AD/B737/299 - Electrical Bonding

The Directive relies on a small set of interlocking concepts. First, "applicability" defines the legal scope: only those model variants listed and specifically identified in SB 737‑28‑1225 Revision 1 are in scope (Applicability). The second concept is action specification by reference: the AD does not set out laboratory methods or repair steps in the body of the document; instead it mandates compliance "in accordance with" Boeing Special Attention Service Bulletin 737‑28‑1225, Revision 1 (Requirement). This means the SB supplies the operative technical procedure, including how to measure electrical resistance and how to inspect and repair bonding jumpers; the AD makes SB compliance compulsory for the listed aircraft.

Third, the Directive establishes temporal obligations. It sets a compliance window for the primary task , the electrical-resistance test and visual inspection , of "within 60 months after the effective date" (Compliance). It then creates an immediate operational constraint for any defects found: "carry out all applicable corrective actions in accordance with SB 737‑28‑1225, Revision 1" and those corrective actions must be done "before further flight after the Requirement 1 electrical resistance test" (Requirement; Compliance). The practical effect is that an aircraft that fails the test or shows defects on inspection cannot lawfully continue to fly until the corrective actions are accomplished in accordance with the SB.

Fourth, the Directive recognises prior compliance and alternative compliance routes. Actions accomplished before the Directive effective date in accordance with an earlier SB dated 12 January 2006 are accepted as meeting the Directive (Requirement). Later revisions of the SB are also acceptable where they have been approved by the FAA as an AMOC to FAA AD 2007‑02‑14 (Requirement; note). The AD therefore uses a chain of technical equivalence anchored in Boeing SB revisions and FAA AMOC approvals to define acceptable methods.

Finally, the stated safety rationale is narrow and technical: preventing arcing or sparking in the fuel tank during a lightning strike that could produce uncontrolled fire or explosion (Background). The Directive therefore targets electrical bonding integrity at a specific interface (bulkhead fitting for the fuel feed line to the wing front spar), together with the installation integrity of adjacent bonding jumpers (Requirement). The document does not quantify risk levels, costs, or provide test thresholds in its text; instead it relies on the SB for technical thresholds and procedures.

The Directive explicitly affects operators, owners and maintainers of Boeing 737-600, -700, -700C, -800 and -900 series aeroplanes that are "identified in Boeing Special Attention Service Bulletin (SB) 737‑28‑1225, Revision 1, dated 30 October 2006" (Applicability). This language narrows the universe of affected aircraft to those specific serials or line numbers identified in the SB; an aircraft of a listed model is not necessarily in scope unless the SB lists it. The Directive does not name airlines, lessors, maintenance organisations or maintenance engineers individually; instead it creates an obligation that attaches to the aircraft and therefore to the person or entity responsible for continuing airworthiness of that aircraft under the civil aviation regulatory regime.

The text does not allocate financial responsibility, nor does it address who must carry out the test (the SB will contain technical procedural requirements and may specify approved personnel or facilities). The Directive does indicate who decides acceptable alternative compliance: later SB revisions are acceptable only if approved by the FAA as an AMOC to FAA AD 2007‑02‑14 (Requirement). The Civil Aviation Safety Authority (CASA) is the issuer , the document is signed by the CASA delegate , and CASA sets the effective date and compliance deadlines; however, the AD itself defers certain technical approvals (AMOCs) to the FAA.

Because the Directive prescribes an action to be done "before further flight" where corrective action is required, the immediate operational effect falls on the entity with authority to dispatch an aircraft for flight; that entity must ensure the corrective actions are completed in accordance with the SB before the aircraft departs again (Requirement; Compliance). The Directive also accepts pre‑effective-date compliance accomplished under the earlier SB dated 12 January 2006 as satisfying the AD (Requirement). This produces a narrow class of entities who need to check their maintenance records against the SBs and the AD to confirm whether prior work already meets the mandatory requirement.

