AD/DHC-2/24 Amdt 4 - Wing Strut Assembly Lower Attachment Fittings

This directive deploys a small set of interlocking regulatory concepts that determine who must act, how, and when.

Applicability and scope: The AD applies only to DHC-2 aircraft fitted with certain wing lift strut part numbers (C2W1103, C2W1103A, C2W1104, C2W1104A). That is the defined universe of affected hardware (Applicability). The directive does not, in the text provided, expand to other parts or to other makes/models.

Dual inspection methods: The AD offers two separate, approved inspection methods:

• Fluorescent penetrant inspection (Part A) per Viking Air Service Bulletin (SB) No. 2/41 Rev C (or later Transport Canada approved revision).
• Eddy current inspection (Part B) per Viking Air SB No. 2/55 (or later Transport Canada approved revision).

This is not a mere technical suggestion: the AD explicitly links regulatory compliance to following the Accomplishment Instructions of the specified SBs or later Transport Canada approved revisions (Requirement). The AD further conditions Part A on the inspector having a "valid appropriate Non-Destructive Testing Authority," making the identity and certification of the person performing the inspection part of compliance.

Conditional intervals: The directive sets differing inspection frequencies depending on two variables:

• whether the aircraft operates in a salt water environment, and
• whether it has complied with Amendment 3 of the Directive.

For aircraft that have already complied with Amendment 3, intervals are generally longer; for those that have not, the AD imposes a short-term requirement (e.g., within 100 hours TIS or one calendar year after 15 March 2007) and then a recurring interval. The matrices differ between Part A and Part B and between salt water and other operations (Compliance).

Immediate operational constraint on cracks: The AD imposes a single, definitive operational constraint on detection of cracks: remove the affected strut from service "before further flight." That converts inspection findings into immediate asset removal and consequent operational disruption.

Inter-jurisdictional calibration: The AD explicitly references and aligns with a Transport Canada airworthiness directive (Transport Canada AD CF-1985-08R4 refers) and makes compliance contingent on service bulletin revisions being Transport Canada approved. Amendment 4 was issued "in response to a revision of the related Transport Canada AD" and provides operators an option tied to that revision. Thus, the AD relies on foreign regulator-approved revisions of manufacturer service bulletins as the technical standard.

Amendment mechanics: The AD embeds an amendment history that changes the instrument over time: Amendment 1 expanded part number applicability and removed serial/date provisions; Amendment 2 changed the penetrant method to fluorescent; Amendment 3 lengthened intervals for non-saltwater operations; Amendment 4 gives operators an option to adopt an alternate inspection method permitting longer intervals (Background). Those mechanics matter because compliance status relative to Amendment 3 alters the inspection schedule.

Operational definitions and uncertainties: The AD distinguishes "aircraft operating in a salt water environment" from "all other aircraft," using that as a determinant of inspection frequency. The directive does not set out a formal definition of "salt water environment" in the text supplied; the phrase functions as a risk classification within the compliance matrices.

In sum, the main regulatory levers are: (1) strict applicability to specific part numbers; (2) mandatory use of specified manufacturer SB procedures subject to Transport Canada approval; (3) certification requirement for the fluorescent penetrant inspector; (4) conditional interval matrices tied to marine operation and prior amendment compliance; and (5) immediate removal from service upon crack detection.

Operators of aircraft: Primary compliance is placed on the registered operators or owners of DHC-2 aircraft fitted with the enumerated strut part numbers (Applicability). Those operators must ensure inspections are scheduled and carried out according to the chosen method (Part A or Part B) and the correct interval matrix.

Maintenance organisations and personnel: The AD requires that the fluorescent penetrant inspection (Part A) "shall be carried out by a person holding a valid appropriate Non-Destructive Testing Authority." That makes qualified NDT personnel and organisations that employ them directly affected. Maintenance providers who perform eddy current inspections under Part B are also affected because they must follow the Accomplishment Instructions of Viking Air SB No. 2/55 or a later Transport Canada approved revision.

Aircraft registered in salt-water operations: Operators conducting operations in salt water environments are specifically affected by shorter inspection intervals for both Part A and Part B, and by differences that depend on whether Amendment 3 was previously complied with (Compliance). Those operators carry a higher frequency and therefore higher inspection burden.

Operators who have not complied with Amendment 3: The AD sets an immediate short-term compliance window for aircraft that "have not complied with Amendment 3," typically imposing an initial inspection "within 100 hours time in service or one calendar year after 15 March 2007, whichever occurs first." That subgroup faces a near-term action requirement.

