{"id":"F2006B09976","name":"AD/FU24/12 - Rudder Lowr Rib - Inspection","slug":"ad-fu24-12-rudder-lowr-rib-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55267,"registerId":"commonwealth-F2006B09976-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/FU24/12 - Rudder Lowr Rib - Inspection","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Airparts (NZ) Ltd. FU 24 Series Aeroplanes\n\n \n\nAD/FU24/12 Rudder Lowr Rib - Inspection 6/68\n\nApplicability: All models not incorporating James Aviation Mod. HA/FU24/116.\n\n \n\nRequirement: Detach the torque tube from the rudder and examine the rudder lower rib assembly P/N 242406 at the attachment of the rudder torque tube flange P/N 242410 for cracking and corrosion.\n\n \n\nCompliance: At intervals not exceeding 500 hours time in service.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive sets a specific inspection requirement for the rudder lower rib assembly on FU 24 series aeroplanes and excludes aircraft fitted with James Aviation Mod. HA/FU24/116 (see \"Applicability\"). There is no indication in the instrument text that it widens or narrows scope beyond that stated applicability and the single inspection requirement."},"complexity_factors":["Single, narrowly defined inspection task (low procedural complexity).","Technical specificity of parts by part number (P/N 242406 and P/N 242410) requiring correct part identification.","Requirement to detach the torque tube increases labour, access and time compared with only visual checks.","Recurring compliance interval (every 500 hours TIS) creates ongoing scheduling and cost considerations.","Applicability carve‑out for aircraft fitted with James Aviation Mod. HA/FU24/116 requires operators to verify modification status.","No accept/reject criteria or prescribed remedial action contained in the text, which places decision-making burden on maintenance personnel and may require reference to other documents or approvals."],"plain_english_summary":"### What this instrument does\n\nThis Airworthiness Directive requires an inspection of the rudder lower rib assembly on Airparts (NZ) Ltd. FU 24 series aeroplanes. Mechanically, it directs a maintenance technician to detach the rudder torque tube from the rudder and examine the rudder lower rib assembly (part number 242406) where the rudder torque tube flange (part number 242410) attaches, specifically looking for cracking and corrosion (\"Requirement\").\n\n### Who it affects\n\n- Operators and owners of FU 24 series aeroplanes unless the aeroplane has James Aviation Modification HA/FU24/116 installed (\"Applicability\").\n- Maintenance organisations, licensed aircraft maintenance engineers, and any third‑party repairers contracted to carry out the inspection.\n\n### When it must be done\n\nThe inspection must be carried out at intervals not exceeding 500 hours time in service (\"Compliance\").\n\n### Why it matters (stated purpose and practical implications)\n\nThe stated purpose is to detect cracking and corrosion at the torque tube attachment to the rudder lower rib so defects can be identified before they present a safety risk (expressed by the inspection requirement). Mechanically, the directive creates the following concrete effects:\n\n- Who pays: aircraft owners/operators pay for the labour to detach the torque tube, perform the inspection, and for any remediation (repair or replacement) if cracking or corrosion is found (see \"Requirement\" and \"Compliance\").\n- Who decides: licensed maintenance personnel decide whether the part shows cracking or corrosion and whether further corrective action is required; the AD sets the inspection obligation and the aviation regulator enforces compliance (the directive is issued under the Civil Aviation Regulations framework shown on the document header).\n- Behaviour change: operators must schedule a recurring maintenance task every 500 hours TIS, potentially increasing maintenance downtime and recurring maintenance costs.\n\n### Costs, incentives and trade-offs\n\n- Direct costs are inspection labour and any parts or repairs required when defects are found (implicit from the Requirement to examine for cracking and corrosion).\n- The inspection interval creates a recurring compliance burden on operators (500-hour interval stated under \"Compliance\").\n- The directive excludes aeroplanes that have the specified modification (HA/FU24/116), which creates an incentive for operators to fit that modification if it removes the inspection requirement (see \"Applicability\").\n- The AD specifies what to examine but does not prescribe accept/reject criteria or specific remedial actions in this text; that leaves judgement and follow-up work to maintenance organisations and may require further documentation or repair approvals.\n\n### Implementation and enforcement notes\n\n- The action requires physical detachment of the torque tube, so it is not a quick visual check; it requires access, time and appropriately qualified personnel (see \"Requirement\").\n- The directive is presented in the Airworthiness Directives schedule under the Civil Aviation Regulations heading on the document, indicating regulatory enforceability.\n\n(References: the AD lines headed \"Applicability\", \"Requirement\" and \"Compliance\".)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive focused on a specific aircraft part. It has not expanded beyond its original purpose of ensuring rudder structural integrity on the FU 24 series."},"complexity_factors":["Very short document (approximately 150 words)","Only 2 defined technical terms (P/N 242406 and P/N 242410 — part numbers)","Single, clear requirement with no exceptions or nested conditions","No cross-references to other legislation or regulations","Simple compliance trigger (time-in-service hours only)"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to certain small aircraft made by Airparts (NZ) Ltd, specifically the FU 24 series.\n\n**What it requires:**\nOwners and operators of these planes must **inspect the rudder lower rib** (a structural part of the tail that helps steer the aircraft) for **cracks and corrosion**. This involves detaching the torque tube (a metal shaft that transfers steering forces to the rudder) to get proper access.\n\n**Who must comply:**\nAnyone operating an FU 24 series aircraft that **doesn't** have a specific modification called \"James Aviation Mod. HA/FU24/116\" installed.\n\n**When:**\nThis inspection must be done **every 500 hours of flight time**.\n\n**Why it matters:**\nCracks or corrosion in the rudder structure could cause the rudder to fail in flight, potentially leading to loss of control. This directive prevents accidents by catching damage before it becomes critical."}},"importantCases":[],"_links":{"self":"/api/acts/ad-fu24-12-rudder-lowr-rib-inspection","history":"/api/acts/ad-fu24-12-rudder-lowr-rib-inspection/history","analysis":"/api/acts/ad-fu24-12-rudder-lowr-rib-inspection/analysis","conflicts":"/api/acts/ad-fu24-12-rudder-lowr-rib-inspection/conflicts","importantCases":"/api/acts/ad-fu24-12-rudder-lowr-rib-inspection/important-cases","documents":"/api/acts/ad-fu24-12-rudder-lowr-rib-inspection/documents"}}