AD/B737/357 - In-Flight Entertainment Systems

The directive is structured around a small set of interlocking concepts: applicability by aeroplane model and service bulletin identification, defined hardware modifications and tests, sequencing of tasks (some actions required prior to or concurrent with others), specified compliance windows, and conditional acceptance of alternative compliance material via FAA AMOC approval.

Applicability is not merely by model name. The AD ties applicability to specific models "as identified in" particular Boeing Service Bulletins (SB 737-24-1145 for 737-300/-400/-500 and SB 737-24-1147 Rev 1 for 737-600/-700/-700C/-800/-900). This means that an aeroplane’s inclusion depends on the model and the identification method used in those SBs. The AD also distinguishes discrete groups within the SBs (for example Group 6 in SB 737-24-1145; Groups 3 through 139 in SB 737-24-1147 Rev 1) and identifies specific part numbers (for example P5-13 module assembly P/N 69-37321-81 and P/Ns 285A1840-3 or -4) that trigger additional or alternative actions.

The substantive mechanical changes required are:

• installation of a new circuit breaker, relays and wiring to give the flightcrew direct ability to de‑energise IFE systems (for 737-300/-400/-500 via the IFE/galley switch; for later models via a "utility switch in the flight compartment") , these are detailed as Requirement 1 and Requirement 3 respectively;
• replacement, re‑identification and testing of specific P5-13 module lightplate assemblies where particular P/Ns and group memberships apply , Requirement 2 and Requirement 4;
• for certain 737-800 aeroplanes, additional wiring, an INOP marker, a stow clip and rerouting and continuity testing associated with the No. 4 VDU cluster , Requirement 5.

Testing and re‑identification work is called for by the CSBs: for instance, the P5-13 modification requires re‑identifying and testing the modified module assembly "in accordance with the Accomplishment Instructions" of the relevant Boeing CSB.

Compliance timing and sequencing is explicit: the AD sets a 60‑month window for the primary circuit breaker/utility‑switch installs (Requirements 1 and 3), while the dependent P5‑13 or No. 4 VDU actions must be done prior to or concurrently with the primary installs. The AD treats later revisions of the listed SBs as acceptable only if those revisions have FAA AMOC approval to the referenced FAA AD, thereby creating a cross‑authority acceptance mechanism rather than leaving later SB revisions automatically acceptable.

The safety logic stated in the AD is limited and explicit: the measure aims to ensure the flightcrew can turn off power to IFE and other non‑essential electrical systems because failure to be able to do so during a non‑normal or emergency situation could result in inability to control smoke or fumes in the flight deck or cabin. The AD references FAA material (FAA AD 2009-12-06 Amdt 39-15929) and allows FAA AMOCs to the FAA AD to serve as acceptable alternate methods for compliance.

The AD designates as subject to its requirements the operators and maintainers of Boeing 737 series aeroplanes that match the models, groups and part numbers set out in the referenced SBs and CSBs. Practically this will include the legal entity accountable for the airworthiness of the aeroplane (owner‑operator, registered operator or lessee responsible under national aviation regulations), the maintenance organisations that perform the physical modifications and testing, and the suppliers/manufacturers providing the parts and assemblies called for in the SBs/CSBs.

Affected aircraft are defined narrowly by cross‑reference to the SBs. The AD lists:

• Model 737-300, -400 and -500 series aeroplanes "as identified in Boeing Service Bulletin (SB) 737-24-1145, dated 4 March 2004";
• Model 737-600, -700, -700C, -800 and -900 series aeroplanes "as identified in Boeing SB 737-24-1147, Revision 1, dated 1 March 2007";
• certain 737-300 aeroplanes in SB 737-24-1145 Group 6 fitted with P5-13 module assembly P/N 69-37321-81;
• certain 737-600/-700/-700C/-800/-900 aeroplanes in SB 737-24-1147 Groups 3 through 139 fitted with P5-13 module assembly P/N 285A1840-3 or -4;
• and certain 737-800 aeroplanes identified in paragraph 1.A.1. of SB 737-23-1189 dated 27 June 2002 for the No. 4 VDU cluster work.

Who must act, therefore, is the person or organisation responsible for the aeroplane conforming to its type certificate and continuing airworthiness. The AD prescribes technical actions that maintenance organisations must perform "in accordance with the Accomplishment Instructions" of the stated SBs and CSBs. Those instructions will allocate particular tasks to licensed or authorised maintenance personnel; the AD itself does not reassign maintenance privileges or qualifications but prescribes the outcomes and references the manufacturer documents that contain the step‑by‑step procedures.

