{"id":"F2006B09016","name":"AD/DHC-1/35 Amdt 1 - Engine Mounting Frame Joints","slug":"ad-dhc-1-35-amdt-1-engine-mounting-frame-joints","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52685,"registerId":"commonwealth-F2006B09016-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-1/35 Amdt 1 - Engine Mounting Frame Joints","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Safety Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \n\nAIRWORTHINESS DIRECTIVE\n\n![](image.001.png)  \n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/DHC-1/35 and issues the following AD under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nDe Havilland DHC-1 (Chipmunk) Series Aeroplanes\n\nAD/DHC-1/35\n\nAmdt 1\n\n  \nEngine Mounting Frame Joints 13/2003\n\nApplicability: DHC-1 aircraft with Engine Mounting Frames Part Number C1.EM.1A L.H. and C1.EM.2A R.H. installed.\n\nRequirement: Action in accordance with British Aerospace Technical News Sheet CT (C1) No. 190 Issue 2.\n\nNote: UK CAA AD 003-08-94 refers.\n\nCompliance: Within 90 days after 25 December 2003, unless the initial inspection has already been accomplished in accordance with British Aerospace Technical News Sheet CT (C1) No. 190 Issue 2. Thereafter inspect at intervals not to exceed 600 hours time in service.\n\nThis Amendment becomes effective on 25 December 2003.\n\nBackground: The manufacturer received reports of cracked engine mounting frames.\n\nAmendment 1 is issued to update the Requirement document to the current issue.\n\n![Signature of David Villiers Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority 12 November 2003\n\n![](image.001.png)\n\nThe above AD is notified in the Commonwealth of Australia Gazette on 3 December 2003.\n\n  \n\nPage 1 of 1","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a straightforward amendment updating a referenced technical document to its current issue. The scope remains tightly focused on engine mounting frame inspections for the DHC-1 Chipmunk aircraft, exactly as originally intended."},"complexity_factors":["Very short document (1 page)","Only 2 defined applicability criteria (specific part numbers)","Single requirement referencing external technical document","Simple compliance structure: one-time initial inspection + recurring interval","No nested exceptions or conditional logic","Clear, unambiguous language throughout"],"plain_english_summary":"CASA requires owners/operators of De Havilland DHC-1 Chipmunk aircraft fitted with specified engine mount parts to perform mandatory inspections of the engine mounting frames for cracks, following British Aerospace Technical News Sheet CT (C1) No. 190 Issue 2. First inspection within 90 days of 25 Dec 2003 and every 600 flight hours thereafter. Cracked frames could lead to in‑flight engine separation."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"Amendment 1 updates the referenced Technical News Sheet to the current issue but does not expand applicability, change the aircraft types or part numbers affected, or alter the inspection interval; it replaces the prior AD with an updated requirement document (Background; Amendment 1)."},"complexity_factors":["Narrow technical applicability: limited to DHC-1 aircraft with engine mounting frames P/N C1.EM.1A L.H. and C1.EM.2A R.H. (Applicability).","External normative reference: mandates compliance with British Aerospace Technical News Sheet CT (C1) No. 190 Issue 2, requiring operators to obtain and follow that document (Requirement).","Timing and recurrence: fixed initial compliance window (within 90 days after 25 December 2003) and a recurring inspection interval (every 600 hours TIS) (Compliance).","Regulatory amendment history: this instrument revokes the earlier AD and updates the Requirement document to the current issue (preamble; Background; Amendment 1).","Administrative decision-making: issued by a CASA delegate (signature block), reflecting delegated regulatory authority rather than case-by-case determinations.","Operational and cost burden rests on owners/operators who must schedule inspections and carry out any repairs following the technical sheet (Requirement; Compliance)."],"plain_english_summary":"Requires owners/operators of De Havilland DHC‑1 (Chipmunk) aeroplanes fitted with engine mounting frames P/N C1.EM.1A or C1.EM.2A to inspect and follow British Aerospace Technical News Sheet CT (C1) No. 190 Issue 2. Initial inspection is due within 90 days after 25 December 2003 (unless already done), then at intervals not exceeding 600 hours time in service. CASA (the delegate) issues the requirement; owners/operators pay to perform inspections and any corrective work directed by the technical sheet."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-1-35-amdt-1-engine-mounting-frame-joints","history":"/api/acts/ad-dhc-1-35-amdt-1-engine-mounting-frame-joints/history","analysis":"/api/acts/ad-dhc-1-35-amdt-1-engine-mounting-frame-joints/analysis","conflicts":"/api/acts/ad-dhc-1-35-amdt-1-engine-mounting-frame-joints/conflicts","importantCases":"/api/acts/ad-dhc-1-35-amdt-1-engine-mounting-frame-joints/important-cases","documents":"/api/acts/ad-dhc-1-35-amdt-1-engine-mounting-frame-joints/documents"}}