{"id":"F2005L02382","name":"AD/CL-600/68 - Aileron Power Control Unit Links","slug":"ad-cl-600-68-aileron-power-control-unit-links","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":36795,"registerId":"commonwealth-F2005L02382-current","compilationNumber":null,"startDate":"2026-04-01","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-600/68 | Aileron Power Control Unit Links | 10/2005 |\n| ------------ | -------------------------------- | ------- |\n\n| Applicability: | Bombardier CL-600-2C10, serial numbers 10003 and subsequent.Bombardier CL-600-2D15 and CL-600-2D24, serial numbers 15001 and subsequent. |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. Accomplish the following in accordance with Bombardier ASB A670BA-27-023, Revision A, dated 18 May 2005, or later Transport Canada approved revisions:(a) Conduct a detailed visual inspection of the four aileron PCU output links for fractures/cracks and replace any fractured/cracked links prior to further flight;(b) As part of the replacement of any fractured/cracked link, perform the following checks:(i) Measure the torque value of the forward and aft attachment bolts for both the damaged PCU output link and the adjacent PCU output link;(ii) For any damaged link, check for and if required, measure, any mismatch between PCU output link and the aileron lugs;(iii) For any damaged link, perform an eddy current inspection of the aileron lugs and the flange bushings of the aileron lug; and if crack found or suspected, contact the Technical Help Desk, Bombardier Aerospace for instructions; and(iv) Record the information requested in Appendix A of the above mentioned Bombardier ASB.Note 1: Inspections and checks carried out in accordance with Bombardier ASB A670BA-27-023, dated 3 May 2005, also meet the requirements of Requirement 1 of this directive.2. Forward the information requested in Appendix A of the above mention ASB, to Bombardier Aerospace at the address provided in the ASB.3. Repeat the visual inspection and if required, the special check for fractured/cracked links, detailed above in Requirements 1(a) and 1(b) of this directive.Note 2: Transport Canada AD CF-2005-23 refers. |\n| Compliance: | 1. Comply with the following schedule:(a) Aircraft that have accumulated 2000 hours time in service (TIS) or more upon the effective date of this directive; prior to accumulating 550 hours TIS from the effective date of this directive; and(b) Aircraft with less than 2000 hours TIS upon the effective date of this directive; prior to reaching 2000 hours TIS or prior to accumulating 550 hours TIS from the effective date of this directive, which ever is reached later.2. Within 14 days of completing the inspection.3. At intervals not to exceed 1000 flight hours. |\n| | This Airworthiness Directive becomes effective on 29 September 2005. |\n| Background: | Transport Canada has received reports of aileron power control unit (PCU) link fractures on in-service CL-600-2B19 aircraft. The same links are also used on the CL-600-2C10, CL-600-2D15 and CL-600-2D24 aircraft. Failure of one PCU link may result in a dormant failure; failure of both PCU links to an aileron could result in reduced lateral control of the aircraft. |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n18 August 2005","sortOrder":0},{"sectionNumber":"AD/CL-600/68","sectionType":"part","heading":"AD/CL-600/68","content":"## AD/CL-600/68","sortOrder":1},{"sectionNumber":"Aileron Power Control Unit Links","sectionType":"part","heading":"Aileron Power Control Unit Links","content":"## Aileron Power Control Unit Links","sortOrder":2},{"sectionNumber":"10/2005","sectionType":"part","heading":"10/2005","content":"## 10/2005","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with focused, targeted scope. It addresses a specific safety defect in specific aircraft serial numbers without expanding beyond the original safety purpose."},"complexity_factors":["Multiple conditional compliance deadlines based on aircraft flight hours (two-tier system: 2000+ hours vs under 2000 hours)","Nested sub-requirements (Requirement 1 contains parts a, b, i, ii, iii, iv)","Cross-reference to external technical document (Bombardier ASB A670BA-27-023) which contains the actual detailed procedures","Specific technical terminology requiring aviation engineering knowledge (eddy current inspection, PCU output links, flange bushings)","Dual reporting requirements (to Bombardier and implicit CASA compliance)","Note providing alternative compliance path (Note 1 allows earlier version of ASB)"],"plain_english_summary":"This CASA Airworthiness Directive orders owners/operators of specific Bombardier Challenger CL-600-2C10/2D15/2D24 serials to inspect and, if necessary, replace aileron PCU output links that can crack or fail. It mandates more detailed checks when replacement occurs, reporting results to Bombardier, and recurring inspections to manage the risk. It affects airlines and private operators of those Challengers in Australia because link failure can reduce roll control and threaten safe flight."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive stays within the original, narrow safety purpose: detect and remove fractured/cracked aileron PCU output links to prevent reduced lateral control. It applies the inspection, measurement, non-destructive testing and reporting measures to the specific CL-600 variants that use the same links as the model where fractures were found, without introducing requirements beyond investigating and mitigating the same failure mode. The directive does extend the operational requirement (inspections and reporting) to additional serial-numbered variants that share the part, but that extension follows directly from the stated safety cause (same links used across models) rather than a change of purpose."},"complexity_factors":["Single airworthiness directive focused on one component (aileron PCU output links)","Cross-reference to one primary external document: Bombardier ASB A670BA-27-023 (and later TC-approved revisions)","Two-branch initial compliance schedule (>=2000 TIS and <2000 TIS) plus recurring interval (every 1000 flight hours)","Several specific follow-up checks required when a damaged link is replaced (torque measurements, mismatch measurement, eddy-current inspection, Appendix A recording)","Reporting requirement with a short deadline (forward Appendix A data within 14 days of inspection)","Conditional step: contacting Bombardier Technical Help Desk if crack found or suspected","Notes referencing an equivalent earlier ASB date and a related Transport Canada AD"],"plain_english_summary":"**What this directive does (mechanically)**\n\n- Requires operators of certain Bombardier CL-600 Challenger series aeroplanes to inspect the four aileron power control unit (PCU) output links for cracks or fractures, replace any fractured or cracked links before further flight, perform specified checks when a link is replaced, and send specified information to Bombardier Aerospace. (See Requirement 1 and 2.)