AD/B737/113 Amdt 1 - Rudder Power Control Unit Replacement

The instrument rests on a small set of interlocking concepts stated in the text: applicability by model and identified components; mandatory incorporation of a manufacturer's Alert Service Bulletin; explicit procedural parts for testing and component replacement; fixed compliance times; termination by satisfying a later FAA AD; and interaction with prior CASA ADs.

Applicability: The directive is limited to Model 737 aeroplanes with the particular rudder PCU and vernier control rod bolts identified in Boeing ASB 737-27A1202 Revision 2 (Applicability). That is a component-and-configuration based scope, not all 737s unconditionally. The ASB revision and date are specified, making the ASB the operative technical standard: "Boeing Alert Service Bulletin (ASB) 737-27A1202 Revision 2, dated August 7, 1997" (Applicability).

Mandatory manufacturer instructions: The AD "makes compliance with a Boeing ASB mandatory" (Background). The Requirement section lists discrete parts of the ASB (Parts I-V of the Accomplishment Instructions) and turns those parts into mandated tasks: testing, replacement of PCU, dual servo valve and bolt, vernier control rod and two dual load path bolts, and two nutplates (Requirement items 1-5). The AD thereby converts non-binding manufacturer guidance into a binding regulatory compliance obligation for the relevant aircraft.

Timing and recurring obligations: The AD sets recurring obligations , item 1 (test requirements) must be completed "every 'A' check and every time a PCU is replaced" (Compliance). Items 2-5 have a one‑off compliance interval relative to a historic date: "Within 24 months after 26 February 1998" (Compliance). The document explicitly states that "The compliance times remain unchanged by this issue," indicating this amendment does not alter the previously established timeframes.

Termination and supersession rules: The AD contains a terminating-action provision: "Accomplishment of the requirements of AD/B737/201 (FAA AD 2002-20-07) constitutes terminating action for the requirements of this Directive" (Requirement). It also states that it "supersedes AD/B737/79 & AD/B737/99" and that, "Pending the cancellation of ADs B737/79 & 99, compliance with this directive can be considered as achieving compliance with ADs/B737/79 & 99" (Requirement, Note 1). The Background further links this amendment to FAA action: "Amendment 2 is issued in response to FAA AD 2002-20-07, which requires incorporation of a new rudder control system; which when incorporated, supersedes the requirements of AD 97-14-04, the Requirement document of this Directive" (Background).

Cross-references to external directives: The ASB itself references multiple FAA ADs , "FAA ADs 97-14-04, 96-23-51 and 94-01-07 all refer to inspection, test and replacement actions on Boeing 737 rudder systems and are all referenced in Boeing ASB 737-27A1202" (Requirement, Note 2). Thus the AD explicitly situates the Australian requirement within a chain of international airworthiness instructions.

Objective stated in the document: The Background sets the operational objective: ensure the secondary servo slide in the dual servo valve operates correctly and replace components to eventually fit modified rudder PCUs "which is not prone to jamming." The AD declares that the ASB "incorporates a comprehensive test, inspection and component replacement procedure which overcomes the possible effects of a jam in the secondary slide of the rudder PCU assembly" (Background). The concept-to-action link is therefore explicit: identify a failure mode (jam in the secondary slide) and mandate actions described in the ASB believed to mitigate it.

Authority and effective date: The directive is signed by a CASA delegate and "becomes effective on 29 September 2005" (text). That pinpoints the regulatory date from which mandatory compliance is required under this instrument.

These concepts frame who must act, what technical standard must be followed, when actions must occur, and how this AD relates to prior and later directives.

The AD directly affects operators and maintainers of Model 737 series aeroplanes that have a main rudder PCU and specific vernier control rod bolts as identified in Boeing ASB 737-27A1202 Revision 2 (Applicability). That group is delimited by model and by the presence of particular components identified by the ASB; aircraft without those identified PCU/bolt configurations fall outside the stated applicability.