The Directive is silent about record-keeping, reporting back to CASA, or penalties. Therefore, within the text itself, the only named decision-makers are the CASA delegate who issued the AD (signature) and the FAA where approvals of later SB revisions as AMOCs are required (Requirement). The Boeing SB and FAA AD referenced function as the technical instruments that define procedures, acceptable revisions and AMOC mechanisms; operators must consult those documents to determine whether their particular aircraft are included and which technical steps to follow.

The Directive sets a concise set of duties and leaves certain matters to referenced documents. Duties in the AD are:

• Identify whether an aeroplane is included in the Applicability, which ties applicability to the list in Boeing Special Attention Service Bulletin 737‑28‑1225, Revision 1 dated 30 October 2006 (Applicability). The AD thereby requires the operator or responsible person to cross-reference the SB’s list.

• Perform the electrical-resistance test and a general visual inspection as specified in Requirement 1: "Test the electrical resistance of the bond between the bulkhead fitting for the fuel feed line and the wing front spar on the left and right wings and carry out a general visual inspection of adjacent bonding jumpers to make sure they are installed correctly" and to do so "in accordance with the SB 737‑28‑1225, Revision 1" (Requirement).

• Perform all applicable corrective actions identified in the SB as required by Requirement 2: "Carry out all applicable corrective actions in accordance with SB 737‑28‑1225, Revision 1" (Requirement).

• Observe the timing constraints: Requirement 1 within 60 months after the effective date; Requirement 2 must be done before further flight following the Requirement 1 electrical-resistance test (Compliance).

Rights and discretion are limited in the AD’s text but include:

• Acceptance of prior work: "Actions accomplished before the effective date of this Directive in accordance with Boeing Special Attention Service Bulletin 737‑28‑1225 dated 12 January 2006, are considered acceptable for compliance with the actions required by this Directive" (Requirement). This gives operators the right to rely on historical maintenance if it conforms to that specific earlier SB.

• Acceptance of later SB revisions as an alternate compliance path, but only where those later revisions have been approved by the FAA as an AMOC to FAA AD 2007‑02‑14: "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 2007‑02‑14, are considered acceptable for compliance with the equivalent Requirements of this Directive" (Requirement). This grants a conditional right to rely on subsequent SB revisions subject to FAA approval.

The AD does not detail operational exemptions, reporting protocols, who must perform the test, or who pays. It also does not specify acceptable resistance threshold values or the detailed steps for inspection and corrective action,those technical specifics are delegated to the referenced Boeing SB (Requirement). The AD therefore creates mandatory duties that are procedural and temporal but relies on the SB and FAA AMOC process to define technical compliance standards and possible alternative methods.

The AD text contains no explicit penalties, monetary fines, or enforcement procedures. The document states the required actions, the compliance timeframes and the effective date, and is signed by a CASA delegate (Effective date; signature). It does not include enforcement mechanisms, civil or criminal sanctions, or administrative process steps for non-compliance within the text provided.

Because the AD converts the Boeing SB actions into a mandatory regulator-issued directive, the practical implication is that compliance is required under the civil aviation regulatory framework; however, the AD itself does not spell out enforcement steps or penalties. The Directive also does not prescribe reporting requirements, acceptance criteria for maintenance organisation authorisations or personnel qualifications, nor does it specify the administrative consequences of non-compliance in the text provided.

The AD does refer to FAA AD 2007‑02‑14 and to FAA AMOC approvals for later SB revisions (Requirement; note). That linkage indicates that FAA action and approvals are part of the compliance landscape: in particular, the AD accepts later SB revisions only when approved by the FAA as AMOC to the FAA AD (Requirement). The AD therefore establishes a technical enforcement boundary in that later SB revisions are only acceptable if the FAA has approved them as alternate methods of compliance to the referenced FAA AD; this places some enforcement-relevant decision-making with the FAA rather than CASA with respect to AMOCs.

