AD/B767/234 - Cargo Compartment Fire Extinguishing System - Time Delay Relays

The directive operates through identification, verification, and removal of potentially defective components. Its core concepts are: applicability, inspection to identify suspect relays, mandated replacement when a suspect relay is present, prohibition on installing certain spare relays, and acceptance of later SASB revisions if the FAA approves them as AMOC to the related FAA AD.

Applicability is precise: Model 767-200, 767-300 and 767-300F series aeroplanes as identified in Boeing SASB 767-26-0131 dated 24 July 2006. The inspection called for is a "general visual inspection" of the specific time delay relay P/N TDH6103-1804, K826, located in the main equipment centre, to determine manufacture date code. The text requires replacement only if the relay was manufactured during the date range specified in the SASB; it does not require blanket replacement of all relays. Replacement options are tightly specified: replace with a relay not manufactured in the specified date range, or with a relay that the supplier has tested and found unaffected by thermal expansion, per the SASB. This links acceptability to either provenance (manufacture date) or supplier testing status.

A discrete procurement restriction follows: time delay relay P/N TDH6103-1804 with a date code between 0000 and 0343, and lacking an additional date code with the letter "T", "may not be installed on any aeroplane as a replacement spare" as of the directive's effective date. That creates a forward-looking supply restriction for spares inventories and replacement practices.

Finally, the AD recognises the FAA’s role in alternative compliance: later revisions of the SASB approved by the FAA as AMOC to FAA AD 2007-23-08 are acceptable for compliance with equivalent requirements in this directive. The background explains the operational risk the AD addresses: a relay failure that can delay activation of the secondary fire suppressant bottles, potentially leaving insufficient suppressant when the aircraft is more than the relay delay time from a suitable airport. The document is signed by the Delegate of the Civil Aviation Safety Authority (CASA), indicating domestic regulatory authority enacted in response to information from the FAA and supplier testing.

The AD directly affects three categories of parties named or implied in the directive text: operators (aircraft owners and operators) of Model 767-200, 767-300 and 767-300F aircraft identified in Boeing SASB 767-26-0131 dated 24 July 2006; maintenance organisations and technicians who perform inspections and replacements in accordance with the SASB; and parts suppliers and stock controllers who provide or manage inventories of time delay relay P/N TDH6103-1804.

Operators: Aircraft owners and operators of the listed 767 variants must ensure the "general visual inspection" (Requirement 1) is carried out within 24 months of the directive’s effective date. If an operator discovers a suspect relay, they must remove and replace it within 30 days (Requirement 2). Operators are also constrained from installing certain relays as replacement spares (Requirement 3) as of the effective date. These are mandatory operational requirements for continued airworthiness under the directive.

Maintenance organisations and technicians: The AD expressly requires inspection "in accordance with SASB 767-26-0131". That places the SASB’s procedural content and any specified techniques or checkpoints at the centre of the technical work. Maintenance organisations will need access to that SASB and to any later revisions accepted as AMOC by the FAA, and they are responsible for carrying out inspections and replacements to those specifications.

Parts suppliers and inventory managers: The prohibition in Requirement 3 that relays with date codes 0000-0343 lacking an additional "T" code may not be installed as replacement spares means procurement and inventory policies must account for those date codes. Suppliers selling replacement spares to affected operators must ensure relays supplied are either outside the specified date range or carry the additional "T" marking indicating supplier testing or rework status. This affects forward stocking and supply choices.

Regulatory and oversight entities: CASA (the delegate signed the directive) is the issuing authority. The AD also references the FAA and FAA AD 2007-23-08 and links acceptance of later SASB revisions to FAA approval as an AMOC. Therefore, US FAA approvals and Boeing SASB revisions are relevant to compliance paths and acceptable methods of compliance under this AD.

The directive does not include explicit cost or compensation language. Consequently, the financial burden of inspection, replacement, and compliance falls to operators and maintenance providers unless separate arrangements exist outside the text. The AD also does not specify exemptions or alternative enforcement mechanisms other than the FAA-approved AMOC route for later SASB revisions.

