AD/B717/20 - Electrical Bonding

The Directive deploys a narrow technical fix targeted at a lightning-protection pathway in the wing fuel system. The main technical concepts embedded in the text are the following.

• Electrical bonding attaching hardware: The Directive requires replacement of specific attaching hardware on the bulkhead nipple assemblies for the left and right wing vent boxes with hardware that provides an intentional conductive bond between the nipple assemblies and the airframe structure inside the wing fuel tanks (Requirement). That bond is intended to provide a controlled, low-resistance route for lightning-induced currents.

• Quantified resistance limit: The Directive operationalises the lightning-protection objective by imposing a quantitative upper limit on the resistance of the bond: not to exceed 2.5 milliohm (0.0025 ohm). That limit is carried forward despite terminology changes in Boeing's wiring manual; Note 1 explains that the historical term "class `L'" is no longer used, but the substantive resistance requirement remains (Requirement; Note 1).

• Functional testing after modification: The Directive requires two types of tests post-modification. First, resistance testing of the new electrical bonds to verify compliance with the numerical resistance requirement. Second, fuel leakage testing of the reworked nipple assemblies to ensure the modification has not compromised fuel containment (Requirement).

• Instruction set dependence: The mandated work is to be completed "in accordance with the Accomplishment Instructions of Boeing SB 717-28-0011, Revision 2" (Requirement). The SB thus provides the procedural and technical steps to implement the modification and tests; the AD does not reproduce those steps in full.

• Acceptable prior and alternate compliance routes: The Directive accepts actions done prior to the AD’s effective date when accomplished in accordance with earlier versions of the SB, specifically Boeing SB 717-28-0011 dated 16 April 2004 or Revision 1 dated 24 January 2006 (Requirement). It also accepts later revisions of the SB if those revisions have FAA approval as an AMOC to FAA AD 2007-05-06 (Requirement; Notes).

• Interauthority cross-reference: The Directive explicitly references FAA AD 2007-05-06 (Note 2) and the FAA’s AMOC process for acceptance of later SB revisions (Requirement). The Directive therefore connects its compliance options to FAA determinations regarding the SB.

These concepts collectively define a compliance package: replace hardware, test electrical continuity to a specified maximum resistance, perform fuel leakage tests, and do all that per the Boeing SB, within a fixed compliance window. The Directive is narrowly scoped to the particular assemblies and to model 717-200 aeroplanes identified in the SB (Applicability).

The Directive applies to Model 717-200 aeroplanes as identified in Boeing SB 717-28-0011, Revision 2 (Applicability). That definition ties applicability to the aircraft records used by operators and maintenance organisations, rather than a broad model-wide statement: the exact aeroplanes in scope are those identified in the referenced SB.

Primary affected parties are therefore:

• Registered operators and owners of the identified Boeing 717-200 aeroplanes. They are responsible for ensuring the aircraft in their control comply with the Directive within the prescribed timeframe (Compliance; Requirement). The Directive does not itself name "owners" or "operators", but the procedural responsibility implicit in ADs is to those who maintain and operate the identified aircraft.

• Maintenance organisations and licensed maintenance engineers charged with performing the modification and the specified tests. The Directive requires work be done in accordance with the Accomplishment Instructions of the Boeing SB, so organisations that hold the capability to implement the SB instructions (including replacement hardware installation, precision resistance measurements to milliohm tolerance, and fuel leakage testing) are directly affected (Requirement).

• Airworthiness authorities and their delegates. The Directive is issued by the Civil Aviation Safety Authority (CASA) via its delegate, Charles Lenarcic, and explicitly accepts FAA AMOCs and references FAA AD 2007-05-06 (Background; Notes). CASA staff and delegated inspectors who audit compliance, approve records, or accept AMOCs based on FAA findings will be engaged.

• Parts suppliers and tooling providers. The Directive mandates specific "new electrical bonding attaching hardware" for the bulkhead nipple assemblies (Requirement). Suppliers of those items and any special tooling required by the SB are implicated.

• Record-keepers and continuing airworthiness managers. Because the Directive accepts completed actions performed under prior SB revisions and allows FAA-approved later revisions, accurate documentation mapping work to SB revisions and dates will be necessary to establish compliance (Requirement; Notes).

