{"id":"F2006B09208","name":"AD/DHC-8/52 - Brake Valve Shuttle Valve Inspection","slug":"ad-dhc-8-52-brake-valve-shuttle-valve-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53042,"registerId":"commonwealth-F2006B09208-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-8/52 - Brake Valve Shuttle Valve Inspection","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-8/52 Brake Valve Shuttle Valve Inspection 6/98\n\nApplicability: DHC-8 Aircraft Serial Numbers 003 through 498.\n\nRequirement: Perform inspection and replacement as applicable of brake shuttle valve part number 5084-1 in accordance with manufacturer’s Service Bulletin No. A8-32-139, dated\n\n8 October 1997 or Rev A dated 19 December 1997.\n\nNote: Transport Canada AD CF-98-05 dated 02 March 1998 refers.\n\nCompliance: Within 90 days of the effective date of this directive.\n\nThis airworthiness directive becomes effective on 21 May 1998.\n\nBackground: Defective filters inside shuttle valve part number 5084-1 have failed in service causing blockage of a brake valve port and subsequent failure of the brake to release after selection. The defect has been traced to a specific batch of filter fittings which have been installed in a specific range of shuttle valves. The affected shuttle valves are used in the hydraulic systems of the DHC 7 and DHC 8 aircraft models. This directive inspects for, and removes from service, affected shuttle valves in the DHC 8 aircraft.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific manufacturing defect in a specific aircraft component. It has not expanded beyond its original purpose of removing defective brake shuttle valves from service."},"complexity_factors":["Single, specific mechanical component targeted (brake shuttle valve part number 5084-1)","Narrow applicability: only DHC-8 aircraft with serial numbers 003-498","Clear, single compliance pathway: reference to one manufacturer service bulletin","Simple time-based compliance deadline (90 days from effective date)","No nested exceptions, conditional logic, or alternative compliance methods","Minimal defined terms (only standard aviation terminology like 'Applicability' and 'Compliance')","Short document length (approximately 150 words of substantive content)"],"plain_english_summary":"This CASA Airworthiness Directive orders operators of Bombardier DHC‑8 (serials 003–498) to inspect and, if needed, replace shuttle valve P/N 5084‑1 within 90 days of 21 May 1998. Faulty internal filters can block brake fluid, causing brakes to stick or fail to release; compliance follows Service Bulletin A8‑32‑139."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The background states the defective shuttle valves are used in both DHC-7 and DHC-8 models, but the directive’s mandatory applicability is limited to DHC-8 aircraft serial numbers 003–498. Thus the AD’s enforceable scope is narrower than the broader equipment distribution described in the background."},"complexity_factors":["Narrow applicability by aircraft serial numbers (003–498) requires accurate fleet identification and tracking.","Action ties to a specific part number (5084-1) and a particular batch of filter fittings, creating a traceability task for maintenance records.","Mandatory compliance references an external manufacturer Service Bulletin (two dated revisions), so operators must follow detailed technical procedures outside the AD text.","Short compliance window (90 days) compresses scheduling for inspections and potential replacements across affected operators.","Removal-from-service requirement imposes immediate parts replacement logistics and potential aircraft downtime.","Cross-reference to another regulator’s AD (Transport Canada) may require review of related documentation and coordination."],"plain_english_summary":"This directive requires operators of Bombardier DHC-8 aeroplanes serial numbers 003–498 to inspect and, if necessary, replace brake shuttle valve part 5084-1 using the manufacturer’s Service Bulletin. It targets a specific batch of defective filter fittings that can block a brake valve port and prevent brakes releasing.\n\nThe Civil Aviation Safety Authority sets a 90‑day compliance window; operators must perform the inspection/replacement, remove affected valves from service, follow the manufacturer’s procedure, and bear the cost of the work."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-52-brake-valve-shuttle-valve-inspection","history":"/api/acts/ad-dhc-8-52-brake-valve-shuttle-valve-inspection/history","analysis":"/api/acts/ad-dhc-8-52-brake-valve-shuttle-valve-inspection/analysis","conflicts":"/api/acts/ad-dhc-8-52-brake-valve-shuttle-valve-inspection/conflicts","importantCases":"/api/acts/ad-dhc-8-52-brake-valve-shuttle-valve-inspection/important-cases","documents":"/api/acts/ad-dhc-8-52-brake-valve-shuttle-valve-inspection/documents"}}