AD/B727/210 - Auxiliary Fuel Tank Systems

The AD is built from a small set of discrete concepts and cross‑references that determine its operational effect.

Applicability: The AD applies only to Boeing 727 aeroplanes that have been modified with the listed FAA STCs. The table in the Applicability section maps aircraft model to STC number and STC holder. The AD therefore does not, on its face, apply to unmodified 727s or 727s modified under other STCs. That mapping is the primary delimitation of affected fleet (Applicability).

Deactivation obligation: The core mandatory act is deactivation of the auxiliary fuel tank system. The AD does not prescribe detailed technical steps itself; instead, it requires the owner/operator to implement "a deactivation procedure approved by the Manager" of a specific FAA ACO. For SA1350NM that authority is the FAA Wichita ACO; for ST0158AT, SA2033NM and SA1474SO, it is the FAA Atlanta ACO (Requirement, paragraphs a and b). The AD thus delegates substantive technical approval to designated FAA managers rather than setting the engineering method in the text.

Residual condition constraints: After deactivation, any remaining auxiliary fuel tank system components must be secured and must "have no effect on the continued operational safety and airworthiness of the aeroplane." The AD also expressly provides that deactivation "may not result in the need for additional Instructions for Continued Airworthiness (ICA)" (Requirement). These constraints are operational limits on acceptable deactivation procedures.

Cross‑references to FAA ADs and technical contacts: Note 2 points the reader to FAA AD 2008‑07‑07 Amdt 39‑15448 and FAA AD 2008‑07‑09 Amdt 39‑15450, indicating related regulatory action by the FAA; Note 1 gives contact names, addresses and telephone/fax details for the STC holders who can provide technical information. The AD therefore functions in a transnational regulatory context: CASA issues the AD but directs operators to FAA‑approved procedures and to US STC holders for technical information.

Temporal requirements and authority: The AD becomes effective on 5 June 2008 and requires compliance by 12 December 2008 (Compliance). It is signed by a CASA delegate (James Coyne), indicating the issuing authority. The Background section states the safety rationale as stemming from manufacturer fuel tank system reviews to prevent ignition sources in fuel tanks (Background).

Taken together, the main concepts are (1) targeted applicability based on STC installation, (2) mandatory deactivation executed under FAA ACO‑approved procedures, (3) constraints on residual components and continued airworthiness documentation, (4) reliance on STC holders for technical data, and (5) specified effective and compliance dates. The AD therefore creates a narrow, time‑bound obligation for aircraft operators to eliminate auxiliary fuel tank systems in a prescribed manner, with technical approval allocated to specific FAA certification offices rather than contained within the CASA text itself.

The AD explicitly targets a defined set of stakeholders by technical configuration, and implicitly affects a further set of parties involved in the modification, maintenance and regulatory approval chain.

Primary affected parties are owners and operators of Boeing 727 series aeroplanes that have been modified with one of the listed FAA STCs. The Applicability table identifies the models and STCs: 727‑200 with STC SA1350NM (DTAA, Inc); 727‑100 with STC ST0158AT (Southeast Aero‑Tec, Inc); and 727‑200 & ‑200F with STCs SA2033NM & SA1474SO (Southeast Aero‑Tec, Inc). If an operator's aeroplane has any of those STCs installed, the owner/operator is subject to the deactivation requirement and the compliance timeframe. If the STC is not installed, the AD's requirements, on their face, do not apply.

Secondary affected parties include the STC holders themselves. The AD lists contact details for DTAA, Inc and Southeast Aero‑Tec, Inc for technical information (Note 1). Those entities are placed as the repository of technical information about the auxiliary fuel tanks; operators will likely need to engage them to obtain required technical detail or drawings necessary for deactivation. The AD does not state an explicit duty on the STC holder to provide assistance, but it directs operators to those contacts.

