AD/J4100/25 - Fuel Tank Bonding Leads and Fuel Pipe Clearances

Applicability and scope. The Directive applies to “Jetstream 4100 series aeroplanes, all models, all serial numbers.” The scope is narrowly focused on fuel tank area electrical bonding and fuel pipe clearances within the left and right wings. The defined physical inspection locations are precise: bonding leads between ribs 1 and 9, and between ribs 16 and 19 in both LH and RH wings. The fuel system pipe runs to be examined are “all fuel system pipe runs inside the LH and RH wings” as stated in Requirement 3, and clearances must meet the requirements of the SB.

Prescriptive actions referencing a service bulletin. The AD is prescriptive in that it directs operators to carry out discrete tasks “in accordance with” enumerated paragraphs of SB J41‑28‑013 Revision 1 (paragraphs 2B(2), 2B(3) and 2B(4)-2B(15)). The SB thus supplies the technical methodology and acceptance criteria; the AD makes compliance with that SB mandatory for affected Australian operators. The AD allows later revisions of the SB provided those revisions are approved by EASA, making EASA approval the gatekeeper for alternative SB revisions.

Timing and immediacy. The compliance regime has two tiers. Inspections, examinations and installation of additional bonding are scheduled to occur at the next major inspection or at wing tank access or within 24 months after the effective date, whichever first. Remedial work discovered by those inspections (replacement of defective bonding leads and adjustment of incorrect clearances) must be completed before the next flight after the inspection or examination. That sequencing forces immediate grounding of any aircraft found with defects until corrective action is complete.

Technical identification of the change. The Background identifies the design change by modification number JM41659 and states that the SB introduces additional bonding between pipes, structure and components to improve electrical bond paths within fuel tank areas. The AD therefore ties the regulatory requirement to a specific design modification and a particular SB.

Safety premise stated. The Background explicitly states a causal safety linkage: “Insufficient or defective bonding in the fuel tank area, if not corrected, could lead to ignition of fuel vapours and subsequent fuel tank explosion.” The Directive is presented as addressing that hazard through inspection, replacement, clearance correction and additional bonding.

Cross‑jurisdictional linkage. The AD (an Australian CASA instrument issued by a Delegate) references EASA for two operational points: it accepts later SB revisions if approved by EASA, and it refers to EASA AD 2008‑0040. The AD’s reliance on EASA approvals and cross‑reference indicates interdependence between CASA’s directive and EASA’s certification or airworthiness actions for the same design issue.

Document provenance and authority. The Directive is identified as AD/J4100/25, dated 5/2008 DM, signed by David Punshon as Delegate of the Civil Aviation Safety Authority, and states an effective date. The precise sourcing and signatory anchor CASA as the issuing authority for this mandatory action.

Registered owners and operators of Jetstream 4100 series aeroplanes. The AD’s applicability line states “Jetstream 4100 series aeroplanes, all models, all serial numbers.” Concretely, this means any Australian‑registered Jetstream 4100, and any operator responsible for maintenance and airworthiness of such aircraft operating under Australian jurisdiction, are the primary addressees. Where an operator contracts maintenance, the responsibility to ensure the inspections and required actions are done rests with the operator or the accountable manager under their regulatory maintenance regime; the AD itself imposes the performance requirement on the aircraft (through its registered operator/owner).

Maintenance organisations and approved maintenance staff. Each Requirement refers to performance “in accordance with” specific paragraphs of SB J41‑28‑013 Rev 1. The SB will set out procedural details that normally require qualified maintenance personnel and an organisation authorised to perform the relevant work. Therefore maintenance providers (MROs), certifying staff (licensed aircraft maintenance engineers) and the organisations that supply airworthy parts are materially involved in meeting the Directive’s tasks.

Parts suppliers and manufacturers. Requirement 2 mandates replacement of any defective bonding leads with “airworthy parts.” That specification creates a demand for parts that are certified or otherwise accepted as airworthy for the Jetstream 4100 installation described. BAe Systems (Operations) Ltd and approved component suppliers that supply the bonding leads or modification kits (for modification JM41659) will therefore be affected commercially, as will logistics and supply chains that deliver those parts.