The directive imposes three clear duties on operators and maintenance personnel, with limited procedural discretion tied to the SASB and to FAA AMOC approvals.

Duty 1 , Inspect: Operators must carry out a general visual inspection of relay P/N TDH6103-1804 (K826) in the main equipment centre to determine the relay’s date code as per SASB 767-26-0131 dated 24 July 2006. The compliance window is explicit: "For Requirement 1 - Within 24 months after the effective date of this Directive." This duty is procedural and requires adherence to the SASB’s inspection method rather than a free-form check.

Duty 2 , Replace if found: If the inspection reveals a relay manufactured during the date range specified in the SASB, operators must replace the relay. Replacement options are specified: replace with a relay not manufactured during that date range, or with a relay tested by the supplier and found to be unaffected by thermal expansion. The directive requires this replacement "in accordance with the SASB." The compliance window is strict: "For Requirement 2 - Within 30 days after finding a relay manufactured during the date range specified in the ASAB [sic]." The wording imposes a prompt remedial duty once a suspect component is located.

Duty 3 , Prohibit certain spares: As of the directive’s effective date, relays P/N TDH6103-1804 with a date code between 0000 and 0343 that do not have an additional date code with the letter "T" "may not be installed on any aeroplane as a replacement spare." This is a forward-looking prohibition on installation of specific parts as spares, not merely in-service parts. It affects procurement and maintenance practice.

Rights and alternative compliance: The directive recognises an alternative compliance pathway tied to FAA approvals. It states that "Later revisions of the above SASB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2007-23-08, are considered acceptable for compliance with the equivalent Requirements of this Directive." That gives operators and maintenance organisations the right to comply with later-revised SASBs if those revisions are accepted as AMOCs by the FAA to the referenced FAA AD. The right is conditioned upon FAA approval; the AD does not grant CASA discretion to accept non-FAA-approved revisions in lieu of the SASB. The SASB’s date and FAA AMOC linkage both serve as gating mechanisms for acceptable methods of compliance.

Procedural linkage and limits: The AD ties performance standards to Boeing’s SASB and the FAA’s AMOC process. It therefore delegates significant detail on inspection technique and acceptable replacement parts to those external documents and approval processes. The directive itself does not supply technical steps beyond directing compliance with the SASB and the replacement/prohibition rules. It does not, in the text, establish an appeal or exemption mechanism, nor does it state penalties or the legal consequence of non-compliance within the AD text provided.

The text of the directive specifies required actions and compliance windows, but it does not include explicit penalty provisions or enforcement procedures within the content provided. The directive states the effective date, compliance deadlines for each requirement, and is signed by the Delegate of the Civil Aviation Safety Authority (CASA). From the document itself, enforcement is implied by its nature as an airworthiness directive issued under CASA authority, but the directive text does not set out fines, criminal sanctions, or a schedule of administrative penalties.

Constrained content of the instrument: The directive contains specific mandatory actions and deadlines: inspection within 24 months; replacement within 30 days of finding a suspect relay; and immediate prohibition on installing certain replacement spares from the effective date. Those imperatives imply that an aircraft not meeting these requirements would not be in compliance with this AD. Airworthiness directives are typically enforced through the airworthiness/regulatory framework, but the AD text here does not articulate enforcement mechanisms such as grounding rules, airworthiness certificate conditions, or administrative fines. The document is silent on whether CASA will require proof of compliance, inspection reports, or entry into aircraft maintenance records beyond "in accordance with SASB" techniques.

Relation to issuing authority: The AD is issued by CASA (signature by Charles Lenarcic, Delegate of CASA, dated 10 December 2007), establishing the regulator as the decision-maker for the directive itself. The AD references FAA AD 2007-23-08 and allows FAA-approved AMOCs for later SASB revisions. That relationship indicates FAA determinations play a role in acceptable compliance methods; however, responsibility for enforcement within Australia rests with CASA under its enabling aviation safety framework, though no enforcement language is present in the text.

