{"id":"F2006B02605","name":"AD/B-2/4 - Tail Rotor Drive - Modification","slug":"ad-b-2-4-tail-rotor-drive-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41908,"registerId":"commonwealth-F2006B02605-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B-2/4 - Tail Rotor Drive - Modification","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)  Brantly B-2 Series Helicopters\n\n \n\nAD/B-2/4 Tail Rotor Drive - Modification 12/60\n\nApplicability: All model B-2 prior to S/No. 44. Document:  1. Brantly SB No. 4; or\n\n2. FAA AD 60-26-3.\n\n \n\nCompliance: Forthwith.\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","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument, as presented, applies to all Brantly B-2 helicopters with serial numbers prior to 44 and requires a tail-rotor drive modification by reference to Brantly SB No. 4 or FAA AD 60-26-3, with compliance required forthwith. The text contains no material indicating a change in scope from an earlier version or intent; no amendment history or differing applicability is provided in the supplied text."},"complexity_factors":["Narrow, explicit applicability (only Brantly B-2 helicopters with serial numbers prior to 44). (Applicability)","Short directive text that delegates technical detail to external documents (Brantly SB No. 4 or FAA AD 60-26-3), creating dependency on those documents for actionable steps. (Document)","Immediate compliance requirement (\"Forthwith\") which compresses scheduling and operational flexibility. (Compliance)","Lack of technical description, timelines, cost, or enforcement detail within the AD itself — increases reliance on maintenance organisations and the referenced documents for implementation specifics. (Document; Compliance)"],"plain_english_summary":"What this instrument requires, mechanically:\n\n- It is an airworthiness directive issued under the Civil Aviation Safety Authority (Part 39 - 105). (header)\n- It requires that the tail-rotor drive on Brantly B-2 helicopters with serial numbers prior to 44 be modified. The AD does not set out the technical steps itself; instead it directs compliance with one of two external documents: Brantly Service Bulletin No. 4 or FAA Airworthiness Directive 60-26-3. (Applicability; Document)\n- The required action must be done immediately: the AD states compliance is to be carried out \"Forthwith.\" (Compliance)\n\nWho this affects and who decides:\n\n- Affected persons: owners and operators of Brantly B-2 helicopters with serial numbers before 44. (Applicability)\n- Decision-maker: the Civil Aviation Safety Authority issued the AD under Part 39 - 105 and therefore requires compliance. (header)\n- The AD delegates the exact technical method and detailed instructions to the referenced documents (Brantly SB No. 4 or FAA AD 60-26-3). The operator or maintenance organisation must follow those documents to perform the modification. (Document)\n\nWho pays and what changes in behaviour:\n\n- The AD requires the operator/owner of each affected helicopter to arrange for the modification to be carried out forthwith. That responsibility implies the operator/owner must organise and fund whatever work or parts are required to meet the directive. (Applicability; Compliance)\n- Operational behaviour changes: affected helicopters will need the specified tail-rotor drive modification completed according to the referenced technical document before continuing normal operations, subject to regulatory enforcement. (Applicability; Document; Compliance)\n\nWhy this matters (how the instrument is presented and its implementation trade-offs):\n\n- The AD is a short, prescriptive instrument: it names a limited class of aircraft (B-2 prior to S/No. 44), points to technical documents that contain the modification instructions, and sets an immediate compliance requirement. (Applicability; Document; Compliance)\n- Trade-offs and implementation consequences that follow mechanically from the text:\n  - Reliance on external documents (Brantly SB No. 4 or FAA AD 60-26-3) means the AD itself is brief and the detailed technical, time and resource implications are contained in those referenced documents. Operators must obtain and follow those documents to know exactly what work is required. (Document)\n  - The instruction to comply \"Forthwith\" shortens the window available for scheduling maintenance, which increases short-term demand on maintenance capacity for affected helicopters. The AD text does not set staged timelines or exceptions. (Compliance)\n  - The AD imposes direct compliance obligations on a narrowly defined group (operators/owners of B-2 < S/No.44) rather than a broad class of aircraft. (Applicability)\n\nImplementation and compliance burdens:\n\n- The AD creates an immediate compliance obligation; the practical burden on each operator depends on the modification steps, parts availability and labour/time requirements contained in the referenced service bulletin or FAA AD. Those practical details are not included in the AD text itself. (Document; Compliance)\n- The AD does not itself state enforcement methods, cost recovery, or discretionary exceptions. Any such matters would be dealt with under the regulator's ordinary compliance and enforcement arrangements or within the referenced technical documents. (header; Document)\n\nSource citations from the instrument:\n- Header: \"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES.\" (header)\n- Applicability: \"All model B-2 prior to S/No. 44.\" (Applicability)\n- Document: \"1. Brantly SB No. 4; or 2. FAA AD 60-26-3.\" (Document)\n- Compliance: \"Forthwith.\" (Compliance)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive focused on a specific mechanical defect in early-production Brantly B-2 helicopters. The scope remains tightly confined to the original safety issue identified in the referenced service bulletin and FAA directive."},"complexity_factors":["Extremely short document (under 200 words)","Only 3 operative provisions: applicability, document reference, and compliance timing","No defined terms section","No cross-references to other legislation beyond the enabling Civil Aviation Regulations 1998","Simple conditional logic: serial number cutoff (below S/No. 44) is the only qualifier","Single compliance pathway with alternative reference documents"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** issued by Australia's Civil Aviation Safety Authority (CASA). It mandates a specific safety modification for **Brantly B-2 series helicopters**.\n\n**What it does:**\n- Requires owners and operators to modify the **tail rotor drive system** on certain helicopters\n- Applies to all B-2 models with **serial numbers below 44** (earlier production aircraft)\n\n**Who it affects:**\n- Owners and operators of early-model Brantly B-2 helicopters\n- Maintenance organisations servicing these aircraft\n\n**Why it matters:**\n- Airworthiness Directives are legally binding safety orders\n- \"Forthwith\" compliance means **immediate action required** — no grace period\n- The modification addresses a safety defect in the tail rotor drive system, which is critical for helicopter control and safety\n\n**How to comply:**\n- Follow either:\n  - **Brantly Service Bulletin No. 4**, or\n  - **FAA Airworthiness Directive 60-26-3** (the equivalent US safety order)\n\nThis ensures Australian-registered helicopters meet the same safety standard as those in the United States."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b-2-4-tail-rotor-drive-modification","history":"/api/acts/ad-b-2-4-tail-rotor-drive-modification/history","analysis":"/api/acts/ad-b-2-4-tail-rotor-drive-modification/analysis","conflicts":"/api/acts/ad-b-2-4-tail-rotor-drive-modification/conflicts","importantCases":"/api/acts/ad-b-2-4-tail-rotor-drive-modification/important-cases","documents":"/api/acts/ad-b-2-4-tail-rotor-drive-modification/documents"}}