{"id":"F2006B11061","name":"AD/LA-4/10 Amdt 2 - Aircraft Structure - Inspection for Corrosion","slug":"ad-la-4-10-amdt-2-aircraft-structure-inspection-for-corrosion","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56691,"registerId":"commonwealth-F2006B11061-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LA-4/10 Amdt 2 - Aircraft Structure - Inspection for Corrosion","content":"![](image.001.png)\n\n![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nOn the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/LA-4/10 Amdt 1 and issues the following AD under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)\n\nConsolidated Aeronautics, Colonial and LA-4 Series Aeroplanes\n\nAD/LA-4/10\n\nAmdt 2\n\n  \nAircraft Structure \\- Inspection for Corrosion 1/2005\n\nApplicability: All models.\n\nRequirement: 1. Inspect the aircraft structure in accordance with Lake Aircraft Service Letter No.25.\n\n    2. Inspect all control system push pull rods for corrosion. Where corrosion is suspected under rivet heads, one or more of the following methods may be used to determine if corrosion exists or the joint integrity has been lost:\n\n    Attempts should be made to remove the rivet heads by a light sharp blow with an aluminium tool made from bar stock with a blunt tip, or\n\n    b. If it is possible to rotate the control tube whilst the end fitting is held still, then rivet integrity is lost and all rivets are to be replaced.\n\n    3. When rivets in any control system push pull rod are to be replaced, then the following will apply:\n\n    All rivets are to be removed from the control push rod.\n\n    b. The control push rod tube and end fitting are to be internally and externally inspected for corrosion or damage and repaired as necessary.\n\n    c. Reassemble the control rod in accordance with approved data.\n\nNote: It is recommended that during reassembly of push pull rods, a jointing compound be used to help protect the rivets in the joint from future corrosion.\n\nCompliance: 1. Within 100 hours time in service after 30 April 1974 and thereafter at intervals not exceeding 1 year.\n\n    2. Within 100 hours time in service after 5 November 2003 and thereafter at intervals not exceeding 1 year.\n\n    3. If any rivets are found damaged or corroded.\n\nThis Amendment becomes effective on 20 January 2005.\n\nConsolidated Aeronautics, Colonial and LA-4 Series Aeroplanes\n\nAD/LA-4/10 Amdt 2 (continued)\n\nBackground: This amendment has been issued to correct the referenced requirements document from Service Bulletin No. 25 to Service Letter No.25.\n\nAmendment 1 was issued as a result of extensive corrosion being found in an elevator control push rod joint after it failed in flight. Corrosion was not evident from an external visual inspection because it affected the tails of the rivets attaching the end fitting to the tube.\n\nInitial issue of this Airworthiness Directive resulted from the Type Certificate holder advising of corrosion being found in critical structural elements of the aircraft.\n\n![Signature of David Villiers Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority 30 November 2004\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 22 December 2004.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment is purely technical and corrective — it changes only the document reference from 'Service Bulletin No. 25' to 'Service Letter No. 25'. The scope remains identical to the original 1974 directive and its 2003 amendment: mandatory corrosion inspections for Lake Aircraft structural components and control rods."},"complexity_factors":["Short, single-purpose document (2 pages) with clear applicability and requirements","Only 3 defined compliance dates/intervals to track","Simple conditional logic: 'If rivets damaged → do full replacement protocol'","Minimal cross-referencing (only references to Service Letter No. 25 and CASR 1998 subregulation 39.1(1))","Practical, mechanical instructions (how to test rivets with an aluminium tool) rather than abstract legal provisions","No nested exceptions or complex definitional sections"],"plain_english_summary":"This CASA safety order for Lake Aircraft (Consolidated/Colonial/LA-4 series) revokes a prior directive and mandates inspections to detect hidden corrosion in airframe and control-system components—especially push-pull rods and rivets whose corrosion can be concealed beneath rivet heads. It requires compliance with the manufacturer’s Service Letter inspection procedures on a recurring basis and immediate repair if corrosion is found. The measure responds to an in‑flight elevator‑control failure caused by hidden rivet corrosion."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment corrects the referenced document from 'Service Bulletin No.25' to 'Service Letter No.25' (Background) and does not alter the AD's applicability, required inspections, or compliance intervals. The technical obligations on owners/operators and maintenance personnel remain the same."},"complexity_factors":["Simple, prescriptive inspection and repair actions (Requirement 1–3) rather than novel regulatory constructs.","Relies on an external maintenance document (Lake Aircraft Service Letter No.25) — compliance requires access to and interpretation of that document (Requirement 1).","Multiple practical detection methods for hidden corrosion (rivet-head removal by aluminium tool; rotation test) introduce minor procedural judgment for technicians (Requirement 2).","Requires reassembly in accordance with “approved data”, adding reliance on approved maintenance data and possible approval processes (Requirement 3.c).","Compliance timing has multiple triggers and historic effective dates, so operators must track periodic intervals and conditional triggers (Compliance)."],"plain_english_summary":"Revokes the prior AD and requires owners/operators of all Consolidated Aeronautics, Colonial and LA‑4 series aeroplanes to inspect aircraft structure and control push–pull rods for corrosion, following Lake Aircraft Service Letter No.25. It mandates rivet removal or rotation tests to detect hidden corrosion, replacement of corroded rivets, internal/external inspection of tubes and reassembly using approved data.\n\nThese inspections must occur at specified intervals or when corrosion is suspected, addressing corrosion that was found to have caused an in‑flight elevator control failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-la-4-10-amdt-2-aircraft-structure-inspection-for-corrosion","history":"/api/acts/ad-la-4-10-amdt-2-aircraft-structure-inspection-for-corrosion/history","analysis":"/api/acts/ad-la-4-10-amdt-2-aircraft-structure-inspection-for-corrosion/analysis","conflicts":"/api/acts/ad-la-4-10-amdt-2-aircraft-structure-inspection-for-corrosion/conflicts","importantCases":"/api/acts/ad-la-4-10-amdt-2-aircraft-structure-inspection-for-corrosion/important-cases","documents":"/api/acts/ad-la-4-10-amdt-2-aircraft-structure-inspection-for-corrosion/documents"}}