AD/B737/185 Amdt 2 - Airframe Limit Cycle Oscillation

The AD is built around a handful of technical and regulatory concepts. The primary technical concept is limit cycle oscillation (LCO), a form of severe airframe vibration that can be initiated or sustained by mass or contamination in control-surface balance cavities or by residue on control-surface external surfaces. The source identifies the mechanism as accumulation of de‑icing/anti‑icing fluid or other residue in the elevator balance panel cavities and on the external surfaces of the elevator tab. This accumulation, when combined with normal maximum operating airspeeds, can initiate LCO or flutter and may lead to loss of controllability in flight (Background).

Operationally, the AD converts a safety finding into mandatory airworthiness actions by referencing a foreign regulator’s AD: CASA requires compliance "in accordance with the technical requirements of FAA AD 2002-08-20 Amdt 39-12732" (Requirement). That FAA AD contains the substantive technical steps: cleaning, modification and AFM revisions (Requirement). The CASA AD specifically notes that those AFM revisions concern the Limitations and Non‑Normal Procedures sections and may be implemented by inserting a copy of the FAA AD into the AFM (Requirement). The AD also cross‑references manufacturer documentation: Boeing Alert Service Bulletin 737‑55A1084 and Service Letter 737‑SL‑12‑017 are referenced as related documents (Requirement, Note 2).

Regulatory flexibility is present in two ways. First, operators may rely on an FAA‑approved alternate method of compliance for certain aircraft populations: the FAA letter 120S‑02‑683 approves an alternate method of compliance for line numbers 1175 and subsequent, which correspond to aircraft in production after a redesign of the elevator and tab (Applicability; Background). CASA’s Amendment 1 recognised that FAA approval. Second, Amendment 2 identifies that compliance with paragraph (b) of a later FAA AD (cited as FAA AD 2003-03-22 Amdt 39-13047, or in another passage 2003-03-33) is a terminating action for this AD (Compliance; Background). That is, a later FAA action addressing the underlying cause can discharge the obligations created by this AD when its specified paragraph (b) is complied with.

Timing and effect: the technical requirements in the FAA AD have a revised effective date of 5 June 2002, and the current CASA Amendment becomes effective 12 May 2005 (Compliance). The AD states compliance with the FAA Requirement document "as specified in the Requirement document", and it confirms that the compliance time remains unchanged by this CASA issue (Compliance). This means the precise timing, sequences and technical detail are located in the FAA AD and associated service documentation, not restated in full in the CASA text.

The AD therefore operates as a directed implementation of a foreign AD for a defined subset of the fleet, with specific reference to AFM changes, cleaning and modification tasks, manufacturer service publications, an FAA letter about alternate compliance for later line numbers, and an explicit terminating action tied to compliance with a later FAA AD paragraph.

The primary persons and entities directly affected by this AD are operators and owners of Boeing Model 737-600, -700, -700BBJ, -700C and -800 series aeroplanes with line numbers up to and including 1174 (Applicability). Those operators must follow the FAA‑specified technical requirements, which include cleaning and modifications of control surfaces and AFM revisions (Requirement). The AD therefore affects the following groups in concrete ways:

• Air operators (airlines, corporate operators, lessors and bareboat operators) who operate any of the listed 737 series aircraft within the line number cutoff: they must ensure their aircraft comply with the FAA AD technical requirements as adopted by CASA and implement the AFM procedures (Applicability; Requirement; Compliance).

• Flight crew and training organisations: the AD requires revisions to the AFM Limitations and Non‑Normal Procedures sections. Pilots and training providers must be aware of and train to any revised operational limitations or non‑normal procedures that the AFM changes impose (Requirement).

• Maintenance organisations, approved maintenance providers and line maintenance teams: the technical requirements include cleaning and modification tasks within elevator balance panel cavities and on elevator tab surfaces. Maintenance providers will perform the cleaning and prescribed modifications, and must follow the FAA AD instructions and the referenced Boeing service bulletin and service letter where applicable (Requirement; Note 2).

• Manufacturers and design organisations: Boeing is implicated as the manufacturer whose service bulletin (737‑55A1084) and service letter (737‑SL‑12‑017) are referenced. Where aircraft from line number 1175 onward incorporate an elevator and tab redesign on the production line, those aircraft can rely on an FAA‑approved alternate method of compliance (Applicability; Background; FAA Letter 120S‑02‑683).