Who pays: costs are borne by the aircraft operator or owner and any contracted maintenance provider, since the Directive sets a mandatory modification and testing regime per aircraft. The Directive text does not provide for direct financial assistance or compensation.

Who decides: the Directive prescribes the technical route,replacement and testing per Boeing SB 717-28-0011 Rev 2,and accepts certain prior or FAA-approved alternative means; thus the immediate decision for how to comply rests with the operator/maintenance organisation within the permitted options. CASA, through its delegate, issued the Directive and is the authority validating compliance, while the FAA’s AMOC approvals influence acceptable alternate procedures (Requirement; Notes).

Duties set out in the Directive are specific, measurable, and time-bound.

Duties

• Perform the hardware replacement: Operators must replace the attaching hardware of the bulkhead nipple assemblies of the left and right wing vent boxes with the specified new electrical bonding attaching hardware (Requirement). The Directive ties the hardware and process to Boeing SB 717-28-0011, Revision 2, Accomplishment Instructions.

• Conduct resistance testing: After installation, operators must carry out resistance testing of the new electrical bonds. The Directive imposes a numerical upper limit on acceptable resistance,no more than 2.5 milliohm (0.0025 ohm),as explained in Note 1 (Requirement; Note 1).

• Conduct fuel leakage testing: Following rework, fuel leakage testing of the nipple assemblies is required to confirm fuel system integrity post-modification (Requirement).

• Adhere to the SB: All actions are to be taken in accordance with the Boeing SB’s Accomplishment Instructions. The AD does not substitute its own methodology for the SB; it uses the SB as the technical HOW (Requirement).

• Meet the compliance timeframe: All required actions must be completed "within 78 months after the effective date of this Directive" (Compliance). The AD becomes effective on 10 May 2007, so the timeframe is explicit in the Directive (Compliance).

Rights and acceptances

• Acceptability of prior work: Work already completed before the effective date carried out in accordance with Boeing SB 717-28-0011 dated 16 April 2004 or Revision 1 dated 24 January 2006 is expressly accepted as compliant with the equivalent actions of this Directive (Requirement). Operators who implemented the SB earlier can treat those actions as satisfying the AD’s requirements.

• Acceptance of FAA-approved later revisions: Later revisions of Boeing SB 717-28-0011, Revision 2, that have FAA approval as an AMOC to FAA AD 2007-05-06 are considered acceptable for compliance with the equivalent requirements of this Directive (Requirement). This creates a route for operators to use FAA-approved updates to the SB as a compliance basis.

• Reference to FAA AD: Note 2 makes clear the AD refers to FAA AD 2007-05-06, giving operators a cross-reference to the FAA directive (Notes).

The Directive does not articulate procedural modalities for demonstrating compliance,such as paperwork, logbook entries, or notifications to CASA,within its text. It also does not set out who must authorise the tests (for example, certified test personnel), so those operational details must be managed pursuant to existing maintenance procedures and the Boeing SB Accomplishment Instructions. The Directive does, however, place an unambiguous technical and temporal obligation on operators of the identified aircraft to effect the modification and tests.

The text of the Directive specifies the required actions, the compliance period, and the effective date, but it does not include specific penalty provisions or a detailed enforcement regime within the document itself. The AD states the technical requirements and the time by which they must be met,becoming effective on 10 May 2007 and requiring compliance within 78 months thereafter (Compliance),and is signed by a CASA delegate (Charles Lenarcic), but it does not elaborate penalties, fines, or sanctions within the AD text.

Because the Directive does not set out enforcement mechanisms, readers should note the following observations strictly grounded in the document’s content:

• Enforcement detail is absent: The Directive contains the mandatory requirements and effective/compliance dates but contains no express schedule of penalties, civil sanctions, or criminal consequences within its text.

• Delegation and issuance: The Directive is issued under the authority of the Civil Aviation Safety Authority as evidenced by the delegate’s signature. That indicates CASA is the issuing authority and its delegate enacted the Directive (signed 16 March 2007), but the Directive text itself does not spell out how CASA will monitor or enforce compliance.

• Reliance on compliance certificate practice: The AD prescribes a hardware modification and tests performed per a Boeing SB. The AD’s operational effect is to change the airworthiness status requirement for the identified aeroplanes. The document does not specify documentary proof required, nor the form of acceptance of compliance. The acceptance of prior actions done under earlier SB revisions and of FAA-approved AMOCs for later revisions shows that procedural acceptance pathways are contemplated, but the AD text does not state how verification will be carried out administratively (Requirement; Notes).

