{"id":"F2006B08581","name":"AD/CL-600/21 Amdt 2 - Tail Cone Fuel Tank","slug":"ad-cl-600-21-amdt-2-tail-cone-fuel-tank","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51424,"registerId":"commonwealth-F2006B08581-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CL-600/21 Amdt 2 - Tail Cone Fuel Tank","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBombardier (Canadair) CL-600 (Challenger) Series Aeroplanes\n\nAD/CL-600/21\n\nAmdt 2\n\n  \nTail Cone Fuel Tank 9/93\n\nApplicability: All CL-600-2A12 and CL-600-2B16 aircraft equipped with a tail cone fuel tank.\n\nRequirement: Action in accordance with the requirements of Transport Canada Airworthiness Directive CF-91-22R3 dated 27 May 1993.\n\nNote: Canadair Alert Service Bulletin A601-0381 Revision No 2 dated 27 January 1992 and Canadair Kit Drawing K601-62011 Issue B refer.\n\nCompliance: The Compliance for the previous issue of this Directive was “as directed in the Requirement Document with a revised effective date of 30 June 1992\". The compliance for this issue is prior to 31 December 1993.\n\nBackground: During maintenance in the aft equipment bay the level control valve sensing line, which runs through the aft equipment bay for the tail cone fuel tank, has been broken. Amendment 1 required a modification to the tail cone fuel tank level control valve sensing line which provided terminating action for the repetitive inspection requirement. This amendment requires the installation of a bonding jumper assembly to remove the threat of an explosion following a lightning strike.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"The directive has expanded from its original purpose. It began as a response to broken sensing lines during maintenance (requiring inspections, then a modification to end those inspections). Amendment 2 adds an entirely separate safety concern — lightning strike protection through electrical bonding. While related to the same physical component (tail cone fuel tank), this represents scope creep from mechanical integrity to electrical safety systems."},"complexity_factors":["Short, single-purpose directive (approximately 200 words)","Only 2 defined applicability criteria (aircraft model and tail cone tank equipment)","Single primary requirement referencing an external document (Transport Canada AD CF-91-22R3)","Two secondary reference documents (Service Bulletin and Kit Drawing)","Simple linear amendment history (original → Amendment 1 → Amendment 2) with clear progression of requirements","No nested conditional logic or exceptions","Clear compliance date with explicit supersession of previous deadline"],"plain_english_summary":"This AD requires owners/operators of certain Bombardier Challenger CL-600-2A12/2B16 jets with the optional tail-cone fuel tank to install a bonding jumper assembly to ensure electrical continuity and prevent ignition from lightning or sparking. It adopts Transport Canada AD CF-91-22R3 and referenced Canadair service documents; the modification must be done before 31 December 1993."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Yes. The original directive required inspection and, under Amendment 1, a sensing-line modification that terminated repetitive inspections. This amendment adds a distinct mandatory modification — installation of a bonding jumper assembly — specifically to remove the lightning-induced explosion risk. That expands the required corrective work beyond the previous terminating modification and therefore increases compliance tasks, parts procurement and maintenance burden for affected operators."},"complexity_factors":["Cross-reference to an external Transport Canada airworthiness directive (CF-91-22R3) — requires obtaining and following another regulator's document.","Technical nature of mandated work (installation of bonding jumper assembly and prior sensing-line modification) — needs certified maintenance skills, parts, and documentation.","Narrow applicability (specific CL-600 variants with tail-cone fuel tank) — identifying affected fleet and individual aircraft records is necessary.","References to prior amendments, service bulletins and kit drawings (Canadair documents) — requires historical compliance checks and part-number tracking.","Fixed compliance deadline (prior to 31 December 1993) — creates scheduling and downtime pressures for operators and maintenance providers.","Safety-critical consequence (risk of explosion from lightning) — increases regulatory scrutiny and may require inspection/sign-off processes by CASA-authorised personnel."],"plain_english_summary":"This amendment directs operators of Bombardier CL-600-2A12 and CL-600-2B16 aeroplanes fitted with a tail-cone fuel tank to carry out the measures in Transport Canada AD CF-91-22R3 (27 May 1993). Mechanically, it requires installing a bonding jumper assembly to remove the risk of explosion after a lightning strike; an earlier amendment modified the level-control sensing line to end repetitive inspections. The requirement imposes a one-off technical modification, associated maintenance downtime and direct costs on affected operators, with compliance due before 31 December 1993."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cl-600-21-amdt-2-tail-cone-fuel-tank","history":"/api/acts/ad-cl-600-21-amdt-2-tail-cone-fuel-tank/history","analysis":"/api/acts/ad-cl-600-21-amdt-2-tail-cone-fuel-tank/analysis","conflicts":"/api/acts/ad-cl-600-21-amdt-2-tail-cone-fuel-tank/conflicts","importantCases":"/api/acts/ad-cl-600-21-amdt-2-tail-cone-fuel-tank/important-cases","documents":"/api/acts/ad-cl-600-21-amdt-2-tail-cone-fuel-tank/documents"}}