AD/B747/367 - Lower Cargo Compartment Fire Extinguishing System - Time Delay Relays

The directive names its affected population under "Applicability": Boeing 747-400, 747-400D and 747-400F series aeroplanes as identified in Boeing SASB 747-26-2281 dated 24 July 2006. The text therefore places the obligation on the operators and owners of those identified aeroplanes to carry out the inspection and replacement actions. The instruction to "carry out general visual inspection" and to "replace the relay" creates an operational requirement that falls on the party with maintenance responsibility for the aeroplane at the time the requirement is due. Practically, those parties will be the aircraft operators, maintenance organisations contracted by operators, or owners if they manage maintenance directly; the directive itself does not specify a different enforcing entity. The main equipment centre location is specified as the place to inspect the relays, so maintenance staff with access to that equipment bay are the actors who must perform the visual checks.

Supply-chain actors are affected indirectly. Requirement 2 accepts replacement with a relay "that has been tested by the supplier and found to be unaffected by thermal expansion", which imposes a documentation and testing role on relay suppliers who wish their parts to be usable as replacements under this AD. Inventory managers and spares suppliers are affected by Requirement 3, which prevents installation of spare relays with date codes between 0000 and 0343 that do not carry an additional "T" date code; such spares must be removed from eligible replacement stock or re-identified if they carry the "T" code.

Regulatory and certifying authorities are implicated through the cross-reference to FAA materials. The directive accepts later revisions of the SASB that the FAA approves as an Alternate Method of Compliance to FAA AD 2007-23-08, thereby creating an avenue for operators to comply by following FAA-approved documentation rather than only the base SASB. The directive does not itself list enforcement penalties or nominate an enforcement agency beyond its issuance by the Civil Aviation Safety Authority; enforcement in the aviation system typically rests with that authority, but the AD text contains no enforcement clause or penalty schedule.

Finally, the directive affects operational planning: the compliance windows (24 months for the inspection, 30 days to replace a found relay, immediate restriction on certain spares) create scheduling and logistics constraints for maintenance programmes, spares procurement, and record-keeping. The directive does not allocate funding or compensation; therefore operators and owners who must meet the requirements will bear the inspection and replacement costs and manage changes to spares inventories.

The directive sets three defined duties, with procedural form and timing requirements, and identifies acceptable methods of compliance.

Duties:

• Duty to inspect: Requirement 1 mandates "carry out general visual inspection, in accordance with SASB 747-26-2281", of relays P/N TDH6103-1204, -1804 and -6003 in the main equipment centre to determine if the relay was manufactured during the date range specified in the SASB. This duty must be completed within 24 months after the effective date of the Directive (see "Compliance").

• Duty to replace if affected: Requirement 2 requires that if, as a result of Requirement 1, a relay manufactured during the specified date range is found, the operator must "replace the relay with a relay that was not manufactured during the specified date range, or with a relay that has been tested by the supplier and found to be unaffected by thermal expansion, in accordance with the SASB." The time for this replacement is within 30 days after finding a relay manufactured during the specified date range.

• Duty to control spares: Requirement 3 provides an immediate prohibition on installing as replacement spares any time delay relay, P/N TDH6103-1204, -1804 or -6003, that has a date code between 0000 and 0343 and does not have an additional date code with the letter "T." This duty is effective as of the directive's effective date.

Rights and compliance options:

• Use of supplier-tested relays: The directive explicitly permits replacement with relays that a supplier has tested and found unaffected by thermal expansion, provided the testing is "in accordance with the SASB." That creates a rights-based route for a supplier to demonstrate a particular part is acceptable despite its date code.

• Acceptance of later SASB revisions approved by the FAA: The directive allows compliance through later revisions of SASB 747-26-2281 if those revisions are approved by the FAA as an Alternate Method of Compliance to FAA AD 2007-23-08. This gives operators the right to comply using FAA-approved AMOCs rather than the exact SASB version dated 24 July 2006.