• CASA and its delegate: CASA issued the AD and a delegate (David Villiers) signed the amendment. CASA is the authority requiring compliance within Australia and set the amendment effective date (Delegate signature; Amendment becomes effective).

• Auditors, insurers and lessors: while not mentioned explicitly in the AD, these stakeholders will be interested in proof of compliance with the CASA AD because it affects continued airworthiness and operational legality. The AD itself does not specify record‑keeping in the excerpt provided: operators must consult the FAA Requirement document for exact compliance procedures and any record duties (Requirement; Compliance).

Entities operating aircraft with line numbers 1175 and later are affected differently: the FAA has approved an alternate method of compliance for those aircraft because of the production redesign, and Amendment 1 of the CASA AD recognised that FAA approval (Applicability; Background). Finally, the AD identifies that compliance with paragraph (b) of a later FAA AD is terminating action for this CASA AD, which creates a path for operators to satisfy CASA's requirement by complying with that specified FAA AD paragraph (Compliance; Background).

Duties imposed by the AD derive primarily from the Requirement and Compliance statements. The principal duties are:

• Carry out the technical requirements of FAA AD 2002‑08‑20 Amdt 39‑12732. The CASA AD does not restate all technical steps; it mandates that operators perform the actions "in accordance with the technical requirements" set out in the FAA AD (Requirement). Those technical requirements include cleaning and modification of elevator balance panel cavities and elevator tab surfaces, and revisions to the AFM Limitations and Non‑Normal Procedures sections (Requirement).

• Implement AFM revisions. The AD requires revisions to the Limitations and Non‑Normal Procedures sections of the AFM and permits those revisions to be accomplished by inserting a copy of FAA AD 2002‑08‑20 into the specified AFM sections (Requirement). That creates a specific, CASA‑approved method for updating the AFM text.

• Comply within the times specified in the FAA Requirement document. CASA expressly states that compliance must be "as specified in the Requirement document" and that the compliance time remains unchanged (Compliance). Operators therefore must consult the FAA AD for the time windows and sequence.

• Use referenced manufacturer documents where relevant. The AD points to Boeing Alert Service Bulletin 737‑55A1084 and Service Letter 737‑SL‑12‑017 as related documents (Requirement, Note 2). Operators implementing the FAA AD technical steps will likely need to consult those Boeing communications as part of the work package.

Rights, options and available compliance pathways:

• Alternate method of compliance for later line numbers. The FAA has approved an alternate method of compliance for aircraft with the elevator and tab redesign implemented at production Line Number 1175; CASA recognises that approval for aircraft with line numbers 1175 and subsequent (Applicability; Background; FAA Letter 120S‑02‑683). Operators of those later‑line aircraft therefore have the right to comply via the FAA‑approved alternate method rather than the cleaning/modification/AFM steps required for earlier line numbers.

• Terminating action through compliance with a later FAA AD paragraph. Amendment 2 identifies that complying with paragraph (b) of FAA AD 2003‑03‑22 (Amdt 39‑13047) , or, as another passage records it, FAA AD 2003‑03‑33 (cross‑reference to CASA AD/B737/210 Amdt 1) , is terminating action for this AD (Compliance; Background). This gives operators a pathway to terminate the CASA AD obligation by meeting other FAA AD requirements, although the AD text contains an inconsistency in the FAA AD citation that operators will need to resolve (Background; see Gotchas).

• AFM insertion method allowed. CASA permits the AFM revisions to be accomplished by inserting a copy of the FAA AD into the AFM sections specified (Requirement). This is a specific acceptable method that operators can use to satisfy the AFM duty.

Duties not specified in the CASA text excerpt: the AD requires compliance with the FAA AD but does not itself specify civil penalties, inspection regimes, or record keeping in the text provided. Operators must therefore rely on the FAA AD and CASA’s broader regulatory framework for details that are not reproduced in this text (Requirement; Compliance). The CASA AD also leaves the technical detail to the FAA AD, so the duty to consult and apply the exact technical instructions sits with the operator.

The AD text provided does not set out express civil or criminal penalties or an enforcement procedure within its body. It is an instrument issued by CASA, signed by a CASA delegate, and it sets mandatory technical requirements by reference to FAA AD 2002‑08‑20 Amdt 39‑12732 (Requirement; Delegate signature). The document gives effective dates for the technical requirements (revised effective date 5 June 2002) and for the current amendment (12 May 2005), but it does not in the excerpt reproduce any statutory penalty provisions, enforcement notice procedures, or administrative sanction mechanisms.

