AD/F50/92 Amdt 2 - Engine Mounting Frame Welds

The directive hinges on a small set of interlocking concepts: applicability, imported technical requirement, a time-limited inspection obligation, and required corrective measures where defects are found. These concepts are expressed through the document headings: Applicability, Requirement, Compliance, Background, and the amendment notes.

Applicability: The AD explicitly covers "Model F27 Mk.050, 0502, and 0604 aircraft, all serial numbers" (Applicability). This is a model‑and‑serial‑number scope, not a fleet size or operator-based scope.

Imported technical requirement: Instead of reproducing detailed inspection and repair procedures in the Australian instrument, the AD requires operators to "Action in accordance with the requirements of Netherlands CAA AD NL-2005-015" (Requirement). The directive thereby incorporates a foreign regulator's AD as the operative technical standard.

Cross-reference to manufacturer guidance: The directive lists specific Fokker Service Bulletins and Component Service Bulletins as the means to perform the work: F50-71-048, F50-71-049, F8200-035-71-10, and F8200-035-71-11, or later CAA-NL approved revisions (Requirement, Note 2). This sets up a technical chain: the Netherlands AD prescribes actions, and the Fokker SBs contain the detailed procedures.

Time-limited inspection obligation: The AD sets a compliance window for the inspection: "Within 2 calendar months after 1 September 2005" (Compliance). The document also clarifies that the amendment does not change the compliance time: "The compliance time remains unchanged by this issue of the Directive" (Compliance). That places a concrete temporal constraint on action.

Nature of corrective work: The Background and Amendment 2 explain the technical problem and the responsive action. Welding defects were discovered by X-ray inspection, caused by movement of the electric arc during manufacture that made some welds run beside the borderline for part of the tube circumference; the consequence could be failure of an engine mounting frame (Background). Amendment 2 expands the earlier AD, specifying the criteria and compliance times for the follow-up NDT inspection and repair or replacement of engine mount frames as necessary (Amendment 2).

Document hierarchy and authority: The directive is presented as an Australian CASA AD that relies on a Netherlands Civil Aviation Authority AD and Fokker service documents. It instructs operators to obtain the Netherlands AD through CASA (Requirement, Note 1), and it accepts later CAA-NL approved revisions as alternatives to the presently referenced Fokker service bulletins (Requirement, Note 2).

Administrative details: The document lists an effective date for Amendment 2 (16 February 2006) and shows the signatory as David Villiers, Delegate of CASA, dated 21 December 2005. It also records that Amendment 1 previously altered certain Paragraph e requirement paragraphs of the original issue (Background). Amendment 2 was issued in response to a new CAA-NL AD; the prior AD NL-2005-07 required a one-time inspection, while the new AD adds criteria and compliance times for follow-up NDT and corrective action (Amendment 2).

In sum, the main concepts are model-specific mandatory inspections, cross‑jurisdictional incorporation of foreign AD content, reliance on manufacturer service bulletins, and a defined compliance window with the possibility of repair or replacement following NDT.

The directive designates specific aeroplane models and thus primarily affects their operators, the organisations that maintain and certify these aircraft, and entities that supply parts or carry out structural repairs. The Applicability clause identifies affected aeroplanes as "Model F27 Mk.050, 0502, and 0604 aircraft, all serial numbers" (Applicability). Any person responsible for continued airworthiness of those specific airframes in Australian civil aviation operations must comply with the AD.

Primary affected parties

• Operators and owners of the listed Fokker F50 variants, who must ensure inspections are carried out within the stated compliance window and that corrective actions are performed where required (Applicability; Compliance).
• Maintenance, repair and overhaul organisations and licensed engineers who must perform the inspections, NDT, repairs or replacements following the technical procedures referenced in NL-2005-015 and the listed Fokker Service Bulletins (Requirement; Note 2).
• Aircraft certification engineers and continuing airworthiness managers who must interpret and apply the imported Netherlands AD and any later CAA-NL approved revisions, and who must document compliance.