Regulatory and technical approvers are also affected. The AD requires deactivation "in accordance with a deactivation procedure approved by the Manager, FAA Wichita Aircraft Certification Office (ACO)" for SA1350NM, and "approved by the Manager, FAA Atlanta ACO" for the other listed STCs (Requirement, a and b). That assigns decision‑making authority for the acceptability of deactivation procedures to those FAA ACO managers. Those FAA officials thus become gatekeepers of the permissible technical method. CASA, through the AD and the signature of its delegate, sets compliance obligations and dates; it is the issuing authority.

Maintenance organisations, licensed engineers and contracted technicians are operationally affected because they must implement the deactivation in line with the approved procedure and ensure any residual components are secured and do not affect operational safety. The AD's constraint that deactivation not produce the need for additional ICA affects maintenance planning and documentation workloads.

Finally, the AD references FAA ADs (Note 2). Regulators, registries and technical records personnel who manage continuing airworthiness may need to reconcile the CASA AD action with the FAA ADs cited. In summary, the AD affects aircraft owners/operators (who pay for and commission the work), the STC holders (as technical data sources), FAA ACO managers (who approve procedures), maintenance providers (who implement deactivation), and CASA staff (who issued the directive and will record compliance).

The AD sets out a small number of clear duties and practical rights, as expressed in its text.

Duties

• Deactivate the auxiliary fuel tank system: For each aeroplane to which the AD applies, the owner/operator must deactivate the auxiliary fuel tank system in accordance with an approved deactivation procedure. The approval must be given by the Manager of a specified FAA ACO: Wichita ACO for SA1350NM; Atlanta ACO for ST0158AT, SA2033NM and SA1474SO (Requirement, a and b).

• Secure remaining components and preserve airworthiness: Any components of the auxiliary fuel tank system that remain on the aeroplane after deactivation must be secured and "must have no effect on the continued operational safety and airworthiness of the aeroplane" (Requirement).

• Avoid creating additional ICA requirements: The prescribed deactivation must not result in the need for additional Instructions for Continued Airworthiness (ICA). That is, the deactivation method must be performed so as not to impose new continuing airworthiness instructions (Requirement).

• Adhere to compliance timing: The AD prescribes an effective date and a compliance deadline: The AD becomes effective on 5 June 2008 and requires action no later than 12 December 2008 (Compliance).

Rights and procedural positions

• Right to follow an FAA‑approved procedure: The AD expressly requires deactivation "in accordance with a deactivation procedure approved by the Manager, FAA [designated ACO]." That gives operators a procedural right to rely on the recognised FAA ACO manager's technical approval, rather than a CASA‑specified method in the AD text (Requirement). The AD therefore channels technical discretion to those FAA managers.

• Access to STC holder technical information: Note 1 supplies named contacts at the STC holders with telephone and fax details, indicating operators can seek technical information from the entities that installed or designed the auxiliary fuel tank systems. While the AD does not create a statutory duty on the STC holders to provide assistance, the presence of contact details operates as an implied route for obtaining technical data (Note 1).

• Cross‑reference to FAA ADs: Note 2 lists FAA AD numbers that "refer" (Note 2). Operators have the right, and logical obligation, to consult those FAA ADs for the detailed technical and regulatory background pertinent to FAA‑approved deactivation procedures.

What the AD does not say

• The AD does not set out penalties, enforcement steps or civil/regulatory sanctioning mechanisms in its text. It also does not provide a step‑by‑step technical deactivation methodology; instead it delegates approval of the method to specific FAA ACO managers (Requirement; Compliance).

Operational consequences of the duties and rights

• The duty to secure remaining components and to avoid new ICA requirements places a technical constraint on the chosen deactivation procedure. In practical terms, an operator must procure or obtain a procedure that both disables the auxiliary fuel tank system and leaves the aeroplane in a state that does not require additional maintenance instructions for continuing airworthiness. Because the AD requires FAA ACO manager approval, the operator must coordinate with the relevant FAA ACO to obtain that approval or an FAA‑approved procedure, and may also need to engage the STC holder for technical inputs (Requirement; Note 1).

