{"id":"F2006B09074","name":"AD/DHC-3/25 - Wing Strut and Attachments - Retirement Lives","slug":"ad-dhc-3-25-wing-strut-and-attachments-retirement-lives","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52851,"registerId":"commonwealth-F2006B09074-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-3/25 - Wing Strut and Attachments - Retirement Lives","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)  DHC-3 (Otter) Series Aeroplanes\n\n \n\nAD/DHC-3/25 Wing Strut and Attachments - Retirement Lives 11/69\n\nApplicability: All models.\n\n \n\nRequirement: Action in accordance with De H Canada SB No 3/10. Compliance:  As detailed in Requirement Document.\n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The AD text, as provided, imposes mandatory action in accordance with De Havilland Canada SB No. 3/10 and applies to all models. The document does not indicate any change of scope from an earlier statement within the text itself; it specifies the requirement and delegates technical detail to the referenced service bulletin and Requirement Document. No internal evidence in the supplied text shows a change from an original intent."},"complexity_factors":["References an external Service Bulletin (De Havilland Canada SB No. 3/10) for substantive technical requirements rather than containing them in the AD itself.","Compliance steps are delegated to a separate Requirement Document, creating an additional document-dependency for implementers.","Universal applicability to \"all models\" requires every operator to check model-specific applicability and possibly adapt maintenance planning.","Operational impacts (retirement of parts, replacements, downtime) depend on technical details not present in the AD text, creating uncertainty about cost and scheduling until the external documents are consulted.","No alternate means of compliance or exemptions are specified in the AD text, which concentrates discretion with the regulator to accept alternatives or provide relief.","Potential supply-chain considerations (availability of replacement parts or approved repair methods) are not addressed in the AD and could affect implementation timelines."],"plain_english_summary":"What this instrument changes mechanically\n\n- It requires operators of DHC-3 (Otter) series aeroplanes to take specific actions on the wing strut and its attachments by following De Havilland Canada Service Bulletin No. 3/10. (See: \"Requirement: Action in accordance with De H Canada SB No 3/10.\")\n- The directive applies to all models of the DHC-3 (Otter). (See: \"Applicability: All models.\")\n- Compliance details and the exact steps, timing and records to be kept are set out in the referenced Requirement Document. (See: \"Compliance: As detailed in Requirement Document.\")\n\nWho this affects and who decides\n\n- Aircraft owners and operators of DHC-3 (Otter) aircraft must carry out the specified actions; they will incur the direct costs of inspections, retirements and any replacements. (Source lines: \"Applicability: All models.\" and \"Requirement: Action in accordance with De H Canada SB No 3/10.\")\n- The Civil Aviation Safety Authority (CASA) is the issuing authority for the Airworthiness Directive. (Header: \"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\")\n- The AD makes following the De Havilland Canada Service Bulletin mandatory for compliance; the Requirement Document sets the operational compliance steps. (See: \"Requirement...\" and \"Compliance...\")\n\nWhy it matters (stated purpose and practical consequences)\n\n- The AD directs retirement lives and related actions for wing struts and attachments. The text itself does not set out the technical rationale in detail; it mandates that operators follow the manufacturer service bulletin and the Requirement Document. (See: \"Requirement...\" and \"Compliance...\")\n- Practical consequences include: a predictable regulatory requirement for part retirement and replacement, direct costs to operators for parts and labour, scheduling and downtime to complete the mandated work, and record-keeping or inspection evidence required by the Requirement Document.\n\nImplementation, incentives and trade-offs\n\n- Incentives and behaviour changes: Operators are incentivised to remove and replace components according to the service bulletin and Requirement Document rather than rely on longer in-service use. This shifts maintenance timing and expenditure toward the retirement schedule specified by the bulletin. (See: \"Requirement...\" and \"Compliance...\")\n- Costs and who pays: The operator or owner bears the cost of complying — inspections, retirement of parts, replacements and associated labour and aircraft downtime. (Inferred from the requirement that operators take action.)\n- Compliance burden and operational risk: The AD references external documents for detail rather than specifying technical limits in the AD text. This requires operators and maintenance organisations to obtain and follow the Service Bulletin and Requirement Document, which can create administrative steps and reliance on availability of parts and service information. (See: \"Requirement...\" and \"Compliance...\")\n- Bureaucratic discretion: The AD prescribes mandatory compliance with an external service bulletin rather than leaving retirement timing to individual operators. The AD text itself contains no discretionary exemptions or alternate means of compliance; any alternatives would need to be sought through the regulator or as provided in the Requirement Document. (See: the absence of alternate measures in the AD text.)\n\nUncertainties and information gaps in the AD text\n\n- The AD does not itself state the numeric retirement lives, inspection intervals, or the technical steps; those details are in De Havilland Canada SB No. 3/10 and the Requirement Document. Operators must consult those documents to know the exact actions required. (See: \"Requirement...\" and \"Compliance...\")\n- The AD applies to all models but does not explain model-specific differences; operators must confirm applicability of the Service Bulletin content to their specific aircraft configuration. (See: \"Applicability: All models.\")"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive focused on a specific safety-critical component (wing struts) for a specific aircraft type (DHC-3 Otter). It has not expanded beyond its original purpose of ensuring structural integrity through mandatory retirement lives."},"complexity_factors":["Very short document (under 200 words)","Only one substantive requirement: comply with an external service bulletin","No defined terms section","No conditional logic or nested exceptions","Single applicability criterion (\"All models\")","Cross-reference to only one external document (De Havilland Canada SB No 3/10)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\n- Requires owners and operators of **De Havilland Canada DHC-3 \"Otter\" aircraft** to follow specific maintenance instructions regarding the **wing struts and their attachment points**.\n- These parts have **\"retirement lives\"** — meaning they must be taken out of service and replaced after a certain number of flight hours or cycles, regardless of whether they look damaged.\n\n**Who it affects:**\n- Anyone who owns, operates, or maintains DHC-3 Otter aircraft in Australia.\n\n**Why it matters:**\n- Wing struts are critical structural components that hold the wings to the fuselage. If they fail, the wing can separate from the aircraft with catastrophic results.\n- This directive prevents structural failures by enforcing hard limits on how long these parts can be used before replacement.\n\n**What must be done:**\n- Follow the instructions in **De Havilland Canada Service Bulletin No. 3/10** (the \"Requirement Document\" referenced). This document specifies the exact retirement life limits and inspection procedures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-3-25-wing-strut-and-attachments-retirement-lives","history":"/api/acts/ad-dhc-3-25-wing-strut-and-attachments-retirement-lives/history","analysis":"/api/acts/ad-dhc-3-25-wing-strut-and-attachments-retirement-lives/analysis","conflicts":"/api/acts/ad-dhc-3-25-wing-strut-and-attachments-retirement-lives/conflicts","importantCases":"/api/acts/ad-dhc-3-25-wing-strut-and-attachments-retirement-lives/important-cases","documents":"/api/acts/ad-dhc-3-25-wing-strut-and-attachments-retirement-lives/documents"}}