AD/B737/239 Amdt 1 - Engine Fuel Feed System Electrical Bonding

The Directive applies to a defined subset of Boeing 737 family aeroplanes: Model 737-100, -200, -200C, -300, -400 and -500 series aeroplanes that are identified in Boeing Service Bulletin 737-28A1174, Revision 1, dated 18 July 2002. The applicability is not automatically the entire model series; it is limited to the aeroplanes specifically identified in that SB revision. Operators who own, operate, maintain or manage such aeroplanes must ensure compliance. The Directive’s Notes expand who can perform certain preparatory tasks: Note 1 allows operators to use their own CASA-accepted equivalent procedures for draining the fuel tanks and gaining access, which implicates the operator’s maintenance organisation and its CASA approvals or accepted procedures.

Decision-makers within the operator are responsible for signing off that the SB work has been done and that any corrective actions are completed. The Directive does not list individual personnel categories, but the actions will typically be performed by maintenance organisations or authorised engineers working under the operator’s maintenance control. The document also affects maintenance planners, as it prescribes a calendar deadline (Requirement 1 before 12 May 2010) and an operational constraint that any corrective action found during that work must be rectified before further flight (Requirement 2). Those constraints will influence aircraft scheduling and downtime decisions by the operator.

Regulatory actors affected include the Civil Aviation Safety Authority, specifically the CASA delegate who issued the Directive, and indirectly the FAA, because FAA approvals of SB revisions as AMOCs are recognised by the Directive as acceptable compliance paths. Boeing is affected as the SB author and technical provider; later Boeing SB revisions that receive FAA AMOC approval become acceptable compliance mechanisms. The Directive also affects maintenance providers who must be able to follow paragraph 3.B of the SB or CASA‑accepted equivalents for tank draining and access, and who must carry out corrective actions discovered during the mandated work. The Directive’s background and structure make clear that commercial operators pay for the work, and that operational control and timing (when to ground an aeroplane, how long for the work) reside with the operator subject to the Directive’s deadlines.

The Directive sets out two explicit duties. Duty 1 (Requirement 1) is to "Action in accordance with paragraph 3.B. of SB 737-28A1174, Revision 1" (the primary remedial or modification action). Duty 2 (Requirement 2) is to "Carry out any necessary corrective actions on deficiencies detected during the accomplishment of Requirement 1." The timing duties attached are specific: Requirement 1 must be completed before 12 May 2010; Requirement 2 must be completed before further flight after accomplishing Requirement 1. Those temporal duties create a fixed compliance horizon for the primary action and a strict operational constraint for corrective actions detected when doing the primary work.

The Directive recognises some operator rights or flexibilities. It permits operators to use their own CASA‑accepted equivalent procedures to drain fuel tanks and gain access to the tanks (Note 1). It also exempts one marking task in the SB,marking of the forward surface of the front spar in accordance with Figures 1 and 2, Step 18 of the SB,from being required for compliance with the Directive (Note 2). Additionally, actions already performed prior to the Directive’s effective date in accordance with Boeing SB 737-28A1174 dated 20 December 2001 are accepted as compliant (Note 3). Finally, the Directive allows later revisions of the SB to be used provided those revisions have FAA approval as an AMOC to FAA AD 2005-04-01; that creates a pathway for operators to comply using updated Boeing instructions once they are FAA‑approved.

The Directive also allocates decision rights. CASA, via its delegate, issued the Directive; FAA approvals of SB revisions as AMOCs are explicitly accepted by the Directive. That means an operator may rely on FAA AMOC approval when choosing to comply with a later SB revision. Operators therefore have the right to choose compliance via the Boeing SB Rev 1, a prior SB (2001) if already done, or a later SB revision if it has FAA AMOC approval. The operator has the duty to ensure corrective actions are performed before further flight. The Directive does not specify which organisation must perform the actions, but the language and the Note about CASA‑accepted procedures make clear that maintenance organisations performing the work must operate under CASA‑accepted procedures and approvals where applicable.

The Directive is prescriptive about what is required to achieve compliance, but not prescriptive about which specific maintenance organisation must carry out the work. It does not specify documentation requirements in this text, but the reference to a Boeing SB implies the record‑keeping and sign‑off practices customary under SB compliance will be relevant. The Directive does not specify penalties or enforcement measures in its text; it establishes mandatory action, timelines and approved compliance variants, leaving enforcement and certification consequences to the broader regulatory framework.

