{"id":"F2006B09256","name":"AD/DHC-8/97 - Control Column Torque Tube","slug":"ad-dhc-8-97-control-column-torque-tube","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53210,"registerId":"commonwealth-F2006B09256-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\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 CASR 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 (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/DHC-8/97 Control Column Torque Tube 7","sectionType":"part","heading":"AD/DHC-8/97 Control Column Torque Tube 7/2004","content":"# AD/DHC-8/97 Control Column Torque Tube 7/2004\n\nApplicability: DHC-8 Models 102, 103, 106, 201, 202, 301, 311, 314, and 315 aircraft, serial\n\nnumbers 003 through 584.\n\nRequirement: Install control column torque tube catchers by incorporating ModSum 8Q101338; in accordance with instructions provided in Bombardier Service Bulletin 8-27-90, dated 28 October 2003.\n\nNote: Transport Canada AD CF-2004-08 refers.\n\nCompliance: Within 5,000 flight hours after 8 July 2004, unless already accomplished.\n\nThis Airworthiness Directive becomes effective on 8 July 2004.\n\nBackground: The manufacturer has identified that a single shear failure in the control column torque tube, inboard of its self-aligning bearings, could result in each of the pilot’s and co-pilot’s control column being supported by only one self-aligning bearing. This condition could result in reduced controllability of the aircraft.\n\n![](image.002.png)  \n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority 26 May 2004\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 16 June 2004.","sortOrder":1}],"analysis":{"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive imposes a targeted mandatory retrofit on the listed DHC‑8 models/serial numbers to correct a specified unsafe condition. It does not expand or narrow applicability beyond the aircraft identified, nor does it alter the underlying regulatory authority; it simply mandates a corrective action and a compliance timeframe."},"complexity_factors":["Technical specificity: requires a mechanical modification (torque‑tube catchers) to mitigate a defined structural failure mode (single shear).","Normative references: compliance depends on following manufacturer ModSum 8Q101338 and Bombardier Service Bulletin 8‑27‑90.","Targeted applicability: limited to named DHC‑8 models and serial numbers (003–584), requiring operators to check serial ranges.","Compliance timing: fixed flight‑hour deadline (5,000 hours after 8 July 2004) and an effective date.","Regulatory authority: issued under CASA subregulation 39.1(1) — delegates enforcement and creates legal obligations for operators.","Cross‑jurisdictional reference: notes Transport Canada AD CF‑2004‑08, which can inform conformity and recordkeeping."],"plain_english_summary":"This Airworthiness Directive requires installation of control‑column torque‑tube catchers (ModSum 8Q101338) per Bombardier Service Bulletin 8‑27‑90 on specified DHC‑8 models/serial numbers within 5,000 flight hours of 8 July 2004 to address a possible single‑shear torque‑tube failure that could reduce controllability. Aircraft operators must arrange and pay for the modification; the CASA delegate enforces compliance under CASR subreg 39.1(1), and non‑compliance can attract regulatory action."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific mechanical safety issue in specific DHC-8 aircraft models. It has not expanded beyond its original purpose of mandating a single safety modification."},"complexity_factors":["Single, specific technical requirement with clear reference to external manufacturer documentation","Limited applicability (9 specific aircraft models, specific serial number range)","Simple compliance deadline (5,000 flight hours from effective date)","No nested exceptions, conditional logic, or extensive cross-referencing to other legislation","Only one defined term of note ('ModSum' — manufacturer's modification summary)","Total length is approximately 250 words"],"plain_english_summary":"This AD mandates installing control column torque tube catchers on certain Bombardier DHC-8 (Dash 8) aircraft to provide backup support for pilots’ control columns. It addresses a design flaw where a torque tube failure could leave both pilots with inadequately supported controls, risking loss of control.\n\nIt applies to early Dash 8s (specific models and serials) and requires the modification per Bombardier Service Bulletin 8-27-90 within 5,000 flight hours from 8 July 2004."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-97-control-column-torque-tube","history":"/api/acts/ad-dhc-8-97-control-column-torque-tube/history","analysis":"/api/acts/ad-dhc-8-97-control-column-torque-tube/analysis","conflicts":"/api/acts/ad-dhc-8-97-control-column-torque-tube/conflicts","importantCases":"/api/acts/ad-dhc-8-97-control-column-torque-tube/important-cases","documents":"/api/acts/ad-dhc-8-97-control-column-torque-tube/documents"}}