\n\n- The checks accompanying any replacement include: measuring torque on forward and aft attachment bolts on the affected and adjacent links; checking and measuring any mismatch between the PCU output link and the aileron lugs; performing an eddy-current inspection of the aileron lugs and flange bushings for cracks; and recording details set out in Appendix A of the Bombardier Alert Service Bulletin (ASB). (See Requirement 1(b)(i)–(iv).)\n\n- The initial inspection timing depends on aircraft accumulated hours: aircraft with 2,000 or more hours must be inspected before accruing another 550 hours; aircraft with under 2,000 hours must be inspected before reaching 2,000 hours or within 550 hours from the directive’s effective date, whichever is later. Thereafter, inspections repeat at intervals not to exceed 1,000 flight hours. Operators must forward the Appendix A information to Bombardier within 14 days of completing the inspection. (See Compliance paragraphs 1–3.)\n\n**Who is affected**\n\n- Aircraft operators and maintenance organisations responsible for Bombardier CL-600-2C10 (serial 10003 and subsequent), CL-600-2D15 and CL-600-2D24 (serials 15001 and subsequent). The work also references procedures in Bombardier ASB A670BA-27-023 (or later Transport Canada–approved revisions). (See Applicability and Requirement 1.)\n\n**Why it matters (stated safety rationale and mechanical effect)**\n\n- Transport Canada reported in-service fractures of aileron PCU links on related CL-600 models. A single PCU link failure could be dormant (not immediately noticeable), but if both links to an aileron fail, it could reduce lateral (roll) control. The directive’s inspections and mandatory replacements aim to find fractured/cracked links and prevent loss of lateral control by ensuring unknown or cracked components are removed and adjacent systems checked. (See Background and Requirement 1.)\n\n**Who pays and who decides**\n\n- Operators pay the direct costs: inspection labour, eddy-current testing, bolt torque checks, possible rework or replacement parts, aircraft downtime, and administrative reporting to Bombardier. The Civil Aviation Safety Authority (via its delegate) imposes the requirement and relies on Bombardier’s ASB for the technical procedure; Bombardier decides the ASB content and provides Technical Help Desk instructions if cracks are suspected. (See Requirement 1 and 2.)\n\n**Implementation mechanics, compliance burden and timing**\n\n- Compliance requires following Bombardier ASB A670BA-27-023 or later approved revisions. The directive sets a two-track initial compliance schedule based on aircraft time-in-service, a 14-day deadline for submitting Appendix A data to Bombardier after inspection, and a recurring inspection interval of 1,000 flight hours. Failure findings trigger additional measurements and non-destructive testing (eddy current). (See Compliance and Requirement 1(b).)\n\n**Costs, incentives and trade-offs**\n\n- Direct costs: labour for inspections and eddy-current testing, replacement link parts, potential torque rework, and administrative effort to record and forward Appendix A data. Operators will also incur aircraft downtime while inspections or replacements occur.\n\n- Incentives: Operators have a safety and regulatory incentive to comply promptly to avoid groundings, possible enforcement action, or increased risk. Bombardier receives fleet data (Appendix A returns), which concentrates safety intelligence with the manufacturer and regulator.\n\n- Trade-offs: Frequent inspections and reporting improve early detection but increase maintenance cost and downtime. Reliance on a manufacturer ASB and the Technical Help Desk concentrates technical reliance on Bombardier for disposition when cracks are suspected, and may create delays if replacement parts or expert guidance are scarce.\n\n**Implementation risk and potential unintended consequences**\n\n- Inspection subjectivity: the initial check is a detailed visual inspection; cracked or early-stage defects can be hard to detect visually, increasing reliance on eddy-current testing when damage is suspected. (See Requirement 1(a) and 1(b)(iii).)\n\n- Supply and scheduling risk: if multiple operators need replacement links or specialist eddy-current technicians at the same time, maintenance scheduling and parts availability could cause additional downtime.\n\n- Information flow: sending Appendix A data to Bombardier centralises reporting and helps trend analysis, but operators incur the administrative cost and must ensure timely submission (within 14 days). (See Requirement 2 and Compliance 2.)\n\n**Concrete behavioural change required**\n\n- Operators must inspect all four aileron PCU output links on the affected serial-numbered aircraft types, replace any cracked/fractured links before further flight, perform specific follow-up checks when replacements occur, record the requested data, and forward that data to Bombardier. They must then continue repeating the visual inspection at intervals not to exceed 1,000 flight hours. (See Requirement 1–3 and Compliance.)\n\n**References within the directive**\n\n- Procedures: Bombardier ASB A670BA-27-023, Revision A, 18 May 2005 (or later TC-approved revisions). (See Requirement 1.)\n\n- Background safety incident reports: Transport Canada AD CF-2005-23 is referenced as related material. (See Note 2 and Background.)"},"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-600-68-aileron-power-control-unit-links","history":"/api/acts/ad-cl-600-68-aileron-power-control-unit-links/history","analysis":"/api/acts/ad-cl-600-68-aileron-power-control-unit-links/analysis","conflicts":"/api/acts/ad-cl-600-68-aileron-power-control-unit-links/conflicts","importantCases":"/api/acts/ad-cl-600-68-aileron-power-control-unit-links/important-cases","documents":"/api/acts/ad-cl-600-68-aileron-power-control-unit-links/documents"}}