{"id":"F2008L00695","name":"AD/J4100/24 - Fuel Boost Pump and Fuel Tank High Level Sensor Wiring","slug":"ad-j4100-24-fuel-boost-pump-and-fuel-tank-high-level-sensor-wiring","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":72735,"registerId":"commonwealth-F2008L00695-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"BAe Systems (Operations) Jetstream 4100 ","sectionType":"division","heading":"BAe Systems (Operations) Jetstream 4100 Series Aeroplanes","content":"### BAe Systems (Operations) Jetstream 4100 Series Aeroplanes\n\n| AD/J4100/24 | Fuel Boost Pump and Fuel TankHigh Level Sensor Wiring | 5/2008 DM |\n| ----------- | ----------------------------------------------------- | --------- |\n\n| Applicability: | Jetstream 4100 series aeroplanes, all models, all serial numbers. |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. Modify the left (LH) and right (RH) wing fuel boost pump wiring in accordance with paragraphs 2B and 2C of BAE Systems (Operations) Ltd Service Bulletin (SB) J41-28-014 Revision 1 dated 21 December 2007. |\n| | 2. Inspect the LH and RH wing fuel high level sensor wiring in accordance with paragraph 2D of SB J41-28-014 Revision 1. |\n| | 3. If excess wiring and/or damaged wiring is found during the Requirement 2 inspection, accomplish the corrective actions as specified in paragraph 2DSB J41-28-014 Revision 1. |\n| | Later revisions of SB J41-28-014, approved by the European Aviation Safety Agency (EASA), are acceptable for compliance with the requirements of this Directive. |\n| | Note: EASA AD 2008-0041 refers. |\n| Compliance: | For Requirement 1 and 2 - At the next major inspection or wing tank access, or within 24 months after the effective date of this Directive, whichever occurs first. |\n| | For Requirement 3 - Before the next flight after the Requirement 2 inspection. |\n| | This Airworthiness Directive becomes effective on 14 March 2008. |\n| Background: | Following the assessment of fuel tank wiring installations required by SFAR 88 and equivalent JAA/EASA policy, BAE Systems identified two features in the Jetstream 4100 where the need for design changes was apparent. One of these is addressed by SB J41-28-014 which introduces changes to the wiring harness installations to the LH and RH fuel boost pumps, identified by modification number JM41672. In addition, to detect excessive cable lengths and evidence of chafing damage, SB J41-28-014 provides instructions to inspect and correct, as necessary, the internal fuel tank wiring routed to the LH and RH high level sensors.Internal fuel tank wiring chafing damage, if not corrected, could lead to ignition of fuel vapours and subsequent fuel tank explosion. |\n\n| | For the reason stated above, this Directive requires the replacement of the (LH and RH) fuel boost pump metallic conduit assemblies with loom assemblies and the inspection of internal fuel tank high level sensor wiring, together with corrective actions, as necessary. |\n| --- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png) \nDavid Punshon \nDelegate of the Civil Aviation Safety Authority\n\n5 March 2008","sortOrder":0},{"sectionNumber":"AD/J4100/24","sectionType":"part","heading":"AD/J4100/24","content":"## AD/J4100/24","sortOrder":1},{"sectionNumber":"Fuel Boost Pump and Fuel TankHigh Level ","sectionType":"part","heading":"Fuel Boost Pump and Fuel TankHigh Level Sensor Wiring","content":"## Fuel Boost Pump and Fuel Tank \nHigh Level Sensor Wiring","sortOrder":2},{"sectionNumber":"5/2008 DM","sectionType":"part","heading":"5/2008 DM","content":"## 5/2008 DM","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive addresses specific wiring installation and inspection tasks identified by an SFAR 88 style assessment. It stays within that original safety‑focused scope (replace conduit with loom assemblies and inspect/correct high level sensor wiring) and does not introduce unrelated regulatory subjects or broaden obligations beyond the fuel‑tank wiring changes and inspections described in the supporting Service Bulletin."},"complexity_factors":["Short, single‑aircraft-type applicability (Jetstream 4100 series)","Three discrete requirements (modify wiring; inspect sensor wiring; corrective actions)","References to one principal external document: SB J41-28-014 Revision 1 (and later EASA‑approved revisions)","Timing conditions with two alternatives (next major inspection or wing tank access, or within 24 months) plus an immediate corrective‑action deadline (before next flight)","Cross‑reference to external regulatory material: EASA AD 2008-0041 and SFAR 88 policy background","A single hardware modification identified (JM41672) rather than multiple, nested options"],"plain_english_summary":"**What this instrument changes (mechanically)**\n\n- Requires physical changes to the fuel pump wiring on BAe Jetstream 4100 aeroplanes: replace the left and right wing fuel boost pump metallic conduit assemblies with loom (bundle) assemblies as set out in BAE Systems (Operations) Service Bulletin (SB) J41-28-014 Revision 1 (dated 21 December 2007) (Requirement 1). The SB identifies this as modification JM41672.\n- Requires an inspection of the left and right wing fuel high level sensor internal wiring for excess length and evidence of chafing, in accordance with paragraph 2D of SB J41-28-014 Revision 1 (Requirement 2).\n- If the inspection finds excess or damaged wiring, requires corrective actions specified in the SB (Requirement 3). Corrective actions must be completed before the next flight after the inspection.\n- Later revisions of SB J41-28-014 are acceptable for compliance if they are approved by the European Aviation Safety Agency (EASA). The directive also cross‑refers EASA AD 2008-0041.\n\n**Who is affected**\n\n- Aircraft operators and owners of all BAe Systems (Operations) Jetstream 4100 series aeroplanes (all models and all serial numbers).\n- Maintenance organisations and licensed engineers who perform inspection and modification work on these aeroplanes.