{"id":"F2006L00361","name":"AD/CL-600/66 Amdt 1 - Rudder Balance Spring Assembly","slug":"ad-cl-600-66-amdt-1-rudder-balance-spring-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116975,"registerId":"commonwealth-F2006L00361-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-600/66 Amdt 1 | Rudder Balance Spring Assembly | 3/2006 |\n| ------------------- | ------------------------------ | ------ |\n\n| Applicability: | Bombardier Inc. Models:CL-600-1A11 - Serial numbers 1004 through 1085.CL-600-2A12 - Serial numbers 3001 through 3066.CL-600-2B16 - Serial numbers 5001 through 5194.CL-600-2B16 - Serial numbers 5301 through 5564.                                                                                                                                                                                                                                                                                                                                                |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | Modify the rudder balance spring assembly; and perform the rigging of the adjustable rudder balance spring assembly in accordance with the instructions of the applicable Service Bulletin (SB) listed below, or later Transport Canada approved revisions.Applicable Service Bulletins:CL-600-1A11 (CL-600) SB 600-0714 dated, 04 April 2003CL-600-2A12 (CL-601) SB 601-0549 dated, 04 April 2003CL-600-2B16 (CL-601-3A/3R) SB 601-0549 dated, 04 April 2003CL-600-2B16 (CL-604) SB 604-27-013 dated, 04 April 2003Note: Transport Canada AD CF-2005-21R1 refers. |\n| Compliance:    | Before the 29 September 2006, unless previously accomplished.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n|                | This Amendment becomes effective on 16 March 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| Background:    | The rudder balance spring assembly, which is intended to position the rudder close to its neutral position in case of a rudder aft linkage disconnect, may not have the correct pre-load on some aircraft. Excessive rudder deflections may occur, reducing controllability of the aircraft. No in-service problems have ever been reported with rudder aft linkage disconnect. A new adjustable balance spring assembly is being introduced to correct this potential problem.                                                                                    |\n\n|     | This amendment changes the applicability of the CL-600-2B16 (CL-604) by serial number.The original issue of this Airworthiness Directive became effective on 29 September 2005. |\n| --- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n1 February 2006","sortOrder":0},{"sectionNumber":"AD/CL-600/66 Amdt 1","sectionType":"part","heading":"AD/CL-600/66 Amdt 1","content":"## AD/CL-600/66 Amdt 1","sortOrder":1},{"sectionNumber":"Rudder Balance Spring Assembly","sectionType":"part","heading":"Rudder Balance Spring Assembly","content":"## Rudder Balance Spring Assembly","sortOrder":2},{"sectionNumber":"3/2006","sectionType":"part","heading":"3/2006","content":"## 3/2006","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Yes. The amendment changes the applicability for the CL-600-2B16 (CL-604) by serial number (Background: \"This amendment changes the applicability of the CL-600-2B16 (CL-604) by serial number\"). The original AD became effective 29 September 2005; this Amendment is effective 16 March 2006 and preserves the same requirement while altering which airframes are captured (Background; Applicability; Compliance)."},"complexity_factors":["Targeted, single-component technical fix (rudder balance spring assembly) — limited engineering scope (Requirement; Background).","Multiple aircraft models and several serial-number ranges listed, requiring operators to check applicability precisely (Applicability).","Work must follow one of several model-specific Service Bulletins or later Transport Canada–approved revisions, creating dependency on external documents and approvals (Requirement).","Single firm compliance deadline and effective date impose scheduling and operational burden on operators to complete modification by 29 September 2006 (Compliance).","Costs and logistics (parts, labour, rigging) fall to aircraft operators; regulator enforces compliance (Requirement; Compliance).","Amendment alters applicability by serial number for one model (CL-604), so affected-operator population changed from the original AD (Background).","No in-service occurrences reported but directive addresses a potential loss-of-control mechanism if preload is incorrect — risk-based precaution rather than response to recorded failures (Background)."],"plain_english_summary":"This airworthiness directive requires operators of specific Bombardier CL-600 Challenger aircraft (listed by model and serial number) to install a new adjustable rudder balance spring assembly and set its rigging according to the applicable Service Bulletin or later Transport Canada–approved revision. The work must be done by 29 September 2006 (directive effective 16 March 2006); aircraft operators pay for and schedule the modification to address a potential excessive rudder-deflection risk (Background; Requirement; Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":true,"description":"This Amendment 1 expands the scope beyond the original 2005 directive. The original AD only covered CL-600-2B16 (CL-604) serial numbers 5001–5194. This amendment adds serial numbers 5301–5564 to the applicability, widening the net of affected aircraft."},"complexity_factors":["Short, single-purpose directive with one clear mechanical requirement","Only 4 defined model/serial number groupings in applicability table","Simple compliance deadline with single condition (unless previously accomplished)","No nested exceptions or conditional logic — straightforward 'do this by this date' structure","Cross-reference to Canadian Transport Canada AD CF-2005-21R1 is informational only, not a dependency for understanding requirements"],"plain_english_summary":"This mandatory CASA Airworthiness Directive requires owners/operators of specified Bombardier CL-600-series jets to fit and properly adjust a new adjustable rudder balance spring assembly to ensure the rudder stays centered if a linkage fails, preventing excessive rudder movement and potential loss of control.  \n\nCompliance was required before 29 September 2006; Amendment 1 expands applicability to include CL-604 serial numbers 5301–5564."},"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-600-66-amdt-1-rudder-balance-spring-assembly","history":"/api/acts/ad-cl-600-66-amdt-1-rudder-balance-spring-assembly/history","analysis":"/api/acts/ad-cl-600-66-amdt-1-rudder-balance-spring-assembly/analysis","conflicts":"/api/acts/ad-cl-600-66-amdt-1-rudder-balance-spring-assembly/conflicts","importantCases":"/api/acts/ad-cl-600-66-amdt-1-rudder-balance-spring-assembly/important-cases","documents":"/api/acts/ad-cl-600-66-amdt-1-rudder-balance-spring-assembly/documents"}}