Manufacturers and parts suppliers: Viking Air Ltd (the service bulletin originator) and any vendor of replacement struts are indirectly affected because compliance is tied to Viking Air SBs and Transport Canada approved revisions. Operators adopting the eddy current inspection or the fluorescent penetrant method must follow the SB detailed procedures, so the manufacturer’s documentation defines work scope and intervals.

Regulators and delegates: Civil Aviation Safety Authority (CASA) is the issuing authority (delegate David Villiers signed the AD). Transport Canada is implicated because the AD references Transport Canada approvals and a related Transport Canada AD (CF-1985-08R4). Those regulators are affected in the sense that the directive aligns CASA requirements with Transport Canada approvals and vice versa.

Operational planners and commercial users: Any commercial operators, charter services, or air taxi services using affected DHC-2 aircraft must incorporate potential downtime for inspections and possible strut removal. The AD’s immediate removal-on-crack rule means scheduling must anticipate the logistical and commercial impacts of removing a strut from service.

In sum, the directive affects the chain from the operator and maintenance providers through to manufacturers and regulators, with concentrated immediate burden on operators of affected part-numbered struts and on maintenance providers holding NDT authority.

Duties imposed by the directive are concrete and procedural; the text sets out who must do what, to what standard, and when.

Obligation to inspect by specified methods: The AD requires compliance with either Part A or Part B inspection regimes. Part A is a fluorescent penetrant inspection to be performed "in accordance with the Accomplishment Instructions of Viking Air Ltd ... Service Bulletin No. 2/41 Revision C, dated 23 June 2006, or a later Transport Canada approved revision" (Requirement: Part A). Part B is an eddy current inspection per Viking Air SB No. 2/55 (Requirement: Part B). The Accomplishment Instructions are the technical standard that translates the AD into maintenance practice.

Qualification requirement: Part A explicitly requires that the fluorescent penetrant inspection "shall be carried out by a person holding a valid appropriate Non-Destructive Testing Authority." That creates a duty to engage qualified NDT personnel and implies a duty on the operator to verify the inspector's authority and hold records as required by their own aviation maintenance and recordkeeping regimes (the AD text itself specifies the qualification; recordkeeping obligations are not detailed in the provided text).

Timing duties: The AD sets initial and recurring inspection intervals. The timing duties differ by inspection method (Part A vs Part B), by environment (salt water vs all other aircraft), and by prior compliance with Amendment 3. Examples from the AD:

• For Part A, aircraft operating in a salt water environment that have complied with Amendment 3: inspect "within one calendar year since the previous inspection, and thereafter at intervals not to exceed one calendar year." For aircraft that have not complied with Amendment 3: inspect "within 100 hours time in service or one calendar year after 15 March 2007, whichever occurs first, and thereafter at intervals not to exceed one calendar year."
• For Part B, eddy current, non-saltwater aircraft that have complied with Amendment 3: "within two calendar years since the previous inspection, and thereafter at intervals not to exceed five calendar years"; for those that have not complied with Amendment 3: "within 100 flight hours or one calendar year after 15 March 2007, whichever occurs first, and thereafter at intervals not to exceed five calendar years." These are duties on the operator to schedule and perform inspections within the prescribed windows.

Immediate action on defects: If cracks are detected during any required inspection under Part A or Part B, the duty is immediate: "before further flight, remove the affected strut from service." The AD leaves no operational discretion once cracks are found.

Choice of inspection option: Amendment 4 expressly grants operators an option: they may continue with "the current inspection intervals" or "incorporat[e] the improved alternate inspection method, to permit an increase in inspection intervals." That is a regulatoryly recognised choice, subject to the condition that the alternate method be followed in accordance with the relevant SB and, for later revisions, Transport Canada approval. The right to choose therefore exists but is bounded by the SB requirements and the AD schedule.

Interaction with Transport Canada approvals: The AD ties compliance to "later Transport Canada approved revision[s]" of the SBs. Operators therefore have a duty to ensure they follow either the specified revision or any later Transport Canada-approved revision, not merely an unapproved manufacturer change.

No penalties specified in text: The AD does not specify sanctions, fines, or enforcement mechanisms within the text provided. It does not set out inspection recordkeeping obligations, reporting obligations to CASA, or penalties for non-compliance in the text supplied. The directive's operational requirements are nonetheless mandatory by virtue of their issuance by the regulator; the text itself confines the duties to inspections, qualifications of inspectors, compliance windows, and immediate removal of cracked parts.