Procedural form:

• Inspection method is specified as "general visual inspection", a low-complexity maintenance action in form, although the directive defers to the SASB for the detailed procedure and acceptance criteria.

• Replacement must be "in accordance with the SASB" when involving supplier-tested parts, so the specificity of acceptable testing methods and documentation resides in the SASB. The AD does not itself provide test protocols or documentation standards.

Timing and record implications:

• The AD sets explicit deadlines: 24 months for inspection, 30 days for replacement after identifying an affected relay, and immediate effect for the spare-install prohibition. These deadlines create operational scheduling duties and imply a record-keeping requirement to demonstrate compliance within the specified windows; the directive does not prescribe the form of records, but compliance will depend on retaining inspection and replacement evidence consistent with regulatory audit practice.

Limitations and scope of discretion:

• The AD gives no discretion to extend the inspection or replacement windows within its text, although the acceptance of FAA-approved AMOCs provides an alternative compliance path where the FAA has granted an AMOC. The AD itself does not set alternative timelines or exemptions; any deviation would require use of an AMOC or other regulatory process outside the AD's text.

The directive text, as provided, does not state any specific penalties, fines or enforcement mechanisms. It contains mandatory requirements and compliance windows, but no express sanctioning provisions or administrative penalty schedules are included in the AD text. The instrument is issued by the Civil Aviation Safety Authority (CASA) delegate, Charles Lenarcic, dated 10 December 2007, and states the AD "becomes effective on 14 February 2008." Beyond the effective date and the mandatory obligations, the directorate does not set out enforcement processes, inspection powers, or remedies for non-compliance within the AD.

Because the AD cross-references FAA AD 2007-23-08 and accepts FAA-approved AMOCs in later SASB revisions, the instrument is presented in the regulatory practice of airworthiness directives, which historically operate within a jurisdictional enforcement framework; however, the text contains no explicit statement that CASA will impose penalties or how it will monitor compliance. In other words, the AD creates binding maintenance obligations for the operators and maintenance organisations of affected aeroplanes, but it leaves the enforcement architecture implicit rather than enacted in the text.

From the AD's own language, the following enforcement-relevant facts can be drawn directly:

• The AD imposes time-limited mandatory actions: an inspection within 24 months, replacement within 30 days after finding a suspect relay, and an immediate prohibition on installing certain spares as of the effective date.

• The AD ties its methods of compliance to Boeing SASB 747-26-2281 dated 24 July 2006, and allows later SASB revisions approved by the FAA as AMOCs; this creates a defined basis for compliance documentation, which an enforcing regulator would reasonably expect operators to retain.

• There is an implicit regulatory hierarchy: CASA issued the AD, while the AD also refers to FAA material and accepts FAA AMOCs. That cross-referencing may affect the mechanics of enforcement, for example by providing accepted methods for demonstrating compliance.

Because the AD text itself contains no penalty clauses, any sanctioning regime, inspection programme, audit timing or administrative enforcement steps must be sourced to CASA's general regulatory powers, enforcement policies, or other instruments outside this AD. The AD does not include alternative dispute or review mechanisms; consequently, operators that wish to vary compliance would need to pursue those avenues through CASA or via FAA AMOCs where appropriate, none of which are described in the directive itself.

The directive explicitly references and interacts with Boeing SASB 747-26-2281 dated 24 July 2006 and with FAA AD 2007-23-08 Amdt 12524. The AD makes the SASB the procedural anchor for inspections and for supplier testing protocols ("in accordance with SASB 747-26-2281"), thereby incorporating that manufacturer's service bulletin into the directive's compliance pathway. The AD also expressly permits later revisions of the SASB that the FAA approves as an Alternate Method of Compliance to FAA AD 2007-23-08 to be used for compliance with the equivalent requirements of this Directive. That creates an inter-regulatory compliance route: operators can comply either with the specific SASB version cited or with later FAA-approved revisions of that SASB that provide an FAA AMOC.