Operational consequence implied: While the AD does not state penalties, failure to comply with a mandatory AD will typically have operational consequences for operators in the aviation regulatory system, potentially affecting an aircraft’s continuing airworthiness status and its legal ability to be flown. The AD does not itself specify administrative steps such as notifications, record-keeping requirements, or validation checkpoints. Any enforcement actions beyond identifying the directive and setting deadlines would derive from the broader regulatory framework and enforcement policies of CASA, not from the AD text provided.

The AD explicitly references and links to an FAA airworthiness directive and to Boeing service documentation, creating an interaction between domestic regulatory action and overseas regulatory approvals and manufacturer service material. The directive notes "Note: FAA AD 2007-23-08 Amdt 12524 refers." It further provides that "Later revisions of the above SASB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2007-23-08, are considered acceptable for compliance with the equivalent Requirements of this Directive." This creates a procedural dependency on the FAA’s AMOC process and on Boeing’s SASB revisions: CASA accepts FAA-recognised AMOCs tied to the FAA AD as meeting the domestic directive’s equivalent requirements.

Manufacturer documents: The AD makes the Boeing SASB 767-26-0131 dated 24 July 2006 the operative technical document for inspection and replacement procedures. That places the SASB’s technical content (scope, inspection method, acceptable replacements, testing criteria) into the compliance chain. If Boeing issues later SASB revisions and the FAA accepts them as an AMOC to the relevant FAA AD, those later SASB revisions can be used to comply with this CASA directive. The AD does not provide for use of any other manufacturer documents or revisions unless they receive FAA AMOC status.

Bilateral regulatory interaction: The AD shows direct regulatory interaction between CASA and the FAA without laying out the statutory basis for CASA’s acceptance of FAA AMOCs. It accepts FAA AMOCs as a mechanism to validate later SASB revisions for Australian compliance purposes. This means an FAA-approved AMOC can substitute for the SASB version specified in the directive, creating a cross-jurisdictional compliance pathway.

Absence of other statutory references: The AD text does not reference other domestic aviation regulations, civil penalty provisions, or details about how compliance must be recorded against the aircraft maintenance log. The instrument’s interaction with domestic legal regimes for enforcement, record-keeping, or administrative consequence is therefore not described in the AD itself; those interactions will be governed by the broader CASA regulatory framework and any applicable domestic aviation safety legislation outside the text provided.

Technical-standard anchoring: The AD anchors a domestic maintenance duty to a foreign regulator's AD and to manufacturer service material, which creates a chain of reliance: CASA enacts the domestic directive; compliance is performed against Boeing SASB content; FAA approval of later SASB revisions as AMOC validates substitution. That interaction assigns functional decision-making on acceptable alternative methods of compliance to the FAA’s AMOC process, not to CASA within the text of this AD.

The directive itself contains limited amendment information. It cites the Boeing Special Attention Service Bulletin (SASB) 767-26-0131 dated 24 July 2006 as the basis for applicability and inspection procedures. It expressly allows for "Later revisions of the above SASB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2007-23-08, [to be] considered acceptable for compliance with the equivalent Requirements of this Directive." That sentence is the only statement in the AD about amendments to the technical material referenced.

There is no document history of revisions to AD/B767/234 contained in the text provided. The AD records dates relevant to its issuance and effect: the directive is signed by Charles Lenarcic, Delegate of the Civil Aviation Safety Authority, on 10 December 2007, and the AD becomes effective on 14 February 2008. The AD references FAA AD 2007-23-08 Amendment 12524, indicating an external FAA amendment that is relevant to this directive’s context.

The AD does not set out a process by which CASA will itself amend or revoke AD/B767/234 in the future, nor does it list prior versions of this domestic directive. It does not enumerate transitional arrangements beyond the compliance deadlines provided, and it provides no internal schedule for CASA-driven amendment. The only explicit mechanism for changing the operative technical compliance document is through Boeing SASB revisions that are approved by the FAA as AMOC to the FAA AD; such FAA-approved SASB changes will be treated as acceptable for compliance with the equivalent requirements of this directive.

