{"id":"F2006B09019","name":"AD/DHC-1/38 - Re-Classification of Existing Modifications to Mandatory Status","slug":"ad-dhc-1-38-re-classification-of-existing-modifications-to-mandatory-status","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52692,"registerId":"commonwealth-F2006B09019-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-1/38 - Re-Classification of Existing Modifications to Mandatory Status","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  De Havilland DHC-1 (Chipmunk) Series Aeroplanes\n\n \n\n# AD/DHC-1/38 Re-Classification of Existing Modifications\n\nto Mandatory Status\n\nApplicability: All DHC-1 Chipmunk aircraft.\n\n# 7/97\n\n \n\nRequirement: Action in accordance with British Aerospace Mandatory Technical News Sheet (TNS) CT (C1) No. 200.\n\n \n\nNote 1: TNS CT (C1) No.200 also informs operators how to determine that the required modifications have been incorporated on their aircraft.\n\n \n\nNote 2: UK CAA AD 006-03-97 refers.\n\n \n\nCompliance: Unless already accomplished, before 19 September 1997.\n\n \n\nThis airworthiness directive becomes effective on 19 June 1997.\n\n \n\nBackground: The UK CAA requires that certain modifications be incorporated, in order to ensure the continued airworthiness of Chipmunk aircraft.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The instrument changes the scope of certain existing modifications from non‑mandatory/recommended to mandatory for all DHC‑1 aircraft, requiring operators to implement or verify incorporation per BAe TNS CT (C1) No.200 by a fixed deadline (Requirement; Compliance)."},"complexity_factors":["External normative reference: requires action “in accordance with British Aerospace Mandatory Technical News Sheet CT (C1) No. 200” (Requirement) — operators must consult and follow an external technical document.","Verification burden: TNS also informs how to determine whether modifications are already incorporated, creating record‑checking and inspection obligations (Note 1).","Universal applicability: applies to “All DHC‑1 Chipmunk aircraft” (Applicability) so affects every owner/operator of the type.","Fixed compliance window: a specific deadline and effective date create scheduling pressure (Compliance; effective 19 June 1997; comply before 19 September 1997).","Cross‑jurisdictional reference: refers to UK CAA AD 006‑03‑97 (Note 2), tying domestic requirement to overseas airworthiness action and potentially to foreign technical standards.","Technical implementation risk: modifications are technical and may require parts, skilled labour, inspection access and aircraft downtime (implied by Requirement and TNS reliance).","Limited legislative detail: the AD delegates procedural specifics to the TNS, increasing reliance on the external document for scope and methods."],"plain_english_summary":"This airworthiness directive makes certain previously non‑mandatory modifications mandatory for all De Havilland DHC‑1 (Chipmunk) aircraft. Operators and owners must carry out the changes in accordance with British Aerospace Mandatory Technical News Sheet CT (C1) No. 200 by 19 September 1997; the AD is effective from 19 June 1997.\n\nMechanically, the rule shifts the compliance burden onto aircraft owners/operators who must inspect records, implement the TNS instructions if missing, and absorb associated costs and downtime."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive with a single, specific purpose: mandating particular modifications for one aircraft type. It has not expanded beyond its original safety intent."},"complexity_factors":["Very short document (under 300 words)","Only 1 substantive requirement (comply with TNS CT (C1) No. 200)","No defined terms section — relies entirely on external document","Single applicability criterion (all DHC-1 Chipmunk aircraft)","Simple compliance structure (binary: done by date or already done)","Minimal cross-referencing (one UK CAA AD and one British Aerospace document)"],"plain_english_summary":"Owners and operators of De Havilland DHC‑1 Chipmunk aircraft in Australia must comply with a CASA Airworthiness Directive reclassifying previously optional safety modifications as mandatory. It requires following British Aerospace Technical News Sheet CT (C1) No. 200 to install or verify the specified fixes — compliance was required by 19 September 1997. This is a time‑critical safety order tied to UK regulator findings."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-1-38-re-classification-of-existing-modifications-to-mandatory-status","history":"/api/acts/ad-dhc-1-38-re-classification-of-existing-modifications-to-mandatory-status/history","analysis":"/api/acts/ad-dhc-1-38-re-classification-of-existing-modifications-to-mandatory-status/analysis","conflicts":"/api/acts/ad-dhc-1-38-re-classification-of-existing-modifications-to-mandatory-status/conflicts","importantCases":"/api/acts/ad-dhc-1-38-re-classification-of-existing-modifications-to-mandatory-status/important-cases","documents":"/api/acts/ad-dhc-1-38-re-classification-of-existing-modifications-to-mandatory-status/documents"}}