Secondary affected parties

• Part suppliers and component repair organisations that may be called upon to supply replacement engine mounting frames, welding repairs, or related structural parts if repairs or replacements are warranted by inspection findings (Background; Amendment 2).
• CASA and its delegates, who have administrative responsibilities to provide the referenced Netherlands AD to Australian stakeholders (Requirement, Note 1), and to monitor compliance with Australian ADs.

Who pays

• The source document does not specify cost allocation or funding. The practical implication from the Requirement and Compliance instructions is that the owner/operator bears the direct cost of inspections, follow-up NDT, and any repairs or replacements necessitated by defects, because they are the parties responsible for airworthiness and for actioning the requirements of the AD (Requirement; Compliance).

Decision-makers and discretionary actors

• The directive does not identify a process for alternative methods of compliance within the text. It does allow "later CAA-NL approved revisions" of the listed Fokker service documents to be used (Requirement, Note 2), which permits reliance on future revisions approved by the Netherlands authority. That mechanism vests decision-making about acceptable technical revisions in the CAA-NL approval process rather than in CASA, though CASA is the issuer of the Australian AD.

Timing implications and operational impact

• The inspection compliance window is time-limited: "Within 2 calendar months after 1 September 2005" (Compliance). Operators that had not completed inspections by that date would be out of compliance. Amendment 2 became effective 16 February 2006 (Compliance), which creates a temporal overlap between the compliance window and the amendment effective date. Operators who missed the original compliance window may need to consider the directive language and any subsequent CASA or CAA-NL guidance.

Geographic and jurisdictional reach

• The AD is an Australian instrument that directly controls Australian-registered aircraft and operations under CASA's remit; however, it accomplishes this by mandating action in accordance with a Netherlands AD and manufacturer service bulletins. That means affected parties must obtain and follow externally authored technical material, as provided through CASA (Requirement, Note 1).

In short, the operators of the specified Fokker models and the maintenance organisations that service those aeroplanes are the direct, financially responsible parties for carrying out inspections and corrective actions mandated by the AD.

The directive sets out binding duties for those responsible for affected aircraft, and it includes limited rights or options concerning the specific documents that may be followed. The text frames duties through the Requirement and Compliance entries and provides limited discretion through acceptance of later approved revisions.

Primary duties

• Follow the Netherlands CAA AD NL-2005-015. The Requirement mandates that operators must "Action in accordance with the requirements of Netherlands CAA AD NL-2005-015" (Requirement). That duty imports the substantive inspection, NDT, repair and replacement procedures contained in that foreign AD into the Australian compliance obligation.
• Use identified Fokker technical documents. The Requirement further directs action "Note 2: Fokker Service Bulletins F50-71-048 and F50-71-049; and Fokker Component Service Bulletins F8200-035-71-10 and F8200-035-71-11; or later CAA-NL approved revisions" (Requirement, Note 2). That requires reliance on manufacturer service bulletins as the source of procedural detail, unless later CAA‑NL approved revisions are adopted.
• Meet the compliance timing. For the inspection requirement, the Compliance clause commands action "Within 2 calendar months after 1 September 2005" and states "The compliance time remains unchanged by this issue of the Directive" (Compliance). That is a clear temporal obligation for performing the inspection.

Secondary duties and implied duties

• If inspections reveal defects, perform follow-up NDT and corrective action, including repair or replacement of engine mounting frames as necessary. Amendment 2 expands on the earlier AD to "specify the criteria and compliance times for the follow-up NDT inspection, and repair or replacement of engine mount frames, as necessary" (Amendment 2). The specific technical criteria and repair methods are those set out in the Netherlands AD and the cited Fokker Service Bulletins.
• Obtain the referenced documents. Note 1 instructs that "AD NL-2005-015 may be obtained by contacting CASA e-mail address airworthiness.directives@casa.com.au" (Requirement, Note 1). That imposes on duty holders the practical obligation to obtain the Netherlands AD in order to know exactly what procedures to follow.

Rights and limited discretion

• Use of later CAA-NL approved revisions. The Requirement allows operators to use "later CAA-NL approved revisions" of the listed Fokker service bulletins (Requirement, Note 2). That gives operators the right to rely on updated technical instructions so long as those revisions are approved by the Netherlands CAA.
• Implicit right to seek clarification or document access from CASA. The directive provides a CASA email contact for obtaining the Netherlands AD (Requirement, Note 1), which gives operators a route to obtain the operative document.

