{"id":"F2008L04606","name":"AD/CL-600/106 - Auxiliary Fuel Tanks","slug":"ad-cl-600-106-auxiliary-fuel-tanks","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":120951,"registerId":"commonwealth-F2008L04606-current","compilationNumber":null,"startDate":"2026-04-03","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-600/106 | Auxiliary Fuel Tanks | 1/2009 |\n| ------------- | -------------------- | ------ |\n\n| Applicability: | Bombardier CL-600-2B19 (Regional Jet Series 100 and 440) aeroplanes fitted with auxiliary fuel tanks as detailed in STC ST00365NY, ST00365NY-D (unless installed with Configuration 5).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Submit a report to the Manager, Systems and New Technologies, Airworthiness Engineering Group CASA, Fax (02) 6217 1914.The report must include the following information:(a) The aeroplane registration and auxiliary tank STC number installed.(b) The usage frequency in terms of total number of flights per year and total number of flights per year for which the auxiliary tank is used.2. Deactivate the auxiliary fuel tanks, in accordance with a deactivation procedure approved by CASA. Any auxiliary tank component that remains on the aeroplane must be secured and must have no effect on the continued operational safety and airworthiness of the aeroplane. Deactivation must not result in the need for additional instructions for continued airworthiness.Note 1: Appendix A of this AD provides criteria that should be included in the deactivation procedure. The proposed deactivation procedures should be submitted to the Manager, Systems and New Technologies, as soon as possible to ensure timely review and approval.Note 2: FAA AD 2008-22-01 Amdt 39-15696 dated 9 October 2008 refers. |\n| Compliance:    | For Requirement 1 - Within 45 days after the effective date of this AD.For Requirement 2 - Before 16 December 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |\n|                | This Airworthiness Directive becomes effective on 15 January 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n\n| Background: | This AD requires deactivation of PATS Aircraft, LLC, auxiliary fuel tanks. This AD results from fuel system reviews conducted by the manufacturer, which identified unsafe conditions for which the manufacturer has not provided corrective actions. The issuing of this AD is intended to prevent the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapours, could result in fuel tank explosions and consequent loss of the aeroplane. |\n| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n27 November 2008\n\n| AD/CL-600/106Appendix A | Auxiliary Fuel Tanks | 1/2009 |\n| ----------------------- | -------------------- | ------ |\n\nDeactivation Criteria\n\nThe auxiliary fuel tank deactivation procedure as detailed in Requirement 2 of this AD should address the following actions.\n\n1. Permanently drain auxiliary fuel tanks, and clear them of fuel vapours to eliminate the possibility of out-gassing of fuel vapours from the emptied auxiliary tank.\n\n2. Disconnect all electrical connections from the fuel quantity indication system (FQIS), fuel pumps if applicable, float switches, and all other electrical connections required for auxiliary tank operation, and stow them at the auxiliary tank interface.\n\n3. Disconnect all pneumatic connections if applicable, cap them at the pneumatic source, and secure them.\n\n4. Disconnect all fuel feed and fuel vent plumbing interfaces with aeroplane original equipment manufacturer (OEM) tanks, cap them at the aeroplane tank side, and secure them in accordance with a method approved by CASA; one approved method is specified in AC 25-8 Auxiliary Fuel System Installations. In order to eliminate the possibility of structural deformation during cabin decompression, leave open and secure the disconnected auxiliary fuel tank vent lines.\n\n5. Pull and collar all circuit breakers used to operate the auxiliary tank.\n\n6. Revise the weight and balance document, if required, and obtain CASA approval.\n\n7. Amend the applicable sections of the applicable aeroplane flight manual (AFM) to indicate that the auxiliary fuel tank is deactivated. Remove auxiliary fuel tank operating procedures to ensure that only the OEM fuel system operational procedures are contained in the AFM. Amend the Limitations Section of the AFM to indicate that the AFM Supplement for the STC is not in effect. Place a placard in the flight deck indicating that the auxiliary tank is deactivated. The AFM revisions specified in this paragraph may be accomplished by inserting a copy of this AD into the AFM.\n\n8. Amend the applicable sections of the applicable aeroplane maintenance manual to remove auxiliary tank maintenance procedures.\n\n9. After the auxiliary fuel tank is deactivated, accomplish procedures such as leak checks and pressure checks deemed necessary before returning the aeroplane to service. These procedures must include verification that the aeroplane FQIS and fuel distribution systems have not been adversely affected.\n\n10. Revise the instructions for continued airworthiness, as required, after deactivation.