{"id":"F2006B09212","name":"AD/DHC-8/56 - Main Landing Gear Uplock Actuator Modification","slug":"ad-dhc-8-56-main-landing-gear-uplock-actuator-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53054,"registerId":"commonwealth-F2006B09212-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-8/56 - Main Landing Gear Uplock Actuator Modification","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes\n\nAD/DHC-8/56 Main Landing Gear Uplock Actuator Modification 12/98\n\nApplicability: All DHC 8 aircraft, serial numbers 3 through 339, without Bombardier Modification 8/1828 incorporated.\n\nRequirements: Unless previously accomplished, install Bombardier Modification 8/1828 (Landing Gear \\- Redesigned Main Gear Uplock Actuator) on both left and right main landing gear in accordance with the instructions in Bombardier Service Bulletin 8-32-98, Revision C, dated 31 July 1998.\n\nNote: Transport Canada Airworthiness Directive CF-98-26 dated 26 August 1998 refers.\n\nCompliance: Within 12 months of the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 5 November 1998.\n\nBackground: Operators are reporting incidents of main landing gears failing to extend when a down selection is made. The cause is attributed to failure of the gear uplock unit to disengage. The alternate extension system must then be used to extend the landing gear. This modification is introduced to improve the reliability of the gear uplock and minimise the risk of experiencing landing gear hang up.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive (AD) — a targeted safety instrument with a narrow, specific purpose from inception. It has not expanded beyond its original intent; it addresses exactly one known defect in one aircraft series with a prescribed technical solution."},"complexity_factors":["Single, specific technical requirement with no conditional exceptions","Only one defined applicability criterion (serial number range plus modification status)","Straightforward compliance deadline (12 months from effective date)","No nested definitions or cross-references to other legislation beyond a single reference to a Canadian directive for information purposes","Clear, single-purpose scope limited to one aircraft type and one specific mechanical component"],"plain_english_summary":"The Civil Aviation Safety Authority requires operators and maintenance organisations of Bombardier DHC‑8 (Dash 8) aircraft, serials 3–339 without Modification 8/1828, to install redesigned uplock actuators on both main landing gears per Bombardier Service Bulletin 8‑32‑98 Rev C. Work must be done within 12 months of 5 Nov 1998. The fix prevents uplock failures that can leave wheels stuck up and avoids reliance on emergency extension systems."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"No. The directive confines action to DHC‑8 serial numbers 3–339 that have not incorporated Modification 8/1828 and requires that specific retrofit (Requirements; Applicability). It does not broaden to other aircraft types, systems, or additional measures beyond the single redesign described."},"complexity_factors":["Single clear technical action required (install Bombardier Modification 8/1828) — low procedural complexity (Requirements).","Limited affected population: specific serial numbers 3–339 without the modification — simplifies compliance targeting (Applicability).","Installation must follow a specified service bulletin (Bombardier Service Bulletin 8‑32‑98 Rev C) — requires technical/maintenance capability and parts availability (Requirements).","Fixed compliance window of 12 months creates scheduling and operational planning needs for operators (Compliance).","Mandate applies to both left and right main landing gear — doubles scope per aircraft but is mechanically straightforward (Requirements).","Operational interim risk: until retrofit, crews may need to use alternate extension procedures (Background)."],"plain_english_summary":"This directive requires operators of Bombardier DHC‑8 aeroplanes (serial numbers 3–339) that have not incorporated Bombardier Modification 8/1828 to install the redesigned main landing gear uplock actuator on both left and right gears, following Bombardier Service Bulletin 8‑32‑98 Rev C. Compliance is required within 12 months and the directive became effective 5 November 1998.\n\nThe stated purpose is to reduce incidents where the uplock fails to disengage, forcing use of the alternate extension system. Operators bear the retrofit cost and scheduling burden until the modification is fitted."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-56-main-landing-gear-uplock-actuator-modification","history":"/api/acts/ad-dhc-8-56-main-landing-gear-uplock-actuator-modification/history","analysis":"/api/acts/ad-dhc-8-56-main-landing-gear-uplock-actuator-modification/analysis","conflicts":"/api/acts/ad-dhc-8-56-main-landing-gear-uplock-actuator-modification/conflicts","importantCases":"/api/acts/ad-dhc-8-56-main-landing-gear-uplock-actuator-modification/important-cases","documents":"/api/acts/ad-dhc-8-56-main-landing-gear-uplock-actuator-modification/documents"}}