Instruments of compliance: The principal instruments are the manufacturer service bulletins and Transport Canada approvals for revisions of those SBs, and the requirement for qualified personnel for fluorescent penetrant inspections. The interplay of these elements defines the operator’s duties.

The text provided for AD/DHC-2/24 Amendment 4 does not set out any penalties, fines, or enforcement procedures. There is no express clause in the printed directive text that prescribes civil penalties, administrative sanctions, or criminal sanctions for breach of the AD within the material provided. The AD contains technical mandates , specific inspection methods, personnel qualification requirements, compliance intervals, and immediate removal of cracked struts , but it does not, in the supplied text, specify how CASA will enforce non-compliance or what penalties apply for failure to comply.

What the directive does do, in enforcement-relevant terms, is convert a safety risk into a mandatory maintenance requirement. The operational consequences built into the AD are themselves a form of enforcement on safety grounds: inspection findings must be acted upon immediately (the directive requires removal from service of any affected strut where cracks are detected, "before further flight"). That provision converts an inspection failure into an immediate operational constraint.

The AD also establishes reliance on manufacturer Service Bulletins and Transport Canada approvals as the technical standard for compliance. Compliance therefore requires adherence to those documents; failure to follow them would constitute failure to follow the AD as written. The AD does not, however, set out a reporting mechanism back to CASA for completed inspections or for detected defects in the text given. It likewise does not specify a discretionary enforcement procedure such as notices, rectification orders, or suspension of an aircraft’s certificate; none of those mechanisms are described in the supplied AD text.

Because the directive references a Transport Canada AD and Transport Canada-approved SB revisions, there is an implication that regulatory coordination exists, but the AD as supplied does not specify what enforcement action either CASA or Transport Canada would take if the inspection requirements were ignored. This absence should be noted by operators and maintenance organisations: the AD imposes operationally significant duties but does not, within the supplied text, articulate enforcement processes or penalties.

If an operator requires clarity on enforcement consequences, or on evidentiary requirements to demonstrate compliance to a regulator, that will need to be sought from CASA guidance, the operator’s Continuing Airworthiness obligations, or the broader regulatory framework, none of which are specified inside the AD text provided.

The directive explicitly cross-references and aligns with external technical and regulatory materials, but within the supplied text it does not purport to displace or elaborate primary regulatory powers of CASA or other national aviation safety frameworks. The interactions the AD identifies are principally technical and administrative.

Reference to Transport Canada: The AD states that "Transport Canada AD CF-1985-08R4 refers," and Amendment 4 was issued "in response to a revision of the related Transport Canada AD" (Background). The directive also conditions applicability of later revisions of manufacturer service bulletins on Transport Canada approval: both SB No. 2/41 and SB No. 2/55 must be followed "or a later Transport Canada approved revision." That creates an operational interaction where CASA's directive requires compliance with manufacturer service bulletins as approved by another national regulator (Transport Canada).

Manufacturer service bulletins: The AD requires performance "in accordance with the Accomplishment Instructions of Viking Air Ltd Service Bulletin No. 2/41 Revision C" and "Service Bulletin No. 2/55." Service bulletins are not legislation, but when an AD refers to them as the technical standard for compliance they become de facto regulatory instruments. The AD’s references make those SBs the normative maintenance instructions within the scope of the AD; they interact with any other legal or contractual obligations that require maintenance to conform to manufacturer instructions.

CASA-Transport Canada calibration: The AD shows CASA aligning its requirements with Transport Canada approvals, effectively incorporating Transport Canada’s approvals into CASA’s compliance matrix. Amendment 4 being issued in response to a Transport Canada AD revision indicates bilateral regulatory calibration: CASA’s AD gives operators an option that mirrors a revised Transport Canada position on inspection methods and intervals.

Operator certification regimes and continuing airworthiness obligations: While not spelled out in the AD text, obligations to maintain aircraft in an airworthy condition and to conduct maintenance according to approved data are typically embedded in broader aviation law and regulation. The AD slots into that regime by specifying which inspections and methods are required to maintain airworthiness with respect to the wing strut lower attachment fittings. The AD does not itself restate those broader legal responsibilities, but it prescribes the specific actions required to meet them insofar as they relate to this risk.

