{"id":"F2012L01734","name":"AD/SA-TP/23 Amdt 2 - Structural Components Fatigue Lives","slug":"ad-sa-tp-23-amdt-2-structural-components-fatigue-lives","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":89702,"registerId":"commonwealth-F2012L01734-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"British Aerospace (Scottish Aviation) Tw","sectionType":"division","heading":"British Aerospace (Scottish Aviation) Twin Pioneer Series Aeroplanes","content":"### British Aerospace (Scottish Aviation) Twin Pioneer Series Aeroplanes\n\n| AD/SA-TP/23 Amdt 2 | Structural Components Fatigue Lives | 17/2012 |\n| ------------------ | ----------------------------------- | ------- |\n\n| Applicability: | All models.                                                                                                                                                                                                                                                                                                     |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the technical requirements of Scottish Aviation Service TNS No. 33 Issue 2.Note: Appendices refer to specific serial numbers; if no Appendix is specified then carryout the instructions of Appendix S of the requirement document.                                                   |\n| Compliance:    | As specified in the requirement document.                                                                                                                                                                                                                                                                       |\n|                | This Amendment becomes effective on 23 August 2012.                                                                                                                                                                                                                                                             |\n| Background:    | Scottish Aviation Service promulgates fatigue lives of components based on full scale fatigue testing and the analysis of operator submitted flight plans. If no flight plans were submitted or operational role differs from that originally advised, the manufacturer specifies Appendix S to be appropriate. |\n\n![](image.001.png)  \nMike Higgins  \nDelegate of the Civil Aviation Safety Authority\n\n17 August 2012","sortOrder":0},{"sectionNumber":"AD/SA-TP/23 Amdt 2","sectionType":"part","heading":"AD/SA-TP/23 Amdt 2","content":"## AD/SA-TP/23 Amdt 2","sortOrder":1},{"sectionNumber":"Structural Components Fatigue Lives","sectionType":"part","heading":"Structural Components Fatigue Lives","content":"## Structural Components Fatigue Lives","sortOrder":2},{"sectionNumber":"17/2012","sectionType":"part","heading":"17/2012","content":"## 17/2012","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"The amendment explicitly applies to 'All models' and centralises compliance on Scottish Aviation Service TNS No. 33 Issue 2; it also clarifies that, where no serial-specific appendix or applicable operator flight data exist (or operational role differs), Appendix S is to be used as the default (Applicability; Requirement; Background)."},"complexity_factors":["Dependence on an external technical document (Scottish Aviation Service TNS No. 33 Issue 2) to prescribe required actions (Requirement).","Serial-number specific appendices create need to check aircraft identity against multiple possible instructions (Requirement; Note on Appendices).","Default rule when operator flight plans are absent or role differs — manufacturer discretion to designate Appendix S — introduces conditional compliance pathways (Background).","Technical subject matter (fatigue lives, testing and flight-plan analysis) requires specialist engineering interpretation and record checks (Background).","Compliance timing and procedures are set 'as specified in the requirement document', so regulators/operators must consult that document to determine concrete timelines and tasks (Compliance)."],"plain_english_summary":"This airworthiness directive requires operators of all British Aerospace (Scottish Aviation) Twin Pioneer aeroplanes to follow the manufacturer’s technical instructions in Scottish Aviation Service TNS No. 33 Issue 2 for fatigue lives of structural components (effective 23 Aug 2012). The manufacturer decides which appendix applies to specific serial numbers and, if operator flight data are missing or the aircraft’s role differs, directs use of Appendix S, which imposes inspection, maintenance or replacement duties on owners/operators."},"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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive amendment maintaining the original scope of ensuring structural fatigue management for the Twin Pioneer aircraft type. It represents a routine update (Amendment 2) to an existing directive, not an expansion beyond the original safety purpose."},"complexity_factors":["Short, single-purpose directive (approximately 200 words of substantive content)","Only one primary technical reference (Scottish Aviation Service TNS No. 33 Issue 2)","Simple conditional logic: use specific appendix if serial number matches, otherwise default to Appendix S","No defined terms section — relies on external technical document for definitions","No cross-references to other legislation or regulations within the text itself","Straightforward compliance structure: single action required, timing determined by external document"],"plain_english_summary":"This CASA Airworthiness Directive requires all British Aerospace (Scottish Aviation) Twin Pioneer operators and maintenance organisations to apply Service TNS No. 33 Issue 2 to manage structural component fatigue lives. It ensures parts are inspected, tracked and replaced per the manufacturer’s fatigue-life instructions—using the appendix that matches the aircraft’s serial number or the conservative Appendix S if none applies—to prevent unsafe metal fatigue failures in flight. Effective 23 August 2012."}},"importantCases":[],"_links":{"self":"/api/acts/ad-sa-tp-23-amdt-2-structural-components-fatigue-lives","history":"/api/acts/ad-sa-tp-23-amdt-2-structural-components-fatigue-lives/history","analysis":"/api/acts/ad-sa-tp-23-amdt-2-structural-components-fatigue-lives/analysis","conflicts":"/api/acts/ad-sa-tp-23-amdt-2-structural-components-fatigue-lives/conflicts","importantCases":"/api/acts/ad-sa-tp-23-amdt-2-structural-components-fatigue-lives/important-cases","documents":"/api/acts/ad-sa-tp-23-amdt-2-structural-components-fatigue-lives/documents"}}