Suppliers of parts (circuit breakers, relays, wiring looms, lightplate assemblies, P5-13 module components, INOP markers and stow clips) are implicated because the AD requires replacement or installation of specific hardware. Where the AD identifies specific P/Ns, compatibility and correct part procurement will be an operational requirement. The AD also implicitly involves national and foreign regulators: CASA issued the AD and explicitly references the FAA AD and FAA AMOC approval process; the AD accepts FAA‑approved AMOCs as acceptable for compliance with the equivalent requirements of this Directive.

Finally, passengers and airlines will be indirectly affected because the modifications alter the availability of IFE during non‑normal operations: the flightcrew will gain the ability to turn power to IFE and other non‑essential systems off from the flight deck. The AD does not quantify service or commercial impacts, but the modification changes operational capability to de‑energise cabin systems.

Duties

• Accomplish specific hardware installations and modifications as prescribed. The AD sets out five numbered Requirements. Requirement 1 directs installation of a new circuit breaker, relays and wiring on 737-300/-400/-500 series aircraft to let the flightcrew turn off electrical power to IFE systems via the IFE/galley switch, as per the Accomplishment Instructions of SB 737-24-1145. Requirement 3 is the parallel obligation for 737-600/-700/-700C/-800/-900, requiring installation of a new circuit breaker, relays and wiring to let the flightcrew turn off IFE and other non‑essential electrical systems via a utility switch, in accordance with Parts 1, 2 or 3 of the Work Instructions of SB 737-24-1147 Rev 1.

• Perform related parts replacement, modification, re‑identification and testing where the aeroplane is in the specified groups and is fitted with the listed P5-13 module assembly P/Ns. Requirement 2 (for certain 737-300 Group 6 aeroplanes with P/N 69-37321-81) requires replacement of the lightplate assembly and re‑identification/testing per CSB 69-37321-31-03. Requirement 4 requires modification of the P5-13 module per CSB 285A1840-24-02 for certain groups and P/Ns in the later model families.

• Install and test No. 4 VDU cluster wiring and associated hardware for certain 737-800 aeroplanes as specified in SB 737-23-1189 (Requirement 5), including continuity testing.

• Observe the specified compliance windows and sequencing. Requirements 1 and 3 are due within 60 months of the Directive’s effective date (30 July 2009). Requirements 2 must be completed prior to or concurrently with Requirement 1; Requirements 4 and 5 must be completed prior to or concurrently with Requirement 3.

• Use the Accomplishment Instructions in the named SBs and CSBs. The AD is prescriptive in that the technical procedures are contained in manufacturer's SB/CSB documents.

Rights and conditional flexibilities

• Use later revisions of the listed SBs for compliance only if those later revisions have been approved by the FAA as an Alternate Method of Compliance (AMOC) to FAA AD 2009-12-06. The AD explicitly states that "Later revisions of the above SBs, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2009-12-06 are considered acceptable for compliance with the equivalent Requirements of this Directive." This creates a conditional right to rely on later SB revisions, but only under the FAA AMOC process. The AD does not provide an independent CASA AMOC pathway in the text; it accepts FAA AMOCs.

• The AD does not enumerate exemptions, extensions, or derogations within its text. No explicit administrative appeals or penalty mitigation provisions are included in the AD as published.

Processes and documentation

• The AD requires actions "in accordance with" the Accomplishment Instructions of specified Boeing SBs and CSBs. Those manufacturer documents will contain the step‑by‑step technical processes, testing and re‑identification requirements that must be followed. The AD does not itself restate the procedural steps or specify acceptable alternative technical methods other than via the FAA AMOC route for later SB revisions.

Who decides compliance sufficiency

• The AD makes acceptance of alternate SB revisions explicitly contingent on FAA approval as an AMOC to the FAA AD, which places the FAA in the decision role for alternate SB revision acceptance. CASA's AD, by permitting FAA AMOCs to serve as acceptable compliance methods, effectively delegates acceptance of alternate SB revisions to FAA AMOC determinations for the purposes of this Directive. The AD itself is issued by CASA and became effective on the stated date; it does not in text establish an independent CASA AMOC process for later SB revisions.

The text of this Airworthiness Directive (AD/B737/357) does not set out specific penalties, fines, or the enforcement mechanisms within its body. The document records the technical requirements, applicability, compliance deadlines and the effective date, and it is signed by a CASA delegate. It does not include civil or criminal penalty schedules, nor does it state administrative enforcement procedures or notice/action timelines for non‑compliance within the text provided.

