{"id":"F2007L00384","name":"AD/B737/299 - Electrical Bonding","slug":"ad-b737-299-electrical-bonding","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":63414,"registerId":"commonwealth-F2007L00384-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 737 Series Aeroplanes","sectionType":"division","heading":"Boeing 737 Series Aeroplanes","content":"### Boeing 737 Series Aeroplanes\n\n| AD/B737/299 | Electrical Bonding | 3/2007 |\n| ----------- | ------------------ | ------ |\n\n| Applicability: | Model 737-600, -700, -700C, -800 and -900 series aeroplanes, as identified in Boeing Special Attention Service Bulletin (SB) 737-28-1225, Revision 1, dated30 October 2006.                                                                                                                                                                                   |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| 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. Both actions are to be accomplished in accordance with the SB 737-28-1225, Revision 1. |\n|                | 2. Carry out all applicable corrective actions in accordance with SB 737-28-1225, Revision 1.                                                                                                                                                                                                                                                                 |\n|                | 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.                                                                                                        |\n|                | 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.                                                                                           |\n|                | Note: FAA AD 2007-02-14 refers.                                                                                                                                                                                                                                                                                                                               |\n| Compliance:    | For Requirement 1 - Within 60 months after the effective date of this Directive.                                                                                                                                                                                                                                                                              |\n|                | For Requirement 2 - Before further flight after the Requirement 1 electrical resistance test.                                                                                                                                                                                                                                                                 |\n|                | This Airworthiness Directive becomes effective on 15 March 2007.                                                                                                                                                                                                                                                                                              |\n\n| Background: | This Directive requires testing the electrical resistance of the bond between the bulkhead fitting for the fuel feed line and the front spar of the left and right wings, inspecting an adjacent bonding jumper to make sure it is installed correctly and, if necessary, performing corrective and other specified actions as applicable. The Directive is issued to prevent arcing or sparking in the fuel tank in the event of a lightning strike, which could result in an uncontrolled fire or explosion. |\n| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n1 February 2007","sortOrder":0},{"sectionNumber":"AD/B737/299","sectionType":"part","heading":"AD/B737/299","content":"## AD/B737/299","sortOrder":1},{"sectionNumber":"Electrical Bonding","sectionType":"part","heading":"Electrical Bonding","content":"## Electrical Bonding","sortOrder":2},{"sectionNumber":"3/2007","sectionType":"part","heading":"3/2007","content":"## 3/2007","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This directive stays within the original technical purpose: verify and restore electrical bonding at the fuel feed-line bulkhead fitting to prevent arcing under lightning strike. It does not broaden to additional systems or aircraft models beyond those identified in the Boeing SB, and it explicitly recognises prior compliance and FAA-approved AMOCs rather than imposing new or expanded obligations. The directive primarily implements Boeing/FAA technical guidance for the specified models without expanding scope beyond that safety-focused intent."},"complexity_factors":["Short, single-purpose Airworthiness Directive with two discrete actions (test/inspect and corrective action).","References a single external technical document: Boeing Special Attention Service Bulletin 737-28-1225, Revision 1.","Accepts earlier Boeing SB dated 12 January 2006 for prior compliance (one explicit exception).","Allows later SB revisions only if approved by U.S. FAA as an AMOC to FAA AD 2007-02-14 (cross-jurisdictional cross-reference).","Two-tier compliance timing: one long window (60 months) for the test/inspection, immediate requirement (before further flight) for corrective actions.","No extensive defined-terms section, no nested exceptions beyond the single acceptance of previous compliance and FAA-approved AMOCs."],"plain_english_summary":"**What this directive does (mechanically)**\n\n- Requires operators of certain Boeing 737 series aeroplanes to test the electrical resistance of the bonding connection between the fuel feed-line bulkhead fitting and the wing front spar on both left and right wings, and to visually inspect the adjacent bonding jumper to confirm it is correctly installed (Requirement 1).