What the directive does not set out

• The AD text does not state a procedure for seeking an alternative method of compliance or for CASA to approve deviations; no alternative methods or exemptions are specified in the instrument itself. The absence of an explicit alternative compliance mechanism in the text means any such process would need to be sought from CASA by established administrative routes outside the AD text.
• The AD does not include explicit inspection reporting or return-to-service documentation steps in the text. Those details are likely contained in the referenced Netherlands AD or in operator continuing airworthiness records, but they are not recited in this instrument.

Who decides compliance conclusions

• The technical determination of whether a specific weld is acceptable and whether repair or replacement is required will be made by the organisation performing the NDT and by the engineer certifying the work, using the acceptance criteria set out in the Netherlands AD and the Fokker service bulletins. The AD imports those criteria rather than restating them.

In practical terms, the directive imposes a duty on operators to obtain and implement the Netherlands AD and the specified Fokker documents within a fixed timeframe, and it gives limited rights to rely on later CAA-NL approved revisions. It does not, in its text, provide internal CASA procedures for alternative compliance or explicit reporting timelines.

The document provided is an Airworthiness Directive amendment; it specifies technical requirements and compliance timings but does not itself articulate penalties or enforcement procedures in its text. The AD sets mandatory actions and a compliance window, but it does not include a clause enumerating sanctions, civil penalties, or criminal consequences for non-compliance.

Express statements in the instrument

• The Compliance section sets the inspection deadline: "Within 2 calendar months after 1 September 2005" and notes that "The compliance time remains unchanged by this issue of the Directive" (Compliance). The instrument also states an effective date for the amendment: "This Amendment becomes effective on 16 February 2006" (Compliance). These are prescriptive obligations and dates but are not accompanied by penalty provisions in the text.

What enforcement implications are present in the text

• By imposing a mandatory technical action and a specific compliance window, the AD creates an enforceable regulatory obligation for holders of the affected aircraft under CASA's regulatory system. The document does not, however, specify enforcement mechanisms such as notice to comply, infringement notices, or consequences for failing to comply. The absence of penalty language in the AD text means that any enforcement, sanctioning, or administrative follow-up would derive from the broader regulatory framework and enforcement powers vested in CASA under other legislation and policy, not from the text of this AD itself.

Practical enforcement steps likely to be relevant, though not stated in the AD text

• Compliance assessment. Regulators or inspectors would typically verify that the inspection occurred within the specified timeframe and that any required repairs or replacements were performed in accordance with the Netherlands AD and relevant service bulletins. The AD gives a single compliance date for inspection and references the technical criteria for follow-up NDT and repairs (Compliance; Amendment 2).
• Record keeping and certification. Although not specified in the AD text, operators and maintainers are ordinarily required under continuing airworthiness obligations to record inspections and corrective actions. The AD does not recite such record-keeping requirements explicitly.
• Interaction with approvals and certifications. Repaired or replaced engine mounting frames would need to be certified for return to service in accordance with applicable certification processes. The AD references external documentation that sets technical standards but does not prescribe how CASA will verify certification or acceptance.

Limits of the source text

• The AD does not identify who within CASA monitors compliance, the form of evidence required to show compliance, any deadlines for submitting compliance reports, or any sanctioning process for breaches. Those operational enforcement mechanisms are not contained in the provided document and would be found, if at all, in CASA procedural materials or other instruments.

In summary, the AD mandates actions and dates but contains no explicit penalty or enforcement provisions in its text. Compliance obligations are specific; enforcement consequences, processes and authorities are not specified within this document and would be determined under the wider regulatory framework outside the AD text.

This Australian Airworthiness Directive operates by incorporating technical requirements issued by another national aviation authority and by referencing manufacturer service bulletins. The AD’s interaction with other legal or regulatory materials in the document is explicit and narrow. The AD does not itself recite wider statutory or regulatory crossover provisions; it instead imports foreign regulatory material and manufacturer guidance as the operative technical standard.