Regulatory bodies. The AD is issued by CASA (signed by its Delegate). The text references EASA approvals and EASA AD 2008‑0040, so EASA and any European airworthiness actions affect what later SB revisions are acceptable. Although not elaborated in the text, CASA, via this AD, sets the compliance schedule and may record compliance outcomes in its oversight processes.

Airworthiness records and continuing airworthiness management. The Directive’s requirements impose obligations that will interact with an aircraft’s continuing airworthiness documentation and maintenance schedule. The specific compliance times (next major inspection or wing tank access or within 24 months, and remediation before next flight) will affect maintenance planning. Operators that plan tight maintenance windows or frequent short‑turn operations are affected because the temporal constraints may require immediate maintenance access or unscheduled grounding if defects are found.

Safety auditors and insurers. While the AD does not name insurers or audit bodies, the mandatory nature of the Directive and the explicit safety rationale mean auditors and underwriters have an interest in whether the work is done to the SB standard within the prescribed timing. Insurers and auditors are therefore indirect stakeholders.

International operators and leasing chains. The AD applies to the aeroplane type irrespective of ownership. Aircraft that are on lease, in international operation or entering Australian registry will be affected as the Directive applies to the airframe; compliance may be required on entry to Australian airspace or registry, given the AD’s applicability to Australian CASA jurisdiction.

Duties imposed by the Directive. The Directive sets out five numbered Requirements. They impose the following duties:

• Requirement 1: Inspect the bonding leads between ribs 1 and 9, and between ribs 16 and 19, in the left (LH) and right (RH) wings in accordance with paragraph 2B(2) of SB J41‑28‑013 Revision 1 dated 10 January 2008. This is a mandatory inspection task focused on specific bonding lead locations.
• Requirement 2: If the Requirement 1 inspection finds any defective bonding leads, replace those bonding leads with airworthy parts. This is a mandatory corrective duty triggered by the inspection finding.
• Requirement 3: Examine all fuel system pipe runs inside the LH and RH wings in accordance with paragraph 2B(3) of SB J41‑28‑013 Revision 1. This is a mandatory inspection/examination of pipe routing and clearances within the wing fuel system.
• Requirement 4: If incorrect clearances are found as a result of Requirement 3 examination, adjust the clearances to meet the requirements of the SB. This is a mandatory corrective task tied to the pipe clearance standard set in the SB.
• Requirement 5: Install additional electrical bonding of components within the LH and RH wings in accordance with paragraphs 2B(4) to 2B(15) of SB J41‑28‑013 Revision 1. This is a mandatory modification/installation task to implement the design change (identified as modification JM41659 in the Background).

Timing duties. The Directive prescribes compliance windows. For Requirements 1, 3 and 5, compliance is required at the next major inspection or next wing tank access, or within 24 months after the effective date of the Directive, whichever occurs first. For Requirements 2 and 4, any corrective actions discovered by the inspections must be done before the next flight after the applicable inspection or examination. These timing provisions create an immediate duty to schedule the inspections and to remediate faults promptly.

Method and standards duties. The Directive binds operators to complete the tasks “in accordance with” specified paragraphs of SB J41‑28‑013 Rev 1. The SB therefore constitutes the normative technical standard for how the inspections, adjustments and additional bonding are to be performed. The AD also states that later SB revisions approved by EASA are acceptable, which creates a conditional route for compliance by following an EASA‑approved revision rather than Revision 1.

Rights and allowances in the text. The AD provides a limited procedural right: compliance may be achieved using later revisions of SB J41‑28‑013, provided those later revisions are approved by EASA. This gives operators the right to adopt an EASA‑approved updated SB instead of the Revision 1 cited in the AD. The AD also cross‑references EASA AD 2008‑0040, signalling that consideration should be given to related EASA requirements, although the text does not turn that cross‑reference into a right or duty beyond the acceptance of EASA‑approved SB revisions.