Parties within operators likely affected include maintenance organisations and engineers responsible for line and base maintenance, because the AD requires both recurring testing at "A" checks and multiple component replacements. The Compliance section makes the recurring test obligation explicit: item 1 test requirements "To be completed every 'A' check and every time a PCU is replaced," which assigns repeated work to maintenance schedules and potentially to contracted maintenance providers. The requirement to "Replace the rudder PCU in accordance with Part II" and to replace other components (Parts III-V) assigns parts-replacement obligations to whichever entity is responsible for airworthiness and component procurement in the operator’s organisation.

Aircraft owners and registrants who must ensure their fleet satisfies mandatory ADs are affected because the AD makes Boeing ASB procedures mandatory: "This AD makes compliance with a Boeing ASB mandatory" (Background). That converts previously advisorial Boeing instructions into regulatory obligations for the identified fleet. The operator must therefore reconcile their maintenance programmes, maintenance records, and aircraft status against the AD.

Parts suppliers and OEMs are implicated indirectly because the AD requires specific parts replacement (rudder PCU, dual servo valve, bolts, vernier control rod, nutplates). The Background states the ASB "requires the replacement of the vernier control rod and two dual loadpath bolts in the rudder PCU assembly" and aims "to have all rudder PCUs replaced with a modified item." Those replacements will create demand for the specified components and any modified PCUs.

Maintenance schedulers and planners are affected by the recurring nature of the test requirement and by the timing language. Item 1 is recurring at each "A" check; items 2-5 were set to be completed "Within 24 months after 26 February 1998." The AD also states "The compliance times remain unchanged by this issue," which may create administrative complexity for operators reconciling the historic 1998 compliance triggers with a 2005 effective date.

Regulatory personnel at CASA and their delegates are involved in administering the AD. The document is signed by "David Punshon, Delegate of the Civil Aviation Safety Authority" (signature block), showing the chain of delegation within CASA for issuing ADs.

Finally, the AD references FAA ADs and earlier CASA ADs (Notes and Background), which affects aircraft moving between jurisdictions and operators who track international airworthiness requirements. The AD explicitly links compliance with certain FAA ADs to terminating action for parts of this directive ("Accomplishment of the requirements of AD/B737/201 (FAA AD 2002-20-07) constitutes terminating action for the requirements of this Directive"), so operators who have complied with the FAA AD identified may adjust their Australian compliance stance accordingly.

The document does not list penalties, exemptions, or approvals; it therefore places the affirmative obligation to implement the ASB’s instructions on those operators and maintenance organisations whose aircraft fit the defined applicability.

The AD imposes specific duties on operators and maintenance providers for identified 737 aeroplanes. The central duty is to carry out the actions specified in Boeing ASB 737-27A1202 Revision 2, turned into mandatory regulatory requirements. The Requirement section lists five discrete mandated actions:

• Duty to perform tests: "Perform the test requirements of Part I of the Accomplishment Instructions of Boeing ASB 737-27A1202." This duty recurs "every 'A' check and every time a PCU is replaced" (Requirement item 1; Compliance).

• Duty to replace the rudder PCU: "Replace the rudder PCU in accordance with Part II of the Accomplishment Instructions of Boeing ASB 737-27A1202." The Compliance table places this replacement under the "Within 24 months after 26 February 1998" timing (Requirement item 2; Compliance).

• Duty to replace dual servo valve and bolt: "Replace the dual servo valve and a bolt in the PCU in accordance with Part III" (Requirement item 3; Compliance timing shows within 24 months after 26 February 1998).

• Duty to replace vernier control rod and two dual load path bolts: "Replace the vernier control rod and two dual load path bolts in accordance with Part IV" (Requirement item 4; Compliance timing same 24-month interval).

• Duty to replace two nutplates on the control rod: "Replace two nutplates on the control rod in accordance with Part V" (Requirement item 5; same 24-month interval).