The AD text itself does not set out specific penalties, fines, or the enforcement mechanisms that CASA will deploy for non‑compliance. The document contains the compliance timeline and is signed by a CASA delegate; it does not, in the published text provided, describe a sanction regime, civil penalty amounts, administrative processes for enforcement, or criminal liability for failure to comply.

What the AD does provide, and thus what can be used operationally to infer enforcement touchpoints from the text, is:

• A clear compliance deadline and effective date: the AD becomes effective on 5 June 2008 and requires compliance by 12 December 2008 (Compliance). Those dates establish the temporal requirement CASA expects operators to meet.

• A delegating of technical approval to specified FAA ACO managers: the deactivation must be done "in accordance with a deactivation procedure approved by the Manager" of the specified FAA ACOs (Requirement). That creates a compliance standard: the procedure must be FAA‑ACO‑approved.

Because the AD text does not expressly detail enforcement processes, readers relying on this AD must note that the instrument nevertheless creates an airworthiness obligation against which CASA or another competent authority could take action, even if those enforcement steps are not set out in the text. The AD’s signature by a CASA delegate indicates it is an official regulatory instrument issued by CASA (signed James Coyne, Delegate of the Civil Aviation Safety Authority, dated 21 April 2008). The presence of compliance dates and explicit technical approval requirements establishes the normative standard of conduct.

Practical enforcement implications (grounded on the AD text)

• Compliance verification: Organisations charged with continuing airworthiness recordkeeping and oversight would use the AD’s compliance date and approval requirement as a criterion when reviewing maintenance records or airworthiness status. The AD requires the deactivation to be done according to an FAA‑approved procedure and to ensure no residual components affect operational safety. Those conditions provide a measurable line for verifying compliance: whether an FAA‑approved deactivation procedure exists on the aircraft’s technical records and whether the aircraft’s configuration after deactivation meets the specified constraints.

• Cross‑jurisdictional coordination: The AD points to FAA ADs and requires FAA ACO approval. Operational enforcement may therefore involve communication between CASA and FAA certification offices or reliance on documentation produced by FAA authorities to evidence compliance.

Limitations of the source

• Since the AD does not specify penalty provisions, practitioners should consult the broader regulatory regime, CASA enforcement policies and relevant aviation safety legislation for the precise enforcement tools and remedies available to CASA. That information is not contained in the AD text provided. The AD itself sets normative technical requirements and a deadline but omits express enforcement mechanics in its published content.

The text of the AD explicitly cross‑references FAA instruments and FAA certification authorities, indicating the AD is designed to operate in a transnational regulatory space where CASA action is informed by or aligned with FAA action.

References to FAA STCs and FAA ACOs: The AD applies to auxiliary fuel tank systems installed under United States FAA Supplemental Type Certificates (STCs). It directs that deactivation be performed "in accordance with a deactivation procedure approved by the Manager, FAA Wichita Aircraft Certification Office (ACO)" for STC SA1350NM, and by the Manager, FAA Atlanta ACO for STCs ST0158AT, SA2033NM and SA1474SO (Requirement). By requiring FAA ACO approval, CASA’s AD delegates substantive technical approval to named FAA certification officials rather than prescribing the engineering solution itself.

Cross‑reference to FAA ADs: Note 2 in the AD explicitly states that FAA AD 2008‑07‑07 Amdt 39‑15448 and FAA AD 2008‑07‑09 Amdt 39‑15450 "refer." This is an affirmative link to parallel FAA regulatory action addressing the same technical concern. The AD therefore does not exist in isolation; operators must consider both CASA’s AD and the referenced FAA ADs when establishing compliance.

Implications for Australian regulatory frameworks: The document is a CASA Airworthiness Directive; however, the AD text does not quote or rely upon any specific Australian Civil Aviation Regulations or mention national statutory provisions. It establishes an airworthiness obligation via CASA's administrative instrument but does so by aligning the technical approval process with FAA certification office decisions and by pointing operators to FAA AD references. The AD therefore creates a practical interaction where compliance with CASA’s requirement involves obtaining approvals or procedures from FAA bodies and consulting FAA ADs.