Who decides how work is performed. The Directive requires work to be done “in accordance with” particular SB paragraphs. The SB will define procedures, acceptance criteria and installation details. In practical terms this delegates technical method and workmanship standards to the SB author (BAE Systems (Operations) Ltd), subject to the approval mechanism for later SB revisions by EASA. CASA’s Delegate issued the AD, so CASA is the regulator enforcing the Directive; however the technical content and methods arise from the SB.

Documentation of airworthiness parts. The AD requires replacement “with airworthy parts.” The Directive thereby creates a duty to use parts meeting the airworthiness standard for the aeroplane and modification, although the AD does not specify certification paperwork or part numbers beyond what the SB will provide.

No explicit penalty clauses in the text. The Directive prescribes mandatory requirements and an effective date. It does not, within the text provided, set out civil or criminal penalties, nor does it specify administrative enforcement steps such as revocation of certificates. The AD does identify CASA by signature as the issuing authority and gives a compliance timeline, but the text does not contain expressed penalty provisions.

The Directive prescribes mandatory inspection, corrective and modification duties, and sets specific compliance timings. It becomes effective on 14 March 2008, as stated in the Compliance line. The instrument is signed by David Punshon, Delegate of the Civil Aviation Safety Authority, indicating the issuing authority. Beyond this, the text supplied does not set out explicit civil, administrative or criminal penalties for non‑compliance, nor does it describe the enforcement mechanisms CASA will deploy (for example grounding, enforcement notices, or prosecutions). The Directive’s provisions are mandatory, and the effective date fixes the period within which the specified actions must be completed, but the AD itself, in the printed table and background provided, does not spell out sanctions.

Enforcement elements that are present. The AD contains mandatory phrasing: “Requirement … Inspect …”, “If … replace …”, “Examine …”, “adjust …”, and “Install …”. It ties the method of compliance to specific SB paragraphs and to EASA approval of later SB revisions. The presence of an effective date and definitive compliance windows (next major inspection or wing tank access, or within 24 months, and remedials before next flight) creates a verifiable standard against which compliance may be assessed. The AD’s signature by a CASA Delegate supplies institutional provenance and indicates that CASA is the issuing regulatory body.

Enforcement elements not stated. The AD does not specify how CASA will verify compliance in this text (for example, whether CASA will require notice of compliance, submission of maintenance records, or audit). The text does not indicate any particular inspection, audit timetable, or reporting channel tied to CASA. The AD likewise does not list monetary fines, certificate actions, or criminal penalties in its body. It does not provide transitional enforcement arrangements, such as amnesty periods, beyond the stated compliance windows.

Implications for operators. Given the mandatory phrasing and the specificity of the requirements and timing, the practical implication is that operators must implement the AD’s Requirements within the stated timeframes. The AD’s remedial deadlines (before next flight) make certain defects immediate grounds for grounding until rectified. The AD also references EASA approval for later SB revisions and EASA AD 2008‑0040, meaning operators should track the EASA material to ensure they adopt technically acceptable procedures. The absence of penalty text in the AD means operators must look to the broader regulatory framework under which CASA operates (not set out here) to determine what enforcement actions may follow if they do not comply.

Reference to SFAR 88 and JAA/EASA policy. The Background explicitly states that the actions flow from “the assessment of fuel tank wiring installations required by SFAR 88 and equivalent JAA/EASA policy.” That statement ties this CASA AD to an international safety policy impetus (SFAR 88 was a US FAA special Federal Aviation Regulation addressing fuel tank safety), and to JAA/EASA policy in Europe. The AD therefore functions as an implementation measure responding to those higher‑level assessment requirements.

Interplay with EASA documents. The AD explicitly accepts later revisions of SB J41‑28‑013 if those revisions are approved by EASA. It also contains the note “EASA AD 2008‑0040 refers.” These references indicate that compliance routes acceptable to CASA can be those accepted by EASA for the same design issue, and that operators should consult EASA AD 2008‑0040 for related or parallel requirements. The Directive therefore creates an interaction between CASA’s airworthiness direction and EASA’s airworthiness approvals and ADs.

