{"id":"F2007L04540","name":"AD/CL-600/90 - Fuel Line Couplings","slug":"ad-cl-600-90-fuel-line-couplings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":71043,"registerId":"commonwealth-F2007L04540-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Bombardier (Canadair) CL-600 (Challenger","sectionType":"division","heading":"Bombardier (Canadair) CL-600 (Challenger) Series Aeroplanes","content":"### Bombardier (Canadair) CL-600 (Challenger) Series Aeroplanes\n\n| AD/CL-600/90 | Fuel Line Couplings | 13/2007 |\n| ------------ | ------------------- | ------- |\n\n| Applicability: | Bombardier Inc. Model CL-600-2B19 aircraft, serial numbers 7003 through 7067, and 7069 through 7981. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement: | Replace the fuel tube couplings inside the wing and centre fuel tanks with redesigned couplings, according to the Accomplishment Instructions of Bombardier Service Bulletin (SB) 601R-28-054, Revision A, dated 7 August 2006, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.Note: Transport Canada AD CF-2007-23 dated 18 October 2007 refers. |\n| Compliance: | Within 5000 flight hours after the effective date of this AD. |\n| | This Airworthiness Directive becomes effective on 20 December 2007. |\n| Background: | Bombardier Aerospace has completed a system safety review of the CL-600-2B19 aircraft fuel system against new fuel tank safety standards, introduced in Chapter 25 of the Transport Canada Airworthiness Manual through Notice of Proposed Amendment (NPA) 2002-043. The identified non-compliances were assessed using Transport Canada Policy Letter No. 525-001 to determine if mandatory corrective action is required.The assessment and lightning tests showed that certain fuel tube self-bonded couplings do not provide sufficient lightning current capability. The assessment also showed that single failure of the integral bonding wire of the self-bonded couplings or excessive axial clearance at the reducer ferrules of certain self-bonded couplings could affect electrical bonding between fuel tubes.Insufficient electrical bonding between fuel tubes or insufficient current capability of fuel tube couplings, if not corrected, could result in arcing and potential ignition source inside the fuel tank during lightning strikes and consequent fuel tank explosion. To correct the unsafe condition, this AD mandates the replacement of certain fuel tube couplings with redesigned couplings. |\n\n![](image.001.png) \nDavid Punshon \nDelegate of the Civil Aviation Safety Authority\n\n25 October 2007","sortOrder":0},{"sectionNumber":"AD/CL-600/90","sectionType":"part","heading":"AD/CL-600/90","content":"## AD/CL-600/90","sortOrder":1},{"sectionNumber":"Fuel Line Couplings","sectionType":"part","heading":"Fuel Line Couplings","content":"## Fuel Line Couplings","sortOrder":2},{"sectionNumber":"13/2007","sectionType":"part","heading":"13/2007","content":"## 13/2007","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope: addressing a specific fuel system safety defect in a specific aircraft model. It has not expanded beyond its original purpose of correcting the lightning protection deficiency in fuel tube couplings."},"complexity_factors":["Single, specific technical requirement with clear applicability criteria (specific aircraft model and serial number ranges)","Only one compliance pathway specified (follow the referenced Service Bulletin)","No nested exceptions, conditional logic, or alternative compliance methods","Simple time-based compliance deadline (5000 flight hours)","Minimal cross-referencing (only references one Transport Canada AD and one Bombardier Service Bulletin)","No defined terms section — uses standard aviation terminology","Short document (approximately 300 words of substantive content)"],"plain_english_summary":"This AD requires owners/operators of certain Bombardier Challenger 600 series (CL-600-2B19, s/n 7003–7067, 7069–7981) to replace wing and centre tank fuel-tube couplings with redesigned, electrically conductive parts because the originals can arc during lightning, risking fuel-tank ignition.\n\nCompliance is mandatory within 5,000 flight hours after 20 Dec 2007 using Bombardier Service Bulletin 601R-28-054, Revision A (or later approved revisions)."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD stays within the original safety-focused purpose: correcting identified non-compliances in the fuel system’s lightning-bonding capability by mandating a technical retrofit. It does not broaden the scope beyond that purpose (no additional systems, no inspection expansion beyond the specified couplings, and no new operational restrictions). The linkage to the Bombardier Service Bulletin and Transport Canada approval processes is consistent with typical airworthiness-directive practice and does not materially expand the original intent."},"complexity_factors":["Single clear requirement: replace specified fuel-tube couplings per one Bombardier Service Bulletin","Narrow applicability: one aircraft model (CL-600-2B19) limited to two serial-number ranges","Short compliance window: single deadline metric (within 5,000 flight hours)","Reference to external documents: Bombardier SB 601R-28-054 Rev A and Transport Canada AD CF-2007-23","Regulatory approval clause for later SB revisions (creates limited discretionary approval point)","Technical subject-matter (lightning bonding capability) requiring specialist maintenance and parts"],"plain_english_summary":"**What this direction does (mechanically)**\n\n- It requires operators of certain Bombardier CL-600-2B19 Challenger aeroplanes to replace specific fuel-tube couplings inside the wing and centre fuel tanks with redesigned couplings. The replacement must follow the Accomplishment Instructions in Bombardier Service Bulletin SB 601R-28-054, Revision A (7 August 2006), or a later revision that Transport Canada’s Chief, Continuing Airworthiness, has approved. (See \"Requirement\".)