Interaction with technical documentation and Instructions for Continued Airworthiness: The AD contains the constraint that deactivation "may not result in the need for additional Instructions for Continued Airworthiness (ICA)" (Requirement). That places the AD in direct operational relation to the continuing airworthiness documentation regime: a deactivation that created new ICA obligations would be disallowed by the AD. This interaction affects maintenance documentation and could therefore intersect with any regulatory requirements for updating or issuing ICAs under applicable continuing airworthiness rules, though the AD does not itself specify those other rules.

Cross‑border administrative coordination: By instructing reliance on FAA ACO approvals and by citing FAA ADs, the AD operationalises a coordination mechanism between CASA and FAA technical authorities: CASA issues the directive to Australian operators, but the technical procedural approval is to come from named FAA certification managers. This is an interaction at the administrative level between two national aviation safety authorities as expressed in the AD text.

Limitations in the AD text concerning other laws: The AD does not detail how it interacts with Australian civil liability rules, contractual obligations, airworthiness certification processes beyond the deactivation requirement, or specific enforcement or administrative appeal mechanisms. Those legal interactions are not described within the AD as provided. Practitioners should therefore treat the AD’s content as imposing the specific technical and timing obligations described, but must consult the broader statutory and regulatory framework for precise interactions with enforcement processes, certification consequences, and rights of appeal or review.

The AD text provided contains a single dated instrument identifier and associated dates; it does not include an internal amendment record or history of prior versions within the text supplied.

Key temporal entries present in the AD text:

• AD identifier and date code: The document is labelled AD/B727/210 and "6/2008" appears repeatedly beside the title "Auxiliary Fuel Tank Systems", indicating the AD was issued in mid‑2008 or corresponds to the 6/2008 release cycle.

• Signature and issuance date: The AD bears the signature of James Coyne, Delegate of the Civil Aviation Safety Authority, dated 21 April 2008. That records the administrative act of issuance.

• Effective date: The AD states it "becomes effective on 5 June 2008" (Compliance).

• Compliance deadline: The AD requires deactivation "No later than 12 December 2008" (Compliance).

• Cross‑references to FAA ADs: Note 2 states "FAA AD 2008‑07‑07 Amdt 39‑15448 and FAA AD 2008‑07‑09 Amdt 39‑15450 refer." Those FAA ADs likely contain the FAA amendment history for related FAA actions, but the CASA AD text does not recount any subsequent amendments to the CASA AD itself.

The AD as provided does not document any amendments, revocations, supersessions or follow‑up CASA ADs. There is also no mention of earlier CASA instruments that this AD replaces or modifies. If a practitioner needs the full amendment history (for example to determine whether the AD was later superseded, extended, varied, or withdrawn), that information is not in the AD text supplied and must be sought from CASA records or an official AD database. The document as published simply establishes the AD, the effective date, the compliance deadline and the administrative signature, without an embedded amendment log.

Given the compliance date is in 2008, this AD should be treated as a historical instrument in the absence of amended text in the source. However, the AD itself does not record whether its obligations remain extant for aircraft still configured with the listed STCs where deactivation was not completed by the deadline. That inference falls outside the provided text. For an authoritative amendment history, consult CASA's official AD registers and any FAA documents cited in Note 2.

The AD text supplied contains no references to litigation, judicial review, administrative appeals, or court proceedings connected to this particular directive. It does not cite any cases, complaints, appeals to tribunals, or recorded disputes over the content or application of AD/B727/210.

Absence of litigation references in the instrument means the AD, as published in the supplied text, does not document any legal challenges. It also does not identify or reference any prior adjudicated decisions that might interpret AD obligations, or provide precedent on enforcement. The AD is drafted as a technical safety instrument rather than as a judgment or adjudicative decision and therefore contains no litigation history within its text.

Practitioners requiring information on any litigation or administrative review arising from this AD will need to search external records , for example, CASA administrative records, tribunal or court databases, or industry reports for disputes about deactivation requirements, costs, or the administrative process of approving deactivation procedures. None of those records are contained in the AD text provided, so no further claims about litigation can be made from the source alone.

