{"id":"F2006B06837","name":"AD/SD3-30/35 - Emergency Brake Accumulator Mounting Structure","slug":"ad-sd3-30-35-emergency-brake-accumulator-mounting-structure","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114701,"registerId":"commonwealth-F2006B06837-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/SD3-30/35 - Emergency Brake Accumulator Mounting Structure","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)  Short SD3-30 Series Aeroplanes\n\n \n\nAD/SD3-30/35 Emergency Brake Accumulator Mounting Structure\n\n\n2/99\n\n \n\nApplicability: All SD3-30 aircraft.\n\n \n\nRequirement: Action in accordance with Shorts Mandatory Service Bulletin SD330-29-19.\n\n \n\nNote: UK CAA AD 008-10-98 refers.\n\n \n\nCompliance: Unless already accomplished, before 25 May 1999.\n\n \n\nThis Airworthiness Directive becomes effective on 25 February 1999.\n\n \n\nBackground: The manufacturer received reports of cracking of the emergency brake accumulator mounting structure. This Directive requires an inspection for cracks, and if required, the replacement of the mounting angle.\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","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD as presented sets a targeted requirement: inspect the emergency brake accumulator mounting structure on all SD3-30 aeroplanes and replace the mounting angle if cracks are found (Applicability; Requirement; Background). There is no indication in the text that the scope has been expanded or narrowed from the instrument’s own stated purpose. The directive applies uniformly to the defined fleet, prescribes compliance as per the manufacturer’s Mandatory Service Bulletin, and sets a single compliance deadline (Requirement; Compliance)."},"complexity_factors":["Narrow technical scope: single component and single inspection/replace action (Background; Requirement).","Uniform applicability to a defined fleet: all SD3-30 aircraft (Applicability).","Clear, short compliance window and effective date (This Airworthiness Directive becomes effective on 25 February 1999; Compliance).","Dependence on manufacturer’s Mandatory Service Bulletin for the method of compliance (Requirement), limiting regulatory complexity but adding dependence on an external document.","Cross-reference to another regulator’s AD (UK CAA AD 008-10-98) introduces minor cross-jurisdictional coordination.","No alternative compliance pathways or detailed procedural options contained in the AD text, reducing interpretive complexity."],"plain_english_summary":"- What the instrument does mechanically: This Airworthiness Directive (AD/SD3-30/35) requires all Short SD3-30 series aeroplanes to be inspected for cracks in the emergency brake accumulator mounting structure and, if cracks are found, to have the mounting angle replaced. The required work must be carried out in accordance with Shorts Mandatory Service Bulletin SD330-29-19 (Requirement). The AD has an effective date of 25 February 1999 and a compliance deadline of 25 May 1999 unless the work has already been done (This Airworthiness Directive becomes effective on 25 February 1999; Compliance).\n\n- Who it affects: All owners and operators of SD3-30 aircraft (Applicability). Maintenance organisations that perform inspections and structural replacements for these aeroplanes will also be affected because they must carry out the specified inspection and any necessary replacement according to the manufacturer's service bulletin (Requirement).\n\n- Why it matters (stated purpose and practical trade-offs): The manufacturer reported cracking of the emergency brake accumulator mounting structure; the AD implements inspection and replacement to address that condition (Background). The stated purpose is to find and remediate cracks before they lead to component failure. Mechanically, this imposes a discrete compliance obligation (inspect; replace if necessary) on the operator/maintainer within a fixed time window (Compliance).\n\n- Who pays, who decides, and what behaviour changes: Aircraft owners/operators pay for the inspection and for any replacement parts and labour; the AD places the obligation on them to ensure compliance (Applicability; Requirement). The regulator (Civil Aviation Safety Authority) mandates compliance by issuing the AD; the specific technical steps are prescribed by the manufacturer's Mandatory Service Bulletin SD330-29-19 (Requirement). Behaviourally, operators must schedule and permit the inspection within the compliance window and replace the mounting angle where cracks are found.