The AD also imposes a duty to recognise terminating action: if an operator complies with "AD/B737/201 (FAA AD 2002-20-07)" then that compliance "constitutes terminating action for the requirements of this Directive" (Requirement). That creates a pathway by which meeting certain alternative regulatory standards eliminates the AD’s continuing applicability for the implicated actions.

Rights and procedural recognitions in the text are limited. The AD declares that it "supersedes AD/B737/79 & AD/B737/99" and that "Pending the cancellation of ADs B737/79 & 99, compliance with this directive can be considered as achieving compliance with ADs/B737/79 & 99" (Requirement, Note 1). This is a recognition that compliance with the current directive can be credited against earlier CASA AD obligations while the earlier ADs remain on the books. That is an administrative right of credit or equivalence afforded to operators who comply with the present AD.

The Background and Notes cross-reference FAA ADs, and the Requirement explicitly incorporates actions from Boeing ASB 737-27A1202, which itself references FAA ADs 97-14-04, 96-23-51 and 94-01-07 (Requirement Note 2). The AD thereby affords operators a structured mapping between different regulatory documents: compliance with the ASB implements the corrective measures described in the referenced FAA ADs.

The AD does not set out explicit waiver or exemption procedures, nor does it list rights of review, appeal, or indemnity in this text. Nor does it specify who pays for parts or labour; the document turns the ASB instructions into duties but leaves practical cost allocation to the parties responsible for aircraft airworthiness and maintenance. The AD is signed by a CASA delegate and becomes effective 29 September 2005, which fixes the regulatory date from which the duties are to be treated as current obligations (signature and effective date).

In short, the text sets mandatory technical duties tied to the Boeing ASB, recognises equivalence to certain FAA and prior CASA ADs in specified circumstances, and does not explicitly provide statutory rights, waivers, or penalty provisions within the document itself.

The AD text itself does not specify penalties, fines, or the detailed enforcement procedures within its pages. The instrument repeatedly describes mandatory obligations , "This AD makes compliance with a Boeing ASB mandatory" (Background) and lists the required steps and compliance timings , but it does not set out the sanctions that attach to failure to comply. There is no penalty schedule, compliance-reporting form, or enforcement protocol included in the text provided.

The directive is issued under the authority of the Civil Aviation Safety Authority and is signed by its delegate, "David Punshon" with an effective date of 29 September 2005. That signature and effective date indicate the formal issuance of the AD, and the AD’s phrasing uses regulatory language of obligation (e.g. "Replace", "Perform", "To be completed"), which signals that the measures are not advisory within the context of this document. However, any operational enforcement mechanisms , such as administrative notices, grounding orders, civil penalties, or other regulatory enforcement actions , are not detailed here.

The AD does refer to other regulatory instruments (FAA ADs and earlier CASA ADs) and to the Boeing ASB as the technical standard; it also contains a terminating-action clause referencing FAA AD 2002-20-07. These cross-references shape how compliance will be assessed in practice, because demonstrating compliance with the listed ASB parts or with the terminating FAA AD is the core way for an operator to show adherence to the directive. The AD also states that compliance with this directive may be considered as achieving compliance with prior CASA ADs B737/79 & 99 pending their cancellation, which affects administrative recognition of compliance.

Absent from the text are process details on how operators must record or notify CASA of completed actions, what documentary evidence is required, or what administrative steps CASA will take to monitor or enforce compliance. The AD does not list a specific date by which operators must have filed compliance reports, nor does it list penalties for non-compliance. For the precise enforcement consequences and procedures, one would need to consult CASA's enforcement rules and the broader civil aviation regulatory framework outside this document. The AD, as written, sets the mandatory technical duties and compliance timing but leaves enforcement mechanics unspecified within the document itself.

