{"id":"F2006B09092","name":"AD/DHC-3/6 - Rudder Control","slug":"ad-dhc-3-6-rudder-control","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115645,"registerId":"commonwealth-F2006B09092-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-3/6 - Rudder Control","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-3/6 Rudder Control NK\n\nApplicability: As detailed in Requirement Document.\n\n \n\nRequirement: Action in accordance with De H Canada EB “O” Nos 1 and 3.\n\n \n\nNote: Canadian AD 55-3 refers.\n\n \n\nCompliance: Forthwith.\n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"The instrument itself sets out a focused scope: remedial action for rudder control on DHC-3 (Otter) series aeroplanes to be carried out immediately, and it directs readers to the Requirement Document for precise applicability and to De Havilland Canada emergency bulletins for the technical steps (Applicability; Requirement; Compliance). There is no indication within the text that the AD’s scope has been altered from that expressed in the instrument. However, because applicability and technical details are determined by the referenced Requirement Document and external bulletins, the effective operational scope depends on those documents."},"complexity_factors":["Delegation of technical content to external documents (De H Canada EB “O” Nos 1 and 3) increases procedural complexity and requires operators to locate and interpret those bulletins (Requirement).","Applicability is not stated in the AD text but deferred to a separate Requirement Document, creating uncertainty about which individual aircraft are in scope (Applicability).","Immediate compliance requirement (“Forthwith”) compresses the timeline for action and increases logistical and operational complexity for affected operators (Compliance).","Cross-reference to a foreign regulator’s AD (Canadian AD 55-3) requires consultation of multiple regulatory instruments to assemble the full compliance picture (Note).","Lack of technical detail in the AD itself means enforcement and verification depend on correctly applying and interpreting the external documents (Requirement; Applicability)."],"plain_english_summary":"### What this instrument does, in plain English\n\nThis is an Airworthiness Directive (AD) issued under the Civil Aviation Regulations 1998 requiring immediate action relating to rudder control on DHC-3 (Otter) series aeroplanes. It is identified as AD/DHC-3/6 and appears in the Civil Aviation Safety Authority's Schedule of Airworthiness Directives (header).\n\nMechanically, the directive does three things:\n\n- It says which aeroplanes are covered by referring to a separate \"Requirement Document\": “Applicability: As detailed in Requirement Document.” (Applicability). This means the AD does not list individual aircraft or serial ranges in the text itself; those details are in the Requirement Document. \n- It mandates that the required steps be taken as set out in De Havilland Canada Emergency Bulletins labelled \"O\" Nos 1 and 3: “Action in accordance with De H Canada EB “O” Nos 1 and 3.” (Requirement). The AD itself does not reproduce the technical steps—those are in the referenced bulletins. \n- It sets the compliance timing to be immediate: “Compliance: Forthwith.” (Compliance).\n\nThe AD also points readers to a related Canadian directive: “Note: Canadian AD 55-3 refers.” (Note).\n\nWho this affects and who pays\n\n- Owners and operators of DHC-3 (Otter) series aircraft that fall within the Requirement Document are the parties responsible for complying (Applicability; Requirement). The AD places the obligation to carry out the actions specified in the referenced emergency bulletins on those in control of the affected aircraft. \n- Any direct costs (for example, buying parts, paying for labour, ground time while inspections or modifications occur) will therefore be borne by those owners/operators, as the AD requires them to perform the referenced actions (Requirement; Compliance).\n\nWhy it matters (stated purpose and practical implications)\n\n- The AD is titled \"Rudder Control,\" and it requires immediate adherence to emergency bulletins from the aircraft manufacturer; the stated or implied purpose is to address an identified rudder-control safety issue by ordering the remedial steps set out in those bulletins (title; Requirement). \n- Because the AD requires action “forthwith,” affected aircraft cannot defer compliance; this may lead to immediate operational effects such as aircraft being taken out of service until the specified actions are completed (Compliance).