From the material present in the AD, the following points about enforcement and practical legal risk can be made strictly on textual grounds:

• The AD prescribes mandatory technical actions and compliance times. An AD is an instrument that imposes legally binding airworthiness requirements; the Directive sets deadlines (for example, "Within 60 months after the effective date of this Directive" for Requirements 1 and 3); adherence to those deadlines and requirements is the primary compliance obligation stated in the AD.

• The AD implicitly ties compliance to following the Accomplishment Instructions of specified Boeing SBs and CSBs. Those manufacturer documents will provide the tests and re‑identification steps that must be performed to meet the Directive's requirements. Compliance will therefore be judged against the installed configuration and maintenance/inspection records that demonstrate the actions called for were completed as required by the SB/CSB instructions. The AD itself does not elaborate record‑keeping or evidence standards, but the requirement to "accomplish" the named tasks imports the expectation that the work be done to the SB/CSB standards.

• The AD explicitly accepts later revisions of the listed SBs only where those later revisions have been approved by the FAA as an Alternate Method of Compliance (AMOC) to FAA AD 2009-12-06. This creates a defined pathway for alternative compliance via FAA AMOC approval. The AD does not state whether CASA will independently evaluate or accept other alternative methods.

• Enforcement actions, inspections, and any sanctions for non‑compliance are not detailed in the AD text. The AD records its effective date and the delegate who issued it; responsibility for enforcing Airworthiness Directives typically sits with the issuing aviation authority, but the AD text does not describe the specific enforcement processes.

Because the AD contains no explicit penalties or enforcement clauses, anyone analysing legal exposure must look beyond the AD text to the broader statutory and regulatory regime under which CASA operates for details on enforcement powers, notices, suspension of operations, and penalties. Those instruments and procedures are not contained in the AD itself and are not part of the source text provided for this analysis.

The AD expressly cross‑references and integrates with specific manufacturer service documents and a United States Federal Aviation Administration (FAA) airworthiness action. The AD’s interaction with other regulatory and technical authorities is explicit and limited to the references contained in the text.

References to FAA action

• The AD cites FAA AD 2009-12-06 Amdt 39-15929. The AD includes a note stating "FAA AD 2009-12-06 Amdt 39-15929 refers," thereby signposting that the FAA AD is a related regulatory instrument. The CASA AD then provides that "Later revisions of the above SBs, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2009-12-06 are considered acceptable for compliance with the equivalent Requirements of this Directive." This creates a specific interaction: CASA will accept later SB revisions if those revisions have FAA AMOC approval to the FAA AD. The AD therefore relies on the FAA’s AMOC determinations as an acceptable mechanism for alternative or updated compliance material.

Interaction with manufacturer documents

• The AD requires actions specifically "in accordance with the Accomplishment Instructions" of named Boeing Service Bulletins and Component Service Bulletins (SB 737-24-1145; SB 737-24-1147 Rev 1; CSB 69-37321-31-03; CSB 285A1840-24-02; SB 737-23-1189). The AD thus integrates CASA’s regulatory requirement with Boeing’s technical procedures. Operators will need to consult those SBs/CSBs , and any FAA‑approved AMOCs relating to their later revisions , to perform compliant work. Therefore, CASA’s AD places the manufacturer’s SB/CSB content effectively inside the regulatory requirement.

Jurisdictional and procedural cross‑recognition

• By accepting FAA AMOCs regarding later SB revisions, the AD establishes an inter‑authority recognition that can reduce duplication of AMOC approvals for operators following FAA processes. The AD does not expressly provide for CASA AMOCs or other national approvals in its text; it specifically identifies the FAA AMOC path. The AD’s acceptance of FAA AMOCs is therefore an explicit cross‑jurisdictional interaction point.

No explicit mention of other national laws, civil aviation regulations, workplace safety law, customs, import/export controls or contractual rights appears in the AD text. The AD therefore stands as a technical airworthiness requirement that refers operators to specific manufacturer documents and to the FAA AD and FAA AMOC process for later SB revisions.