The AD is concise, but there are several specific operational and legal details in the text that can catch operators unprepared if not read carefully. These items are grounded directly in the AD text.

Narrow applicability: The AD applies only to aeroplanes modified in accordance with the named FAA STCs. It does not apply to all Boeing 727s or to auxiliary fuel tanks installed under different approvals. Operators should not assume broad applicability , they must confirm whether the specific STC number is present on the aircraft's modification records. The Applicability table lists STC numbers and STC holders for each aircraft model, so validation against the aircraft's records is essential.

Delegation of technical approval: The AD does not supply a technical deactivation method; it mandates that deactivation be done in accordance with a deactivation procedure approved by the Manager of a specified FAA ACO. For SA1350NM that is the Manager, FAA Wichita ACO; for other listed STCs it is the Manager, FAA Atlanta ACO (Requirement, a and b). Operators must therefore secure an FAA‑approved procedure, not merely rely on internal maintenance judgement. Failure to obtain that approval may leave an operator without a conforming record of compliance.

Two different FAA ACOs: Different STCs require approval from different FAA ACOs. If an aircraft has multiple STCs or mixed modifications, operators must be careful to get approval from the correct FAA ACO for the relevant STC. The AD assigns the approval authority by STC, not by operator jurisdiction or CASA.

Residual components constraint and ICA prohibition: The AD requires that any component left on the aeroplane "must be secured and must have no effect on the continued operational safety and airworthiness of the aeroplane" and that "Deactivation may not result in the need for additional Instructions for Continued Airworthiness (ICA)" (Requirement). That second phrase can be read strictly: if a deactivation approach would create a new requirement for ICAs, that approach is disallowed. Operators must ensure the chosen deactivation method leaves the aeroplane in a state where no new ICA is required. That can reduce available technical options.

Contacts are US‑based: Note 1 lists US contacts for technical information (DTAA, Inc and Southeast Aero‑Tec, Inc) with US telephone and fax numbers. Operators and maintenance organisations outside the US will need to coordinate across time zones and possibly with differing administrative practices. The AD effectively directs Australian operators to US technical resources.

Cross‑reference to FAA ADs: Note 2 cites FAA ADs 2008‑07‑07 and 2008‑07‑09. The CASA AD "refers" to those FAA ADs, so a complete picture of required technical action may require consulting those FAA documents. Operators should not assume the CASA AD text alone contains all necessary technical detail.

Deadlines already passed: The AD’s compliance deadline is 12 December 2008 and it becomes effective on 5 June 2008. For present‑day recordkeeping and continuing airworthiness assessments, operators should verify whether compliance was completed and properly documented at the time. The AD text does not state consequences for late or non‑completion. If an aircraft still retains an affected auxiliary fuel tank system after the compliance date, the AD text does not itself explain whether additional steps (or subsequent CASA instruments) apply; practitioners must consult CASA records.

No penalties listed in the AD: The AD does not set out enforcement or penalty mechanisms in its text. Operators should not read that absence as absence of enforcement authority in general; rather note that enforcement detail is not in the AD itself.

STC‑specific procedural variance risk: Because approval is by different FAA ACO managers, the specific acceptable deactivation procedures may differ by STC. Operators with multiple affected aircraft may face different technical procedures, approvals and recordkeeping obligations. Ensure recordkeeping associates the correct FAA ACO approval documentation with the specific aircraft and STC.

The AD sets a limited but concrete compliance pathway. The following steps are grounded in the AD text and the practical implications of its requirements.

1. Confirm applicability: Review the aircraft’s modification records to determine whether the auxiliary fuel tank system was installed under one of the STCs listed in the Applicability table: SA1350NM (DTAA, Inc) for certain 727‑200s; ST0158AT (Southeast Aero‑Tec, Inc) for 727‑100s; SA2033NM and SA1474SO (Southeast Aero‑Tec, Inc) for 727‑200 and 727‑200F (Applicability). Do not assume model identity alone; the AD applies by STC installation.