In the absence of explicit penalties or enforcement language in the document provided, readers must consult the broader civil aviation regulatory framework, CASA rules and enforcement policy for how non-compliance is treated in practice. The AD text itself is limited to requirements, timing and acceptable SB revisions and AMOCs, and does not set out a sanctions regime.

The Directive explicitly references and interacts with other regulatory instruments and a Boeing service bulletin. It refers to FAA AD 2007‑02‑14 (Note: FAA AD 2007‑02‑14 refers) and accepts later revisions of Boeing SB 737‑28‑1225 only if those revisions have been approved by the FAA as an Alternate Method of Compliance to that FAA AD (Requirement). This creates a cross-jurisdictional compliance path in which the CASA AD recognises FAA AMOCs as authoritative for purposes of substituting later SB revisions.

The Directive also ties mandatory compliance to a Boeing Special Attention Service Bulletin: SB 737‑28‑1225, Revision 1, dated 30 October 2006. The SB is the technical standard that operators must follow to meet the Directive’s requirements (Applicability; Requirement). It also accepts prior work performed under Boeing SB 737‑28‑1225 dated 12 January 2006 as satisfying the AD (Requirement). Thus the AD interacts with manufacturer technical documentation by making that documentation normative.

Beyond those specific references, the AD does not cite or incorporate other Australian statutes, regulations, or CASA advisory material within the text provided. There is no mention in the AD body of how it interfaces with Australian continuing airworthiness rules, maintenance organisation approvals, or air operator certificates; the document confines itself to the AD actions, timing and acceptable SB revisions/AMOCs. In practice, such ADs operate within the broader civil aviation safety framework, but those broader instruments and enforcement mechanisms are not invoked or described in this AD text.

Additionally, the AD’s acceptance of FAA AMOCs creates an inter-authority reliance: FAA technical approvals of later SB revisions constitute an accepted Australian compliance route under this AD. That interaction transfers some technical approval authority to the FAA in the narrow context of acceptable later SB revisions as AMOCs to the referenced FAA AD, per the AD’s own text (Requirement). The AD therefore creates a specific interaction with foreign regulatory action rather than attempting to independently re-authorise later SB revisions.

The AD text itself documents a very limited amendment history relating to service bulletin versions that affect compliance. It explicitly states that actions performed before the effective date "in accordance with Boeing Special Attention Service Bulletin 737‑28‑1225 dated 12 January 2006, are considered acceptable for compliance with the actions required by this Directive" (Requirement). That acceptance treats the 12 January 2006 version of the SB as an antecedent acceptable method of compliance for work done prior to the AD’s effective date. The AD’s own mandating version is Boeing SB 737‑28‑1225, Revision 1, dated 30 October 2006 (Applicability; Requirement). The AD also anticipates later revisions of the SB, but makes acceptance conditional on FAA approval as an AMOC to FAA AD 2007‑02‑14: "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 2007‑02‑14, are considered acceptable for compliance with the equivalent Requirements of this Directive" (Requirement).

The AD document is dated with an issuance signature dated 1 February 2007 (signature block), and it specifies its effective date as 15 March 2007 (Compliance). No other amendments to the AD text itself are recorded within the document provided. There is no internal schedule of amendments, no sunset clause, and no statement about subsequent AD revisions in the AD body. The only dynamic element left open for amendment is the acceptability of later SB revisions subject to FAA AMOC approval.

Readers are therefore to treat: (a) SB dated 12 January 2006 as acceptable for prior compliance, (b) SB Revision 1 dated 30 October 2006 as the primary referenced document for compliance, and (c) later SB revisions as acceptable only when FAA AMOC approval exists. The AD thus sets a narrow amendment pathway tied to FAA AMOC approvals and to specific SB revision dates; it does not itself provide further amendment mechanisms or thresholds beyond those references.