\n- Parts suppliers who provide the loom assemblies or other replacement components called up by the Service Bulletin.\n\n**Timing and compliance mechanics**\n\n- The replacement (Requirement 1) and the inspection (Requirement 2) must be done at the next major inspection or next wing tank access, or within 24 months from the directive’s effective date — whichever comes first.\n- Any corrective action required after the inspection (Requirement 3) must be finished before the aeroplane’s next flight.\n- The directive became effective on 14 March 2008 and expressly permits later EASA‑approved revisions of the SB for compliance.\n\n**Why this matters (official rationale and operational test)**\n\n- Official rationale: following a fuel‑tank wiring assessment (SFAR 88 and equivalent JAA/EASA policy), BAE identified that the existing metallic conduit assemblies and certain internal wiring arrangements could lead to excess cable length or chafing inside the fuel tank. Chafing can produce electrical faults or hot surfaces that could ignite fuel vapours; the AD’s stated purpose is to reduce that ignition risk by changing the conduit to a loom assembly and by inspecting and correcting sensor wiring.\n\n- Practical implications and trade‑offs:\n - Who pays: aircraft owners/operators pay for parts, labour and any downtime required to carry out the modification and inspections (Requirements 1 and 2) and for corrective work if defects are found (Requirement 3).\n - Who decides/times the work: the operator schedules the work, but must meet the AD’s deadlines (next major inspection/wing tank access or within 24 months). Licensed maintenance organisations must perform the work to the SB instructions; regulators (CASA and EASA) determine which SB revisions are acceptable.\n - Behaviour change: operators will have to plan and budget for the modification and inspections, and may combine them with scheduled maintenance to reduce aircraft downtime. Maintenance providers must follow the SB and may need to source new parts (loom assemblies).\n - Costs vs benefits: the measure imposes concentrated, identifiable costs on operators (parts, labour, downtime). The benefit is a reduced probability of wiring‑related ignition in the fuel tank—an event with very low frequency but very high severity. The directive converts a latent design/installation risk into a managed maintenance obligation.\n - Substitution and opportunity costs: operators can choose when (within the compliance window) to perform the work; doing it during other scheduled checks reduces incremental downtime but may shift workload for maintenance providers. If parts or qualified technicians are scarce, scheduling delays could occur.\n - Implementation risk and compliance burden: the AD relies on the SB for technical steps; complexity of access (wing tank access) and correct execution of inspections influence the real cost and effectiveness. The AD allows later SB revisions approved by EASA, which centralises technical approval but requires operators to track regulatory approvals.\n\n**Concrete references in the instrument**\n\n- Requirements 1–3 specify the actions (replace conduit with loom; inspect sensor wiring; perform corrective actions) and reference SB J41‑28‑014 Revision 1 (21 December 2007).\n- Compliance timing is set out under the “Compliance” heading: at next major inspection or wing tank access, or within 24 months (Requirements 1 & 2); corrective actions before next flight (Requirement 3).\n- The background links this AD to SFAR 88 assessments and to EASA AD 2008‑0041 and names modification JM41672 for the hardware change.\n\n**Bottom line**\n\nThis AD mandates a specific wiring modification and inspection regime for all Jetstream 4100 aircraft to address identified risks of excess wiring and chafing inside the wing fuel tanks. Operators and maintenance organisations bear the direct costs and planning burden; the regulator enforces a defined compliance window and accepts EASA‑approved SB revisions for technical detail."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing specific wiring safety issues in Jetstream 4100 fuel tanks identified through SFAR 88 assessments. The requirements remain tightly focused on the two identified wiring hazards (boost pump conduits and high level sensor wiring) without expansion into unrelated systems."},"complexity_factors":["Single, specific aircraft type (Jetstream 4100 series) with clear applicability","Only 3 main requirements with straightforward conditional logic (if damage found → repair)","References external technical document (Service Bulletin J41-28-014) but provides specific paragraph citations","Simple compliance timeline with only two conditions (next inspection/24 months vs before next flight)","No nested definitions, interpretation sections, or extensive cross-referencing to other legislation","Background clearly explains the safety rationale (fuel tank explosion risk from wiring chafing)"],"plain_english_summary":"This CASA Airworthiness Directive requires operators of BAe Jetstream 4100 series aircraft in Australia to replace the metal conduit around left and right fuel boost pump wiring with new loom assemblies, inspect high‑level sensor wiring for excess length or damage, and repair any defects. The work must be done at the next major inspection, when the wing tank is opened, or within 24 months, and any repairs completed before flight."}},"importantCases":[],"_links":{"self":"/api/acts/ad-j4100-24-fuel-boost-pump-and-fuel-tank-high-level-sensor-wiring","history":"/api/acts/ad-j4100-24-fuel-boost-pump-and-fuel-tank-high-level-sensor-wiring/history","analysis":"/api/acts/ad-j4100-24-fuel-boost-pump-and-fuel-tank-high-level-sensor-wiring/analysis","conflicts":"/api/acts/ad-j4100-24-fuel-boost-pump-and-fuel-tank-high-level-sensor-wiring/conflicts","importantCases":"/api/acts/ad-j4100-24-fuel-boost-pump-and-fuel-tank-high-level-sensor-wiring/important-cases","documents":"/api/acts/ad-j4100-24-fuel-boost-pump-and-fuel-tank-high-level-sensor-wiring/documents"}}