\n\n- Implementation, incentives and costs: The AD channels technical specification and repair instructions to the manufacturer’s service bulletin (Requirement). That concentrates the technical specification with the manufacturer, while enforcement of compliance is exercised via the AD (Requirement). Costs are direct and borne by operators: inspection labour, parts for replaced mounting angles, and aircraft downtime during inspection/repair (Compliance). There is a trade-off between the near-term expense and operational disruption for operators versus reducing the risk of in-service failure (Background).\n\n- Compliance burden and discretion: The AD makes a single, time-bound requirement and refers operators to the manufacturer’s mandatory service bulletin for the method of compliance, so discretion for how to comply is constrained to the options in that bulletin (Requirement). The AD itself provides no alternative compliance route in the text provided; any variation would typically require regulatory approval, but that pathway is not described here.\n\n- Effects on markets and business: The directive imposes a uniform technical requirement across all SD3-30 operators (Applicability). Independent maintenance organisations can perform the inspection and replacement so long as they follow the service bulletin; the AD does not itself allocate work to particular providers (Requirement). The requirement may produce concentrated benefits to materially affected parties (operators that avoid structural failure) and diffuse costs across all operators who must perform the inspection even if no defect is found.\n\n- Risks and unintended consequences noted as mechanisms: The concrete risks addressed are cracking of the mounting structure and consequent component failure (Background). The directive raises implementation risks that are purely operational and economic: aircraft downtime, parts procurement and the possibility that inspections find cracking requiring replacement (Compliance). The AD references the UK CAA AD 008-10-98 (Note), indicating coordination or cross-reference with another authority; the AD text does not specify additional requirements arising from that reference.\n\nSource citations: Applicability; Requirement (Shorts Mandatory Service Bulletin SD330-29-19); Compliance (deadline before 25 May 1999); Background (reports of cracking); Effective date (25 February 1999); Note (UK CAA AD 008-10-98)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of mandating inspection and repair of the emergency brake accumulator mounting structure."},"complexity_factors":["Very short document (approximately 150 words)","Only 1 defined applicability criterion (All SD3-30 aircraft)","Single requirement referencing an external technical document (Service Bulletin SD330-29-19) rather than spelling out detailed steps","No nested exceptions or conditional logic — simple binary compliance (inspect/replace if cracked)","Clear, fixed compliance date with single exception clause ('Unless already accomplished')","No cross-references to other legislation beyond a non-binding note about UK equivalent"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nOrders owners and operators of **Short SD3-30 series aircraft** (a type of regional turboprop plane) to inspect the **emergency brake accumulator mounting structure** for cracks. If cracks are found, the mounting angle must be replaced.\n\n**Why it matters:**\nThe manufacturer received reports that this mounting structure was cracking. Since the emergency brake accumulator is a critical safety component (it stores pressure for emergency braking), structural failure could compromise the aircraft's ability to stop safely in an emergency.\n\n**Who must comply:**\nAnyone operating an SD3-30 aircraft in Australia. They must follow the specific instructions in **Shorts Mandatory Service Bulletin SD330-29-19** (a technical repair notice from the manufacturer).\n\n**Deadline:**\nThe inspection and any necessary repairs must be completed **before 25 May 1999** (unless already done). The directive itself took effect on **25 February 1999**.\n\n**Note:** This aligns with a similar UK safety order (UK CAA AD 008-10-98), showing this was an international safety concern."}},"importantCases":[],"_links":{"self":"/api/acts/ad-sd3-30-35-emergency-brake-accumulator-mounting-structure","history":"/api/acts/ad-sd3-30-35-emergency-brake-accumulator-mounting-structure/history","analysis":"/api/acts/ad-sd3-30-35-emergency-brake-accumulator-mounting-structure/analysis","conflicts":"/api/acts/ad-sd3-30-35-emergency-brake-accumulator-mounting-structure/conflicts","importantCases":"/api/acts/ad-sd3-30-35-emergency-brake-accumulator-mounting-structure/important-cases","documents":"/api/acts/ad-sd3-30-35-emergency-brake-accumulator-mounting-structure/documents"}}