{"id":"F2009L02772","name":"AD/CL-600/112 - Main Landing Gear Torque Link Apex Pin","slug":"ad-cl-600-112-main-landing-gear-torque-link-apex-pin","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":79930,"registerId":"commonwealth-F2009L02772-current","compilationNumber":null,"startDate":"2026-04-02","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-600/112 | Main Landing Gear Torque Link Apex Pin | 8/2009 |\n| ------------- | -------------------------------------- | ------ |\n\n| Applicability: | Bombardier Inc. Models:CL-600-2C10 - serial numbers 10003 and subsequent.CL-600-2D15 and CL-600-2D24 - serial numbers 15001 and subsequent. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement: | 1. Inspection of the Torque Link Apex Joint – Applicable to CL-600-2C10 Serial Numbers 10003 through 10223, and CL-600-2D15 and CL-600-2D24 Serial Numbers 15001 through 15035, 15038, 15039 and 15042.Perform a one-time detailed visual inspection and any required action(s) on the torque link apex joint in accordance with Part A of the Accomplishment Instructions in Bombardier Aerospace Service Bulletin (SB) 670BA-32-019, Revision A, dated 18 September 2008, or later revision approved by the Chief, Continuing Airworthiness, Transport Canada.Inspection performed in accordance with the original issue of SB 670BA-32-019, dated 16 March 2006, satisfies the Requirement 1 of this AD.Requirement 1 of this AD is not required if Requirement 2 of this AD has already been accomplished.Requirement 1 of this AD is not required if Repair Engineering Order (REO) 670-32-11-0022 or Goodrich Service Concession Request (SCR) 0056-05 has been incorporated.2. Replacement of the Torque Link Apex Nut – Applicable to CL-600-2C10 Serial Numbers 10003 through 10239, and CL-600-2D15 and CL-600-2D24 Serial Numbers 15001 through 15057.Replace or rework the apex nut in accordance with Part B of the Accomplishment Instructions in Bombardier Aerospace SB 670BA-32-019, Revision A, or later revision approved by the Chief, Continuing Airworthiness, Transport Canada.Replace or rework performed in accordance with the original issue of SB670BA-32-019, satisfies Requirement 2 of this AD. |\n\n| | 3. Prohibition of Installation of Certain Main Landing Gear Shock Strut Assembly -Applicable to CL-600-2C10 Serial Numbers 10003 and subsequent, and CL-600-2D15 and CL-600-2D24 Serial Numbers 15001 and subsequent.a) No replacement/spare main landing gear shock strut assembly (P/N49000-11 through 49000-22) with a serial number in the range 0001 through 0284 (the serial number can start with MA, MAL or MA-) is permitted to be installed on any aircraft unless it has been reworked in accordance with Part B of the Accomplishment Instructions in Bombardier Aerospace SB670BA-32-019, Revision A, dated 18 September 2008, or later revision approved by the Chief, Continuing Airworthiness, Transport Canada.b) No replacement/spare main landing gear shock strut assembly (P/N 49050-5 through 49050-10) with a serial number in the range 1001 through 1114 (the serial number can start with MA, MAL or MA-) is permitted to be installed on any aircraft unless it has been reworked in accordance with Part B of the Accomplishment Instructions in Bombardier Aerospace SB 670BA-32-019, Revision A, dated 18 September 2008, or later revision approved by the Chief, Continuing Airworthiness, Transport Canada.Rework performed in accordance with the original issue of SB 670BA-32-019, satisfies Requirement 3 of this AD.Note: Transport Canada AD CF-2009-20 dated 1 May 2009. |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | For Requirement 1 - Within 900 flight hours after the effective date of this AD.For Requirement 2 - Within 4,500 flight hours after the effective date of this AD.For Requirement 3 - As of the effective date of this AD. |\n| | This Airworthiness Directive becomes effective on 30 July 2009. |\n| Background: | There have been four reports of loose or detached main landing gear torque link apex pin locking plate and the locking plate retainer bolt. This condition could result in torque link apex pin disengagement, heavy vibration during landing, damage to main landing gear components and subsequent main landing gear collapse. |\n\n| | Investigation has determined that incorrect stack-up tolerances of the apex joint or improper installation of the locking plate and apex nut could result in torque link apex pin disengagement. This directive mandates inspection of the torque link apex joint and replacement of the torque link apex nut. |\n| --- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n16 June 2009","sortOrder":0},{"sectionNumber":"AD/CL-600/112","sectionType":"part","heading":"AD/CL-600/112","content":"## AD/CL-600/112","sortOrder":1},{"sectionNumber":"Main Landing Gear Torque Link Apex Pin","sectionType":"part","heading":"Main Landing Gear Torque Link Apex Pin","content":"## Main Landing Gear Torque Link Apex Pin","sortOrder":2},{"sectionNumber":"8/2009","sectionType":"part","heading":"8/2009","content":"## 8/2009","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"The directive preserves the original safety focus and affected fleet defined by serial‑numbered CL‑600 models and aligns compliance routes with the Bombardier Service Bulletin (original or revised). It does not broaden the types of aircraft or introduce new categories of mandatory work beyond inspection, nut replacement and installation restrictions; earlier-completed SB work or specified REO/SCR actions remain acceptable substitutes (Applicability; Requirement notes; Note: Transport Canada AD CF-2009-20)."