What the AD does show about enforcement in practical terms is:

• The CASA delegate issued the AD, indicating an administrative direction from the regulator (Delegate signature). The instrument prescribes required compliance pathways and effective dates (Compliance). In Australian regulatory practice, ADs are regulatory instruments requiring operators to maintain airworthiness; however, the text here does not itself state the penalties for non‑compliance.

• The AD specifies that compliance must be "as specified in the Requirement document" and that a particular FAA AD paragraph can act as terminating action (Compliance). This implies a monitoring role: operators will need to demonstrate compliance with the FAA AD technical requirements or with the terminating FAA AD paragraph (if applicable) to meet CASA’s directive, but the excerpt contains no procedural details for how CASA will verify compliance, inspect aircraft, or apply sanctions.

• The AD introduces cross‑references to FAA documents and Boeing service publications as the operative technical content. Enforcement therefore will be predicated on whether operators have executed those steps within the timing specified; the CASA instrument points to the FAA AD for the detailed technical timeline and thereby channels enforcement to the presence or absence of compliance with the FAA AD.

Because the instrument as reproduced does not state enforcement mechanisms or penalties, operators and compliance officers must consult CASA’s statutory framework and the full text of the FAA AD for the precise obligations, record‑keeping requirements, evidence of compliance that CASA will expect, and any explicit sanctioning powers that CASA may exercise for failure to comply. The CASA AD itself only records the regulatory requirement and the paths to terminating the obligation (Compliance). The AD’s effective dates and the delegate’s signature establish it as an operative regulatory instrument as of the dates given (Compliance; Amendment becomes effective; Delegate signature).

This CASA AD operates through direct cross‑reference to foreign regulator material and manufacturer communications, creating a network of interaction rather than standalone provisions. The AD centrally adopts the technical requirements of FAA AD 2002‑08‑20 Amdt 39‑12732 as the operative compliance standard for the specified Australian‑registered aircraft (Requirement). Thus the CASA AD creates an interaction between Australian regulation and a US Federal Aviation Administration (FAA) action: CASA requires Australian operators to perform the FAA‑specified technical actions to maintain airworthiness in Australia.

The AD also links to additional FAA actions as potential terminating actions. The text refers to compliance with paragraph (b) of FAA AD 2003‑03‑22 Amdt 39‑13047 (cross‑referenced as CASA AD/B737/210 Amdt 1) as a terminating action (Compliance). In the Background section, that terminating action reference appears again but with a different FAA AD number (2003‑03‑33). The AD therefore interacts with later FAA ADs by permitting those later FAA actions to discharge the CASA AD obligation when the specified paragraph (b) requirements are met (Background; Compliance). This creates dependency on the content and numbering of FAA ADs.

The AD also cross‑references manufacturer materials: Boeing Alert Service Bulletin 737‑55A1084 and Service Letter 737‑SL‑12‑017 are noted as relevant documents (Requirement, Note 2). Those manufacturer publications are not reproduced in the CASA AD but are part of the technical documentation package operators will consult. The CASA AD’s reliance on manufacturer service bulletins aligns with standard airworthiness practice where ADs and service bulletins interact , the regulator prescribes mandatory compliance with the technical steps, and the manufacturer provides the methods and parts information.

Where an FAA‑approved alternate method of compliance exists for certain aircraft, the CASA AD recognises that alternate method. Specifically, the FAA approved an alternate method for aircraft with the elevator and tab redesign implemented on production aircraft at line number 1175, via FAA Letter 120S‑02‑683, and CASA’s Amendment 1 was issued in response to that FAA approval (Applicability; Background). That recognises foreign regulator determinations about design changes that remove the root cause and makes the CASA AD contingent on FAA design approvals for those aircraft.

Potential legal interaction issues apparent from the source:

• The CASA AD relies on FAA documents for substance and timing. Operators must therefore reconcile the CASA AD’s references with the live FAA AD texts to determine exact obligations, and discrepancies in citations (see paragraph below) create interactional ambiguity that requires clarification. The CASA AD text itself does not reproduce the entire FAA AD, so the full legal obligations effectively span CASA and FAA documents.