Incorporation by reference of a foreign regulator's AD

• The central interaction is with the Netherlands Civil Aviation Authority AD NL-2005-015. The Requirement expressly commands action "in accordance with the requirements of Netherlands CAA AD NL-2005-015" (Requirement). By doing so, the Australian AD makes compliance with the Netherlands AD a de facto requirement for Australian operators of the specified aircraft. That creates a cross-jurisdictional link: technical standards and acceptance criteria set out by CAA-NL become operative within the Australian regulatory context via CASA’s AD.

Interaction with manufacturer guidance

• The AD references Fokker Service Bulletins F50-71-048 and F50-71-049 and Fokker Component Service Bulletins F8200-035-71-10 and F8200-035-71-11 as the procedural means to implement the NL AD requirements (Requirement, Note 2). It also allows for "later CAA-NL approved revisions" of those documents. The legal effect is that manufacturer technical instructions, when approved by the relevant civil aviation authority, are incorporated into the compliance obligation.

CASA’s administrative role

• The Requirement Note 1 instructs that "AD NL-2005-015 may be obtained by contacting CASA e-mail address airworthiness.directives@casa.com.au" (Requirement, Note 1). That indicates CASA’s role as the conduit for distributing the incorporated foreign AD to Australian stakeholders. The AD itself is the instrument through which CASA asserts a regulatory obligation on Australian operators, but it relies on the foreign AD to set the detailed technical standards.

Limits and interaction with other domestic instruments

• The AD text does not cite or amend any Australian statute, regulation, or instrument beyond being an AD issued by CASA. It contains no explicit cross-references to Australian aviation regulations, enforcement provisions, or certification processes. Thus, the AD’s interaction with domestic law is implicit: compliance with the AD would be a part of the broader continuing airworthiness obligations that operators owe under Australian aviation law, but the AD text does not set out those links.

Handling of revisions and alternative technical standards

• The AD explicitly permits use of "later CAA-NL approved revisions" of the listed Fokker service bulletins (Requirement, Note 2). That mechanism ties permissible technical updates to CAA-NL approval. It does not provide, in the AD text, for CASA to approve alternative methods of compliance or other technical standards. Therefore, operators seeking to apply an alternative standard would need to consult CASA outside the wording of this AD or rely on processes not described in this document.

Temporal interaction and amendments

• Amendment 2 was issued in response to a "new CAA-NL AD" that advances the earlier NL-2005-07 AD, and Amendment 1 had previously changed requirement paragraphs in the original issue (Background; Amendment 2). That shows an interaction where Australian ADs respond to successive foreign ADs and manufacturer service bulletin revisions. The compliance window in this AD remains tied to the original compliance date "Within 2 calendar months after 1 September 2005" even though Amendment 2 became effective on 16 February 2006 (Compliance). This creates an interaction between the timing of foreign-mandated actions and the timing of Australian administration.

Practical consequence

• In practice, operators must coordinate between Australian regulatory obligations, the incorporated Netherlands AD, and Fokker service bulletins. The AD does not explicitly describe how conflicts between the incorporated documents and Australian law would be resolved; the positioning in the instrument suggests that technical compliance is achieved by following the Netherlands AD and the indicated Fokker documents, subject to any further CASA guidance not included in the present text.

In short, the AD principally interacts with foreign regulatory and manufacturer documents by importing them into Australian obligations. It provides limited internal mechanisms for alternatives and leaves broader enforcement, certification, and procedural interactions to the wider regulatory framework that is not spelled out in the AD text.

The provided document is headed "AD/F50/92 Amdt 2", indicating this is the second amendment to AD/F50/92. The body of the instrument includes explicit historical remarks about earlier amendments and the reasons for the current amendment.