The AD does not purport to amend, repeal or supersede any statute, regulation or other AD; instead it fits into the standard regime of airworthiness directives as mandatory maintenance instructions issued by the national aviation authority. The AD contains a "Note" that explicitly refers to FAA AD 2007-23-08 Amdt 12524, which indicates that the FAA action is a parallel or predecessor regulatory step. The "Background" paragraph draws its factual rationale from an FAA-advised report concerning relay failures in a Boeing Model 777 and subsequent testing of similar relays at Boeing and the supplier. This cross-reference indicates that the CASA AD is part of an international safety response coordinated by account taken of FAA findings and Boeing service information.

Operational interactions include:

• Manufacturer documents: The AD directs compliance "in accordance with SASB 747-26-2281", which imports the technical specifics and testing requirements from Boeing's service bulletin into the regulatory obligation. The AD also allows FAA-approved revisions of that SASB to serve as an AMOC; this links CASA's directive to FAA approval processes and the FAA AD.

• Supply-chain testing and certification: Because one compliance path allows supplier-tested relays found "unaffected by thermal expansion", the AD effectively recognises supplier testing as part of the compliance chain. The AD does not define the testing protocol itself; it ties acceptance of supplier testing back to the SASB.

• International regulatory alignment: The AD explicitly recognises FAA-approved alternate compliance methods, which reduces potential duplication where operators already comply with FAA ADs or FAA-approved SASB revisions. It does not, however, state whether compliance with an FAA AD alone suffices in all circumstances; the AD requires compliance "in accordance with SASB" or with FAA-approved SASB AMOCs for equivalence.

Because the AD contains no penalty or enforcement text, the formal interaction with domestic enforcement laws, administrative procedure acts, or civil aviation regulations is not specified in the directive itself. Any enforcement action, appeals process or alternative compliance mechanism beyond the stated AMOC route will therefore be handled through CASA's broader regulatory powers and procedures, which are not set out in the AD.

The documentary record contained in the AD text is self-contained and short. The instrument is identified as AD/B747/367, Lower Cargo Compartment Fire Extinguishing System - Time Delay Relays, 2/2008. The AD states that it "becomes effective on 14 February 2008", and bears the signature block "Charles Lenarcic, Delegate of the Civil Aviation Safety Authority" dated 10 December 2007. The AD cites Boeing SASB 747-26-2281 dated 24 July 2006 as the service bulletin forming the core method of compliance.

Beyond that single AD issuance, the text does not list any amendments to AD/B747/367 itself, nor does it include an internal amendment log or later AD numbers. The AD explicitly states that later revisions of the SASB 747-26-2281 that are approved by the FAA as an Alternate Method of Compliance to FAA AD 2007-23-08 are considered acceptable for compliance with the equivalent requirements of this Directive. That is not presented as an amendment to the AD itself, but rather as an acceptance of FAA-approved revisions of the manufacturer service bulletin as alternate compliance methods.

The only temporal markers present in the document are:

• SASB referenced date: 24 July 2006.
• Signature date of the CASA delegate: 10 December 2007.
• Effective date of the AD: 14 February 2008.
• AD identification: AD/B747/367 and designation 2/2008.

No further amendment history is recorded within the text supplied. If an operator requires a record of subsequent amendments, superseding ADs, or revocations, those would need to be sought in CASA's public AD registry or by checking subsequent AD issuances; the directive as presented contains no updated or amended versions, and no revocation language.

The AD text makes no reference to litigation, judicial review, or any contested administrative proceedings related to AD/B747/367. There are no cases named, no disputes referenced, and no mention of court decisions or appeals. The document simply records the safety concern, the requirements, the compliance deadlines, and the cross-references to Boeing SASB 747-26-2281 and FAA AD 2007-23-08.

Therefore, based solely on the text provided, there is no recorded litigation history associated with AD/B747/367 in this instrument. Any litigation, judicial review, enforcement proceedings, or administrative appeals that might have arisen after this AD's issuance are not documented in the text and would have to be identified by consulting court records, CASA enforcement records, or subsequent public announcements outside this AD.