Because the AD ties acceptable future technical revisions to FAA AMOC approvals, the practical amendment path for acceptable compliance material runs through the FAA’s regulatory processes and Boeing’s service bulletin revisions. The AD does not indicate whether CASA would independently accept alternative methods of compliance or issue its own AMOC pathway separate from FAA approvals.

The directive text does not reference any litigation, judicial decisions, or dispute history relating to AD/B767/234. There is no mention within the document of legal challenges, administrative appeals, or precedent decisions. The background provides factual context for why the AD was issued (FAA notification of a time delay relay failure on a Boeing Model 777 and subsequent testing), but it does not identify any court or tribunal proceedings concerning the relay issue, the FAA AD, Boeing’s SASB, or CASA’s issuance of this directive.

Given the absence of litigation references in the AD, there is no record in the text of contested interpretations, judicial reviews, or enforcement actions adjudicated in courts arising from this specific directive. Any litigation history that might exist outside the text provided is not within the scope of this directive as presented.

Operators and maintenance organisations considering the legal enforceability, appeal routes, or potential for contested administrative action would need to consult the broader CASA administrative procedural framework and relevant aviation safety legislation for information on how airworthiness directives may be challenged or how enforcement decisions are reviewed. None of that framework or any related case law is cited or summarised in the AD text supplied.

The directive contains a number of operational specifics and linkages that can create compliance pitfalls if overlooked.

Precise part number and location: The relay in question is P/N TDH6103-1804, identified as time delay relay K826, located in the main equipment centre. The AD requires a "general visual inspection" of that specific relay in that location "in accordance with SASB 767-26-0131." A superficial or incorrectly scoped inspection that does not follow the SASB could fail to identify relevant date codes or markings.

Date-code nuance: Requirement 3 prohibits installing as a replacement spare any relay P/N TDH6103-1804 that has a date code between 0000 and 0343, "and does not have an additional date code with the letter 'T'." That creates two distinct markers: (a) a date-code numeric range that is suspect; and (b) the presence of an additional date code with a "T" which, if present, negates the prohibition. Inspectors must be trained to recognise both the numeric and the additional alphanumeric code. Missing the "T" marking or misreading date codes could lead to non-compliant installations.

Compliance windows differ by action: Requirement 1 must be completed within 24 months of the effective date. Requirement 2 must be completed within 30 days of finding a relay within the specified date range. Requirement 3 is effective immediately at the effective date. Mixing up these timeframes or assuming a single compliance window across all requirements could create violations.

Reliance on the SASB and FAA AMOC: The AD mandates following SASB 767-26-0131 dated 24 July 2006 for the inspection. It also permits later SASB revisions if approved by the FAA as an AMOC to FAA AD 2007-23-08. Operators who treat any later SASB revision as acceptable without verifying FAA AMOC approval may not be complying with this directive. The AD does not permit unilateral acceptance of later SASB revisions absent FAA AMOC endorsement.

Supply and spares management: Requirement 3 effectively makes certain relays unusable as replacement spares. Operators maintaining inventory levels of P/N TDH6103-1804 must ensure relays with date codes 0000-0343 lacking the "T" marking are segregated and not used. If an operator inadvertently installs such a relay under maintenance pressure, they would be in breach of the AD. The AD does not provide guidance on disposition of prohibited spares,whether they may be returned, reworked, or scrapped,beyond the SASB and supplier testing route; operators must consult the SASB and supplier for disposition procedures.

Ambiguity in the AD text: There is a minor typographical inconsistency in the AD text where "ASAB" appears instead of "SASB" in the compliance line for Requirement 2. Practitioners should read the directive in context and follow SASB 767-26-0131 as cited elsewhere in the AD.

No explicit enforcement or recordkeeping language: The directive does not include explicit instructions on documentation or proof-of-compliance submissions. Operators must rely on the broader CASA recordkeeping and maintenance regulation framework to determine how to evidence compliance. Failure to maintain adequate records of inspections and replacements could complicate demonstrating compliance, even though the AD itself does not specify recordkeeping steps.