Chronology visible in the text

• Original AD and Amendment 1. The Background notes state that "Amendment 1 changed the Requirement paragraphs specified in Paragraph e. of the original issue." That confirms a prior revision to the original AD changed certain requirement paragraphs designated in the original text as Paragraph e. The specific content of those Paragraph e. changes is not reproduced in the present document, but the AD records that Amendment 1 made such a modification (Background).
• Amendment 2 issuance and rationale. The Background and the separate Amendment 2 note explain: "Amendment 2 is issued in response to a new CAA-NL AD. Previous AD NL-2005-07 was issued to require a one-time inspection for improper welds, while the new AD further specifies the criteria and compliance times for the follow-up NDT inspection, and repair or replacement of engine mount frames, as necessary." Amendment 2 therefore reacts to a substantive escalation or clarification in the Netherlands AD regime by importing the new criteria and timing for follow-up NDT and corrective actions (Background; Amendment 2).
• Effective date. The document states "This Amendment becomes effective on 16 February 2006" (Compliance). The AD is signed and dated 21 December 2005 by David Villiers, Delegate of the Civil Aviation Safety Authority (signatory block). That shows the administrative signature precedes the stated effective date.

Compliance timing relative to amendments

• The Compliance clause specifies the inspection must be done "Within 2 calendar months after 1 September 2005" and states "The compliance time remains unchanged by this issue of the Directive." That indicates the compliance deadline was set in an earlier issue and was not extended or shortened by Amendment 2. The effective date of the Amendment (16 February 2006) post-dates the compliance window start and may post-date the end of that window, creating a temporal relationship where the obligation’s deadline predates the amendment’s effective date. The AD records this but does not elaborate on remedial steps for operators who might have missed the prior window.

Document provenance and signatory

• The AD includes a signatory block with an image placeholder, the name David Villiers, the title "Delegate of the Civil Aviation Safety Authority" and the date "21 December 2005." That establishes an administrative record of issuance and delegation (signatory block).

References to external documents and revision acceptance

• The Requirement includes "or later CAA-NL approved revisions" of the specified Fokker service bulletins (Requirement, Note 2). That establishes that future revisions approved by the Netherlands CAA can be relied upon and that Amendment 2 responds to Netherlands AD developments.

Notes on traceability

• The AD provides a CASA contact for obtaining NL AD NL-2005-015 (Requirement, Note 1). That assists recipients in accessing the authoritative document that Amendment 2 imports. The AD also records that the initial discovery of welding defects occurred during scheduled X-ray inspections and that the defect appears to have been present on unknown numbers of engine mounting frames (Background). Amendment history reflects an iterative regulatory response: initial one‑time inspection requirement, followed by additional specification of follow-up inspection criteria and repair or replacement obligations.

What the AD does not include about earlier amendments

• The instrument does not reproduce the full text of the original AD nor of Amendment 1. It records the fact of changes and the reasons for Amendment 2 but does not include the text of prior versions. Recipients must obtain earlier versions if they need a complete amendment chain.

In summary, the AD record shows an original directive, a first amendment that altered requirement Paragraph e, and a second amendment that imported and implemented further detail from a new Netherlands AD, with an effective date of 16 February 2006 and a signatory dated 21 December 2005.

The provided document contains no references to any litigation, court decisions, administrative appeals, or legal challenges. The text records the technical background, the operative requirements, the compliance timing, amendment notes, and administrative details, but it does not mention any legal proceedings or disputes related to the AD.

Explicit absence in the source

• There is no litigation or case citation in the AD text. The Background discusses manufacturing welding defects and administrative amendments. Amendment history describes prior ADs and amendments. No part of the document reports appeals, enforcement proceedings, judicial review, or legal argumentation.

Implications of the absence

• Because the AD text contains no litigation history, readers cannot infer from the instrument itself whether any party challenged the AD, sought judicial review, or raised disputes about the technical or procedural basis of the directive. Any such litigation, if it occurred, would not be reflected in this document and would require independent confirmation from court records or administrative files, which are not included in the source provided.

Administrative remedies and dispute routes

• The AD does not set out an appeal procedure or alternative compliance petition process within its text. The absence of such procedures in the AD does not mean they do not exist elsewhere under CASA’s broader administrative framework, but the instrument does not make any reference to them. Operators needing to dispute or seek variation of the AD would, therefore, need to consult CASA’s procedural materials or other applicable regulation for routes of review or application for exemption.

Record completeness

• The document records amendments and their technical rationale, but it does not record any follow-up legal action. The signatory date and effective date are administrative facts contained in the AD.