No other statutes or maritime, labour, or commercial laws are mentioned in the AD text. The AD uses the terms "salt water environment" and "Non-Destructive Testing Authority" but does not define them or explain how those terms sit within other legal instruments or standards. There may be interpretive interaction with an operator’s safety management system, maintenance organisation approvals, or certification records, but those interactions are not described in the AD text.

In sum, the AD interacts with other regulatory instruments principally by:

• Requiring adherence to manufacturer SBs and to later Transport Canada‑approved revisions (linking CASA compliance to Transport Canada approvals).
• Responding to a related Transport Canada AD revision (Amendment 4’s issuance context).
• Embedding SB procedures into the operator’s continuing airworthiness duties by reference.

The directive’s text does not specify enforcement mechanisms across jurisdictions, nor does it provide definitions that would otherwise interact with other legal instruments. Any further legal interaction (for example, recordkeeping obligations, investigation triggers, or cross-border enforcement) would need to be located outside the AD text in CASA regulations, the Civil Aviation Act or equivalent, or bilateral agreements; none of these are contained in the AD text provided.

The AD text sets out an internal amendment history that records prior changes leading to Amendment 4. The directive’s Background paragraph summarises the sequence and substance of the amendments:

• Original directive genesis: The AD was prompted by "a report ... of stress corrosion cracking occurring in the wing lift strut lower clevis fitting." That risk formed the basis for the initial directive and the actions it has required to preclude strut failure (Background).

• Amendment 1: "Amendment 1 expanded the part number applicability and removed the serial number range and date of manufacture provisions." This indicates the first amendment widened the population of affected parts by reference to part numbers and removed limitations that had been based on serial number ranges and manufacture dates. The exact wording of Amendment 1 is summarised in the Background but the AD text supplied does not reproduce the original Amendment 1 text.

• Amendment 2: "Amendment 2 replaced the dye penetrant inspection with the fluorescent penetrant inspection." That is a technical change in the mandated inspection method, shifting from one non-destructive technique (dye penetrant) to a fluorescent variant. The current Part A reflects that fluorescent penetrant method (Requirement: Part A).

• Amendment 3: "Amendment 3 allowed a longer inspection interval for aircraft which are not operated in a salt water environment." This amendment created the environmental differentiation in the inspection intervals. It is also operative in the current compliance matrices because several of the compliance timings are conditioned on whether the aircraft "have complied with Amendment 3." The AD’s compliance schedule therefore depends on the distinction created by Amendment 3.

• Amendment 4 (the current amendment as recorded): "Amendment 4 is issued in response to a revision of the related Transport Canada AD, which allows operators the option of continuing with the current inspection intervals or incorporating the improved alternate inspection method, to permit an increase in inspection intervals." Thus Amendment 4 introduces an operator choice to continue with existing intervals or to adopt an alternate method with potentially longer intervals, reflecting a recalibration based on a Transport Canada decision.

Administrative dates and signature: Amendment 4 is effective on 15 March 2007 (Compliance: "This Amendment becomes effective on 15 March 2007."). The AD is signed by the CASA delegate David Villiers, with a signature date of 2 February 2007.

Notes on content omitted from supplied text: The Background refers to specific technical changes and prior amendments but does not reproduce the complete text of Amendments 1-3. The AD summarises their effect. The SB cross-references (SB No. 2/41 Rev C and SB No. 2/55 dated 23 June 2006) are linked to the current amendment.

This amendment history is operationally significant because compliance obligations for each aircraft depend on whether the aircraft "have complied with Amendment 3," and because Amendment 4 permits operators to choose an inspection path that may alter the inspection frequency. The AD therefore creates transitional compliance states tied to historical compliance with older amendments.

The AD text supplied does not contain any litigation history, case citations, or references to legal proceedings arising from this AD or its subject matter. The directive’s text does not mention enforcement actions, appeals, tribunal proceedings, or court decisions related to the AD.

Given the absence of litigation references in the supplied document, there is no recorded litigation history contained within this instrument. Practitioners requiring information on any judicial or administrative challenges to AD/DHC-2/24 or any of its amendments would need to consult external legal records, court decisions, or administrative appeal registers; none of those sources are included in the AD text provided.

Therefore, within the scope of this document, the litigation history is empty: the supplied AD contains no cases, proceedings, or precedent. Any inference about litigation arising from the AD would require information outside the AD text and is not supported by the document itself.