Difference in aircraft models and serials: The AD applies only to Model 767-200, 767-300 and 767-300F series aeroplanes "as identified in Boeing SASB 767-26-0131." That means not all 767-200/300/300F airframes will necessarily be captured; practitioners should verify applicability against the SASB's serial-number lists or identification criteria rather than assuming all 767-200/300 series aircraft are automatically subject.

Stepwise compliance actions, drawn directly from the directive text and linked to the SASB, are as follows.

1. Confirm applicability: Consult Boeing SASB 767-26-0131 dated 24 July 2006 to confirm whether each aeroplane in your fleet (Model 767-200, 767-300, 767-300F) is identified by the SASB as within the AD’s applicability. The AD’s applicability is explicitly tied to the SASB, so do not assume applicability without consulting the SASB list or criteria.

2. Schedule the inspection: For affected aeroplanes, schedule and perform a general visual inspection of the time delay relay P/N TDH6103-1804, K826, in the main equipment centre "in accordance with SASB 767-26-0131." The AD requires Requirement 1 to be completed "within 24 months after the effective date of this Directive." Document the inspection method and findings consistent with your maintenance recordkeeping obligations.

3. Identify date codes and markings: During the inspection, determine the relay manufacture date code. Pay attention to whether the relay carries a date code between 0000 and 0343, and whether it has an additional date code bearing the letter "T." These markings determine whether replacement or prohibition applies.

4. Replace when required: If the inspection shows the relay was manufactured during the date range specified in the SASB, replace it "in accordance with the SASB" either with a relay not manufactured during that date range, or with a relay that has been tested by the supplier and found to be unaffected by thermal expansion. The AD requires replacement "within 30 days after finding a relay manufactured during the date range specified in the [SASB]." Ensure replacement parts conform to SASB specifications and supplier testing documentation where applicable.

5. Do not install prohibited spares: As of the effective date of the AD, do not install as a replacement spare any P/N TDH6103-1804 relay that has a date code between 0000 and 0343 and does not have an additional date code with the letter "T." Review spares inventories, tag or segregate prohibited items, and update procurement specifications to avoid acquiring prohibited relays.

6. Use approved SASB revisions as applicable: If Boeing issues later revisions of SASB 767-26-0131 and the FAA approves those revisions as an AMOC to FAA AD 2007-23-08, those later revisions are acceptable for compliance with the equivalent requirements of this directive. To rely on a later SASB revision, confirm the FAA AMOC approval status and document that approval in maintenance records as the basis for following the revised SASB procedures.

7. Liaise with supplier for testing evidence: If choosing to replace with a relay "tested by the supplier and found to be unaffected by thermal expansion," obtain and retain supplier test documentation that demonstrates the relay’s acceptability for the purpose specified in the SASB. The AD ties acceptability to supplier testing per the SASB; keep supplier certificates or test reports in aircraft maintenance records.

8. Maintain records consistent with regulatory practice: Although the AD itself does not specify recordkeeping steps, maintain records of inspections, findings, replacements, parts installed (including part numbers and date codes), supplier test reports, and any FAA AMOC approvals relied upon. These records will be necessary to demonstrate compliance under regulatory oversight.

9. Train maintenance personnel on marking recognition: Ensure maintenance personnel are aware of the specific date-code formatting (numeric codes and the additional "T" marking) and of the precise prohibition language. Training reduces risk of misidentifying a part as compliant when it is not.

10. Coordinate with procurement and logistics: Update purchasing specifications and spare parts inventory procedures to ensure prohibited relays are not ordered or installed. Communicate with parts suppliers to confirm that relays supplied for replacement are either outside the suspect manufacturing date range or accompanied by supplier testing evidence per the SASB.

11. Monitor FAA and Boeing communications: Track FAA AD 2007-23-08, FAA AMOCs, and Boeing SASB revisions relevant to SASB 767-26-0131. The AD allows later SASB revisions approved by the FAA as AMOC to be used for compliance; operators relying on updated procedures must verify FAA AMOC status before applying later SASB revisions.

Following these steps aligns actions with the directive’s three requirements and with the SASB reference, and ensures a documented chain from identification to remediation consistent with the AD’s text.