Conclusion based on source

• From the contents of the AD alone, there is no litigation history to report. Any assertion about litigation would require sources beyond the AD text provided.

The instrument contains a number of concrete features and potential pitfalls that recipients should note because they affect interpretation, timing, and operational action. The following issues are drawn directly from the document text.

1. Compliance window predates amendment effective date

• The Compliance clause requires the inspection "Within 2 calendar months after 1 September 2005" and states "The compliance time remains unchanged by this issue of the Directive" (Compliance). However, the Amendment is stated to "become effective on 16 February 2006" (Compliance). That means the inspection compliance window was set to begin and likely end before the Amendment’s effective date. Operators should note this timing relationship and confirm whether they are required to show retrospective compliance if the inspection deadline has already passed.

2. Incorporation of external documents

• The AD does not include the detailed inspection and repair procedures. It mandates action in accordance with Netherlands CAA AD NL-2005-015 and specific Fokker Service Bulletins (Requirement; Note 2). Operators must obtain those external documents to know the exact technical steps and acceptance criteria. Failure to obtain and follow the referenced documents would mean non-compliance, but the AD places the burden on the recipient to source those documents via CASA’s provided email (Requirement, Note 1).

3. Acceptance of later CAA-NL approved revisions only

• The AD allows "later CAA-NL approved revisions" of the listed Fokker Service Bulletins (Requirement, Note 2). This explicitly ties acceptable procedural updates to approval by the Netherlands CAA. Revisions approved by other authorities or unapproved manufacturer revisions are not authorised by the AD text.

4. No explicit penalties or reporting requirements in the AD

• The AD contains no express enforcement or penalty provisions nor does it set out a required reporting format or documentation submission process in the text (Penalties and enforcement). Operators should not assume there are no consequences for non-compliance, but must recognise that the AD itself does not specify enforcement procedures; these will be governed by broader regulatory powers outside the AD text.

5. Incomplete reproduction of amendment chain and prior text

• The Background notes that Amendment 1 "changed the Requirement paragraphs specified in Paragraph e. of the original issue" but the AD does not reproduce the original or Amendment 1 texts (Background). Recipients who need the exact historical wording must obtain earlier documents to understand prior obligations or any substantive differences.

6. Unknown population of affected parts

• The Background says "The defective welding process appears to have occurred at some of the welds in an unknown number of engine mounting frames" (Background). The AD therefore does not enumerate affected serial numbers of engine mount frames; instead, it applies to all serial numbers of specified aircraft models and uses inspection to identify affected frames. This places the identification burden on operators.

7. Technical specificity is delegated

• The AD delegates technical criteria and repair instructions to the Netherlands AD and Fokker service bulletins. Those documents will contain the NDT acceptance criteria and repair instructions necessary to determine whether a weld is acceptable or whether a frame must be repaired or replaced. Implementers must ensure they are using the correct revision that is CAA‑NL approved.

8. Email contact for obtaining the Netherlands AD

• The AD states that "AD NL-2005-015 may be obtained by contacting CASA e-mail address airworthiness.directives@casa.com.au" (Requirement, Note 1). Recipients should be prepared to use that channel to obtain the operative foreign AD; the AD provides no alternative distribution method in the text.

9. Repair or replacement may involve supply chain time

• While the AD requires repair or replacement "as necessary" following NDT criteria (Amendment 2), it does not address lead times for procuring replacement engine mounting frames or arranging specialised welding and NDT services. Operators should anticipate logistical and scheduling impacts even though the AD does not specify remedies for delayed parts or scoped maintenance windows.

10. Ambiguity about alternative compliance paths

• The AD does not describe a process for seeking an alternative method of compliance or a deviation. If an operator wishes to apply a different repair or inspection technique, they will need to consult CASA outside the AD text for any approval mechanism.

These are not speculative concerns. Each arises from explicit wording or conspicuous absences in the AD text. Operators and maintainers should verify historical compliance dates, obtain the referenced external documents, document their inspections and repairs, and contact CASA where clarification or administrative relief is required.