Practical consequence of these interactions

• Compliance must satisfy the AD’s technical aims (ability to isolate IFE and non‑essential systems via cockpit switches) and must be accomplished using the detailed procedures in the Boeing SBs/CSBs. If an operator proposes to rely on a later SB revision, that reliance is permitted only if the FAA has approved the later SB revision as an AMOC to FAA AD 2009-12-06; otherwise the operator must follow the SB revision versions specified in the AD. The AD thus creates a single compliance pathway contingent on manufacturer procedures and selective acceptance of FAA AMOCs.

Because the AD text does not include procedural rules about appeals, enforcement, or adjudication, any interaction with administrative law or court processes would need to be assessed against the broader CASA statutory and regulatory regime, which is outside the AD document provided.

The AD text itself contains limited explicit amendment history. From the document provided, the following factual points can be extracted:

• The Directive is identified as AD/B737/357, captioned "In‑Flight Entertainment Systems" and dated 8/2009. The AD states: "This Airworthiness Directive becomes effective on 30 July 2009." The AD is signed by "James Coyne, Delegate of the Civil Aviation Safety Authority" and dated 16 June 2009 in the signature block.

• The AD references specific Boeing service documents by date and revision, establishing the versions that are required for compliance unless superseded by FAA AMOC‑approved later revisions. The referenced service documents and their dates/revisions are:

  • Boeing Service Bulletin 737-24-1145, dated 4 March 2004 (used for Model 737-300, -400 and -500 series);
  • Boeing Service Bulletin 737-24-1147, Revision 1, dated 1 March 2007 (used for Model 737-600, -700, -700C, -800 and -900 series);
  • Boeing Component Service Bulletin 69-37321-31-03, dated 21 August 2003 (for lightplate replacement on certain P5-13 assemblies);
  • Boeing Component Service Bulletin 285A1840-24-02, dated 28 August 2003 (for modification of certain P5-13 assemblies);
  • Boeing Service Bulletin 737-23-1189, dated 27 June 2002 (for No. 4 VDU cluster work on certain 737-800 aeroplanes).

• The AD contains a note that "Later revisions of the above SBs, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2009-12-06 are considered acceptable for compliance with the equivalent Requirements of this Directive." That sentence functions as a limited forward‑looking amendment pathway: it permits later SB revisions to be treated as compliant methods only if the FAA has approved them as an AMOC to the relevant FAA AD.

• The AD references FAA AD 2009-12-06 Amdt 39-15929 but does not include text of that FAA AD or list any amendments to the CASA AD itself. The CASA AD does not record previous versions of AD/B737/357 or amendments to it within the text provided; it presents a single directive entry with an effective date.

• Other than the conditional acceptance of FAA AMOCs, no additional amendment history, reissues, supersessions or replacements appear in the AD text provided. In short, the AD as published in this document is a single directive with an effective date and reference to specific manufacturer documents and the FAA AD, and it provides a limited conditional route for later SB revisions via FAA AMOC approval.

If parties require a formal chain of subsequent amendments, superseding ADs, or revocations, that material is not contained in this text and would need to be checked through CASA’s airworthiness directive registry or the FAA AD records, neither of which are reproduced in the AD text provided.

The AD/B737/357 document as provided does not contain any information about litigation, court challenges, administrative appeals, or judicial review concerning this Directive. The text is limited to technical requirements, applicability, compliance timing and cross‑references to Boeing SBs/CSBs and an FAA AD. It records the issuing delegate and date but provides no indication of legal disputes, contested interpretations, or prior or subsequent litigation with respect to the AD.

Conclusions that can be drawn strictly from the AD text regarding litigation history are therefore limited to the following factual statements:

• No litigation or legal proceedings are referenced in the AD text. There are no footnotes, references, or annexes indicating contested matters, injunctions, stays, or judicial decisions relating to the AD.

• The AD does reference FAA AD 2009-12-06 Amdt 39-15929 and accepts FAA AMOCs for later SB revisions. That cross‑reference is an administrative policy choice within the AD and may affect dispute paths (for example if an operator sought to rely on an FAA AMOC), but no litigation outcomes or disputes are recorded.

• Any litigation history relating to this directive, the underlying FAA AD, the Boeing SBs/CSBs, or operational consequences would not be discoverable from the AD text provided and would require searching judicial and administrative records external to the AD document.

Accordingly, the AD as provided contains no litigation history to summarise.

The AD contains several technical and procedural details that can lead to non‑obvious compliance traps if not handled precisely. The following list identifies those points strictly on the basis of the AD text and explains their practical implications.