• Cross-reference to FAA AD: The Directive references FAA AD 2007-05-06 and accepts FAA AMOCs when relevant. This indicates an interoperability in acceptable means of compliance but does not itself impose or specify enforcement mechanisms (Notes).

Given the absence of penalty or enforcement specifics in the AD text, any enforcement action, administrative follow-up, or sanctions would derive from the broader legal and regulatory framework under which CASA operates and enforces airworthiness directives. Those frameworks and penalty structures are not contained within this AD text and thus are outside the scope of what can be stated based solely on the Directive.

The Directive itself makes explicit reference to a parallel FAA airworthiness directive and to Boeing service documentation; it does not otherwise cite or reproduce other statutes, regulatory instruments, or enforcement provisions. Within the text, the following interactions are set out.

• Cross-reference to FAA AD 2007-05-06: The Directive contains a direct reference to FAA AD 2007-05-06 (Note 2). That connection signals that the CASA Directive aligns with or mirrors the FAA’s directive on the same technical issue and provides a locus for coordinated compliance options.

• Acceptance of FAA AMOCs for later SB revisions: The Directive states that "Later revisions of the SB 717-28-0011, Revision 2, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2007-05-06, are considered acceptable for compliance with the equivalent Requirements of this Directive" (Requirement). This creates an explicit operational interaction: FAA decisions regarding AMOCs to the referenced FAA AD can render later Boeing SB revisions acceptable for satisfying CASA’s AD obligations.

• Relationship to Boeing SBs and Boeing SWPM terminology: The Directive delegates the detailed procedural steps to Boeing SB 717-28-0011, Revision 2, for the Accomplishment Instructions (Requirement). It also refers to terminology changes in the Boeing Standard Wiring Practices Manual (SWPM) when discussing the historical "class `L' " term and confirms the substantive resistance limit despite the terminology change (Requirement; Note 1). The AD therefore interacts with Boeing’s technical documentation directly, making those documents part of the compliance architecture.

• No broader statutory cross-references included: The Directive text does not expressly cite domestic statutes, CASA regulations, or other Australian legislative provisions governing airworthiness directives, maintenance standards, or enforcement. It also does not state how the AD should be recorded in maintenance logs or aircraft records in legal terms. Those procedural or statutory interactions are not referenced in the AD and therefore cannot be inferred from this text alone.

In short, the AD’s explicit interactions are with Boeing technical publications and with the FAA’s AD and AMOC processes. The Directive delegates technical methodology to the SB and allows FAA-approved AMOCs to determine acceptable later revisions of the SB. Any additional interaction with other domestic laws, regulations, or enforcement mechanisms is not set out in the Directive’s text.

The Directive itself documents a small set of document-level amendment and acceptability references tied to the Boeing Service Bulletin and FAA processes. The AD records these points:

• Boeing SB versions referenced: The primary procedural reference is Boeing SB 717-28-0011, Revision 2, dated 19 July 2006 (Applicability; Requirement). The Directive also notes earlier SB versions by date: Boeing SB 717-28-0011, dated 16 April 2004, and Revision 1 dated 24 January 2006. Actions accomplished before the AD’s effective date in accordance with those earlier SB versions are explicitly accepted for compliance (Requirement).

• Treatment of SB later revisions: The Directive accepts later revisions of Boeing SB 717-28-0011, Revision 2, provided they have FAA approval as an AMOC to FAA AD 2007-05-06. Those later FAA-approved SB revisions are considered acceptable for compliance with the equivalent requirements of this Directive (Requirement).

• Terminology change noted: Note 1 records an internal change in Boeing’s Boeing Standard Wiring Practices Manual (SWPM): earlier versions used the term "class L' " resistance test related to lightning protection, specifying a maximum resistance of 0.0025 ohm; the SWPM no longer refers to class L'. The AD preserves the substantive test parameter by explaining that the term is not important in this context and the resistance must not exceed 2.5 milliohm (0.0025 ohm) (Requirement; Note 1).