The AD explicitly interacts with prior CASA ADs and with FAA ADs, creating a web of cross-recognition and termination among airworthiness directives. The Requirement section states that "Accomplishment of the requirements of AD/B737/201 (FAA AD 2002-20-07) constitutes terminating action for the requirements of this Directive." That establishes a direct interaction: compliance with a named FAA AD is treated as terminating the obligations imposed by this AD. The AD also declares that it "supersedes AD/B737/79 & AD/B737/99" and further provides that "Pending the cancellation of ADs B737/79 & 99, compliance with this directive can be considered as achieving compliance with ADs/B737/79 & 99" (Requirement, Note 1). That creates administrative equivalence between compliance with this AD and compliance with earlier CASA ADs while those previous ADs remain formally active.

The Boeing ASB that the AD makes mandatory itself references several FAA ADs: "FAA ADs 97-14-04, 96-23-51 and 94-01-07 all refer to inspection, test and replacement actions on Boeing 737 rudder systems and are all referenced in Boeing ASB 737-27A1202" (Requirement, Note 2). Therefore, this CASA AD imports the technical remedies described in Boeing’s ASB, which in turn was drafted with reference to multiple FAA actions, effectively aligning the Australian regulatory requirement with a body of international airworthiness material.

The Background states that "Amendment 2 is issued in response to FAA AD 2002-20-07, which requires incorporation of a new rudder control system; which when incorporated, supersedes the requirements of AD 97-14-04, the Requirement document of this Directive." This sentence indicates that FAA regulatory activity (AD 2002-20-07) influenced the Australian amendment process, and that the FAA’s adoption of a solution (a new rudder control system) can change which previous directives remain applicable. The AD therefore functions not in isolation but as part of a chain of international directives that reference and sometimes supersede one another.

The AD also creates operational interactions for operators who have complied with relevant FAA directives. Because the AD identifies FAA AD/B737/201 as terminating action, an operator who can demonstrate compliance with that FAA AD will, according to this text, have satisfied the Australian requirement. The AD further allows compliance with this directive to be used to satisfy earlier CASA ADs, until such time as those earlier ADs are formally cancelled. This cross-crediting reduces duplicative work where the same technical remedy can satisfy multiple regulatory instruments.

What the text does not do is articulate interaction with statute beyond CASA’s directive-making role , it does not reproduce or cite enabling legislation, nor does it provide procedural enforcement rules, nor does it set out interactions with other classes of regulation (for example, civil liability, commercial contract terms, or insurance), within this document. The AD’s interaction with other legal instruments is confined to its cross-references to CASA ADs and FAA ADs and its incorporation of a specific Boeing ASB as the technical standard.

The document identifies itself as "AD/B737/113 Amdt 1" and as dated "10/2005" in its header. It further states "This Amendment becomes effective on 29 September 2005" (effective date). The signatory block records "David Punshon, Delegate of the Civil Aviation Safety Authority" with the date "19 August 2005," which shows the internal signing date preceding the stated effective date. The header repeats the AD designation and the title "Rudder Power Control Unit Replacement" and includes the date stamp "10/2005."

Within the Background the text contains the sentence "Amendment 2 is issued in response to FAA AD 2002-20-07, which requires incorporation of a new rudder control system; which when incorporated, supersedes the requirements of AD 97-14-04, the Requirement document of this Directive." That sentence in the supplied document mentions "Amendment 2" even though the document is labelled "Amdt 1." The supplied text therefore records both the present amendment identification and, in the Background, a reference to an Amendment 2 being issued in response to FAA AD 2002-20-07. The document does not otherwise outline any earlier amendment texts or provide the full amendment history chronology within its pages beyond indicating that it supersedes AD/B737/79 & AD/B737/99.

The AD also notes that "Some aircraft may already meet some of the requirements of Boeing ASB 737-27A1202 through compliance with previous CASA ADs (B737/79 and B737/99), however, these aircraft may still require on-going inspections and/or component replacement dependent on the scope of previous actions completed. This directive supersedes AD/B737/79 & AD/B737/99. Pending the cancellation of ADs B737/79 & 99, compliance with this directive can be considered as achieving compliance with ADs/B737/79 & 99" (Requirement, Note 1). That passage establishes a relationship between the present amendment and two named predecessors, and it explains how compliance credit is to be handled administratively while the previous ADs remain recorded.