The AD contains several precise technical, procedural and timing features that create practical pitfalls for compliance if not properly noted.

1. Applicability is by SASB identification, not just by generic model name. The AD applies to "Model 747-400, 747-400D and 747-400F series aeroplanes as identified in Boeing Special Attention Service Bulletin (SASB) 747-26-2281, dated 24 July 2006." This means operators must consult the SASB to determine whether particular airframes are included; simply relying on a colloquial model variant may miss precise serial-number limitations embedded in the SASB.

2. Part-number specificity. The AD identifies the relays by specific part numbers: TDH6103-1204, -1804 and -6003. Only those part numbers are targeted by the AD; other relay part numbers are outside the AD’s stated scope. Failure to check the exact P/N marking on installed relays could lead to either unnecessary replacement or missed identification of affected components.

3. Date-code logic and the "T" exception. The installation prohibition in Requirement 3 targets relays with date codes between 0000 and 0343 unless they have "an additional date code with the letter 'T'." That exception is narrow and raises inventory- and labelling-related risks: spares with ambiguous or multiple date codes, unclear stamping or additional markings could be misread, leading to either wrongful removal of usable spares or retention of prohibited ones. Operators must be careful in reading date codes and any secondary date-code markings.

4. Timing gaps and sequencing. Requirement 1 inspection must be completed "within 24 months after the effective date of this Directive"; Requirement 2 replacement must occur "within 30 days after finding a relay manufactured during the date range specified in the ASAB." There is therefore a two-stage window: an extended window to look for affected relays, and a short window for remedial replacement once a suspect relay is found. Operators must plan maintenance schedules to ensure that affected relays found near the end of the 24-month inspection window are replaced within 30 days, otherwise they will have a short runway to procure compliant spares.

5. Spare-parts management. Requirement 3 is effective as of the AD effective date, and prohibits installation of specified spares immediately. That creates an immediate effect on spare stock eligibility from the AD effective date, even if the operator has not yet performed their inspection. Operators must segregate inventory and prevent inadvertent installation of prohibited spares between the AD effective date and their inspections.

6. Reliance on supplier testing. One compliance route permits use of relays "tested by the supplier and found to be unaffected by thermal expansion." That dependence on supplier testing makes an operator's compliance contingent on the supplier providing acceptable testing and documentation in accordance with the SASB. If the supplier's testing is deficient or not documented as required by the SASB, the relay may be non-compliant despite supplier claims.

7. Cross-jurisdictional treatment. The AD accepts later SASB revisions that the FAA approves as Alternate Methods of Compliance to FAA AD 2007-23-08. That creates an AMOC opportunity, but operators must confirm FAA approval status of later SASB revisions. Relying on a revised SASB that lacks FAA AMOC approval would not satisfy the AD under its express terms.

8. No penalties set out in the AD. The directive contains no penalty or enforcement language. That does not mean there are no enforcement consequences; rather, enforcement and penalties would come from CASA's broader regulatory framework. Operators cannot assume the absence of penalty language means an absence of enforcement risk.

9. Limited procedural detail in the AD. The AD defers to the SASB for inspection and test procedures. If the SASB contains ambiguities or evolving clarifications, operators must track SASB revisions and any FAA AMOC activity to ensure compliance.

10. Effective date vs sign date. The AD is signed on 10 December 2007 but becomes effective on 14 February 2008. Requirement 3 is effective as of 14 February 2008, which is the date from which the spare-install prohibition applies. Operators should not rely on the signature date as the compliance start point.

Taken together, these points create non-obvious operational risks: inventory tagging errors, supplier-documentation gaps, compressed remedial windows, and potential misalignment between the SASB being followed and FAA AMOC approvals. Close attention to P/N marking, date-code reading, SASB content, supplier test evidence and spares segregation is necessary to avoid inadvertent non-compliance.

