{"id":"F2006B03620","name":"AD/BEECH 18/21 - Main Landing Gear Walking Beam Upper Attach Bolt - Inspection and Replacement","slug":"ad-beech-18-21-main-landing-gear-walking-beam-upper-attach-bolt-inspection-and-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43211,"registerId":"commonwealth-F2006B03620-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEECH 18/21 - Main Landing Gear Walking Beam Upper Attach Bolt - Inspection and Replacement","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)  \nBeechcraft 18 Series Aeroplanes\n\nAD/BEECH 18/21 Main Landing Gear Walking Beam Upper\n\nAttach Bolt \\- Inspection and Replacement\n\n  \n11/81\n\nApplicability: All models C-45G, TC-45G, C-45H, TC-45H, TC-45J (SNB-5) RC-45J (SNB-5P), D18C, D18S, E18S-9700, G18S, H18, JRB-3N, 3NM and 3TM fitted with Volpar\n\ntricycle landing gear.\n\nRequirement: 1. Visually inspect the main landing gear walking beam upper attach bolt P/No. AN 179-46A for integrity and adequate installation.\n\n    2. Remove AN 179-46A bolt and associated hardware and install NAS 149-80 bolt and associated hardware as specified in “Description of Change” section of Volpar Inc. SB No. 22 dated 1 June 1981.\n\n    3. Visually inspect bolt P/No. NAS 149-80 installation for Integrity and replace with like serviceable part as necessary.\n\nNote: FAA AD 81-18-07 Amdt. 39-4204 refers.\n\nCompliance: 1. Within 10 hours time in service after 25 September 1981.\n\n    2. Within 200 hours time in service after 25 September 1981.\n\n    3. At intervals not to exceed 3000 hours time in service.\n\nBackground: Failure of the MLG walking beam upper attach bolt may occur in normal service.\n\nFederal Register of Legislative Instruments F2006B03620","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 mechanical defect. It has not expanded beyond its original purpose of mandating inspection and replacement of a single critical component."},"complexity_factors":["Single, specific technical subject matter (one bolt on one landing gear type)","Only 3 compliance requirements with clear timeframes","Minimal cross-referencing (one FAA AD reference and one manufacturer service bulletin)","No nested conditions or exceptions","Short document (approximately 200 words)","Only 2 defined part numbers and specific aircraft models listed"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of Beechcraft 18-series aircraft fitted with Volpar tricycle landing gear to inspect and replace a potentially failing walking-beam bolt (AN179-46A). \n\nIt mandates an immediate visual check, replacement within 200 flight hours with a stronger NAS149-80 bolt per Volpar service instructions, and recurring inspections every 3,000 flight hours. The action prevents landing-gear collapse; non-compliance grounds the aircraft."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"No. The directive implements an inspection-and-replacement requirement aimed at preventing walking-beam upper attach bolt failure as stated in the Background and Compliance sections. It confines action to the listed Beechcraft models fitted with Volpar tricycle gear and prescribes specific parts, installation procedures, and compliance intervals rather than broadening applicability."},"complexity_factors":["Technical specificity: mandates inspection and replacement of a particular bolt (part numbers referenced) and associated hardware.","Multiple compliance windows: immediate inspection (10 hours), mandated replacement (200 hours), and recurring inspection interval (3,000 hours).","Applicability across many model variants fitted with a specific Volpar tricycle landing gear conversion (requires accurate fleet identification).","Mandates adherence to a manufacturer service bulletin (Volpar SB No. 22) for installation details, creating dependency on that external document.","Enforcement and cross-reference: cites FAA AD for related authority, introducing cross-jurisdictional traceability for operators.","Operational impact: requires maintenance time, replacement parts procurement, and potential aircraft downtime."],"plain_english_summary":"This airworthiness directive requires owners/operators of specified Beechcraft 18-series aeroplanes fitted with Volpar tricycle landing gear to inspect the main landing-gear walking-beam upper attach bolt, replace the identified bolt with the specified NAS part, and carry out recurring inspections. Actions must be completed within set flight-hour windows (inspect within 10 hours, replace within 200 hours, then inspect every 3,000 hours). Maintenance organisations perform the work and bear the direct costs; CASA enforces compliance."}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-18-21-main-landing-gear-walking-beam-upper-attach-bolt-inspection-and-replacement","history":"/api/acts/ad-beech-18-21-main-landing-gear-walking-beam-upper-attach-bolt-inspection-and-replacement/history","analysis":"/api/acts/ad-beech-18-21-main-landing-gear-walking-beam-upper-attach-bolt-inspection-and-replacement/analysis","conflicts":"/api/acts/ad-beech-18-21-main-landing-gear-walking-beam-upper-attach-bolt-inspection-and-replacement/conflicts","importantCases":"/api/acts/ad-beech-18-21-main-landing-gear-walking-beam-upper-attach-bolt-inspection-and-replacement/important-cases","documents":"/api/acts/ad-beech-18-21-main-landing-gear-walking-beam-upper-attach-bolt-inspection-and-replacement/documents"}}