The directive requires a practical, document-driven compliance pathway. The following step-by-step checklist is grounded in the AD text and guides duty holders toward meeting the mandatory requirements. Each step cites the relevant part of the AD where applicable.

1. Confirm applicability

• Check whether the aircraft is one of the models specified: "Model F27 Mk.050, 0502, and 0604 aircraft, all serial numbers" (Applicability). If so, the AD applies; no serial number carve-outs are listed in the AD text.

2. Obtain the operative Netherlands AD and relevant service bulletins

• Obtain Netherlands CAA AD NL-2005-015 via CASA using the provided email address airworthiness.directives@casa.com.au (Requirement, Note 1). Also obtain Fokker Service Bulletins F50-71-048 and F50-71-049 and Fokker Component Service Bulletins F8200-035-71-10 and F8200-035-71-11, or confirm whether there are "later CAA-NL approved revisions" to use (Requirement, Note 2).

3. Read and adopt the NL AD requirements and SB procedures

• Implement the inspection procedures, NDT criteria and repair/replacement methods exactly as set out in NL-2005-015 and the referenced Fokker service bulletins or in later CAA-NL approved revisions (Requirement; Note 2; Amendment 2). The AD imports those documents as the operative technical standard.

4. Schedule and perform the inspection within the required timeframe

• Perform the inspection required "Within 2 calendar months after 1 September 2005" (Compliance). The AD states that "The compliance time remains unchanged by this issue of the Directive" (Compliance). Given this date-based obligation, record the inspection date and the method used (e.g. X-ray, NDT) consistent with the techniques and acceptance criteria in NL-2005-015.

5. If defects are found, perform follow-up NDT and corrective work

• Where the initial inspection or NL-2005-015 criteria indicate investigation or action, perform the follow-up NDT and then repair or replace engine mounting frames "as necessary" in accordance with NL-2005-015 and the Fokker SBs (Amendment 2; Requirement, Note 2). Use the acceptance criteria and repair methods specified by the Netherlands AD and the manufacturer.

6. Use only CAA-NL approved revisions where applicable

• If relying on later revisions of the Fokker service bulletins, confirm that those revisions are approved by the Netherlands CAA, because the AD permits only "later CAA-NL approved revisions" (Requirement, Note 2).

7. Certify and document the work

• Although the AD does not state the precise form of certifications or records, standard continuing airworthiness practice requires that inspections, NDT results, repairs and parts replacements be recorded in the aircraft maintenance records. Record the documents relied upon (NL-2005-015, bulletin revision numbers), dates of inspection, NDT results, descriptions of repairs or replacements, sign‑off by appropriately licensed personnel and certification for return to service.

8. Coordinate with maintenance providers and parts suppliers

• Arrange for qualified NDT providers, licensed maintenance engineers and, if necessary, sources of replacement engine mounting frames. The AD does not provide supply chain guidance, so procurement and scheduling must be managed by the operator.

9. Seek clarification from CASA if timelines or documents are unclear

• If there is uncertainty about the compliance window, about acceptable revisions of service bulletins, or about alternative methods of compliance, contact CASA at the AD email address given in the AD (Requirement, Note 1). Any request for variation or confirmation should be in writing and should reference the AD and the specific requested relief.

10. Retain proof of compliance for regulator verification

• Keep copies of the Netherlands AD, the service bulletins used, NDT reports, repair records, and return-to-service certifications. Although the AD does not prescribe a reporting format, those records constitute the primary evidence of compliance if the regulator subsequently audits or inspects.

11. Monitor for further amendments or revised ADs

• The AD arises from a chain of NL ADs and service bulletin revisions. Operators should monitor CASA communications and CAA-NL publications for any additional amendments or new ADs that may alter criteria or compliance times.

12. Note the amendment effective date

• While the Amendment is effective 16 February 2006 (Compliance), that effective date does not change the inspection deadline (Compliance). Operators should reconcile these dates when documenting compliance.

By following these steps an operator will align its actions with the specific phrasing and requirements of the AD as provided in the document. The two core technical inputs required to perform the substantive work are NL-2005-015 and the referenced Fokker service bulletins, so obtaining and applying those documents correctly is central to compliance.