• The AD’s reference to compliance with paragraph (b) of a later FAA AD as terminating action introduces a dependency on the precise content and numbering of that FAA AD. The source text contains inconsistent FAA AD identifiers (2003‑03‑22 Amdt 39‑13047 and 2003‑03‑33 in another passage), creating a need to reconcile which FAA AD paragraph CASA intended to accept as terminating action (Background). That ambiguity can create legal uncertainty for operators unless cleared by CASA.

• The instrument operates within CASA’s regulatory reach but leverages foreign regulator determinations and manufacturer service material; operators must therefore manage both domestic regulatory obligations and adherence to the referenced foreign AD and service documents to demonstrate compliance to CASA.

In sum, the AD interacts with FAA ADs and Boeing service material by adopting those documents as the operative technical standard and by recognising FAA actions as possible terminating steps. The CASA AD does not itself restate enforcement or record requirements; those details are left to the FAA documents and CASA’s broader regulatory framework.

The CASA AD traces a short but specific amendment history in the text. The chronological elements provided are:

• Original issue became effective on 5 June 2002. The AD’s technical requirements include a revised effective date of 5 June 2002 for the FAA Requirement document that CASA adopts (Requirement; Compliance).

• Amendment 1 was issued after the FAA approved an alternate method of compliance for aircraft incorporating an elevator and tab redesign implemented on the production line at Line Number 1175. Amendment 1 therefore recognised the FAA’s alternate compliance for those later line numbers (Background; Applicability).

• Amendment 2 (the current instrument in the supplied text) was issued to identify that compliance with paragraph (b) of a later FAA AD is considered terminating action for this CASA AD. The AD states Amendment 2 becomes effective on 12 May 2005 and is dated with a delegate’s signature on 31 March 2005 (Amendment becomes effective; Delegate signature). The text also repeats that the original issue of the AD became effective on 5 June 2002 (Background).

• The AD notes that the FAA has approved an alternate method of compliance to the cleaning, modification, and AFM requirements of paragraphs (a) through (h) of FAA AD 2002‑08‑20 for line numbers 1175 and subsequent, and references FAA Letter 120S‑02‑683 (Applicability; Background). That FAA letter is the basis for Amendment 1’s recognition of the alternate method.

• The AD also notes that compliance with paragraph (b) of FAA AD 2003‑03‑22 Amdt 39‑13047 (CASA AD/B737/210 Amdt 1) is terminating action for this AD (Compliance). However, the Background summary later states Amendment 2 identifies that compliance with paragraph (b) of FAA AD 2003‑03‑33 (CASA AD/B737/210 Amdt 1) is considered terminating action for this Airworthiness Directive (Background). This duplication with differing FAA AD numbers constitutes an inconsistency in the text that may need resolution.

• Throughout, the AD clarifies that the compliance time remains unchanged by this issue (Compliance). That indicates the amendments adjusted the qualifying population and terminating action references rather than altering the timing of the substantive tasks.

The AD also references Boeing technical communications (Alert Service Bulletin 737‑55A1084 and Service Letter 737‑SL‑12‑017) in the Requirement note (Requirement, Note 2). Those are not termed amendments but are part of the technical reference set that operators should consult when performing the mandated work.

In short, the amendment history shows an original CASA adoption of the FAA AD (effective 5 June 2002), recognition of FAA-approved alternate compliance for later‑line aircraft via Amendment 1, and a further clarification in Amendment 2 that a particular FAA AD paragraph provides terminating action, with the current amendment effective on 12 May 2005 and signed by a CASA delegate on 31 March 2005.

The AD text provided contains no record of litigation, court proceedings, appeals, or legal challenges. It is an administrative regulatory instrument issued by CASA and signed by a delegate; the document lists the technical requirements, applicability, effective dates, and background safety rationale, but it does not reference any judicial decisions, administrative appeals, or unresolved legal disputes (entire text).

Because the AD itself does not recount any litigation, the material in this instrument does not identify contested points that have been subject to adjudication, nor does it provide references to any case law. The AD simply records regulatory action and cross‑references FAA ADs and Boeing service material (Requirement; Background; Note 2). Accordingly, there is no litigation history recorded in the source material to analyse or cite.

Operators or stakeholders seeking information on any subsequent legal challenges or administrative reviews would need to consult external sources , for example CASA public records of enforcement actions, regulatory appeals, or court databases , because the AD excerpted here contains no such information. The AD does, however, create compliance obligations and effective dates that would be relevant to any enforcement or judicial proceedings, but the text does not itself document any such proceedings.