1. Applicability is tied to SB identification, not model name alone

• The AD ties applicability to models "as identified in" particular Boeing SBs (SB 737-24-1145 and SB 737-24-1147 Rev 1). That means an operator must consult the relevant SB to determine whether a particular tail number or production variant is within the groups identified there. Treating model name alone as determinative may be insufficient.

2. Group and part number triggers

• The AD uses group numbers in the SBs (for example Group 6 in SB 737-24-1145 and Groups 3 through 139 in SB 737-24-1147 Rev 1) and specifies P5-13 module assembly part numbers (P/N 69-37321-81; P/Ns 285A1840-3 or -4). Operators must confirm both group membership and installed P/Ns. Failure to check P/Ns and groups may result in omitted but required sub‑work such as lightplate replacement, re‑identification and testing.

3. Sequencing requirements: "prior to or concurrently with"

• Requirements 2, 4 and 5 are tied to the primary installs by "prior to or concurrently with" language. Practically this means that you cannot delay the P5-13 or No. 4 VDU actions until after the primary install is completed unless they are done concurrently. Planning maintenance slots must accommodate concurrent work where required; otherwise an operator could miss the sequencing obligation.

4. Acceptance of later SB revisions is conditional

• The AD accepts later revisions of the listed SBs only if they have been approved by the FAA as an AMOC to FAA AD 2009-12-06. Operators who prefer to use a later Boeing SB revision must ensure FAA AMOC approval exists for that revision. A later Boeing SB without FAA AMOC approval is not automatically acceptable under this AD.

5. Different switch terminology and scope

• Requirement 1 refers to the IFE/galley switch for 737-300/-400/-500 aircraft; Requirement 3 refers to a "utility switch in the flight compartment" for later models that covers IFE and "other non‑essential electrical systems". The textual difference implies scope differences: for the later models the modification is expressly to enable de‑energising other non‑essential systems as well as IFE. Operators must ensure the install conforms to the wording of the applicable SB and the AD‑required outcome.

6. Testing and re‑identification obligations are in the CSBs

• The AD requires re‑identification and testing of modified P5-13 module assemblies "in accordance with" CSBs. Those testing and labelling details are not stated in the AD; failure to follow the CSB's re‑identification and test steps would not meet the AD even if the physical parts were changed.

7. The AD references FAA AD and FAA AMOC process

• The AD explicitly links acceptable alternative SB revisions to FAA AMOC approvals to FAA AD 2009-12-06. Operators should not assume CASA will accept a different national AMOC or an in‑house engineering alternative without FAA AMOC approval, since the AD’s text limits the acceptance route it describes to FAA AMOCs.

8. Effective and issue dates differ

• The AD is signed 16 June 2009 and becomes effective on 30 July 2009, with compliance windows measured from the effective date. Ensure calculations of "within 60 months" are from 30 July 2009, not the signing date.

9. No penalties or enforcement detail in the AD text

• The AD provides no explicit enforcement or penalty provisions. That does not mean there are none under the broader regulatory framework. Operators should not treat the AD’s silence on penalties as licence to ignore the AD; it simply means that the AD document itself does not set out enforcement mechanisms.

10. Narrowly expressed aircraft subsets for certain tasks

• Requirement 5 applies only to 737-800 aeroplanes identified in paragraph 1.A.1. of SB 737-23-1189 dated 27 June 2002. The AD does not reproduce paragraph 1.A.1. in full; operators need to consult that SB to determine if their particular 737-800 is captured.

These "gotchas" are rooted in the precise language of the AD. Addressing them requires operators to consult the specified SBs/CSBs and, where applicable, seek or rely upon FAA AMOC approvals for later revisions. Failure to reconcile group/P/N applicability, sequencing, SB revision status, or CSB testing steps risks non‑conformance with the AD as written.

The AD prescribes concrete technical actions tied to specified service documents and a clear sequencing and timing framework. The following is a practical step‑by‑step compliance checklist strictly reflecting the AD’s text; it does not add procedures beyond those the AD requires but organises the actions so an operator or maintenance provider can plan work in compliance with the Directive.

1. Confirm applicability

• Obtain and consult Boeing SB 737-24-1145 (dated 4 March 2004) for Model 737-300/-400/-500 aeroplanes and Boeing SB 737-24-1147 Revision 1 (dated 1 March 2007) for Model 737-600/-700/-700C/-800/-900 aeroplanes. Use those SBs to determine whether each tail number is included and identify the group number assigned to the aeroplane in the SB.

• For 737-800 No. 4 VDU cluster work, consult Boeing SB 737-23-1189 (dated 27 June 2002) and identify whether the aeroplane is listed in paragraph 1.A.1.