The Directive text does not specify monetary penalties, infringement provisions, enforcement mechanisms, or explicit certification consequences within the printed content. What the Directive does provide are mandatory actions, a delegate’s signature, and effective dates: it became effective on 19 January 2006, and it provides compliance dates for Requirement 1 (before 12 May 2010) and Requirement 2 (before further flight after accomplishing Requirement 1). The Directive is signed by a CASA delegate, showing it is an enforceable airworthiness instrument issued by the Civil Aviation Safety Authority. The Directive also references FAA AD 2005-04-01 Amdt 39-13973 and permits FAA‑approved AMOCs to be used for compliance, which ties the Directive into a recognised regulatory compliance pathway between CASA and the FAA.

Because the Directive itself does not set out enforcement penalties in the text provided, readers should infer that enforcement and penalties, if any, would be applied under the broader civil aviation regulatory framework administered by CASA rather than by this Directive’s text. The Directive does create mandatory timelines and operational constraints that, if not adhered to, would leave an aircraft in a non‑compliant state with respect to this airworthiness direction. The Directive’s requirement that corrective actions be carried out "before further flight" after Requirement 1 means that any detected deficiencies must be rectified before the aeroplane flies again, which operationally requires an operator to withhold return to service until corrections are completed. The text does not identify the procedures CASA will follow to verify compliance, inspect operators, or prosecute non‑compliance.

The Directive references FAA AD 2005-04-01, which is cited as a relevant authority; FAA approval of AMOCs serves as an accepted compliance pathway. The Directive does not discuss administrative review, appeal processes, or dispute resolution mechanisms in its own text. The signature of the CASA delegate indicates the instrument’s provenance and where responsibility for its issuance rests. For concrete enforcement mechanisms, records, audits or sanctions, readers must look to CASA’s wider enforcement policies and aviation safety laws, because those elements are not detailed inside the Directive as provided.

The Directive expressly interfaces with United States FAA regulatory instruments and with Boeing technical guidance. It explicitly references FAA AD 2005-04-01 Amdt 39-13973, stating in the Notes that "FAA AD 2005-04-01 Amdt 39-13973 refers." The Directive accepts later revisions of Boeing SB 737-28A1174 as compliant only where those later revisions have been approved by the FAA as an Alternate Method of Compliance to FAA AD 2005-04-01. That constructs an explicit vertical interaction: CASA’s Directive requires compliance with a Boeing SB, but it leaves open the pathway whereby the FAA’s approval of updated SB revisions as AMOCs will be accepted as an equivalent compliance route under this CASA Directive. The Directive also acknowledges earlier Boeing SB work: actions done prior to this Directive’s effective date in accordance with Boeing SB dated 20 December 2001 are accepted as meeting the Directive’s requirements.

Within the domestic regulatory framework, the Directive is an instrument of CASA, signed by a CASA delegate. It therefore sits inside Australian civil aviation law as an airworthiness requirement issued by CASA. The Directive permits operator use of "their own CASA accepted equivalent procedures" for certain preparatory steps (draining fuel tanks and gaining access). That provision presupposes the existence of CASA acceptance processes for operator procedures and creates an interaction between the Directive and CASA’s procedural acceptance schemes: operators who have CASA‑accepted procedures may rely on them instead of strictly following the SB’s procedural text for the drained‑tank and access steps.

The Directive does not discuss interaction with criminal law, workplace health and safety law, environmental law, or contract law. It likewise does not reference the Civil Aviation Act or other specific Australian statutes in the text provided. The technical and compliance interaction is primarily with Boeing SB 737-28A1174 (Rev 1, 18 July 2002), any earlier Boeing SB dated 20 December 2001, and FAA AD 2005-04-01. The acceptance of FAA AMOCs creates a cross‑jurisdictional regulatory linkage where an FAA approval can alter an operator’s options for complying with a CASA Directive. The Directive’s alignment with FAA materials and the recognition of FAA AMOCs is the principal locus of its interstate regulatory interaction as presented in the text.