There is no further chronological detail in the text about when the predecessor ADs were originally issued, nor does the document reproduce their wording. The AD does provide the practical compliance timing for its own requirements (recurrence at each "A" check for tests and 24 months after 26 February 1998 for other replacements) and explicitly states "The compliance times remain unchanged by this issue," which confirms that this amendment leaves earlier timing requirements intact rather than resetting them.

In summary, the supplied text identifies itself as Amendment 1 effective 29 September 2005, records a delegate’s signature dated 19 August 2005, notes that it supersedes two prior CASA ADs and that it interacts with FAA AD actions including a named FAA AD (2002-20-07), and contains an apparent in-text reference to an "Amendment 2" without reproducing that amendment’s wording in full. The document does not include a full history table of previous amendments beyond those references.

The AD as supplied does not record any litigation history. The text contains no references to court decisions, judicial reviews, or other litigation outcomes, and it names no cases. The only juridical markers present are administrative: the instrument is issued by the Civil Aviation Safety Authority, signed by a delegate ("David Punshon, Delegate of the Civil Aviation Safety Authority"), and carries an effective date of 29 September 2005. The document lists and cross-references other regulatory instruments (FAA ADs and prior CASA ADs) but does not mention any disputes, enforcement proceedings, or judicial challenges relating to this AD.

Because the AD cross-references FAA ADs and prior CASA ADs, an absence of litigation mentions here does not indicate absence of any litigation in the broader public record concerning the underlying technical problem or related directives; it only reflects that the instrument itself does not incorporate or summarise court involvement. The AD does include explanatory background material describing the safety concern (the potential for a jam in the secondary slide of the rudder PCU assembly) and why the manufacturer’s ASB procedures are being made mandatory, but it does not assert any litigation history connected to that factual account.

Readers requiring a record of any litigation concerning this AD, the Boeing ASB referenced, or the related FAA ADs would need to consult external court databases, regulatory enforcement records, or administrative law repositories. Those sources are not reproduced in the AD text itself. Within the supplied document, the only legal instruments mentioned are CASA AD/B737/79, AD/B737/99, FAA ADs 97-14-04, 96-23-51, 94-01-07, and FAA AD 2002-20-07 (AD/B737/201), and no case law or litigation outcomes are supplied alongside those references.

Therefore, this document supplies no litigation history to analyse or to cite; it is an administrative directive that sets out technical and compliance measures, signatures, dates, and cross-references to other regulatory documents but contains no record of adjudication or legal challenge within itself.

This AD contains several features that may create practical or administrative pitfalls for operators and maintainers if not noticed carefully.

1. Historic compliance dates remain in force. The Compliance section requires items 2-5 "Within 24 months after 26 February 1998" and states "The compliance times remain unchanged by this issue." Operators reading the AD in 2005 (effective 29 September 2005) should note that the specified 24‑month compliance window is anchored to a 1998 date. The AD therefore continues to rely on historic compliance deadlines rather than resetting them to the amendment effective date. That means that, on paper, many of the one‑off replacements required by the ASB should already have been completed before the amendment date; the operator must check records for retrospective compliance and for any continuing inspection obligations.

2. Test recurrence is tied to "A" checks and PCU replacement events. The test duty in Requirement item 1 must be performed "every 'A' check and every time a PCU is replaced." An "A" check is a maintenance scheduling term; operators must ensure their planned maintenance intervals incorporate the ASB Part I test requirements consistently. Because the AD converts the ASB into a mandatory requirement, failure to align maintenance planning with "A" checks could create inadvertent non‑compliance.

