{"id":"F2008L01927","name":"AD/CL-600/100 - Fuel Tube Coupling - Electrical Bonding","slug":"ad-cl-600-100-fuel-tube-coupling-electrical-bonding","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":74154,"registerId":"commonwealth-F2008L01927-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-600/100 | Fuel Tube Coupling - Electrical Bonding | 7/2008 |\n| ------------- | --------------------------------------- | ------ |\n\n| Applicability: | Bombardier Inc. Model CL-600-2C10 aircraft, serial numbers 10003 through 10169 and CL-600-2D24 aircraft, serial numbers 15001 through 15025.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. For aircraft that have not incorporated the original issue of Bombardier Service Bulletin (SB) 670BA-28-014, replace the fuel tube couplings inside the wing and centre fuel tanks with redesigned couplings, according to Part A of the Accomplishment Instructions of Bombardier SB 670BA-28-014, Revision A, dated 7 May 2007, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.2. For aircraft that have already incorporated the original issue of Bombardier SB 670BA-28-014, inspect the aft scavenge ejector fuel couplings inside the LH and RH wing fuel tanks and replace with redesigned couplings if necessary, according to Part B of the Accomplishment Instructions of Bombardier SB 670BA-28-014, Revision A, dated 7 May 2007, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.Note: Transport Canada AD CF-2008-02 dated 3 January 2008 refers. |\n| Compliance:    | Within 4500 hours flight time after the effective date of this directive.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n|                | This Airworthiness Directive becomes effective on 3 July 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| Background:    | Bombardier Aerospace has completed a system safety review of theCL-600-2C10/CL-600-2D24 aircraft fuel system against new fuel tank safety standards.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 could affect electrical bonding between fuel tubes.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n\n|     | 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 directive mandates the replacement of certain fuel tube couplings with redesigned couplings. |\n| --- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n22 May 2008","sortOrder":0},{"sectionNumber":"AD/CL-600/100","sectionType":"part","heading":"AD/CL-600/100","content":"## AD/CL-600/100","sortOrder":1},{"sectionNumber":"Fuel Tube Coupling - Electrical Bonding","sectionType":"part","heading":"Fuel Tube Coupling - Electrical Bonding","content":"## Fuel Tube Coupling - Electrical Bonding","sortOrder":2},{"sectionNumber":"7/2008","sectionType":"part","heading":"7/2008","content":"## 7/2008","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard single-issue Airworthiness Directive addressing a specific safety defect identified through manufacturer system safety review and lightning testing. The scope remains tightly focused on the original safety concern (fuel tube coupling electrical bonding) without expansion into unrelated systems or operational requirements."},"complexity_factors":["Single, specific technical requirement with two alternative compliance paths based on prior maintenance history","References external technical document (Bombardier Service Bulletin 670BA-28-014) without reproducing its contents","Limited applicability scope (two specific aircraft models with defined serial number ranges)","Simple compliance deadline (single time-based threshold: 4,500 flight hours)","No nested exceptions, conditional logic, or extensive defined terms","Clear causal chain in background section explaining the safety risk"],"plain_english_summary":"This CASA Airworthiness Directive mandates owners/operators of Bombardier Challenger CL-600-2C10 (s/n 10003–10169) and CL-600-2D24 (s/n 15001–15025) to replace or inspect fuel-tube couplings in wing and centre tanks to ensure proper electrical bonding. Required within 4,500 flight hours of 3 July 2008, the AD prevents arcing during lightning strikes that could ignite fuel vapours and cause explosions."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive stays within the original safety-focused purpose: correct specific fuel-tube coupling designs that failed lightning-current and bonding assessments. It does not broaden regulatory reach beyond replacing or inspecting the identified couplings on the listed serial numbers. Allowing later approved revisions of the referenced Service Bulletin introduces procedural flexibility but does not materially change the substantive scope of the safety requirement."},"complexity_factors":["Single-subject Airworthiness Directive (AD) with limited length","Applicability limited to two model variants and specific serial-number ranges","Two conditional compliance paths: full replacement (Part A) versus inspection+selective replacement (Part B) depending on prior incorporation of original SB","Dependence on external document: Bombardier Service Bulletin 670BA-28-014 Revision A (7 May 2007) or later revisions approved by Chief, Continuing Airworthiness, Transport Canada","Fixed compliance window: 4,500 flight hours from effective date","Cross-reference to Transport Canada AD CF-2008-02","Regulatory approval mechanism for later SB revisions (introduces limited administrative discretion)"],"plain_english_summary":"**What this directive does (mechanically)**\n\n- Applies to Bombardier Inc. Model CL-600-2C10 (serial nos. 10003–10169) and CL-600-2D24 (serial nos. 15001–15025). (See \"Applicability\".)