\n\n- The work must be completed within 5,000 flight hours from the AD's effective date. The AD became effective on 20 December 2007. (See \"Compliance\".)\n\n- The rule applies only to Bombardier Inc. Model CL-600-2B19 aircraft with serial numbers 7003–7067 and 7069–7981. (See \"Applicability\".)\n\n**Who is affected**\n\n- Aircraft owners and operators who operate the specified CL-600-2B19 serial-numbered aircraft. They are legally required to have the replacement work done.\n\n- Maintenance organisations or workshops doing the work, because they must follow the Bombardier Service Bulletin instructions and any approvals from the regulator.\n\n- Parts suppliers for fuel-tube couplings, because the AD requires use of the redesigned part or an approved alternative.\n\n**Why the regulator requires this (stated purpose)**\n\n- Bombardier conducted a safety review against new fuel-tank standards and, together with Transport Canada testing, found that some self-bonded fuel-tube couplings lacked sufficient lightning-current capability. Failures of integral bonding wires or excessive axial clearance at reducer ferrules could impair electrical bonding between fuel tubes. (See \"Background\".)\n\n- The regulator’s stated safety concern is that insufficient electrical bonding or inadequate current capability could allow arcing inside a fuel tank during a lightning strike, creating a potential ignition source and risk of explosion. The replacement is mandated to remove that unsafe condition.\n\n**How the rule changes behaviour and who pays**\n\n- Operators must schedule and fund the inspection/repair action, buy the redesigned couplings (or approved alternative parts), and have qualified maintenance personnel carry out the replacement per the Service Bulletin. The direct costs are parts, labour, and potential aircraft downtime. The AD shifts the choice away from continued operation with the original couplings to mandatory retrofit within the 5,000 flight-hour window.\n\n**Practical implementation and compliance considerations (mechanics and trade-offs)**\n\n- The AD ties compliance to a Bombardier Service Bulletin. That centralises the technical method (reduces ambiguity) but also means operators rely on Bombardier-specified parts and procedures unless an alternative is approved by the regulator.\n\n- The AD allows later revisions of the Service Bulletin only if approved by the Chief, Continuing Airworthiness, Transport Canada. That gives the regulator discretion to accept changes and creates a formal approval path for updates.\n\n- Implementation risks and burdens include parts availability, workshop capacity, and aircraft downtime while work is done. Those are the primary opportunity costs for operators: time and money spent on retrofit instead of other uses.\n\n**Costs, incentives and market effects (light analytical lens)**\n\n- Who pays: aircraft owners/operators pay for parts and labour. There is no indication of direct financial assistance in the AD.\n\n- Concentrated benefits: operators of the retrofitted aircraft gain the direct safety benefit and reduced regulatory risk; the public gains from reduced risk of catastrophic fuel-tank ignition. The benefit is concentrated on the affected aircraft and their users.\n\n- Diffuse costs: the costs are distributed across the fleet of affected aircraft; for each operator, the cost may be significant relative to individual maintenance budgets.\n\n- Supplier effect: mandatory use of the redesigned coupling (per Bombardier SB) may favour Bombardier or approved parts suppliers; an approved-alternative pathway exists but requires regulator sign-off. That creates a dependence on either OEM parts or regulator-approved substitutes.\n\n**Regulatory trade-offs and residual risks**\n\n- The measure removes an identified ignition-risk mechanism (lightning-induced arcing) only if replacements are installed correctly and within the compliance window. Residual risk remains if work is delayed beyond 5,000 flight hours or is performed incorrectly.\n\n- Administrative discretion is present because Transport Canada (the Chief, Continuing Airworthiness) must approve later SB revisions and may approve alternatives, which concentrates some decision-making in the regulator.\n\n**Source references within the instrument**\n\n- Applicability: serial-numbered range of CL-600-2B19 aircraft.\n- Requirement: replacement of fuel tube couplings per Bombardier SB 601R-28-054 Rev A (7 Aug 2006) or later approved revisions.\n- Compliance: within 5,000 flight hours; effective date 20 Dec 2007.\n- Background: findings from a system safety review and lightning tests that identified insufficient lightning-current capability and bonding failures as the unsafe condition.\n\n(Analyst note: the AD is narrowly targeted to a technical retrofit to address lightning and bonding deficiencies identified by the manufacturer and regulator. The main economic effects are the direct costs and downtime to operators and the dependency on OEM or regulator-approved parts.)"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-cl-600-90-fuel-line-couplings","history":"/api/acts/ad-cl-600-90-fuel-line-couplings/history","analysis":"/api/acts/ad-cl-600-90-fuel-line-couplings/analysis","conflicts":"/api/acts/ad-cl-600-90-fuel-line-couplings/conflicts","importantCases":"/api/acts/ad-cl-600-90-fuel-line-couplings/important-cases","documents":"/api/acts/ad-cl-600-90-fuel-line-couplings/documents"}}