Service Bulletin as technical standard. The AD makes compliance contingent upon following SB J41‑28‑013 Rev 1 (and later EASA‑approved revisions). In effect the SB is elevated from manufacturer guidance to normative legal standard for Australian compliance. This intertwines the manufacturer’s technical instructions with the regulator’s mandatory requirement, so legal compliance is achieved by following the SB paragraphs cited.

Modification identification within continuing airworthiness processes. The Background names modification JM41659 as the design change introduced by SB J41‑28‑013. Operators performing the modification will need to align with any applicable national continuing airworthiness rules governing modifications and minor/major changes for their registry. The AD itself does not restate those regulatory processes, but the identification of JM41659 links the AD to the modification control and certification practices applicable in the airworthiness regime.

Potential overlap with other ADs and international obligations. The AD sits within a broader regime of airworthiness directives that a regulator may require. The cross‑reference to EASA AD 2008‑0040 suggests there may be parallel or complementary obligations from EASA. Operators under multiple jurisdictions, or aircraft that cross registries, will need to manage any differences between CASA and EASA directions. The AD’s explicit allowance for EASA‑approved SB revisions provides a mechanism for harmonisation but does not by itself resolve all cross‑jurisdictional procedural obligations such as record submission or enforcement actions, which will be set out in the respective regulators’ processes.

No statutory penalty text within the AD. The AD does not itself change primary aviation statutes or specify offences; it prescribes mandatory actions under the airworthiness direction mechanism. Any statutory enforcement powers or offences are outside the textual scope of the AD as provided. Operators need to consider the broader aviation regulatory framework for consequences of non‑compliance.

Document identifiers and dates. The AD is referenced as AD/J4100/25 and labelled 5/2008 DM. It was signed by David Punshon, Delegate of the Civil Aviation Safety Authority, on 5 March 2008. The AD states that it becomes effective on 14 March 2008.

Service Bulletin versioning. The AD cites BAE Systems (Operations) Ltd Service Bulletin J41‑28‑013 Revision 1 dated 10 January 2008 as the prescriptive technical document for compliance. The AD also expressly permits “Later revisions of SB J41‑28‑013, approved by the European Aviation Safety Agency (EASA),” as acceptable for compliance. Thus the AD includes an internal amendment pathway for the technical means of compliance: if the SB is revised and EASA approves the revision, operators may rely on that revision instead of Revision 1.

Design modification identifier. The Background identifies the design change introduced by SB J41‑28‑013 as modification number JM41659. That links the AD to a particular modification configuration and, implicitly, to the manufacturer’s change control history for the type.

Absence of subsequent AD amendments in the text. The supplied text contains no later amendments to this AD itself, no revocations, and no superseding CASA documents. It only states that later SB revisions approved by EASA are acceptable. There is no explicit record in the text of subsequent AD versions, reissuances, or amendments to the AD number or its compliance dates.

Cross‑reference to EASA AD. The AD contains the notation “Note: EASA AD 2008‑0040 refers.” That is the only cross‑document reference to another airworthiness directive. The AD does not in the supplied text indicate whether EASA AD 2008‑0040 amends, endorses, or differs from the CASA AD; it only signals a relationship worth consulting in practice.

Practical consequence for amendment tracking. Because the AD allows EASA‑approved later SB revisions and references an EASA AD, operators and maintainers must monitor both the SB revision history and EASA AD issuances if they intend to rely on later SB revisions for compliance. The AD itself was issued in March 2008 and set a 24‑month window for parts of the work, so the immediate amendment history relevant to operators concerned their ability to adopt EASA‑approved SB updates in that period.

The supplied AD text does not include any litigation history. There are no cases, prosecutions, appeals, or court decisions mentioned in the document. The Background recounts the technical and policy antecedents (SFAR 88 and JAA/EASA policy) that prompted the manufacturer to produce SB J41‑28‑013 and the regulator to issue this AD, but it does not record disputes, objections, or legal challenges to the Directive.