3. Equivalence and terminating-action pathways need documentary proof. The AD allows that "Accomplishment of the requirements of AD/B737/201 (FAA AD 2002-20-07) constitutes terminating action for the requirements of this Directive." Operators relying on compliance with FAA AD/B737/201 to terminate obligations under the Australian AD will need to be able to demonstrate that compliance in sufficient detail for CASA to accept that terminating action. The AD text creates the equivalence, but operators must ensure maintenance records and compliance evidence are complete.

4. Supersession and credit are administratively conditional. The directive "supersedes AD/B737/79 & AD/B737/99" and states that pending their cancellation, "compliance with this directive can be considered as achieving compliance with ADs/B737/79 & 99." That conditional phrasing requires operators to track whether earlier ADs have been formally cancelled and to document that their compliance with AD/B737/113 Amdt 1 maps to the requirements of the older ADs. Operators cannot simply assume administrative cancellation; they must verify the current regulatory record.

5. The AD depends on an external, dated technical document. The operative technical standard is Boeing ASB 737-27A1202 Revision 2 dated 7 August 1997. Reliance on a specific ASB revision means that the precise instructions to be followed are not printed in the AD; operators must obtain and follow the Boeing ASB Revision 2 text. The AD does not reproduce the ASB details in full, so implementers need to ensure they have the correct revision and that their maintenance actions mirror the parts (Parts I-V) cited by the AD.

6. Apparent internal numbering ambiguity. The Background contains the phrase "Amendment 2 is issued in response to FAA AD 2002-20-07" although the document is labelled "Amdt 1" at the top. That discrepancy may create confusion when searching for the correct amendment history or when reconciling administrative records. Operators and regulatory staff should not assume the numbering in the Background aligns with the header without checking CASA’s AD registry.

7. No enforcement mechanics or penalty details included. The AD mandates action but does not set out enforcement procedures or penalty amounts in the text provided. Operational staff should not treat absence of penalty language as absence of enforceability. The AD makes obedience to the ASB mandatory; the practical consequences of non‑compliance will be determined under CASA’s wider regulatory framework, which is not reproduced in this document.

8. Parts availability and modified PCUs. The Background states the "eventual aim of the ASB is to have all rudder PCUs replaced with a modified item which is not prone to jamming." That raises potential logistical and supply considerations: replaced or modified PCUs and the dual servo valve assemblies and bolts specified by the ASB must be procured and installed. The AD does not comment on lead times, availability, or interim measures while awaiting modified components.

9. Cross-referenced FAA ADs and earlier service bulletins. The ASB "references FAA ADs 97-14-04, 96-23-51 and 94-01-07" (Requirement, Note 2). Implementers should be careful to ensure that compliance with the ASB as mandated by this AD addresses those referenced FAA AD concerns as intended, and that no additional steps contained in those FAA ADs are overlooked if they are not duplicated in the ASB parts adopted here.

10. Record‑keeping for retrospective compliance. Given the 1998 anchor dates for some items, operators must be prepared to demonstrate whether the required replacements were performed historically and whether ongoing inspection obligations remain. The AD’s language requires demonstrable compliance though it does not set out what documentary format is required.

These points are directly anchored in the AD text and the ASB reference it makes mandatory. They identify places where misunderstanding of timing, equivalence, documentation, or parts logistics could produce operational surprises.

Compliance under this AD requires converting the Boeing ASB 737-27A1202 Revision 2, dated 7 August 1997, into executed maintenance actions on affected aircraft, and documenting that those actions have been performed in accordance with the specified timing rules in the AD.

1. Identify applicability: Confirm which aircraft in the fleet are within scope. The AD applies to "Model 737 series aeroplanes, having a main rudder power control unit (PCU) and vernier control rod bolts that are identified in Boeing Alert Service Bulletin (ASB) 737-27A1202 Revision 2, dated August 7, 1997." Operators must compare their aircraft configurations and component part numbers to the identification criteria in ASB 737-27A1202 Rev 2 to determine which airframes are covered.

