schedule amendment (Req 2), and immediately for parts prohibition (Req 3). Operators must plan both immediate inventory controls to prevent prohibited part use and schedule engineering work to meet the longer flight-hour window. The three-track timeline requires coordinated short-term and medium-term actions.

Cross-jurisdictional approvals. The AD allows use of "later Transport Canada approved revisions" to the Bombardier Service Bulletin. This means that acceptable technical revisions may be those approved by a foreign regulator. Operators should confirm whether their national regulator accepts such cross-approved revisions for compliance certification in their jurisdiction, or whether local approval is also required.

Documentation burden. Demonstrating compliance will require maintenance records showing Modsum incorporation, maintenance programme amendments and parts provenance for overhauls. Operators and maintenance organisations should be prepared to produce such records to inspectors. The AD does not outline the exact form of the records, so familiar formats used for maintenance records and modifications will likely be needed.

No penalty text in AD. The AD itself does not set out penalties or an explicit enforcement mechanism in the text provided. That may create uncertainty about the process to follow if compliance cannot be achieved within the prescribed windows; operators should not infer an absence of enforcement but should engage with the regulator proactively for guidance.

The AD sets out concrete steps and timeframes. A practical compliance checklist, structured against the AD’s three requirements, is as follows. Each listed step quotes or references the instrument’s required action and its timing.

Step 1 , Identification (immediate)

• Inventory affected aircraft: Identify all DHC-8 Models and serial numbers under your control to determine whether they fall within the serial number ranges specified in Requirements 1, 2 and 3.
• Identify shock strut serials: For each aircraft identified, check the serial numbers of the installed main landing gear shock struts. For Requirement 1, determine whether any installed or spare shock struts have serial numbers within DCL3501/90 to DCL3768/97. The AD applies to both installed and spare shock struts in that serial-number range.

Step 2 , Parts control (as of effective date)

• Implement parts embargo: As Requirement 3 is effective as of the AD effective date, immediately prohibit use of the legacy parts listed (Upper Bearing P/N 10130-3, 10130-551; Damper Ring P/N 10129-3, 10129-551) in any repair or overhaul of shock strut assemblies for affected models/serials. Circulate the prohibition to maintenance organisations, line stations, overhaul shops and procurement.
• Confirm replacement parts: Ensure availability or procurement channels for required replacement part numbers: Upper Bearing P/N 10130-5; Damper Ring P/N 10129-5 and 10129-553. For reworked oversize cylinder bores, ensure supply or access to CRS85-167-11, CRS85-167-31 or CRS85-167-33, and CRS85-167-21 as directed by the CMM.

Step 3 , Technical modification (Requirement 1)

• Plan Modsum incorporation: For aircraft and spares in the specified DCL serial-number range, schedule incorporation of Modsum 8/3331 to remove the anti-rotation needle roller from the upper bearing in accordance with Bombardier Service Bulletin 8-32-144 Revision A (29 April 2002) or later Transport Canada approved revisions, or, where applicable, rely on documented prior incorporation under the original SB dated 10 August 1998 (Note 1).
• Record work: After incorporation, record the Modsum action in the aircraft and component maintenance records to evidence compliance.
• Timing: The AD requires this work within 3000 flight hours after the AD’s effective date unless already accomplished. Calculate remaining hours and schedule the work accordingly to meet the threshold.

Step 4 , Maintenance programme amendment (Requirement 2)

• Amend Maintenance Program Manual: Incorporate MLG Shock Strut Servicing task 3210/15 into Part 1 of the DHC-8 Maintenance Program Manual for the relevant PSM number and revision as specified by aircraft series. The AD lists PSM No. and Rev No. for Series 100 (1-8-7 Rev 20), Series 200 (1-82-7 Rev 11), Series 300 (1-83-7 Rev 20).
• Seek approval if required: The AD directs amendment of the "Transport Canada approved maintenance schedule." Ensure that any required submission to the approving authority is made in accordance with local regulatory procedures. Document the amendment and the date it was incorporated.
• Timing: The AD requires the amendment within 30 days after the effective date of the directive unless already accomplished.

Step 5 , Overhaul compliance processes

• Update overhaul procedures: Ensure that overhaul shops follow the AD’s prohibited and mandated parts list during repair or overhaul of any shock strut assembly for the applicable models/serials. If working on a reworked oversize cylinder bore unit, consult the applicable CMM and use the CRS85-167 parts as specified.
• Quality control checks: Integrate checks into incoming inspection to verify that legacy prohibited parts are not present, and that required replacement parts or CRS85-167 series parts are used where applicable.

Step 6 , Records and audit trail

• Maintain documentation: Keep clear records of Modsum incorporation, maintenance program amendments, procurement invoices and part numbers used for any overhaul or repair, and correspondence with regulators if approvals or clarifications were sought.
• Evidence of prior work: Where relying on Note 1 (prior incorporation under the original SB dated 10 August 1998), ensure that the original work is evidenced by signed maintenance records and references to the original SB.

Step 7 , Communication and training

• Notify maintenance staff: Disseminate the AD and its specific parts prohibitions and required actions to all relevant maintenance staff and contractors.
• Train procurement and stores: Alert parts procurement and stores personnel to the P/N changes and prohibition so that legacy parts are quarantined and replacement P/Ns are ordered.

Step 8 , Engage regulator if impeded

• If an operator cannot meet the AD’s compliance timeframes for reasons outside its control (for example, inability to obtain prescribed parts or to secure an approved maintenance schedule amendment in the expected timeframe), engage the regulator proactively for guidance. The AD text does not set out an exemption procedure in its body, so early contact with the regulator is advisable to clarify acceptable alternatives or extensions, if any.

Step 9 , Cross-reference Transport Canada documentation

• Where the AD allows use of later Transport Canada approved revisions, obtain and rely on the Transport Canada approved revision of Bombardier Service Bulletin 8-32-144 if appropriate. Also consult Transport Canada AD CF-2006-14 (14 June 2006) as referenced in the AD to ensure consistent compliance across referenced documents.

Step 10 , Ongoing monitoring

• Incorporate the servicing task 3210/15 into the recurrent maintenance plan and ensure that scheduled inspections/servicing occur as required going forward.

Following the AD’s exact language and timelines, keeping complete maintenance records that show Modsum incorporation and maintenance manual amendment, and ensuring parts compliance are the central compliance actions. Operators should verify the serial numbers for both aircraft and shock struts, manage spares inventories accordingly, and update procedures and documentation to demonstrate compliance.