\n- Requires either a full replacement of certain fuel tube couplings in the wing and centre fuel tanks, or an inspection and selective replacement of the aft scavenge ejector fuel couplings inside the left and right wing tanks, depending on whether an earlier Bombardier Service Bulletin (SB 670BA-28-014 original issue) has been incorporated. The specific work is done according to Part A or Part B of the Accomplishment Instructions of Bombardier SB 670BA-28-014, Revision A (7 May 2007) or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada. (See \"Requirement\".)\n- Sets a compliance deadline of within 4,500 flight hours from the directive’s effective date. (See \"Compliance\".)\n\n**Who must act and who pays**\n\n- Aircraft operators/owners of the affected serial-numbered CL-600 aircraft must arrange the inspection and/or replacement. Maintenance organisations or approved repair facilities will carry out the work per the service bulletin. The operator bears the direct costs (parts, labour, downtime). The regulator (Transport Canada, via approval of SB revisions) sets which SB versions are acceptable.\n\n**Why it matters (stated safety issue and mechanical effect)**\n\n- A system safety review and lightning testing identified that some fuel tube self-bonded couplings lack sufficient capability to carry lightning current, and that a single failure of the integral bonding wire can interrupt electrical bonding between fuel tubes. Insufficient bonding or current capability can allow arcing inside a fuel tank during a lightning strike, creating a potential ignition source and risk of fuel tank explosion. The directive requires replacement with redesigned couplings intended to restore bonding capability and lightning-current capacity. (See \"Background\".)\n\n**Practical implications, trade-offs and implementation issues**\n\n- Costs and downtime: Operators must schedule maintenance to perform replacement/inspection within 4,500 flight hours. This creates direct costs (new couplings, labour, potential aircraft out-of-service time) and indirect costs (rescheduling flights, repositioning aircraft).\n- Implementation risk: Availability of redesigned couplings and MRO capacity may constrain how quickly operators can comply. If parts or qualified technicians are scarce, compliance could be delayed or require multiple scheduled outages.\n- Compliance discretion: The directive accepts later revisions of the referenced Bombardier SB only if approved by the Chief, Continuing Airworthiness, Transport Canada. That gives the regulator controlled discretion over acceptable procedural changes and technical variations.\n- Behavioural choices for operators: Operators can choose to comply early (spread cost, reduce operational disruption later) or defer compliance to the allowed deadline. They must also decide whether to perform full replacement (Part A) or inspection/conditional replacement (Part B) depending on prior incorporation of the original SB. Operators may contract the work to third-party MROs.\n- Concentrated benefits and costs: The safety benefit (reduced lightning-arcing risk) accrues to all operators and passengers but is concentrated as a regulatory safety requirement for the specified serial-numbered aircraft. Suppliers and MROs supplying couplings and labour capture much of the spending (concentrated economic benefit). Costs are borne by the aircraft owners/operators (diffuse among them). There is limited scope for substitution: the directive prescribes a specific engineering fix rather than optional mitigation measures.\n- Record-keeping and verification: Operators must retain records proving compliance; the regulator may require evidence (inspection reports, parts installed, SB revision used and approval). The directive cross-references a Transport Canada AD (CF-2008-02), which may be used for parallel regulatory tracking.\n\n**Net mechanical effect**\n\nOperators of the listed CL-600 aircraft will have redesigned fuel tube couplings installed (or inspected and selectively replaced) in the wing and centre tanks within the prescribed time. The change is intended to restore or ensure electrical bonding and lightning-current handling of fuel-tube couplings, thereby reducing the risk of arcing inside fuel tanks during lightning strikes. (See \"Requirement\" and \"Background\".)"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-cl-600-100-fuel-tube-coupling-electrical-bonding","history":"/api/acts/ad-cl-600-100-fuel-tube-coupling-electrical-bonding/history","analysis":"/api/acts/ad-cl-600-100-fuel-tube-coupling-electrical-bonding/analysis","conflicts":"/api/acts/ad-cl-600-100-fuel-tube-coupling-electrical-bonding/conflicts","importantCases":"/api/acts/ad-cl-600-100-fuel-tube-coupling-electrical-bonding/important-cases","documents":"/api/acts/ad-cl-600-100-fuel-tube-coupling-electrical-bonding/documents"}}