Because the document contains no litigation history, the following must be noted as absent from the source: there is no recorded administrative appeals process, no catalogue of enforcement actions taken under this AD, and no references to judicial review or tribunal decisions challenging the AD in the provided text. If a practitioner needs litigation or enforcement precedents, they will need to consult CASA records, tribunal or court databases, or the operators’ public filings; none of that material is contained within the AD excerpt supplied here.

The AD’s cross‑reference to EASA AD 2008‑0040 is a pointer to related regulatory action in another jurisdiction but does not, within this text, indicate any litigation connected to that EASA AD. Likewise, the AD’s identification of the modification (JM41659) and the SB does not include any dispute records about the technical change.

Scope is absolute across models and serials. The AD states applicability as “Jetstream 4100 series aeroplanes, all models, all serial numbers.” Where an operator may assume a later production batch or variant is excluded, that assumption would be incorrect for this AD: the Directive’s applicability is blanket for the type as stated.

Precisely defined inspection locations. Requirement 1 narrows inspection to bonding leads between ribs 1 and 9, and between ribs 16 and 19, in both LH and RH wings. Failure to inspect the exact locations specified, or to follow the SB paragraph (2B(2)) specified for the method, risks non‑compliance even if other bonding leads are inspected. The AD’s terminology is prescriptive: inspections must be “in accordance with paragraph 2B(2) of SB J41‑28‑013 Revision 1 dated 10 January 2008.”

Sequencing and timing traps. Requirements 1, 3 and 5 have a compliance window tied to next major inspection or wing tank access or within 24 months after the effective date. If an operator delays past the earliest of those triggers, the AD’s deadline is the sooner of those events. Requirements 2 and 4 require rectification “before the next flight after the applicable inspection/examination.” That leaves no operational margin for aircraft discovered with defects: the aircraft must not return to flight until remedial work is complete. Operators with high utilisation or with remote maintenance logistics must plan for the potential for immediate grounding.

“Airworthy parts” requirement. Requirement 2 requires replacement of defective bonding leads with “airworthy parts.” The AD does not list part numbers or acceptance paperwork in the text; the SB will provide technical detail. Operators must ensure that replacement items meet the airworthiness standard applicable to the aircraft and the modification JM41659. Sourcing the correct parts or kits may introduce lead‑time and supply issues that affect availability.

Dependency on the Service Bulletin detail. The AD delegates technical detail to specific SB paragraphs. For example, Requirement 5 refers to paragraphs 2B(4) to 2B(15) for installing additional electrical bonding. If an operator uses a later SB revision, it must ensure that the revision is approved by EASA for acceptance under the AD. Operators that do not secure or follow the precise SB paragraphs risk non‑compliance despite having performed related work.

EASA approval condition. The AD permits later revisions of the SB only where those revisions are “approved by the European Aviation Safety Agency (EASA).” An operator cannot rely on an unapproved SB revision even if the later revision is available from the manufacturer. They must confirm EASA approval for that revision for it to be acceptable under this AD.

Cross‑reference to EASA AD. The AD’s note “EASA AD 2008‑0040 refers” suggests there is a related EASA AD. Operators should not assume that compliance with the CASA AD alone resolves all international obligations. The AD text does not describe whether EASA AD 2008‑0040 imposes different or additional measures; the lack of that elaboration is a potential source of oversight error if operators ignore the EASA material.

Modification identification expectation. The Background identifies modification JM41659 as the design change introduced by the SB. Operators must ensure that any installation of additional bonding is consistent with the modification reference. The AD text does not mandate recording the modification in any specific fashion in the supplied excerpt; however confusion can arise if installations are not matched to the JM41659 configuration.

No express enforcement mechanics in the AD text. The AD does not spell out what CASA will do to verify compliance or what administrative or criminal penalties apply in the event of non‑compliance. Operators may mistakenly assume presence or absence of enforcement actions; the AD itself does not clarify that. Practical enforcement mechanisms may be set out elsewhere in CASA rules and not in the AD.

Follow the AD’s five Requirements and the SB paragraphs it cites, within the specified timing windows.

