{"id":"F2006B09014","name":"AD/DHC-1/33 Amdt 1 - Tailplane Support Struts","slug":"ad-dhc-1-33-amdt-1-tailplane-support-struts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52680,"registerId":"commonwealth-F2006B09014-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-1/33 Amdt 1 - Tailplane Support Struts","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)  \nDe Havilland DHC-1 (Chipmunk) Series Aeroplanes\n\nAD/DHC-1/33\n\nAmdt 1\n\n  \nTailplane Support Struts 12/93\n\nApplicability: English production Chipmunk.\n\nRequirement: Action in accordance with British Aerospace Mandatory TNS CT(C1) 186 issue 2.\n\nCompliance: 1. Unless already accomplished in accordance with the initial issue of this Directive and holding a BAe radiographic acceptable assessment from that inspection; within three months after 11 November 1993.\n\n    2. Seven years, with repeat inspections at periods not exceeding seven years after:\n\n    the installation of new struts, or\n\n    b. compliance with either the initial issue or this amendment of this Directive.\n\nNote: Compliance date for the initial issue of this Directive was 20 November 1992.\n\nBackground: A case of internal corrosion in a tailplane attachment strut was reported. The initial issue of the Directive required an external visual inspection, rework and NDI. Amendment 1 introduces a repeat inspection, and revises and clarifies the technical requirements via the TNS.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1723},"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"The amendment maintains the original scope covering tailplane support struts on English production Chipmunks. While Amendment 1 introduces recurring inspection intervals (every 7 years) versus the original one-time requirement, this does not constitute an expansion of the regulatory subject matter — it remains limited to the same aircraft component and corrosion issue."},"complexity_factors":["Actual technical requirements contained in externally referenced document (British Aerospace Mandatory TNS CT(C1) 186 issue 2) not reproduced in the directive","Conditional compliance logic with multiple pathways depending on prior actions and component replacement history","Assumes technical knowledge of aviation maintenance terminology (NDI, tailplane, TNS)","Amendment structure requires cross-referencing with initial issue requirements for full context"],"plain_english_summary":"Owners and maintainers of English-built De Havilland DHC-1 Chipmunk aircraft must carry out mandatory inspections of the tailplane support struts after discovery of internal corrosion that could cause in-flight loss of control.\n\nInspections follow British Aerospace TNS CT(C1) 186 issue 2, including external checks, rework and NDI (e.g., ultrasound/X‑ray). First check was due within 3 months of 11 Nov 1993; repeat every 7 years."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-1-33-amdt-1-tailplane-support-struts","history":"/api/acts/ad-dhc-1-33-amdt-1-tailplane-support-struts/history","analysis":"/api/acts/ad-dhc-1-33-amdt-1-tailplane-support-struts/analysis","conflicts":"/api/acts/ad-dhc-1-33-amdt-1-tailplane-support-struts/conflicts","importantCases":"/api/acts/ad-dhc-1-33-amdt-1-tailplane-support-struts/important-cases","documents":"/api/acts/ad-dhc-1-33-amdt-1-tailplane-support-struts/documents"}}