2. Identify the approving FAA ACO: For aircraft modified under SA1350NM, the required approving authority is the Manager, FAA Wichita ACO; for aircraft modified under ST0158AT, SA2033NM or SA1474SO, the approving authority is the Manager, FAA Atlanta ACO (Requirement, a and b). Prepare to liaise with the correct FAA office for procedure approval.

3. Obtain or develop a deactivation procedure and secure FAA ACO approval: The AD requires deactivation "in accordance with a deactivation procedure approved by" the relevant FAA ACO Manager. Operators should either obtain an FAA‑approved procedure (for example from the STC holder or FAA) or arrange for a proposed deactivation procedure to be submitted to the designated FAA ACO manager for approval. Ensure the documentation evidencing FAA ACO approval is preserved in the aircraft’s technical records to demonstrate compliance.

4. Validate residual condition and ICA impact: Any auxiliary fuel tank components that remain after deactivation "must be secured" and must not affect operational safety or airworthiness. Additionally, deactivation "may not result in the need for additional Instructions for Continued Airworthiness (ICA)" (Requirement). Before executing the procedure, confirm that the method will leave the aircraft in a stable configuration that does not require new ICA publications or continuing maintenance obligations. If the proposed deactivation would necessitate changes to ICAs, the method must be revised because the AD disallows producing new ICA needs.

5. Engage STC holders for technical information where necessary: The AD provides contact details for DTAA, Inc and Southeast Aero‑Tec, Inc for technical information (Note 1). Operators should contact those entities for design data, drawings or technical guidance that will be relevant to either obtaining an FAA‑approved deactivation procedure or documenting the deactivation work. Capture correspondence and technical data from the STC holders as part of the compliance record.

6. Consult related FAA ADs for technical background: The AD "refers" to FAA AD 2008‑07‑07 Amdt 39‑15448 and FAA AD 2008‑07‑09 Amdt 39‑15450 (Note 2). Those FAA ADs likely contain the technical analysis and, in some cases, prescribed actions that informed the FAA ACO’s approach. Operators should obtain and review those FAA ADs in order to understand the technical rationale and any detailed requirements that might be incorporated into the FAA‑approved deactivation procedure.

7. Complete the deactivation within the compliance period and document it: The AD requires completion "No later than 12 December 2008" and becomes effective 5 June 2008 (Compliance). Although these dates are historical, for compliance records practitioners should ensure the deactivation was completed by the deadline and that appropriate entries, evidence of FAA ACO approval, photographs, maintenance releases and any STC holder documentation are retained in the aircraft’s continuing airworthiness records.

8. Maintain records demonstrating no adverse airworthiness effect: As the AD requires that residual components be secured and not affect airworthiness, maintain evidence , e.g. inspection reports, sign‑offs by appropriately licenced engineers, and statements or approvals from the FAA ACO , that the aeroplane remains airworthy following deactivation and that no additional ICA was required.

9. Audit and reconcile: Where aircraft operating certificates, registries or continuing airworthiness records are reviewed, ensure that the AD‑mandated deactivation and the FAA ACO approval are documented and accessible. If any doubt exists about whether the deactivation produced a need for ICA, or whether the FAA ACO approval covers the actual work performed, seek clarification from the FAA ACO or CASA.

10. Seek regulatory clarification if needed: The AD itself does not set out enforcement mechanisms or administrative appeal routes. If an operator requires clarification on the acceptable form of FAA ACO approval, recordkeeping expectations, or how to document that no ICA changes were necessary, approach CASA for guidance and obtain written confirmation where possible.

These steps follow directly from the AD’s requirements: confirm STC applicability, secure an FAA‑ACO‑approved deactivation procedure, ensure the aircraft is left in a condition that does not affect operational safety or necessitate additional ICA, consult STC holders and FAA ADs for technical information, and record completion by the stated compliance timeline. The AD’s contact details and FAA AD references are tools for meeting those requirements (Applicability; Requirement; Note 1; Note 2; Compliance).