\n\n11. Include with the operator's proposed procedures any relevant information or additional steps that are deemed necessary by the operator to comply with the deactivation and return the aeroplane to service.","sortOrder":0},{"sectionNumber":"AD/CL-600/106","sectionType":"part","heading":"AD/CL-600/106","content":"## AD/CL-600/106","sortOrder":1},{"sectionNumber":"Auxiliary Fuel Tanks","sectionType":"part","heading":"Auxiliary Fuel Tanks","content":"## Auxiliary Fuel Tanks","sortOrder":2},{"sectionNumber":"1/2009","sectionType":"part","heading":"1/2009","content":"## 1/2009","sortOrder":3},{"sectionNumber":"AD/CL-600/106Appendix A","sectionType":"part","heading":"AD/CL-600/106Appendix A","content":"## AD/CL-600/106  \nAppendix A","sortOrder":4}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"The AD changes operational scope for aeroplanes fitted with the listed STC auxiliary tanks by mandating deactivation rather than allowing continued use under the STC. Where the STC previously authorised auxiliary tank operation, the AD narrows that permission (Applicability; Requirement 2) and imposes mandatory engineering, documentation and approval steps (Appendix A paras 1–10). Operators must now remove operational capability of the auxiliary tanks, revise AFM/maintenance material, and obtain CASA approvals."},"complexity_factors":["Technical scope: fuel system work (draining, vapour clearance, FQIS/pump/float-switch electrical disconnection, vent and plumbing capping) requires specialist avionics and fuel-system skills (Appendix A).","Regulatory approvals: deactivation procedures, weight-and-balance revisions and AFM/maintenance manual changes require CASA approval, adding administrative and review time (Requirement 2; Appendix A paras 6–7).","Operational impact: deactivation removes STC supplement procedures from AFM and may change aircraft range/operations, imposing direct operational costs on operators (Requirement 2; Appendix A para 7).","Compliance timing: two-tier deadlines (report within 45 days; deactivation by a fixed date) create scheduling and resource pressures for fleet operators (Compliance).","Safety assurance steps: post‑deactivation checks (leak/pressure checks, verification of OEM FQIS and fuel distribution) are required before return to service, increasing complexity of recertification (Appendix A para 9).","STC nuance and exceptions: applicability limited to specific STCs and excludes installations in 'Configuration 5', requiring record checks to determine applicability (Applicability).","Cross-reference to FAA AD: reliance on related FAA action may require alignment with non‑Australian documentation and standards (Requirement 2 Note 2)."],"plain_english_summary":"This Airworthiness Directive requires operators of Bombardier CL-600-2B19 aeroplanes fitted with specified PATS auxiliary fuel tanks to report tank usage to CASA (within 45 days) and to deactivate those tanks by a CASA‑approved procedure (by 16 Dec 2009). The directive aims to remove potential ignition sources inside auxiliary tanks to reduce the risk of fuel vapour ignition. Aircraft operators pay for deactivation work, must secure remaining components, amend manuals and maintenance instructions, and obtain CASA approvals for procedures and weight/balance changes."},"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":4,"scope_assessment":{"changed":false,"description":"This AD appears tightly focused on its original safety purpose — addressing specific unsafe conditions in PATS auxiliary fuel tanks installed on CL-600-2B19 aircraft. The scope is precisely defined by aircraft model, STC numbers, and tank configuration. The detailed deactivation criteria in Appendix A represent necessary implementation detail rather than scope creep."},"complexity_factors":["Multiple defined exceptions and applicability criteria (specific STC numbers, specific aircraft model variant, explicit exclusion for Configuration 5)","Two-tier compliance structure with different deadlines for reporting versus deactivation","Detailed technical appendix with 11 specific deactivation criteria requiring cross-reference to other documents (AC 25-8, AFM, maintenance manuals)","Requires CASA approval for deactivation procedures rather than prescribing a single mandatory method","Cross-reference to FAA AD 2008-22-01 indicating harmonisation with foreign regulatory action","Conditional language throughout ('if applicable', 'if required', 'deemed necessary') creating situational compliance obligations"],"plain_english_summary":"This CASA Airworthiness Directive applies to Bombardier CL-600-2B19 (Regional Jet 100/440) aircraft fitted with PATS auxiliary fuel tanks under STCs ST00365NY/ST00365NY-D (except Configuration 5). It requires operators to notify CASA about affected aircraft and permanently deactivate those tanks.\n\nCASA orders this because the auxiliary tanks can create ignition sources in fuel tanks, posing an explosion risk; with no manufacturer fix, deactivation is required to eliminate the hazard."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cl-600-106-auxiliary-fuel-tanks","history":"/api/acts/ad-cl-600-106-auxiliary-fuel-tanks/history","analysis":"/api/acts/ad-cl-600-106-auxiliary-fuel-tanks/analysis","conflicts":"/api/acts/ad-cl-600-106-auxiliary-fuel-tanks/conflicts","importantCases":"/api/acts/ad-cl-600-106-auxiliary-fuel-tanks/important-cases","documents":"/api/acts/ad-cl-600-106-auxiliary-fuel-tanks/documents"}}