\n\nImplementation mechanics, incentives, trade-offs and risks\n\n- Delegation to external documents: the AD delegates the technical content and the exact list of affected aircraft to external materials—De Havilland Canada EB \"O\" Nos 1 and 3 and the Requirement Document (Applicability; Requirement). This reduces the amount of technical detail in the AD itself but obliges operators to obtain and follow those external documents. That creates an administrative step and a dependency on external sources for exact obligations. \n- Compliance burden and timing: the immediate compliance requirement (“Forthwith”) concentrates the timing of disruption and costs on operators who are in scope (Compliance). The measure transfers costs (parts, labour, downtime) to those operators while directing the specific technical remedy to the manufacturer’s bulletins (Requirement). \n- Enforcement and scope determination: the AD does not itself define which serials or individual aircraft are covered; that determination is made in the Requirement Document referenced by the AD (Applicability). This leaves the practical scope to that separate document, which affects how many operators are caught by the directive and what they must do. \n- Cross-jurisdictional reference: the AD explicitly refers to a Canadian AD (Canadian AD 55-3), indicating that the issue and the technical remedies have correspondence with action taken in Canada (Note). Operators may need to consult multiple documents to understand the full technical and regulatory picture. \n\nTrade-offs and likely effects on private choices\n\n- Operators must choose how quickly and where to obtain the external bulletins and carry out the required actions. The AD’s reliance on external technical documents means private service providers (maintenance organisations) and parts suppliers will play a central role in implementation. \n- The immediate compliance obligation shortens the time window for operators to plan and may increase short-term costs (labour, expedited parts, scheduling). \n- The AD centralises the decision about the specific remedy in the referenced manufacturer bulletins rather than in the AD text itself, reducing regulatory detail within the AD but increasing dependence on those external technical instructions.\n\nConcise summary of legal mechanics\n\n- Legal instrument: Airworthiness Directive AD/DHC-3/6 under the Civil Aviation Regulations 1998 (Schedule of Airworthiness Directives). (header)\n- Subject: Rudder control on DHC-3 (Otter) series aircraft (title).\n- Applicability: as specified in the Requirement Document (Applicability).\n- Required action: follow De Havilland Canada Emergency Bulletins \"O\" Nos 1 and 3 (Requirement).\n- Timing: immediate — \"Forthwith\" (Compliance).\n- Cross-reference: Canadian AD 55-3 (Note)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive focused on a specific technical issue (rudder control) for a specific aircraft type (DHC-3 Otter). It represents the original and continuing purpose of ADs: addressing specific safety defects through mandatory maintenance actions."},"complexity_factors":["Extremely short document (under 150 words)","No defined terms section — relies entirely on external reference documents","Single operative requirement referencing external manufacturer bulletins","No conditional logic or exceptions","Simple structure: applicability, requirement, note, compliance","Cross-reference to only one external regulatory document (Canadian AD 55-3)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order — issued by Australia's Civil Aviation Safety Authority (CASA) for a specific type of aircraft: the **de Havilland Canada DHC-3 Otter** series.\n\n**What it does:**\n- Requires owners and operators of these aircraft to take specific actions regarding the **rudder control system** (the part of the plane that steers it left and right).\n- The required actions are detailed in two official documents from the manufacturer: **De Havilland Canada Engineering Bulletins \"O\" Nos 1 and 3**.\n\n**Who it affects:**\n- Anyone who owns, operates, or maintains DHC-3 Otter aircraft in Australia.\n\n**Why it matters:**\n- Rudder control failures can lead to loss of directional control of the aircraft, potentially causing accidents. This directive addresses a known safety issue.\n- The reference to **Canadian AD 55-3** indicates this is a known problem that Canadian authorities have already addressed — Australia is aligning with international safety standards.\n- **\"Forthwith\"** means compliance is required immediately — there's no grace period.\n\n**Key point:** This isn't optional. Failure to comply means the aircraft cannot legally fly in Australian airspace."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-3-6-rudder-control","history":"/api/acts/ad-dhc-3-6-rudder-control/history","analysis":"/api/acts/ad-dhc-3-6-rudder-control/analysis","conflicts":"/api/acts/ad-dhc-3-6-rudder-control/conflicts","importantCases":"/api/acts/ad-dhc-3-6-rudder-control/important-cases","documents":"/api/acts/ad-dhc-3-6-rudder-control/documents"}}