The AD contains several practical traps and ambiguities for operators and compliance professionals, all apparent from the source text:

1. Line number cutoff and alternate compliance. Applicability is strictly limited to aircraft with line numbers up to and including 1174 (Applicability). Aircraft with line numbers 1175 and subsequent are treated differently because the FAA approved an alternate method of compliance for those later aircraft based on a production redesign of the elevator and tab (Applicability; Background; FAA Letter 120S‑02‑683). If an operator misidentifies an aircraft’s line number or relies on an incorrect corporate record, they may apply the wrong compliance path. Operators must verify the aircraft’s line number precisely before choosing the compliance pathway.

2. Dependency on FAA documents for substantive detail. CASA’s AD adopts the FAA AD’s technical requirements by reference ("in accordance with the technical requirements of FAA AD 2002‑08‑20"). The CASA text does not reproduce the cleaning and modification steps, the precise AFM wording changes, or the compliance time windows. Operators must therefore consult FAA AD 2002‑08‑20 (and the referenced Boeing service bulletin and service letter) for complete instructions and timing (Requirement; Note 2). Failure to do so could result in incomplete compliance.

3. Ambiguous terminating action citation. The AD identifies compliance with paragraph (b) of a later FAA AD as terminating action, but the FAA AD number is cited inconsistently within the document: once as FAA AD 2003‑03‑22 Amdt 39‑13047 (Compliance) and later as FAA AD 2003‑03‑33 (Background). This inconsistency creates uncertainty about which FAA AD paragraph CASA intended to accept as terminating action. Operators should seek clarification from CASA or check both FAA ADs to establish which paragraph (b) was intended.

4. AFM insertion vs physical work. The AD explicitly permits the required AFM revisions to be made by inserting a copy of FAA AD 2002‑08‑20 into the specified AFM sections (Requirement). That creates a fast administrative route for AFM compliance. However, the AD still requires cleaning and modification measures as part of the FAA AD technical requirements. There is a risk that an operator might complete the AFM insertion and neglect the physical cleaning/modification steps. The CASA text makes both elements part of the Requirement; operators must ensure they do not conflate AFM compliance with completion of physical maintenance work.

5. Reference to manufacturer documents without prescriptive text. The AD references Boeing Alert Service Bulletin 737‑55A1084 and Service Letter 737‑SL‑12‑017 (Requirement, Note 2). While these are likely to describe methods and materials, CASA’s document does not state whether compliance with those Boeing publications alone satisfies the FAA AD, or whether additional FAA‑specified steps are mandatory. Operators must consult the FAA AD to understand the normative hierarchy of requirements and whether the Boeing service bulletin is informative or mandatory.

6. Compliance time unchanged but not restated. The AD states that the compliance time "remains unchanged by this issue" (Compliance), but it does not restate what that compliance time is. Operators need to consult the FAA AD to find the time limits. The CASA amendment therefore might appear to update or clarify other matters without altering the timeline, but operators must confirm the timeline in the FAA document.

7. Administrative reliance on foreign regulator approvals. The CASA AD relies on FAA determinations (e.g. alternate method of compliance, terminating action). While this is operationally efficient, it places obligation on operators to track FAA AD developments and correspondence to ensure they have satisfied the CASA‑recognised terminating conditions. Operators should not assume CASA’s wording covers all eventualities; they must confirm the intended FAA references and whether any FAA amendments alter CASA’s obligations.

8. No explicit enforcement clause in the excerpt. The AD does not reproduce enforcement or penalty provisions in the text here. Operators should not infer that there are no enforcement consequences; rather, they must consult CASA’s enforcement framework and the full AD and FAA AD texts to determine record‑keeping and proof of compliance obligations.

Each of these gotchas is rooted in textual features of the AD as issued: line number cutoffs, external dependencies, cross‑references, and an inconsistent FAA citation. Operators and compliance personnel should treat the CASA AD as a pointer to FAA and Boeing documents that contain the operational detail and seek clarification from CASA where the AD text is inconsistent or ambiguous.