The Directive is titled AD/B737/239 Amdt 1, indicating this is an amendment (Amdt 1) to an original airworthiness directive. The text records that the original issue of the Directive became effective on 12 May 2005. This amendment (Amdt 1) becomes effective on 19 January 2006. The amendment continues the requirements of the original issue but explicitly allows compliance using later revisions of Boeing SB 737-28A1174 where those later revisions have been approved by the FAA as AMOCs to the corresponding FAA airworthiness directive. The Background section states, "This amendment whilst continuing the requirements of the original issue, allows compliance in accordance with later revisions of SB 737-28A1174 which have been approved by the FAA as an AMOC to the corresponding FAA airworthiness directive." That is the concrete change effected by Amdt 1 when compared to the original issue.

The Directive also documents that certain actions performed prior to the effective date in accordance with Boeing SB 737-28A1174 dated 20 December 2001 are acceptable for compliance (Note 3). That acknowledgement confirms that earlier Boeing SB compliance was recognised during the original issue and remains recognised under the amendment. The text references FAA AD 2005-04-01 Amdt 39-13973, tying the amendment to that FAA action. The signature block at the end shows the delegate action date as 30 November 2005, which precedes the stated effective date of 19 January 2006; the document records that timing. The amendment label and the text together show the evolution from the original Directive effective 12 May 2005, through the issuance of this amendment (Amdt 1), effective 19 January 2006, with the explicit policy change being to permit later FAA‑approved SB revisions as acceptable compliance routes.

No other amendments or amendment dates are listed in the text provided. The Directive text does not list future amendment procedures or sunset clauses beyond the compliance deadlines for the requirements. The explicit amendment content is limited to continuing the original requirements while adding the acceptance of later FAA‑approved SB revisions as AMOCs.

The Directive text contains no statements about litigation, appeals, court decisions or disputes relating to its content or enforcement. It does not record legal challenges, judicial interpretations, or precedent. The only legal‑style references are to FAA AD 2005-04-01 Amdt 39-13973 and to Boeing Service Bulletins (the SB dated 18 July 2002 and the earlier SB dated 20 December 2001). The document is administrative in form, issued by a CASA delegate, and signed on 30 November 2005, but it does not report any litigation history or contested matters.

Because the Directive itself does not mention litigation, readers seeking litigation history must consult court records, tribunal decisions or CASA enforcement files outside this Directive text. The Directive does not describe administrative review rights, appeals processes, or dispute resolution mechanisms in its content. The absence of litigation references in the Directive means that this particular instrument, as provided, contains no embedded record of judicial or tribunal challenges, outcomes, or orders related to its issuance or compliance.

Several practical points in the Directive can be missed if a reader assumes literal conformity to the Boeing SB without checking the Notes and AMOC pathway. First, applicability is limited: the Directive applies only to those Model 737-100, -200, -200C, -300, -400 and -500 series aeroplanes that are "identified in Boeing Service Bulletin (SB) 737-28A1174, Revision 1, dated 18 July 2002." If an aeroplane of those model series is not identified in that SB revision, it is not in the Directive’s applicability list. That identification step is consequential for fleet operators who may have mixed configurations or records.

Second, the Directive mandates compliance with paragraph 3.B of the SB rather than the entire SB; some SB tasks are thereby implicitly not mandated unless paragraph 3.B references them. Note 2 explicitly says that "The marking of the forward surface of the front spar in accordance with SB 737-28A1174, Revision 1, Figures 1 and 2, Step 18, is not required for compliance with this Directive." That is a discrete compliance carve‑out an operator might miss if they merely follow the SB in full without reading the Directive notes.

Third, Note 1 permits operators to use their own CASA‑accepted equivalent procedures for draining fuel tanks and gaining access to the fuel tanks. That means an operator must have CASA‑accepted procedures in place to use this flexibility; lacking CASA acceptance of their procedures would eliminate that option and require strict adherence to the SB’s draining and access methods. Operators must check whether their procedural documentation is CASA‑accepted before relying on that Note.

Fourth, the AMOC pathway matters. The Directive allows "later revisions of the above SB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2005-04-01, [to be] considered acceptable for compliance with the equivalent Requirements of this Directive." Operators must therefore verify that any later SB revision they intend to use has FAA AMOC approval tied to FAA AD 2005-04-01. The Directive does not accept later revisions automatically; FAA approval as an AMOC is required.

Fifth, timing and operational constraints are asymmetric. Requirement 1 has a long calendar deadline (before 12 May 2010), whereas Requirement 2 has an immediate operational constraint: any corrective actions found during Requirement 1 must be done before further flight. That means if an aeroplane has a deficiency discovered during the mandated action, it cannot return to service until the corrective work is completed. Operators must plan for the possibility of immediate grounding if corrective actions are required.