\n- Requires any corrective work found to be necessary after that test/inspection to be done in accordance with Boeing Special Attention Service Bulletin (SB) 737-28-1225, Revision 1 (Requirement 2).\n- Allows work already done before the directive, if done to Boeing SB 737-28-1225 dated 12 January 2006, to count as compliance. Later revisions of the SB that the U.S. FAA has approved as an Alternate Method of Compliance (AMOC) to FAA AD 2007-02-14 are also acceptable (Requirements and notes).\n- Sets compliance timing: the resistance test and inspection must be done within 60 months of the directive's effective date; any required corrective actions must be completed before the aeroplane flies again (Compliance).\n\n**Who is affected**\n\n- Owners and operators of Boeing 737-600, -700, -700C, -800 and -900 series aeroplanes that are identified in Boeing SB 737-28-1225, Revision 1 (Applicability). Maintenance organisations and licensed technicians who service those aeroplanes are also affected because they must perform the tests and repairs.\n\n**Why it matters (stated purpose and mechanical effect)**\n\n- The directive aims to reduce the risk of arcing or sparking in the fuel tank if the aeroplane is struck by lightning. Testing and, if necessary, repairing the electrical bond reduces the likelihood that lightning-induced currents could jump (arc) across a poor bond and ignite fuel vapour (Background).\n\n**Practical implications, incentives and trade-offs**\n\n- Who pays: the operator (airline or aircraft owner) bears the cost of testing, inspections and any corrective maintenance. If corrective work is required immediately, the operator also bears the cost of aircraft downtime and possible schedule disruption (Requirement 2; Compliance).\n- Who decides: the Civil Aviation Safety Authority issued the directive for Australian-registered aircraft; operators decide scheduling and may use later FAA-approved SB revisions as an alternative method of compliance if authorised (Notes on AMOC).\n- Behavioural change required: operators must schedule a resistance test/visual inspection within 60 months and must not return an aeroplane to service after a failed test until required repairs are completed. Maintenance providers must follow Boeing SB 737-28-1225, Revision 1 (or an FAA-approved AMOC).\n- Compliance burden and implementation risk: the directive is short and specific but requires access to the bulkhead fittings and use of appropriate test equipment and trained personnel. If a bond fails the resistance threshold, corrective action must be completed before flight which may cause immediate grounding and increased downtime.\n- Timing trade-off: a 60‑month window gives operators flexibility to align the inspection with scheduled heavy maintenance to reduce incremental downtime, but it also leaves the condition unverified for up to five years.\n- Interaction with existing work: the directive accepts earlier compliance done to the January 2006 SB and permits FAA-approved later SB revisions as AMOCs, which reduces duplication where operators have already followed Boeing/FAA guidance (Requirements/Notes).\n\n**Market and operational effects**\n\n- Directly increases demand for maintenance work from affected fleets, which benefits maintenance providers competent on Boeing 737 structural/electrical work.\n- May impose modest additional operating cost on affected operators (labour, materials, possible downtime). The cost is concentrated on those operators with affected models, while the safety benefit is diffuse (applies broadly to passengers and aircraft integrity).\n\n**Concrete risk and limitations**\n\n- The directive relies on Boeing SB procedures and recognises FAA AMOCs; this cross-reference centralises the technical solution in Boeing/FAA material, so operators are reliant on those documents for exact steps and thresholds.\n- The directive itself does not specify the numerical resistance limit or the detailed repair technique—those are in the referenced SB—so implementers must consult the SB for technical thresholds and corrective action steps (Requirement references)."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope — addressing a specific electrical bonding defect on specific Boeing 737 models to prevent fuel tank explosions. There is no evidence of scope creep; it remains tightly focused on the single safety issue identified in the background."},"complexity_factors":["Single, specific technical requirement (electrical resistance testing and visual inspection)","Only 2 main compliance actions with clear deadlines","Minimal cross-referencing — primarily refers to one Boeing Service Bulletin (SB 737-28-1225)","Simple conditional logic: 'if test fails, repair before next flight'","Short document (approximately 300 words of substantive content)","Only 3 defined technical terms (bonding jumper, bulkhead fitting, front spar) that are standard aviation maintenance terms","No nested exceptions or complex procedural hierarchies"],"plain_english_summary":"This AD mandates testing the electrical resistance of the bond between a fuel line fitting and wing structure, visually inspecting nearby bonding jumpers, and repairing defects on certain Boeing 737-600/700/700C/800/900 series (per Boeing SB 737-28-1225 Rev 1). It affects operators of those aircraft to mitigate a lightning-induced arcing/explosion risk in the fuel tank. Tests/inspections are required within 60 months; any repairs must be done before next flight."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-299-electrical-bonding","history":"/api/acts/ad-b737-299-electrical-bonding/history","analysis":"/api/acts/ad-b737-299-electrical-bonding/analysis","conflicts":"/api/acts/ad-b737-299-electrical-bonding/conflicts","importantCases":"/api/acts/ad-b737-299-electrical-bonding/important-cases","documents":"/api/acts/ad-b737-299-electrical-bonding/documents"}}