The CASA AD delegates the substantive compliance content to FAA AD 2002‑08‑20 Amdt 39‑12732 and references Boeing service publications. A practicable compliance checklist, grounded in the source text, is as follows:

1. Verify applicability by line number. Confirm the aircraft model and line number. The CASA AD applies to Model 737‑600, ‑700, ‑700BBJ, ‑700C and ‑800 series aircraft with line numbers up to and including 1174 (Applicability). If the aircraft is line number 1175 or later, consult the FAA Letter 120S‑02‑683 for the FAA‑approved alternate compliance method (Applicability; Background).

2. Obtain and consult the FAA AD. The CASA AD requires action "in accordance with the technical requirements of FAA AD 2002‑08‑20 Amdt 39‑12732" (Requirement). Obtain the full text of that FAA AD and study its paragraphs (a) through (h) as referenced. Those paragraphs detail the cleaning, modification and AFM revision requirements.

3. Review the Boeing documents referenced. The AD notes Boeing Alert Service Bulletin 737‑55A1084 and Service Letter 737‑SL‑12‑017 (Requirement, Note 2). Acquire those documents and determine whether they provide the step‑by‑step procedures, parts, tools, or instructions needed to carry out the FAA AD actions.

4. Implement cleaning and modification tasks. Follow the FAA AD instructions for cleaning elevator balance panel cavities and external elevator tab surfaces and perform any required modifications. The CASA AD adopts these steps by reference (Requirement).

5. Revise the AFM Limitations and Non‑Normal Procedures sections. The AD requires revisions to these AFM sections as specified in the FAA AD, and CASA permits accomplishing this by inserting a copy of FAA AD 2002‑08‑20 into the specified AFM sections (Requirement). If inserting the FAA AD text, ensure the insertion is placed exactly in the AFM sections designated and that flight crew has access to and training on the new entries.

6. Verify timing and sequence. The CASA AD instructs compliance "as specified in the Requirement document" and states the compliance time remains unchanged (Compliance). Confirm the precise compliance windows and any interim operating limitations in FAA AD 2002‑08‑20.

7. Determine if terminating action applies. Amendment 2 identifies that compliance with paragraph (b) of a later FAA AD (cited variably in the CASA text) may be terminating action for this AD (Compliance; Background). Determine whether the operator has already complied with the relevant FAA AD paragraph, and confirm which FAA AD paragraph CASA intended by resolving the internal citation inconsistency. If the operator complies with the relevant FAA AD paragraph (b) and it is indeed the terminating action CASA recognises, the CASA AD obligation for these actions is discharged.

8. For aircraft with line numbers ≥1175, apply the FAA‑approved alternate method of compliance if appropriate. FAA Letter 120S‑02‑683 approves an alternate method of compliance (Applicability; Background). Confirm whether the aircraft’s production design change is present and whether the aircraft qualifies for the FAA alternate method; implement the FAA‑approved alternative steps where applicable.

9. Record and document compliance. Although the CASA AD text excerpt does not prescribe record‑keeping, operators should document the work performed, AFM revisions made, and references to the FAA AD and Boeing service bulletins used. Hold documentation available for inspection by CASA or other oversight bodies.

10. Seek clarification where necessary. Because the CASA text contains an inconsistent citation to the FAA AD that provides terminating action (2003‑03‑22 vs 2003‑03‑33) and because the CASA AD adopts the FAA AD by reference rather than reproducing it, operators should contact CASA or their assigned Continuing Airworthiness representative for clarification if there is any doubt about which FAA AD paragraph constitutes terminating action or if the line number status is unclear (Background; Compliance).

11. Train flight crew and maintenance staff on the AFM changes and maintenance process. The AFM revisions affect Limitations and Non‑Normal Procedures and therefore operational behaviour. Ensure pilots and relevant maintenance personnel are briefed, trained and competent in the revised procedures and the rationale for any new limitations.

12. Coordinate with lessors, insurers and stakeholders. If aircraft are leased or subject to third‑party operational control, notify and coordinate with the lessor, insurer and operations control as necessary to ensure compliance and to document who bears the cost and responsibility for the maintenance and AFM changes.

In short, compliance under the CASA AD requires identification of affected aircraft, obtaining and following FAA AD 2002‑08‑20 and related Boeing service documents, implementing physical cleaning and modification tasks, revising AFM Limitations and Non‑Normal Procedures (which may be done by AFM insertion), and resolving whether terminating action via the later FAA AD paragraph applies. The CASA AD leaves timing and detailed steps to the FAA AD and therefore requires operators to consult and implement that document in full (Requirement; Compliance).