{"id":"F2006B09078","name":"AD/DHC-3/29 - Engine Mounting Frame","slug":"ad-dhc-3-29-engine-mounting-frame","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52865,"registerId":"commonwealth-F2006B09078-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-3/29 - Engine Mounting Frame","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-description: CASA Airworthiness Directive\nmeta-generator: Aspose.Words for .NET 22.10.0\nmeta-keywords: Issue 1/1978,Aircraft below 5700 kg,DHC-3 (Otter) Series Aeroplanes,Engine Mounting Frame,29\ntitle: Airworthiness Directive - AD/DHC-3/29 - Engine Mounting Frame\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)  DHC-3 (Otter) Series Aeroplanes\n\n \n\nAD/DHC-3/29 Engine Mounting Frame 1/78\n\nApplicability: All models.\n\n \n\nRequirement: Action in accordance with De H Canada SB No 3/31. Compliance:  At engine overhaul.\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\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\nFederal Register of Legislative Instruments F2006B09078\n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This is a narrow, technical safety instrument focused on a specific aircraft component. It has not expanded beyond its original purpose of ensuring the airworthiness of DHC-3 Otter engine mounting frames."},"complexity_factors":["Extremely short document (under 150 words of substantive content)","No defined terms section","No cross-references to other legislation beyond the enabling regulations (Civil Aviation Regulations 1998, Part 39)","Single, unambiguous requirement referencing an external technical standard (manufacturer's service bulletin)","No conditional logic, exceptions, or nested provisions","Clear applicability statement ('All models')","Simple compliance trigger ('At engine overhaul')"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) issued by the Civil Aviation Safety Authority (CASA). Think of it as a mandatory safety notice for aircraft owners and operators.\n\n**What it does:** It requires owners of DHC-3 \"Otter\" series aeroplanes (a type of Canadian-built utility aircraft) to inspect or repair the **engine mounting frame** — the structure that holds the engine to the aircraft body.\n\n**Who must follow it:** Anyone who operates any model of DHC-3 Otter aircraft in Australia.\n\n**What action is required:** Operators must follow the instructions in **De Havilland Canada Service Bulletin No. 3/31** (a technical notice from the aircraft manufacturer). This work must be done **at the next engine overhaul** — when the engine is already being taken apart for major maintenance.\n\n**Why it matters:** The engine mounting frame is critical safety equipment. If it fails, the engine could detach from the aircraft in flight. This AD ensures potential defects are caught before they become dangerous."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The supplied text sets a requirement to carry out De Havilland Canada SB No. 3/31 at engine overhaul and declares applicability to all DHC-3 models. Nothing in the provided instrument indicates an expansion or contraction of scope from an earlier requirement; the directive’s scope, as written, is the application of that Service Bulletin to all models at engine overhaul."},"complexity_factors":["Directive is very short but delegates technical detail to an external document (De Havilland Canada SB No. 3/31), requiring consultation of that Service Bulletin to know precise actions.","Mandatory compliance timing tied to engine overhaul, which interacts with maintenance scheduling and overhaul contract terms.","Applicability to all models produces broad coverage and ensures many operators must monitor their overhaul programme for compliance.","Regulatory enforcement under Civil Aviation Regulations PART 39 creates formal legal obligations and record-keeping requirements.","Uncertainty in cost and labour impact because the AD omits technical specifics (costs depend on SB content and operator maintenance practices)."],"plain_english_summary":"This AD makes compliance with De Havilland Canada Service Bulletin No. 3/31 mandatory for all DHC‑3 (Otter) aeroplanes, requiring the SB‑specified work on the engine mounting frame to be carried out at engine overhaul. Owners/operators must arrange and pay for the work, which CASA enforces; the AD itself prescribes the requirement but relies on the Service Bulletin for the technical details needed to maintain airworthiness."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-3-29-engine-mounting-frame","history":"/api/acts/ad-dhc-3-29-engine-mounting-frame/history","analysis":"/api/acts/ad-dhc-3-29-engine-mounting-frame/analysis","conflicts":"/api/acts/ad-dhc-3-29-engine-mounting-frame/conflicts","importantCases":"/api/acts/ad-dhc-3-29-engine-mounting-frame/important-cases","documents":"/api/acts/ad-dhc-3-29-engine-mounting-frame/documents"}}