},"complexity_factors":["Technical specificity: precise aircraft models, serial-number ranges and part numbers must be identified to determine applicability (Applicability; Requirement 3).","Multiple, conditional obligations: three distinct requirements (inspection, nut replacement, and installation prohibition) with cross‑references and exceptions (Requirement 1, Requirement 2, Requirement 3).","Compliance timing: different actions have different flight‑hour deadlines (Compliance: 900 and 4,500 flight hours; Requirement 3 effective immediately), increasing scheduling complexity.","Interplay with prior work: compliance can be satisfied by earlier revisions of the Bombardier Service Bulletin or specific Repair Engineering Orders/Service Concession Requests, requiring record checks (Requirement 1 note; Requirement 2 note).","Parts control burden: prohibition on installing certain spare shock strut assemblies unless reworked forces operators to track serial numbers of spares and procure reworked units (Requirement 3).","Reference dependence: required actions are specified by parts of an external Service Bulletin and its approved revisions, creating dependency on supplier documentation and regulator approval (Requirement 1, Requirement 2, Requirement 3)."],"plain_english_summary":"This Airworthiness Directive requires inspection and, where necessary, repair or replacement of the main landing gear torque-link apex joint and apex nut on specified Bombardier CL‑600 Challenger aircraft, and bans certain un‑reworked replacement shock strut assemblies. It prescribes compliance deadlines measured in flight hours and makes these actions mandatory. Transport Canada says the measure responds to reports of loose or detached apex‑pin hardware that could cause pin disengagement and gear collapse; the directive shifts inspection, rework and parts costs onto operators and maintenance providers."},"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 focused and targeted. It addresses a specific safety defect (torque link apex pin disengagement) in specific aircraft models with clearly defined serial number ranges. The three requirements form a coherent safety strategy: inspect early-production aircraft, replace/rework components on a broader range, and prevent installation of unmodified spare parts. There is no evidence of scope creep beyond the original safety purpose."},"complexity_factors":["Multiple overlapping applicability ranges: Serial number ranges differ between Requirement 1 (10003-10223), Requirement 2 (10003-10239), and Requirement 3 (10003 and subsequent), creating a matrix of applicability","Nested conditional logic: Requirement 1 is waived if Requirement 2 is completed, or if specific prior repairs (REO 670-32-11-0022 or Goodrich SCR 0056-05) were incorporated","Cross-references to external technical documents: Requires compliance with specific revisions of Bombardier Service Bulletin 670BA-32-019, with grandfathering provisions for the original issue","Complex part number and serial number ranges: Requirement 3 involves two separate part number ranges (P/N 49000-11 through 49000-22 and P/N 49050-5 through 49050-10) with serial number ranges (0001-0284 and 1001-1114) and variable prefixes (MA, MAL, or MA-)","Multiple compliance timeframes: Three different deadlines (900 flight hours, 4,500 flight hours, and immediate/as of effective date)","Delegated approval authority: References to \"Chief, Continuing Airworthiness, Transport Canada\" for approving later revisions of the service bulletin"],"plain_english_summary":"This CASA Airworthiness Directive orders mandatory safety actions for early Bombardier Challenger 600-series business jets to prevent main landing gear collapse. It requires targeted inspections and corrective work on the torque link apex joint, replacement/rework of a critical nut on many aircraft, and prohibits use of certain shock strut spares until reworked.\n\nIt affects aircraft owners/operators, maintenance organisations, and parts suppliers because loose or detached locking hardware has led to gear disengagement and collapse risk."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cl-600-112-main-landing-gear-torque-link-apex-pin","history":"/api/acts/ad-cl-600-112-main-landing-gear-torque-link-apex-pin/history","analysis":"/api/acts/ad-cl-600-112-main-landing-gear-torque-link-apex-pin/analysis","conflicts":"/api/acts/ad-cl-600-112-main-landing-gear-torque-link-apex-pin/conflicts","importantCases":"/api/acts/ad-cl-600-112-main-landing-gear-torque-link-apex-pin/important-cases","documents":"/api/acts/ad-cl-600-112-main-landing-gear-torque-link-apex-pin/documents"}}