Several practical and interpretive nuances in the AD can catch operators, maintainers, and planners if they are not read carefully.

Part-number limitation and applicability: The AD applies only to aircraft "fitted with wing lift strut part numbers C2W1103, C2W1103A, C2W1104, or C2W1104A." Aircraft with other strut part numbers are outside the AD’s scope as written. Operators must confirm part numbers on each aircraft rather than assume all DHC-2 aircraft are covered. The Background records that Amendment 1 "expanded the part number applicability," so historical records and earlier AD drafts may differ.

Qualification requirement for Part A: The fluorescent penetrant inspection "shall be carried out by a person holding a valid appropriate Non-Destructive Testing Authority." Operators must ensure the inspector’s authority is valid and appropriate; informal or in-house inspections by unqualified personnel will not meet the AD’s required standard for Part A.

The Service Bulletin and Transport Canada approval dependency: Both Part A and Part B require adherence to Viking Air SBs "or a later Transport Canada approved revision." Compliance thus depends not merely on following the manufacturer’s latest SB but on ensuring any later revision has Transport Canada approval. Operators who use newer SB revisions must verify that those revisions are Transport Canada approved; using an unapproved revision would not meet the AD’s expressed condition.

Ambiguity of "salt water environment": The AD differentiates between "aircraft operating in a salt water environment" and "all other aircraft" for interval determination but does not define "salt water environment" in the supplied text. That may create interpretive issues: occasional operations into maritime environments versus primary basing near salt water could change applicable intervals. Operators should determine which classification applies to their operations because the inspection intervals differ materially.

Dependence on prior compliance status (Amendment 3): The AD’s interval matrices repeatedly distinguish between "aircraft which have complied with Amendment 3" and those that have not. That creates a transitional state: operators must ascertain and document whether Amendment 3 was complied with for their aircraft; otherwise, they face the short-term initial compliance windows (for example, "within 100 hours time in service or one calendar year after 15 March 2007, whichever occurs first"). Absent careful records of prior compliance, operators could misapply intervals.

Different interval matrices for Part A and Part B: The recurring inspection intervals and initial windows differ between the fluorescent penetrant method and the eddy current method, and those differences are conditional on salt-water operation and Amendment 3 compliance. For example, Part B allows longer recurring intervals (up to five years for non-saltwater aircraft that have complied with Amendment 3), whereas Part A sets shorter recurring intervals (up to two years for comparable non-saltwater aircraft that have complied with Amendment 3). Choosing an inspection method therefore has resource and scheduling trade-offs.

Immediate removal requirement on crack detection: The AD is strict: "If cracks are detected during any Part A or Part B inspection required by this Directive, before further flight, remove the affected strut from service." That rule leaves no discretion to defer action pending a more detailed assessment; operators must plan logistics for replacing struts and accepting aircraft downtime if cracks are found.

Amendment 4’s option mechanics: Amendment 4 "allows operators the option of continuing with the current inspection intervals or incorporating the improved alternate inspection method, to permit an increase in inspection intervals." The AD does not specify required paperwork or approval to switch methods or to document the operator's choice. Operators must ensure any record of the choice and subsequent compliance is maintained in accordance with broader airworthiness and maintenance recordkeeping requirements, which are not specified in the AD text.

Timing of the effective date vs initial windows: This Amendment becomes effective 15 March 2007. For aircraft that had not complied with Amendment 3, the initial compliance windows are specified relative to that date ("within 100 hours time in service or one calendar year after 15 March 2007, whichever occurs first"). Operators must be careful to calculate the correct deadlines relative to either hours-in-service or calendar date.

No explicit reporting requirement in the AD: The directive does not, in the provided text, specify mandatory reporting of inspection results to CASA or Viking Air. While inspection findings that led to part removal are operationally consequential, the AD does not set out reporting channels or timelines.

In short, key gotchas are: verifying affected part numbers; ensuring the NDT qualification for Part A; confirming Transport Canada approval status for SB revisions; correctly classifying salt-water operation and Amendment 3 compliance; choosing inspection method with full awareness of differing intervals; and preparing for immediate strut removal when cracks are detected.

The AD prescribes a discrete set of steps and decision points; operators and maintenance organisations must translate those into maintenance plans, schedules, and qualifications.

1. Confirm applicability:

   • Check each DHC-2 aircraft to determine whether the wing lift strut fitted is one of the listed part numbers: C2W1103, C2W1103A, C2W1104, C2W1104A (Applicability). Only aircraft fitted with those part numbers fall within the AD.