The directive provides a straightforward compliance pathway that ties explicitly to Boeing SASB 747-26-2281 dated 24 July 2006 and to FAA-approved AMOCs. To comply with AD/B747/367, operators should take the following steps in the sequence implied by the AD.

1. Identify applicability. Consult Boeing SASB 747-26-2281 dated 24 July 2006 to confirm whether each Boeing 747-400, 747-400D or 747-400F aeroplane in the operator's fleet is within the SASB's applicability scope. The AD applies only to aeroplanes identified in that SASB.

2. Schedule the inspection within the AD window. Requirement 1 must be completed within 24 months after the AD effective date (effective date 14 February 2008). Plan maintenance windows to complete a "general visual inspection, in accordance with SASB 747-26-2281" of relays P/N TDH6103-1204, -1804 and -6003 in the main equipment centre. Ensure personnel who will perform the inspection have access to the SASB and are familiar with the date-code locations and markings the SASB indicates.

3. Perform the visual inspection as specified. Execute the "general visual inspection" precisely as the SASB prescribes, inspecting the part numbers listed and recording the manufacture date codes. Document the inspection findings in the aircraft maintenance records or logbooks in a form that evidences compliance with the AD's timing requirements.

4. If an affected relay is found, take replacement action within 30 days. Requirement 2 mandates replacement "within 30 days after finding a relay manufactured during the date range specified in the ASAB." Replace the relay either with a relay that was not manufactured during the specified date range, or with a relay the supplier has tested and found to be unaffected by thermal expansion, in accordance with the SASB. Obtain, retain and attach supplier test reports or acceptance documentation where replacement parts are supplier-tested relays, ensuring the documentation expressly meets the SASB requirements.

5. Control spares immediately. As of the AD effective date, do not install as a replacement spare any relay P/N TDH6103-1204, -1804 or -6003 that has a date code between 0000 and 0343 and does not have an additional date code with the letter "T." Implement immediate stock segregation, mark prohibited parts appropriately, and update spares records to prevent inadvertent installation.

6. Use FAA-approved AMOCs where available. The AD accepts later revisions of SASB 747-26-2281 that the FAA approves as Alternate Methods of Compliance to FAA AD 2007-23-08. If relying on a later SASB revision, verify that the FAA has approved that revision as an AMOC to FAA AD 2007-23-08 before treating it as compliant for CASA purposes under this AD.

7. Record-keeping and audit trail. Although the AD does not prescribe the form of documentation, operators should maintain a clear audit trail linking inspection results, serial or part numbers, date-code readings, replacement part identification, supplier test documentation (if used), and dates of action to demonstrate compliance within the AD-specified timeframes. Include cross-references to the SASB revision and any FAA AMOC documentation relied upon.

8. Liaise with suppliers. Where a compliant route depends on supplier testing, engage the supplier early to secure the necessary testing and documentation in accordance with the SASB. Confirm that supplier test methods and reports meet the SASB's expectations; do not accept oral assurances without written evidence aligned to SASB requirements.

9. Coordinate with regulatory contacts. If there is uncertainty about whether a later SASB revision is FAA-AMOC-approved, or if an operator seeks a different compliance approach, contact CASA for clarification on acceptable alternative methods. Remember that the AD itself references FAA AD 2007-23-08 and permits FAA-approved AMOCs, but it does not otherwise authorise deviations from its stated requirements.

10. Note deadlines and operational planning. Plan for procurement lead times and maintenance scheduling so that inspections and any required replacements happen within the AD windows. The 30‑day remedial window after finding an affected relay can be tight if special-order parts or supplier testing is needed.

Following these steps will align actions with the explicit requirements of AD/B747/367: inspect the specified P/N relays in the main equipment centre per SASB, replace any relays within the implicated date-range within 30 days, and segregate and refrain from installing spares with date codes 0000-0343 that lack the "T" additional date code. Keep copies of the SASB pages used and any FAA AMOC documents relied upon with the maintenance records for each aeroplane inspected.