• Check the installed P5-13 module assembly part number on affected aeroplanes to determine whether Requirement 2 (P/N 69-37321-81) or Requirement 4 (P/Ns 285A1840-3 or -4) applies.

2. Sequence the work per the AD

• If Requirement 1 applies (737-300/-400/-500 install), schedule Requirement 2 (lightplate replacement/re‑identification/testing for Group 6 P/N 69-37321-81) to be performed prior to or concurrently with Requirement 1.

• If Requirement 3 applies (737-600/-700/-700C/-800/-900 install), schedule Requirements 4 and 5 to be performed prior to or concurrently with Requirement 3, as the AD specifies.

• Measure all compliance deadlines from the AD’s effective date (30 July 2009). Requirements 1 and 3 must be completed within 60 months after that effective date.

3. Perform the specified technical actions using the manufacturer documents

• Carry out installation of new circuit breaker(s), relays and wiring for the ability to de‑energise IFE (and for later models, other non‑essential systems) via the specified switches by following the Accomplishment Instructions of the relevant SB:

  • SB 737-24-1145 for 737-300/-400/-500 (Requirement 1);
  • SB 737-24-1147 Rev 1, Parts 1, 2 or 3 of the Work Instructions for 737-600/-700/-700C/-800/-900 (Requirement 3).

• For P5-13 module lightplate replacement or modification, complete the replacement, re‑identification and testing in strict accordance with the Accomplishment Instructions of:

  • CSB 69-37321-31-03 dated 21 August 2003 for P/N 69-37321-81 (Requirement 2);
  • CSB 285A1840-24-02 dated 28 August 2003 for P/Ns 285A1840-3 or -4 (Requirement 4).

• For relevant 737-800 aeroplanes, perform the No. 4 VDU cluster wiring install, INOP marker and stow clip installation, wiring reroute between stations 685 and 767 and continuity test per SB 737-23-1189’s Accomplishment Instructions (Requirement 5).

4. Ensure testing and re‑identification steps are completed

• The AD requires testing and re‑identification where called for in the CSBs. Ensure that the exact test procedures (for example continuity tests) and re‑identification labels or tags are applied as per the CSB instructions.

5. Use later SB revisions only if FAA AMOC approved

• If you intend to use a later revision of any of the referenced SBs for compliance, verify that the later revision has been approved by the FAA as an AMOC to FAA AD 2009-12-06. Only such FAA AMOC approvals make later SB revisions acceptable for compliance with this CASA Directive, according to the AD’s own text.

6. Document completion consistent with regulatory expectations

• The AD requires the operator to "accomplish" specified actions in accordance with SB/CSB instructions. While the AD does not state record‑keeping standards, standard airworthiness practice requires maintenance records that demonstrate compliance. Maintain traceable records that show the SB/CSB revision used, the part numbers installed or modified, test results (such as continuity test outcomes), re‑identification markings, dates and names/authorisations of persons and organisations that performed the work.

7. Timing and operational planning

• Schedule the work within operational constraints so that Requirements 2, 4 and 5 can be performed prior to or concurrently with the primary installs where required. Because the AD mandates "prior to or concurrently with" sequencing, deferment of prerequisite work until after a primary install would not meet the AD unless the work was accomplished concurrently.

8. Liaise with parts suppliers and maintenance providers

• Confirm availability of required hardware (circuit breakers, relays, lightplate assemblies, INOP markers, stow clips) and confirm that replacements match the P/Ns and specifications stated in the SBs/CSBs. Procurement lead times and parts compatibility checks should be built into scheduling.

9. Consider reliance on FAA AMOCs when seeking to use different SB revisions

• If a later Boeing SB revision exists that would simplify work or offer improved procedures, obtain confirmation that the FAA has approved that revision as an AMOC to FAA AD 2009-12-06 before relying on it as compliant under this AD.

10. Verify effective date and compliance windows

• Compute all compliance deadlines from the Directive’s effective date, 30 July 2009, and ensure completion of Requirements 1 and 3 within 60 months after that date. Requirements stated to be "prior to or concurrently with" must be scheduled accordingly.

This compliance pathway follows the AD's express text: use the Accomplishment Instructions and Work Instructions in the listed SBs and CSBs, observe the part number and group triggers, respect the sequencing requirements, meet the compliance deadlines measured from the effective date, and use FAA AMOC‑approved later SB revisions only where FAA approval exists.