Sixth, some actions done under an earlier SB (Boeing SB dated 20 December 2001) before the Directive’s effective date are acceptable (Note 3). Operators who performed the earlier SB work should ensure their records demonstrate that the earlier SB was used and the work completed before the Directive’s effective date if they rely on Note 3 to claim compliance.

Finally, while the Directive is silent on enforcement mechanisms and penalties, it is an airworthiness directive issued by CASA. Non‑compliance with the mandatory Requirements will leave an aeroplane in a non‑compliant state relative to this Directive. Operators should therefore treat the Directive’s timelines and the "before further flight" requirement for corrective actions as binding operational constraints even though the text does not specify enforcement procedures or penalties.

To comply with this Directive an operator must do three concrete things, as expressed in the Directive text: (1) perform the action required by Requirement 1, that is, carry out the work in accordance with paragraph 3.B of Boeing Service Bulletin 737-28A1174, Revision 1, dated 18 July 2002; (2) carry out any necessary corrective actions on deficiencies detected during the accomplishment of that work (Requirement 2); and (3) meet the timing constraints: Requirement 1 completed before 12 May 2010, and any corrective actions completed before further flight after Requirement 1.

Operationally, follow these steps based on the Directive’s text and Notes. First, confirm whether each aeroplane is within the Directive’s applicability by checking the aircraft against the identification list in SB 737-28A1174 Rev 1. The Directive applies only to the models identified in that SB revision. Second, obtain and use Boeing Service Bulletin 737-28A1174, Revision 1 (18 July 2002), and execute the work required in paragraph 3.B. The Directive does not repeat the technical procedure; it mandates compliance with the SB paragraph. Third, while executing the SB work, inspect for deficiencies; any deficiencies found must be corrected before the aeroplane is returned to service. The Directive’s Requirement 2 is clear: corrective actions detected during Requirement 1 must be done "before further flight after accomplishing Requirement 1."

Where practical burden or access issues arise, the Directive provides two operator options to reduce compliance friction. Note 1 allows operators to use their own CASA‑accepted equivalent procedures for draining the fuel tanks and gaining access to the fuel tanks. If the operator has CASA‑accepted procedures for those steps, they may use them instead of following the SB’s draining and access steps verbatim. Ensure those procedures remain CASA‑accepted and document the acceptance. Note 2 removes one marking task from the SB’s list of mandatory steps for compliance with this Directive; operators do not need to mark the forward surface of the front spar as per Figures 1 and 2, Step 18 of the SB to be compliant with this Directive.

If an operator prefers to use a later Boeing SB revision, confirm whether that later revision has been approved by the FAA as an AMOC to FAA AD 2005-04-01; the Directive accepts such FAA‑approved AMOCs as acceptable compliance methods. Do not assume a later SB revision is acceptable until FAA AMOC approval is confirmed. If the operator completed equivalent work prior to the Directive’s effective date using Boeing SB dated 20 December 2001, Note 3 confirms those earlier actions are acceptable; ensure robust records document that the earlier SB work was performed before the Directive’s effective date.

Plan logistics and downtime around two timing points. The calendar deadline for Requirement 1 is before 12 May 2010; schedule inspections and work to meet that date. The operational constraint for corrective actions is immediate: if deficiencies are found while accomplishing Requirement 1, those corrective actions must be completed before the aeroplane flies again. That requires the maintenance programme to be prepared to perform corrective repairs promptly and to withhold release to service until they are done.

Finally, keep records of compliance that show: (a) the aeroplane identification check against SB 737-28A1174 Rev 1; (b) the work performed in accordance with paragraph 3.B of the SB (or the later SB revision if FAA AMOC approval exists); (c) any corrective actions taken and the dates they were completed; (d) any use of CASA‑accepted equivalent procedures for tank draining and access; and (e) any reliance on prior SB work (2001) demonstrated by dated records. The Directive does not specify documentation format or record retention in its text, so operators should follow standard CASA recordkeeping practices for SB compliance and airworthiness directives. The Directive was issued by a CASA delegate on 30 November 2005 and became effective 19 January 2006; ensure compliance actions and records reflect those dates and the Directive’s timing requirements.