{"id":"F2006B08606","name":"AD/CL-600/44 - Power Transfer Contactors","slug":"ad-cl-600-44-power-transfer-contactors","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51518,"registerId":"commonwealth-F2006B08606-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)\n\nBombardier (Canadair)\n\nCL-600 (Challenger) Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/CL-600/44 Power Transfer Contactors 1","sectionType":"part","heading":"AD/CL-600/44 Power Transfer Contactors 10/2001","content":"# AD/CL-600/44 Power Transfer Contactors 10/2001\n\nDM\n\nApplicability: Model CL-600-2B19 ‘Regional Jet’ aeroplanes serial numbers 7003 through 7495, 7497 through 7502 and 7505 through 7507.\n\nRequirement: 1. Determine, in accordance with the procedures in Bombardier Alert Service Bulletin (ASB) A601R-24-105 dated 4 July 2001 or Revision A dated 20 July 2001, if installed air driven generator (ADG) emergency hydraulic power transfer contactor K1XC, ADG emergency electrical power transfer contactor K2XD and AC essential power transfer contactor K3XD, all Part Number (P/N) H-A4A-039, have a manufacturing date code of 0011 through 0050. (The power transfer contactors with manufacturing date code 0011 through 0050 are hereafter referred to as ‘suspect contactors’.)\n\n    2. For aircraft, determined in accordance with Requirement 1, to have a suspect K1XC and/or a K2XD contactor installed, dispatch with an inoperative Integrated Drive Generator (IDG) or Auxiliary Power Unit (APU) generator is prohibited until such time as the suspect contactor(s) is/are replaced as detailed in Requirement 3 and 4 of this Directive.\n\n    3. Replace suspect K1XC contactors in accordance with ASB A601R-24-105 or A601R-24-105 Rev A.\n\n    4. Replace suspect K2XD and K3XD contactors in accordance with the above- mentioned ASB.\n\n    5. Power transfer contactors K1XC, K2XD and K3XD P/N H-A4A-039 that have a manufacturing date code of 0011 through 0050, may not be installed in any aircraft.\n\nNote: Transport Canada AD CF-2001-27 refers.\n\nCompliance: For Requirement 1 \\- Within 14 calendar days after the effective date of this Directive.\n\nFor Requirement 2 - Immediately with effect from the date that the Requirement 1 determination was made.","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD stays within a narrow remedial scope: identify suspect contactors by manufacturing date code, prevent certain dispatch conditions, require replacement using the Bombardier Service Bulletin procedures, and ban re-installation of the suspect parts. There is no sign the directive expands beyond that original corrective remediation (no new aircraft types, no additional systems, and no broader operational rules beyond the specific conditional dispatch prohibition)."},"complexity_factors":["Narrow applicability: specific model (CL-600-2B19) and a defined range of serial numbers","Small set of affected parts: three contactor references (K1XC, K2XD, K3XD) with one part number (H-A4A-039)","Single conditional rule: dispatch prohibition triggered only if a suspect part is fitted and an IDG or APU generator is inoperative (Requirement 2)","Short, fixed compliance window for inspection (14 calendar days for Requirement 1)","Cross-reference to an external document for procedure details (Bombardier ASB A601R-24-105 / Rev A)","Prohibition on installation of parts with specific manufacturing date codes (Requirement 5)","Reference to a corresponding foreign AD (Transport Canada AD CF-2001-27)"],"plain_english_summary":"**What this instrument does (mechanically)\n\n- This is an Airworthiness Directive (AD) that applies to certain Bombardier CL-600-2B19 (Challenger/Regional Jet) aeroplanes listed by serial number. It requires operators to check specific power transfer contactors (electrical/hydraulic switch components) and to remove and replace any that were manufactured in a particular range of date codes (0011–0050). The procedures for checking and replacing the parts are those given in Bombardier Alert Service Bulletin A601R-24-105 (or Revision A). The AD also bans re-installation of any of the suspect parts.\n\n**Who it affects\n\n- Aircraft operators and maintainers of the listed CL-600-2B19 serial numbers. Maintenance organisations that perform the inspections and replacements. The regulator enforces compliance.