2. Obtain Boeing ASB 737-27A1202 Revision 2: The AD makes the ASB mandatory and references specific Parts of its Accomplishment Instructions (Parts I-V). Operators must obtain the correct ASB revision (Revision 2, 7 August 1997) and ensure maintenance teams follow the instructions for Part I (tests) and Parts II-V (component replacements) exactly as written in the ASB, since the AD mandates those parts.

3. Perform Part I tests every "A" check and when PCU is replaced: The AD requires that operators "Perform the test requirements of Part I of the Accomplishment Instructions of Boeing ASB 737-27A1202" and specifies in Compliance that item 1 is "To be completed every 'A' check and every time a PCU is replaced." Incorporate Part I test steps into the operator’s "A" check procedures and ensure that test completion is recorded each time.

4. Replace PCU and other components per Parts II-V: The AD requires the following replacements in accordance with the ASB:

   • Replace the rudder PCU per Part II.
   • Replace the dual servo valve and a bolt in the PCU per Part III.
   • Replace the vernier control rod and two dual loadpath bolts per Part IV.
   • Replace two nutplates on the control rod per Part V. Compliance timing for items 2-5 is "Within 24 months after 26 February 1998." Operators should verify whether these replacements were completed historically; if not, they must document the remedial steps taken and the current status.

5. Consider terminating action via FAA AD compliance: If the operator has accomplished the requirements of "AD/B737/201 (FAA AD 2002-20-07)," the AD states that accomplishment "constitutes terminating action for the requirements of this Directive." Operators who have complied with the named FAA AD should gather verifiable records showing that accomplishment and be prepared to present those records to CASA to show terminating action, as the AD creates that equivalence.

6. Record-keeping and administrative credit: Because the AD notes that "Some aircraft may already meet some of the requirements ... through compliance with previous CASA ADs (B737/79 and B737/99)" and that "compliance with this directive can be considered as achieving compliance with ADs/B737/79 & 99" pending cancellation, operators should ensure that their maintenance records clearly map prior compliance actions to the parts and tasks required by the current AD. Maintain clear traceability between earlier AD compliance, ASB tasks, and current AD obligations.

7. Ensure parts and procedures match ASB specifications: The AD mandating replacement actions means installation must follow ASB-specified parts, torque values, and procedures. Confirm that replacement PCUs and dual servo valves meet the ASB’s part numbers or approved equivalents, and that installers are authorised and competent to carry out the work specified in the ASB.

8. Align maintenance scheduling: Integrate the recurring Part I tests into the operator’s maintenance planning system so that "A" checks and PCU-change events automatically trigger the ASB Part I tests. For fleet managers, update scheduled maintenance checks and workpacks to reflect the AD’s mandatory test steps and to ensure no "A" check passes without the required tests.

9. Prepare documentation for regulatory inspection: While the AD does not specify the format for compliance reporting within the document, operators should prepare their maintenance release records, logbook entries, and AD compliance records to show dates, serial numbers, part numbers replaced, workpack references to Boeing ASB Part instructions, and sign‑offs by authorised engineers. If relying on FAA AD/B737/201 as terminating action, include evidence of that FAA AD compliance.

10. Monitor for further amendments and cancellations: The AD indicates it "supersedes AD/B737/79 & AD/B737/99" and references FAA AD 2002-20-07. Operators should monitor CASA publications for any subsequent amendments, for formal cancellation of the earlier ADs, and for any change in the terminating-action mappings. Note the background reference to a modified rudder PCU being the eventual aim of the ASB; be alert for service bulletins and parts releases that facilitate the full modification.

By following these concrete steps,identify applicability, obtain and follow the specified ASB revision, perform tests at each "A" check and upon PCU replacement, replace specified components if not already done, document completions, and use the FAA AD terminating-action pathway where applicable,operators will satisfy the requirements the AD makes mandatory. The AD itself supplies the list of required actions and the timing anchors; successful compliance requires careful record-keeping matched to the ASB parts cited.