• Effective date and issuance: The AD states it "becomes effective on 10 May 2007" and is dated/signed 16 March 2007 by Charles Lenarcic, Delegate of the Civil Aviation Safety Authority (Compliance; signature block). The AD is catalogued as AD/B717/20 Electrical Bonding 5/2007.

The Directive is explicit about acceptability of prior actions under earlier SBs and about acceptance of later FAA-approved SB revisions as AMOCs. The AD itself does not, however, contain a running amendment log for the AD text; it references the SB revision history and FAA AMOC approvals as the operative mechanisms for updating acceptable procedures. The AD therefore establishes a static directive (effective date and compliance window) while delegating technical amendment through the SB and FAA AMOC pathways.

The Directive does not record any litigation history. The document contains no references to legal proceedings, challenges, appeals, or court decisions relating to this Directive or to Boeing SB 717-28-0011. The only adjudicative or administrative evidence present in the text are the signatures, dates, and cross-references to FAA material and Boeing SB revisions.

Given the absence of litigation material in the AD text, the following points are strictly descriptive and limited to what the Directive states:

• No cases or decisions cited: The AD does not cite any case law, administrative rulings, or tribunal decisions as precedents for its issuance.

• No appeal or review procedure described: The AD does not set out a procedure for contesting the Directive, for seeking exemptions, or for submitting a formal appeal. It does, however, provide an explicit acceptability channel for later Boeing SB revisions that have FAA AMOC approval (Requirement), which offers an operational route for alternative compliance rather than a formal litigation or appeal route.

• No record of enforcement litigation: The text does not include any account of enforcement actions brought to date, nor does it indicate that enforcement has been litigated or adjudicated.

Because the Directive contains no litigation history, any investigation into legal challenges, judicial review, or enforcement cases would require sources beyond the AD text itself. That material is not part of this document and therefore cannot be reported here.

The AD is concise and technical, but there are practical details and potential pitfalls implicit in the text that operators and maintenance organisations should note. These are set out strictly on the basis of the Directive’s wording.

• Applicability tied to the SB identification: Applicability is to "Model 717-200 airplanes, as identified in Boeing Service Bulletin (SB) 717-28-0011, Revision 2, dated 19 July 2006" (Applicability). That means simply being a 717-200 is not by itself determinative; the AD applies to those aeroplanes as identified in the referenced SB. Operators should confirm the identification criteria used in the SB to determine whether a given airframe is in scope.

• Procedural dependence on the Boeing SB: The AD requires work "in accordance with the Accomplishment Instructions of Boeing SB 717-28-0011, Revision 2" (Requirement). The AD does not reproduce the Accomplishment Instructions; operators must obtain and follow that SB. Failure to correctly map the AD requirements to the SB instructions could create incomplete compliance.

• Resistance testing precision: Note 1 clarifies a terminology change and restates the substantive limit: the resistance of the bond "must not exceed 2.5 milliohm [0.0025 ohm]" (Requirement; Note 1). Measuring and reliably verifying such low resistance values requires appropriate instrumentation, calibrated test procedures, and competent personnel; the AD imposes the numerical threshold but does not specify test methods beyond deferring to the SB.

• Fuel leakage test requirement: The AD requires fuel leakage testing of the reworked nipple assemblies (Requirement). The SB’s Accomplishment Instructions will set out the method. Operators must ensure that the fuel leakage tests are performed and documented in line with the SB; the AD itself does not provide acceptance criteria for leakage beyond requiring the testing.

• Acceptance of prior work: The AD accepts actions accomplished before the effective date when done in accordance with earlier SB versions (16 April 2004 or Revision 1 dated 24 January 2006) (Requirement). Operators with earlier work must be able to demonstrate that the earlier SB was followed precisely to rely on this acceptability statement.

• Reliance on FAA AMOC approvals: The AD accepts later SB revisions if they are approved by the FAA as an AMOC to FAA AD 2007-05-06 (Requirement). Operators who plan to rely on later SB revisions should verify FAA AMOC status before relying on those revisions for compliance with this AD.

• Lack of explicit enforcement or procedural details: The AD does not specify how compliance is to be evidenced to CASA, nor does it set out who must certify the work. Operators must therefore retain appropriate maintenance records and be prepared to demonstrate compliance in whatever documentary form CASA requires under its broader regulatory framework, noting that the AD itself does not set those forms.

