{"id":"F2006B07330","name":"AD/TB20/26 Amdt 3 - Rudder Balance Weight","slug":"ad-tb20-26-amdt-3-rudder-balance-weight","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49375,"registerId":"commonwealth-F2006B07330-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TB20/26 Amdt 3 - Rudder Balance Weight","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)  \nAerospatiale (Socata) TB20 (Trinidad) Series Aeroplanes\n\nAD/TB20/26\n\nAmdt 3\n\n  \nRudder Balance Weight 6/98\n\nApplicability: Model TB20 and TB21 aircraft with serial numbers 1 through 1554, 1754 through 1757, and 1767 through 1821.\n\nRequirement: Action in accordance with Socata TB Service Bulletin 10-071-55 Revision 3.\n\nNote: DGAC AD 93-012 (A) R2 refers.\n\nCompliance: For aircraft serial numbers 1 through 1554: Before 31 August 1998.\n\nFor aircraft serial numbers 1754 through 1757, and 1767 through 1821:\n\nBefore 31 December 1998.\n\nThis amendment becomes effective on 21 May 1998.\n\nBackground: The DGAC requires certain measures to be taken to avoid development of galvanic corrosion between the balance weight and both rudder tip stiffeners. Amendment 1 reflected a requirement document revision which corrected text anomalies and material information. Amendment 2 reflected a requirement document revision which clarified applicability.\n\nAmendment 3 is issued in response to a revision of the related DGAC AD which reflects a revision of the Requirement document which expands applicability and compliance times.\n\nAmendment 2 to this airworthiness directive became effective on 26 May 1994\\. Amendment 1 to this airworthiness directive became effective on 22 July 1993.\n\nThe original issue of this airworthiness directive became effective on 29 April 1993.","sortOrder":0}],"analysis":{"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":true,"description":"Amendment 3 expands the AD's applicability and adjusts compliance times relative to prior issues — the AD text states it \"reflects a revision of the Requirement document which expands applicability and compliance times.\""},"complexity_factors":["Applicability is specified by multiple, non-contiguous serial-number ranges (requires checking individual aircraft serials against the list).","Mandates action ‘in accordance with’ an external document (Socata Service Bulletin 10-071-55 Rev 3), so compliance requires consulting and following that document.","Staggered compliance deadlines depending on serial-number range (two different final dates).","Multiple historical amendments and cross-reference to DGAC AD require tracing past versions to understand changes over time.","Regulatory enforcement risk (CASA enforces compliance; non-compliance can lead to grounding or regulatory action) increases operational impact."],"plain_english_summary":"This airworthiness directive requires owners/operators of specific Socata TB20 and TB21 aircraft (listed by serial number) to install or modify the rudder balance weight in accordance with Socata Service Bulletin 10-071-55 Revision 3 to prevent galvanic corrosion between the balance weight and rudder tip stiffeners. Operators bear the cost and must complete the work by the stated deadlines (which vary by serial-number range); the Civil Aviation Safety Authority enforces compliance and may ground or take regulatory action for non‑compliance."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":true,"description":"The original 1993 directive has expanded in scope through three amendments. Amendment 3 specifically 'expands applicability and compliance times' compared to the original, adding serial number ranges 1754-1757 and 1767-1821 that weren't in the original issue, and pushing out deadlines from the original 1993 timeframe to late 1998."},"complexity_factors":["Very short document (approximately 200 words)","Only 3 defined applicability groups (by serial number ranges)","Single requirement referencing an external technical document (Service Bulletin)","No nested conditional logic or exceptions","Simple linear structure: applicability → requirement → compliance dates → background","Cross-reference to one French aviation authority document (DGAC AD 93-012) and one external service bulletin"],"plain_english_summary":"This safety order requires owners/operators of certain Socata TB20 and TB21 aeroplanes to carry out the Service Bulletin 10‑071‑55 Rev.3 maintenance fix to stop galvanic corrosion between the rudder balance weight and tip stiffeners, which could weaken rudder control. It amends the original 1993 order (third update), expands the serial-numbered fleet covered, and sets late‑1998 compliance deadlines — non‑compliance affects legal airworthiness."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tb20-26-amdt-3-rudder-balance-weight","history":"/api/acts/ad-tb20-26-amdt-3-rudder-balance-weight/history","analysis":"/api/acts/ad-tb20-26-amdt-3-rudder-balance-weight/analysis","conflicts":"/api/acts/ad-tb20-26-amdt-3-rudder-balance-weight/conflicts","importantCases":"/api/acts/ad-tb20-26-amdt-3-rudder-balance-weight/important-cases","documents":"/api/acts/ad-tb20-26-amdt-3-rudder-balance-weight/documents"}}