{"id":"F2006B08537","name":"AD/CHA/11 Amdt 3 - Undercarriage Attachments","slug":"ad-cha-11-amdt-3-undercarriage-attachments","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51309,"registerId":"commonwealth-F2006B08537-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CHA/11 Amdt 3 - Undercarriage Attachments","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)  \nAmerican Champion (Aeronca, Bellanca) Series Aeroplanes\n\nAD/CHA/11\n\nAmdt 3\n\n  \nUndercarriage Attachments 4/79\n\nApplicability: All models 7ECA, 7GCAA, 7KCAB, 7GCBC, 8KCAB and 8GCBC.\n\nRequirement: 1. Remove the “U” bolt securing the undercarriage spring leg and inspect using the magnetic particle method for cracks particularly in the area of the threads and the radius of the bends.\n\n    2. Remove the AN-7 bolt attaching the inboard end of the under-carriage spring leg and inspect using the magnetic particle method for cracks particularly in the area of the thread and the radius under the bolt head.\n\n    3. Retire from service the AN-7 bolt attaching the inboard end of the undercarriage spring leg.\n\n    4. Modify the undercarriage attachment by replacing the AN-7 bolt and nut attaching the inboard end of the spring leg with a MS20007-34 bolt, MS20002C7 washer under the bolt head, MS20002-7 washers as required under the nut and an NAS679-A7 nut or equivalent self-locking type. Torque nut to 650 to 700 inch pounds.\n\nNote: Bellanca Service Letter No C-135 refers.\n\nCompliance: For Para. 1 \\- Unless already accomplished, within 25 hours time in service after 1 March 1979 and thereafter at intervals not exceeding 300 hours time in service.\n\nFor Para. 2 - Unless already accomplished, within 25 hours time in service after 1 March 1979 and thereafter at intervals not exceeding 100 hours time in service until modified in accordance with Para. 4. For Para. 3 - Unless already accomplished, within 25 hours time in service after 1 March 1979 for bolts in excess of 300 hours total time in service and before exceeding 300 hours total time in service for AN7 bolts with less than 300 hours.\n\nFor Para. 4 \\- At next major inspection after 31 June 1979.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The amendment keeps scope limited to the listed American Champion models and prescribes inspections, part retirement and a mandated modification. It specifies inspection method, replacement parts and torque, and sets differing inspection intervals (see Paras. 1–4 and Compliance). It clarifies and formalises corrective and retrofit steps but does not expand applicability beyond the named models."},"complexity_factors":["Technical inspection method required (magnetic particle inspection) — requires specialist equipment and skills.","Multiple, differing compliance intervals (initial 25‑hour window, recurring intervals of 100–300 hours, and modification by next major inspection) increase scheduling complexity.","Mandatory retirement and replacement of a specific bolt type with a specified parts kit and precise torque (650–700 inch‑pounds) creates parts/procurement and labour demands.","Model‑specific applicability (six named models) limits scope but requires operators to check applicability against their fleet.","Reference to an external service letter (Bellanca Service Letter No C‑135) requires cross‑consultation of another document for details.","Continued inspection requirement until modification means ongoing compliance cost until the retrofit is completed.","Text contains a dated compliance milestone ('next major inspection after 31 June 1979') that is internally inconsistent and may complicate interpretation or enforcement."],"plain_english_summary":"This airworthiness directive requires owners/operators of specified American Champion (Aeronca, Bellanca) aeroplanes to inspect undercarriage spring-leg U‑bolts and AN‑7 bolts using magnetic particle inspection, retire and replace the AN‑7 bolt, and then modify the undercarriage attachment with specified replacement parts torqued to a set value. Compliance deadlines are tight (initial inspections within 25 hours, recurring checks until modification, and modification by the next major inspection), so operators pay inspection, replacement and modification costs and must adjust maintenance schedules."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a narrow, technical airworthiness directive focused specifically on undercarriage bolt inspection and replacement for particular aircraft models. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single technical subject matter (undercarriage bolts only)","Only 4 numbered requirements with clear, sequential steps","No defined terms section or interpretation provisions","Minimal cross-referencing (only one reference to Bellanca Service Letter C-135)","Compliance dates are specific but straightforward (hours-based intervals)","No nested exceptions or conditional logic — each paragraph stands alone"],"plain_english_summary":"This safety directive applies to specific American Champion models and requires owners/operators and maintenance organisations to magnetic-particle inspect two critical undercarriage bolts, retire AN-7 bolts after 300 hours, and replace the attachment with stronger specified hardware. It targets landing-gear spring-leg retention to prevent bolt failure and gear collapse. Compliance is time-sensitive, with some actions required within 25 flight hours after March 1979."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cha-11-amdt-3-undercarriage-attachments","history":"/api/acts/ad-cha-11-amdt-3-undercarriage-attachments/history","analysis":"/api/acts/ad-cha-11-amdt-3-undercarriage-attachments/analysis","conflicts":"/api/acts/ad-cha-11-amdt-3-undercarriage-attachments/conflicts","importantCases":"/api/acts/ad-cha-11-amdt-3-undercarriage-attachments/important-cases","documents":"/api/acts/ad-cha-11-amdt-3-undercarriage-attachments/documents"}}