{"id":"F2006B09216","name":"AD/DHC-8/6 - MLG Uplock Actuator","slug":"ad-dhc-8-6-mlg-uplock-actuator","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53065,"registerId":"commonwealth-F2006B09216-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-8/6 - MLG Uplock Actuator","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-8/6 MLG Uplock Actuator 8/89\n\nApplicability: Model DHC 8 serial number 3 and subsequent with MLG uplock actuator part numbers 10800-103, \\-105, \\-107, \\-109 and \\-111 installed, and which do not have modification 8/1098 incorporated.\n\nRequirement: 1. Unless previously accomplished, inspect/rectify the MLG uplock installation in accordance with De Havilland SB No. 8-32-79 Revision A.\n\n2. Rework and re-identify all uplock actuators in accordance with De Havilland SB No. 8-32-79 Revision A.\n\nNote 1: Compliance with Requirement 2 constitutes terminating action for Requirement 1.\n\nNote 2: Canadian AD CF-89-03 refers.\n\nCompliance: 1. Within 50 hours time in service after 10 August 1989; repeat, prior to further flight, whenever the proximity sensor and/or proximity sensor mounting bracket on an uplock actuator has been reset or replaced.\n\n2. Prior to 28 February 1990.\n\nBackground: A trapped MLG uplock actuator target lever may occur under adverse tolerance conditions combined with a failed target lever return spring. This occurrence will prevent the rotation of the main gear uplock latch and the release of the main landing gear.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, original Airworthiness Directive addressing a specific safety defect. It has not grown beyond its original purpose — it targets one component on one aircraft type with a defined compliance path."},"complexity_factors":["Single, specific technical subject matter (one aircraft component)","Limited applicability criteria (specific serial numbers, part numbers, and modification status)","Two distinct requirements with clear deadlines","One cross-reference to a Canadian Airworthiness Directive (CF-89-03)","Reference to external technical document (De Havilland Service Bulletin) for actual procedures","Conditional logic for repeat inspections (triggered by maintenance action on proximity sensor)","Terminating action clearly noted (Requirement 2 ends Requirement 1 obligations)"],"plain_english_summary":"This CASA Airworthiness Directive mandates owners/operators of certain Bombardier DHC‑8 aircraft with specified MLG uplock actuators to inspect and correct the uplock installation and to rework/re‑identify the actuators. It addresses a condition where an internal lever can stick (especially if a spring fails) and prevent the landing gear from lowering. The rework is the terminating action for the repetitive inspections — it prevents potential gear‑up landings."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The AD text does not indicate any expansion or narrowing of scope beyond the stated applicability and requirements. It targets DHC‑8 aircraft from serial no. 3 with specified uplock actuator part numbers and prescribes inspection and rework to address the identified trapped uplock actuator risk; no wording in the instrument shows a change from that stated purpose."},"complexity_factors":["Technical specificity of applicability: exact aircraft (DHC‑8 serial no. 3 onward) and listed uplock actuator part numbers (Applicability).","Two-stage obligations: immediate inspect/rectify action and a separate rework plus re‑identification requirement (Requirement 1–2).","Short and differing compliance timelines: inspection within 50 hours TIS and a fixed rework deadline (Compliance).","Triggered repeat inspections when proximity sensor or mounting bracket are reset or replaced, creating operational monitoring burden (Compliance 1).","Procedural dependence on a manufacturer service bulletin (De Havilland SB No. 8-32-79 Revision A) for the required work, which centralises technical detail outside the AD (Requirement).","Terminating-action clause: completing rework removes the need for the repetitive inspection, creating a trade-off between upfront cost and ongoing checks (Note 1).","Safety-critical failure mode (trapped target lever with failed return spring) underlies the directive, which raises urgency and operational risk if not complied with (Background).","Regulatory enforcement by the Civil Aviation Safety Authority through the airworthiness directive framework (header/authority)."],"plain_english_summary":"Requires operators of DHC-8 aeroplanes (serial no. 3 onward) fitted with specified main landing gear (MLG) uplock actuator part numbers to inspect and, if necessary, rectify the uplock installation and to rework and re‑identify the actuators per the manufacturer’s service bulletin. The measure is intended to prevent a trapped uplock actuator target lever that can stop the main landing gear from releasing. Compliance deadlines: inspection within 50 hours’ time in service and rework completed by 28 February 1990; operators bear the cost and CASA enforces compliance."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-6-mlg-uplock-actuator","history":"/api/acts/ad-dhc-8-6-mlg-uplock-actuator/history","analysis":"/api/acts/ad-dhc-8-6-mlg-uplock-actuator/analysis","conflicts":"/api/acts/ad-dhc-8-6-mlg-uplock-actuator/conflicts","importantCases":"/api/acts/ad-dhc-8-6-mlg-uplock-actuator/important-cases","documents":"/api/acts/ad-dhc-8-6-mlg-uplock-actuator/documents"}}