• Time window requires planning: The compliance window is "within 78 months after the effective date" with an effective date of 10 May 2007 (Compliance). While lengthy, this period can still be operationally significant; fleet managers need to schedule maintenance and parts procurement within that timeframe.

• Technical scope limited to specific assemblies: The AD applies to "the bulkhead nipple assemblies of the left and right wing vent boxes" (Requirement). Maintenance planners should be careful to implement the correct modification locations; substituting other bonding points or making broader changes without FAA-approved instructions could fail to meet the AD’s terms.

Operators and maintenance organisations will discover the AD’s practical hazards mainly around procedural alignment with the SB, measurement precision for low resistances, documentation to evidence prior compliance, and verification of AMOC status for later SB revisions.

Compliance in the terms of the Directive is a finite sequence of actions tied to a specific SB and a fixed timeframe. The AD prescribes the technical steps at a high level and delegates particulars to Boeing SB 717-28-0011, Revision 2. To comply with the Directive, the following steps, extracted verbatim or by necessary logical sequencing from the AD text, should be followed.

1. Confirm applicability: Determine whether the aircraft in question is a Model 717-200 "as identified in Boeing Service Bulletin (SB) 717-28-0011, Revision 2, dated 19 July 2006" (Applicability). Obtain and review the SB to confirm the aircraft’s inclusion.

2. Obtain the Accomplishment Instructions: Acquire Boeing SB 717-28-0011, Revision 2, dated 19 July 2006, and use its Accomplishment Instructions as the procedural guide for all modification and testing work. The AD requires actions be "carried out in accordance with the Accomplishment Instructions" of that SB (Requirement).

3. Replace attaching hardware: Replace the attaching hardware of the bulkhead nipple assemblies of the left and right wing vent boxes with the new electrical bonding attaching hardware specified in the SB (Requirement). Ensure the parts used match the SB specification.

4. Conduct resistance testing: After installation, carry out resistance testing of the new electrical bonds. Ensure the resistance does not exceed 2.5 milliohm (0.0025 ohm) as articulated in Note 1 (Requirement; Note 1). Use appropriate test equipment, calibration, and procedures as prescribed in the SB or in recognised maintenance practices for low-resistance measurements.

5. Conduct fuel leakage testing: Perform fuel leakage testing of the reworked nipple assemblies in accordance with the SB’s specified method to ensure the rework has not introduced leaks (Requirement).

6. Record and document work: While the AD does not set out specific documentation requirements, operators should record the work performed, reference the Boeing SB revision used, record resistance test results (including measured values), and document fuel leakage test outcomes. Where prior work was done under earlier SB revisions (16 April 2004 or Revision 1 dated 24 January 2006), retain the evidence showing the earlier SB was followed so that the AD’s acceptability clause can be relied upon (Requirement).

7. Verify timeline compliance: Complete the required modification and tests "within 78 months after the effective date of this Directive" (Compliance). The AD is effective 10 May 2007, so calculate the compliance deadline accordingly (Compliance).

8. Consider later SB revisions and FAA AMOCs: If a later revision of Boeing SB 717-28-0011 has been published, check whether it has FAA approval as an AMOC to FAA AD 2007-05-06. If so, the Directive states that such later revisions "are considered acceptable for compliance with the equivalent Requirements of this Directive" (Requirement). Ensure any reliance on later revisions is supported by documented FAA AMOC approval.

9. For prior compliance: If the modification and tests were already accomplished before the AD effective date in accordance with Boeing SB 717-28-0011 dated 16 April 2004 or Revision 1 dated 24 January 2006, retain records that demonstrate the SB revision and the work performed, as the AD explicitly accepts such prior work as compliant (Requirement).

10. Liaise with CASA as needed: Although the AD does not prescribe the administrative process for notifying CASA of compliance, operators should be prepared to provide maintenance records, SB references, and test results to CASA or its delegate on request, consistent with usual airworthiness record-keeping practices and the AD’s technical requirements.

In summary, compliance is achieved by following Boeing SB 717-28-0011 Rev 2 Accomplishment Instructions to replace the specified hardware, verify the electrical bond is at or below 2.5 milliohm, perform fuel leakage testing, and document the work, all completed within the 78-month compliance window. Pre-existing compliance done under earlier SB revisions is accepted, and later SB revisions with FAA AMOCs are acceptable alternatives, subject to verification of FAA approval.