{"id":"F2006B03596","name":"AD/BEA 121/30 - Brake Torque Tube Assembly","slug":"ad-bea-121-30-brake-torque-tube-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43187,"registerId":"commonwealth-F2006B03596-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BEA 121/30 - Brake Torque Tube Assembly","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)  Beagle B121 (Pup) Series Aeroplanes\n\n \n\nAD/BEA 121/30 Brake Torque Tube Assembly 4/96\n\nApplicability: Beagle B121 Series 1, 2, and 3 aircraft.\n\n \n\nRequirement: Action in accordance with Jetstream Aircraft Mandatory Service Bulletin B121/103.\n\n \n\nNote: UK CAA AD 003-10-95 refers.\n\n \n\nCompliance: As specified in the Requirement Document.\n\n \n\nBackground: Reports have been received of cracked brake torque tube assemblies on Bulldog aircraft. The brake torque tube assemblies installed on B121 aircraft, are of similar construction.\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","sortOrder":0}],"analysis":{"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 ensuring brake system integrity."},"complexity_factors":["Very short document (under 200 words)","Only one substantive requirement: follow the referenced service bulletin","No defined terms section","No conditional logic or nested exceptions","Single cross-reference to UK CAA AD 003-10-95 and one service bulletin","Straightforward applicability (three specific aircraft series)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to **Beagle B121 (Pup) Series 1, 2, and 3 aircraft**.\n\n**What it does:**\n- Requires owners/operators of these specific aircraft to inspect and/or repair the **brake torque tube assembly** (a component in the aircraft's braking system that transfers braking force).\n- The work must follow **Jetstream Aircraft Mandatory Service Bulletin B121/103** — a technical instruction document from the manufacturer.\n\n**Why it matters:**\n- **Safety issue:** Cracks have been found in brake torque tube assemblies on similar Bulldog aircraft. Since the B121 uses similar parts, this directive prevents potential brake failure.\n- **Legal obligation:** Compliance is mandatory. Flying without completing this action would violate civil aviation regulations.\n\n**Key point:** This isn't new law in the traditional sense — it's a technical safety order issued under existing aviation regulations (Civil Aviation Regulations 1998, Part 39)."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The scope in this AD is consistent with the stated intent in the source text: it targets Beagle B121 Series 1–3 aircraft to address the risk identified by reports of cracked torque tube assemblies on Bulldog aircraft, and it achieves that by mandating compliance with Jetstream Aircraft Mandatory Service Bulletin B121/103. The AD does not expand its scope in the text beyond those aircraft or beyond actions specified in the referenced Requirement Document. (Applicability; Background; Requirement; Compliance)"},"complexity_factors":["Directive is narrowly targeted to a single aircraft type (Beagle B121 Series 1–3) (Applicability)","Substantive technical requirements are deferred to an external document (Jetstream Aircraft Mandatory Service Bulletin B121/103) rather than set out in the AD text (Requirement; Compliance)","Relies on cross‑reference to an overseas AD for related information (Note)","Administrative enforcement is standard (listed in the Schedule of Airworthiness Directives) so legal structure is straightforward (COMMONWEALTH OF AUSTRALIA... SCHEDULE OF AIRWORTHINESS DIRECTIVES)"],"plain_english_summary":"This AD requires owners/operators of Beagle B121 Series 1–3 aeroplanes to carry out Jetstream Aircraft Mandatory Service Bulletin B121/103, enforced via the Schedule of Airworthiness Directives, to address the risk of cracked brake torque‑tube assemblies. \n\nIt affects those owners/operators and their maintenance providers; inspections, repairs or replacements and any downtime are mandatory and paid by operators. The AD delegates technical detail (intervals, actions, parts) to the service bulletin, so exact costs and timing depend on that document."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bea-121-30-brake-torque-tube-assembly","history":"/api/acts/ad-bea-121-30-brake-torque-tube-assembly/history","analysis":"/api/acts/ad-bea-121-30-brake-torque-tube-assembly/analysis","conflicts":"/api/acts/ad-bea-121-30-brake-torque-tube-assembly/conflicts","importantCases":"/api/acts/ad-bea-121-30-brake-torque-tube-assembly/important-cases","documents":"/api/acts/ad-bea-121-30-brake-torque-tube-assembly/documents"}}