Stepwise actions drawn from the Directive text:

1. Obtain SB J41‑28‑013 Revision 1 dated 10 January 2008 from BAE Systems (Operations) Ltd, and any subsequent revisions only if they are approved by EASA. The AD explicitly references Rev 1 and allows later EASA‑approved revisions. Confirm whether EASA has approved any later SB revision if you intend to use one instead of Rev 1.

2. Schedule the inspections and work. For Requirements 1, 3 and 5, plan to perform them at the next major inspection, or at next wing tank access, or within 24 months after the AD’s effective date (14 March 2008), whichever occurs first. Do not assume more time if a wing tank access or major inspection occurs before 24 months.

3. Perform Requirement 1 inspection. Inspect the bonding leads between ribs 1 and 9, and between ribs 16 and 19, in both LH and RH wings. Execute the inspection “in accordance with paragraph 2B(2) of SB J41‑28‑013 Revision 1.” Use the SB’s procedural steps, gauges, acceptance criteria and access instructions as the normative method.

4. Carry out Requirement 3 examination. Examine all fuel system pipe runs inside the LH and RH wings in accordance with paragraph 2B(3) of the SB. The SB will set out how to inspect routing, clamps, supports, and measure clearances to other structure and components.

5. For any defective bonding leads or incorrect clearances found, complete remedial work before the next flight. Requirement 2 instructs replacing defective bonding leads with “airworthy parts.” Requirement 4 instructs adjusting incorrect fuel pipe clearances “to meet the requirements of the SB.” Both remedial tasks are required to be completed before the next flight after the inspection/examination that discovered them.

6. Install additional electrical bonding. Requirement 5 requires installation of additional electrical bonding of components within the LH and RH wings “in accordance with paragraphs 2B(4) to 2B(15) of SB J41‑28‑013 Revision 1.” Perform the full set of installation tasks in the SB paragraphs cited. The Background identifies this installation as modification JM41659.

7. Use airworthy parts for replacements. Where replacement is required by Requirement 2, ensure that replacement bonding leads and any associated hardware meet the airworthiness standard for the Jetstream 4100. The AD requires “airworthy parts,” but the SB will be the source of specific part numbers and installation methods.

8. If electing to use a later SB revision, confirm EASA approval. The AD expressly accepts later revisions only if approved by EASA. Before relying on a later SB revision for compliance, obtain documentation that EASA approved that revision.

9. Consider EASA AD 2008‑0040. The AD notes “EASA AD 2008‑0040 refers.” Review that EASA AD for complementary requirements or guidance relevant to the same design issue.

10. Adhere to the sequencing and deadlines. Remember the two timing buckets: inspections/installations to be done at next major inspection/wing tank access or within 24 months; remedial replacements and clearance adjustments must be completed before next flight.

Items the AD makes mandatory, verbatim. The actions listed above derive from the AD’s Requirement statements and the Compliance timing lines. The SB paragraphs cited are the technical source documents the AD mandates operators to follow for the detailed methods and acceptance criteria.

Operational notes derived from the AD text. The AD ties the technical method to the SB and identifies a modification number. Practically, implementers must ensure they have access to the correct SB revision, verify EASA approvals where applicable, source airworthy replacement parts, obtain the correct installation kits or change parts related to modification JM41659, and schedule inspections during the earliest of next major inspection, next wing tank access or within the AD’s 24‑month timeline.

Limitations of the AD text. The AD does not prescribe documentation or reporting procedures in the supplied text, nor does it specify which forms or entries to make in maintenance logs after compliance. The AD also does not give explicit instructions about approvals needed for use of non‑standard parts or alternative methods of compliance; such alternatives would presumably require regulatory consultation but are not provided for in this AD excerpt. If an operator anticipates needing an alternative means of compliance, they should engage with the relevant regulatory authority, noting the AD’s specific acceptance language for EASA‑approved SB revisions.

In short, compliance requires executing the five Requirements using the SB paragraphs specified, meeting the airworthy parts standard where applicable, observing the strict remedial deadlines (before next flight), and ensuring any use of later SB revisions is backed by EASA approval, as the AD permits.