2. Decide inspection path (Part A or Part B):

   • Part A requires fluorescent penetrant inspection per Viking Air SB No. 2/41 Revision C (or a later Transport Canada approved revision). Part A requires the inspector to hold a valid, appropriate Non-Destructive Testing Authority.
   • Part B requires eddy current inspection per Viking Air SB No. 2/55 (or later Transport Canada approved revision).
   • Amendment 4 provides an option to either continue with existing inspection intervals or incorporate the alternate inspection method that permits interval increases. Operators should decide which method they will adopt, then apply the correct SB and schedule.

3. Verify qualification and approvals:

   • If choosing Part A, ensure the person performing the fluorescent penetrant inspection has a valid Non-Destructive Testing Authority as required by the AD.
   • Ensure the version of the Viking Air SB you intend to follow is either the one specified in the AD (SB No. 2/41 Rev C for Part A; SB No. 2/55 dated 23 June 2006 for Part B) or a later revision that has been approved by Transport Canada, per the AD’s wording.

4. Determine which interval matrix applies:

   • Ascertain whether the aircraft operates in a "salt water environment" or falls under "all other aircraft" as the AD distinguishes. The AD uses this distinction to set shorter intervals for salt water operation.
   • Determine whether the aircraft "have complied with Amendment 3 of this Directive." If the aircraft complied with Amendment 3, longer recurring intervals may apply; if not, an initial short-term inspection window applies (for example, "within 100 hours time in service or one calendar year after 15 March 2007, whichever occurs first").

5. Schedule the first inspection according to the AD’s specified timing:

   • For aircraft that have not complied with Amendment 3, the AD sets initial inspections typically "within 100 hours time in service or one calendar year after 15 March 2007, whichever occurs first." For those that have complied with Amendment 3, the initial timing follows the prior inspection interval (e.g., one or two calendar years since the prior inspection) as specified in the AD (Compliance section).

6. Perform the inspection to the SB Accomplishment Instructions:

   • Conduct the fluorescent penetrant or eddy current inspection strictly in accordance with the applicable SB’s Accomplishment Instructions and any Transport Canada approved revisions.

7. Act on findings:

   • If cracks are detected during any required inspection, remove the affected strut from service "before further flight" as mandated by the AD. Plan for and execute strut replacement or repair per approved repair data before returning the aircraft to service.

8. Document compliance:

   • Although the AD text does not explicitly prescribe recording formats or reporting to CASA, maintain contemporaneous maintenance records showing:
     • Aircraft identification and serial/part numbers inspected.
     • The SB revision used and confirmation that it was a Transport Canada approved revision (if applicable).
     • The identity and authority of the person performing Part A (NDT Authority).
     • Dates and hours-in-service at inspection.
     • Any findings and remedial action, including removal from service of affected components.
   • These records are necessary to demonstrate to regulators and to support continuing airworthiness responsibilities, even though the AD text itself does not lay out the recordkeeping procedure.

9. Reconcile choice of intervals with operational planning:

   • If adopting the alternate method allowed by Amendment 4 to obtain longer intervals, ensure that all subsequent inspections are performed on the longer schedule and in accordance with the chosen SB. If continuing with current intervals, maintain the existing inspection programme.

10. Monitor Transport Canada approvals and SB revisions:

• Because the AD conditions compliance on "later Transport Canada approved revision[s]" of the SBs, operators should periodically check whether newer SB revisions have received Transport Canada approval and determine whether those revisions change inspection technique, acceptance criteria, or intervals.

11. Coordinate with regulators or the manufacturer if uncertain:

• If there is uncertainty over definitions (for example, what constitutes a "salt water environment") or about whether an SB revision is Transport Canada approved, seek clarification from CASA or the appropriate authority. The AD text does not provide administrative mechanisms for such requests; therefore operators should use standard regulator contact channels.

12. Plan for logistics and downtime:

• Given the immediate removal requirement upon crack detection, ensure spare struts or repair capability is available or have contingency plans for aircraft downtime and scheduling flexibility.

Following these steps aligns operational practice with the AD’s technical and timing requirements: use the correct SB and Transport Canada approvals, ensure qualified personnel for fluorescent penetrant inspection, apply the correct interval matrix based on salt water operation and Amendment 3 compliance, and remove any cracked strut before further flight.