The AD text does not record or reference any litigation, disputes, or judicial review history. The document contains no citations to cases, no mention of ongoing or past legal proceedings, and no indication that its provisions have been the subject of litigation (the Background, Requirements, Compliance, and notes are technical and administrative in nature). The only judicial or administrative bodies mentioned are the Civil Aviation Safety Authority (as issuer) and the United States Federal Aviation Administration (in the context of AMOC approvals).

Because the provided AD is an administrative safety instrument rather than a statute or court judgment, it contains technical and compliance instructions; it does not include a litigation history or references to legal challenges. If a reader requires any litigation or administrative appeal history concerning this AD, or disputes under the civil aviation regulatory framework, that information is not present in the AD text and would need to be obtained from external case records, CASA enforcement records or court archives , sources not included in the text provided.

The Directive presents several operational and compliance traps that are directly visible from the text.

• Applicability requires cross-referencing the Boeing SB. The AD’s applicability is not simply the listed models; the text says "as identified in Boeing Special Attention Service Bulletin (SB) 737‑28‑1225, Revision 1, dated 30 October 2006" (Applicability). Practically, this means an aircraft owner or maintainer must check the SB to determine whether a particular airframe serial or configuration is included. Failure to consult the SB may lead to misapplying the AD to aircraft that are out of scope or missing aircraft that are in scope.

• Timing is uneven: Requirement 1 has a long compliance window , within 60 months of the effective date , but Requirement 2 is immediate in operational effect: any corrective actions required after the test must be done "before further flight" (Compliance; Requirement). That means an operator can lawfully defer the initial test for up to 60 months, but once the test is done, any defects found must be rectified before the next flight. The result is potential operational disruption at the moment of failure discovery, including immediate grounding until repairs are performed.

• Acceptable prior work and acceptable later revisions are tightly defined. Work done under Boeing SB dated 12 January 2006 before the effective date is accepted (Requirement). Later revisions of the SB are acceptable only if the FAA has approved them as an AMOC to FAA AD 2007‑02‑14 (Requirement). Operators who rely on a later SB revision without confirming FAA AMOC approval risk non-compliance with the AD.

• The AD delegates technical detail to the Boeing SB. The AD does not provide the test method, acceptance criteria or corrective-action procedures; it requires compliance "in accordance with" the SB (Requirement). Therefore, the SB’s availability, the purchaser’s or maintenance organisation’s access to that SB and any proprietary limitations on the SB could be a practical bottleneck. The AD text does not specify where to obtain the SB or whether CASA will accept alternative technical data absent FAA AMOC approval.

• The AD does not specify who must perform the work or the required qualifications for personnel. The SB likely contains those technical qualifications; however, the AD’s silence in the text provided means that a maintainer must consult the SB and applicable maintenance regulations to identify authorised personnel.

• The AD contains no record-keeping or reporting obligation in its text. If operators assume they must report completion to CASA they could be wrong; conversely, CASA may have separate expectations under its broader regulatory framework. The AD’s silence on reporting is a potential compliance pitfall.

• The AD references FAA AD 2007‑02‑14 but does not reproduce or summarise it. Operators cannot determine from this AD what the FAA AD’s terms are; they must retrieve that FAA AD to understand the full AMOC landscape.

• The safety purpose is narrowly targeted: "prevent arcing or sparking in the fuel tank in the event of a lightning strike" (Background). If operators or maintenance personnel misread the scope and attempt to broaden the remedial works beyond what the SB specifies, they may perform unnecessary modifications or incur costs not authorised by the AD. Conversely, too-narrow a read risks leaving relevant interface items uninspected.

These "gotchas" are directly inferable from the AD’s text about reliance on the SB, timing asymmetry between Requirement 1 and Requirement 2, the conditional acceptance of SB revisions, and the lack of explicit procedural, reporting or penalty language within the document.

The Directive’s compliance path is short and prescriptive: follow the Boeing Special Attention Service Bulletin named and respect the time limits set out.