\n\n**Key requirements (plain terms)\n\n- Inspect: Within 14 calendar days after the AD becomes effective, check whether any of these contactors are fitted: K1XC (ADG emergency hydraulic power transfer contactor), K2XD (ADG emergency electrical power transfer contactor) and K3XD (AC essential power transfer contactor), all Part Number H-A4A-039, and whether their manufacturing date codes are within 0011–0050 (these are the “suspect contactors”). (Requirement 1)\n\n- Flight restriction: If a suspect K1XC and/or K2XD is fitted, you must not dispatch the aircraft with an inoperative Integrated Drive Generator (IDG) or Auxiliary Power Unit (APU) generator until the suspect contactor(s) has/have been replaced. That prohibition takes effect immediately after you make the determination that a suspect part is fitted. (Requirement 2; Compliance for Requirement 2)\n\n- Replacement: Replace suspect K1XC, K2XD and K3XD contactors in accordance with the Bombardier Alert Service Bulletin referenced in the AD. (Requirements 3 and 4)\n\n- Installation ban: Any power transfer contactor P/N H-A4A-039 with manufacturing date code 0011–0050 may not be installed in any aircraft. (Requirement 5)\n\n**Why the AD exists (stated purpose) and how that maps to costs and incentives\n\n- The AD is issued because the regulator considers there is an unsafe condition linked to certain contactors; the AD directs inspection and replacement as the corrective action. That stated purpose implies a safety benefit concentrated on flights using affected aircraft.\n\n- Who pays: aircraft operators bear the direct costs — labour for inspection, the cost of replacement contactors, and any operational disruption or schedule changes if aircraft are grounded for replacements or cannot be dispatched under the limitation in Requirement 2.\n\n- Who decides and enforces: the operator/maintenance organisation carries out the inspection and replacement actions; the regulator (CASA delegate) enforces compliance under the cited regulation (subregulation 39.1(1) of CAR 1998). The Service Bulletin prescribes the detailed method of compliance.\n\n- Behavioural change required: operators must prioritise inspecting affected serial-number aircraft within 14 days, prevent dispatch when specific inoperative generators coincide with suspect parts, and replace suspect parts before further flight (and never install the banned date-code parts again).\n\n**Trade-offs, practical risks and implementation issues to watch for\n\n- Parts availability and lead time: replacement depends on obtaining non-suspect contactors; shortages could extend aircraft downtime.\n\n- Operational impact: the immediate dispatch prohibition when a suspect K1XC/K2XD and an inoperative IDG or APU generator coincide may cause flight cancellations or re-timing.\n\n- Compliance burden: short inspection window (14 days) and mandatory replacement create direct maintenance cost and scheduling work for operators.\n\n- Cross-reference: the AD notes Transport Canada AD CF-2001-27, indicating a corresponding foreign regulator action and alignment on the identified unsafe condition.\n\n**Where to find the detailed steps\n\n- The Bombardier Alert Service Bulletin A601R-24-105 (or Revision A) contains the step-by-step inspection and replacement procedures; operators must follow those instructions to comply with the AD (Requirements 1, 3 and 4).\n\n(References in summary are to the AD’s numbered Requirements and Compliance provisions.)"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard, targeted Airworthiness Directive addressing a specific unsafe condition in specific aircraft. It has not expanded beyond its original purpose of mandating inspection and replacement of defective power transfer contactors."},"complexity_factors":["Highly specific technical scope — applies only to one aircraft model with specific serial number ranges","Precise part number and manufacturing date code requirements (P/N H-A4A-039, date codes 0011-0050)","Multiple interdependent requirements with cross-references to external manufacturer documents (Bombardier Alert Service Bulletin A601R-24-105 and Revision A)","Conditional compliance timing — Requirement 2 triggers 'immediately' based on findings from Requirement 1","Operational restriction (dispatch prohibition) tied to specific equipment status (inoperative IDG or APU generator)","Standard AD structure with defined sections (Applicability, Requirement, Compliance) but dense technical terminology"],"plain_english_summary":"This AD requires operators of specific Bombardier CL-600-2B19 regional jets to inspect for and remove certain power transfer contactors (date codes 0011–0050) that may fail. \n\nIt affects aircraft with listed serial numbers and aims to prevent simultaneous loss of main and backup electrical/hydraulic power. Aircraft found with these parts cannot be flown under the unsafe condition until the contactors are replaced, and the suspect parts are banned from future installation."},"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-600-44-power-transfer-contactors","history":"/api/acts/ad-cl-600-44-power-transfer-contactors/history","analysis":"/api/acts/ad-cl-600-44-power-transfer-contactors/analysis","conflicts":"/api/acts/ad-cl-600-44-power-transfer-contactors/conflicts","importantCases":"/api/acts/ad-cl-600-44-power-transfer-contactors/important-cases","documents":"/api/acts/ad-cl-600-44-power-transfer-contactors/documents"}}