Step 1 , Confirm applicability: Obtain Boeing Special Attention Service Bulletin 737‑28‑1225, Revision 1, dated 30 October 2006 and determine whether the specific aeroplane(s) under your control appear in the SB’s identification list (Applicability). The AD’s applicability is expressed with reference to that SB; the AD will apply only to aeroplanes that the SB identifies.

Step 2 , Schedule the required test within the compliance window: The AD requires Requirement 1 , testing the electrical resistance of the bond between the bulkhead fitting for the fuel feed line and the wing front spar on the left and right wings and performing a general visual inspection of adjacent bonding jumpers , to be completed "within 60 months after the effective date of this Directive" (Compliance; Requirement). The effective date is 15 March 2007; calculate the deadline accordingly and schedule maintenance tasks within the 60‑month window (Compliance). Note that the test must be performed on both left and right wings and must include the visual inspection of adjacent bonding jumpers.

Step 3 , Use the SB for test and inspection methods: The AD requires that Requirement 1 be accomplished "in accordance with SB 737‑28‑1225, Revision 1" (Requirement). Therefore, use the SB to determine the exact measurement method, resistance thresholds (if any), inspection criteria, required tools and any acceptable measurement tolerances.

Step 4 , If defects are found, apply corrective actions as per the SB before further flight: The AD requires "carry out all applicable corrective actions in accordance with SB 737‑28‑1225, Revision 1" (Requirement), and it specifies that corrective actions required as a result of the test must be done "before further flight after the Requirement 1 electrical resistance test" (Compliance). In plain terms, if the test or inspection identifies an issue the aircraft must not return to service until the applicable repairs per the SB are completed.

Step 5 , Determine whether prior work satisfies the AD: If the electrical-resistance testing and any corrective actions were done before 15 March 2007 in accordance with Boeing SB 737‑28‑1225 dated 12 January 2006, then those actions are "considered acceptable for compliance with the actions required by this Directive" (Requirement). Compile maintenance records to demonstrate this if relied upon.

Step 6 , Consider later SB revisions only with FAA AMOC approval: If you propose to comply using a later revision of the Boeing SB rather than Revision 1, confirm that the later SB revision has been approved by the FAA as an AMOC to FAA AD 2007‑02‑14; only then will the AD accept the later revision as an equivalent method of compliance (Requirement). Obtain and retain evidence of FAA AMOC approval.

Step 7 , Document compliance: While the AD does not prescribe record-keeping in its text, maintain complete maintenance records showing the test results, inspections, corrective actions, dates and referencing the SB revision used. If prior SB-based actions are relied upon for compliance, include the earlier SB reference and records demonstrating that work was done prior to the AD effective date (Requirement).

Step 8 , Coordinate operational decisions: Because corrective actions required after the test must be completed before further flight, coordinate scheduling to minimise disruption. For example, ensure spares, qualified maintenance personnel and repair times are planned if testing is performed late in the allowable window and an unexpected defect is found.

Step 9 , Check the FAA AD and AMOC status: Obtain FAA AD 2007‑02‑14 and any AMOC determinations that affect SB revisions to confirm the status of acceptable later SB revisions and ensure Australian compliance is aligned with FAA approvals as the AD requires (Note).

Step 10 , Keep the DAS/CAA delegate contacts and signatures accessible: The AD is issued by the CASA delegate (James Coyne) and contains an effective date (1 February 2007 signature; effective 15 March 2007). Retain the AD text and any relevant correspondence or approvals that demonstrate compliance in case regulatory authorities request verification.

In short, compliance requires identification of in-scope aircraft via the specified SB, performance of the electrical-resistance test and visual inspection per SB procedures within the 60‑month window, and completion of any corrective action per the SB before further flight. Prior actions done under the 12 January 2006 SB are acceptable, and later SB revisions are acceptable only if the FAA has approved them as AMOCs to the referenced FAA AD. The AD delegates technical particulars to the Boeing SB and to FAA AMOC approvals; operators must therefore obtain, follow and document the SB procedures and any FAA approvals relied upon.