{"id":"F2006B04884","name":"AD/CASA/4 Amdt 1 - Rudder Hinge Fittings - Modification","slug":"ad-casa-4-amdt-1-rudder-hinge-fittings-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44691,"registerId":"commonwealth-F2006B04884-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CASA/4 Amdt 1 - Rudder Hinge Fittings - 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)  Casa 212 Series Aeroplanes\n\n \n\nAD/CASA/4\n\nAmdt 1\n\n\nRudder Hinge Fittings - Modification 10/84\n\n \n\nApplicability: All models CASA-212. Document: CANCELLED. Compliance:  Forthwith.\n\nBackground:  Australian registered aircraft require compliance with S.B. 212-27-25, AD/CASA/8 refers. This modification state is not compatible with the requirements of SB\n\n212-55-07R3.\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":4,"scope_assessment":{"changed":true,"description":"The directive changes scope relative to the cancelled document by (a) cancelling the prior document (Document: CANCELLED) and (b) imposing immediate compliance with S.B. 212-27-25 for all CASA-212 aircraft (Applicability) (Compliance) (Background). The AD also records that the current modification state is incompatible with S.B. 212-55-07R3, which alters the set of permissible configurations for affected aircraft and therefore narrows available compliance options compared with the previously referenced modification state (Background)."},"complexity_factors":["Short directive text but relies on external documents (S.B. 212-27-25, S.B. 212-55-07R3, AD/CASA/8) for technical detail and implementation steps (Background)","\"Forthwith\" compliance creates immediate effect without a detailed timeline or transitional rules (Compliance)","The instrument cancels a prior document but does not state the full scope or content of the cancellation within the text (Document: CANCELLED)","Explicit incompatibility between two service bulletins requires operators to resolve which modification state to adopt, adding operational decision complexity (Background)","Lack of cost, parts, labour, or certification details in the AD shifts those determinations to operators and referenced materials (Background)"],"plain_english_summary":"What this instrument changes, mechanically\n\n- This airworthiness directive (AD/CASA/4 Amdt 1) applies to all CASA-212 aeroplane models and requires immediate compliance with a specific modification instruction referenced as S.B. 212-27-25. The AD is issued by the Civil Aviation Safety Authority as part of the Schedule of Airworthiness Directives (Header). (Applicability) (Compliance) (Background)\n\nKey legal effects and who it affects\n\n- Who decides: the Civil Aviation Safety Authority (CASA) issues this directive as part of its Schedule of Airworthiness Directives and sets the compliance requirement. (Header)\n- Who must act: operators and owners of Australian-registered CASA-212 aeroplanes are subject to the requirement to comply forthwith with S.B. 212-27-25. (Applicability) (Compliance) (Background)\n- What must change: the rudder hinge fittings must be modified in accordance with S.B. 212-27-25; the AD text cancels the prior document and explicitly notes that the existing modification state is not compatible with the requirements of S.B. 212-55-07R3. (Background)\n\nOfficial rationale and how it maps to costs and choices\n\n- The Background section states that Australian-registered aircraft require compliance with S.B. 212-27-25 and cross-references another airworthiness directive (AD/CASA/8) as relevant. It also records that the current modification state (i.e. how the rudder hinge fittings are currently configured) is not compatible with the requirements of S.B. 212-55-07R3. These are statements of required action and incompatibility, not detailed explanations of technical safety analysis. (Background)\n\n- Who pays and what is imposed: the text makes operators/owners of CASA-212 aircraft responsible for compliance (Applicability) (Compliance). The directive itself does not specify costs, parts, labour, or time needed. The financial and operational burden therefore falls to those operators, but the AD does not quantify that burden. (Applicability) (Compliance) (Background)\n\n- Trade-offs and interactions: the AD cancels the prior document and flags that following S.B. 212-27-25 is inconsistent with S.B. 212-55-07R3. That creates a concrete choice: to be compliant with this AD, operators must adopt the S.B. 212-27-25 modification and cannot rely on the alternative specified by SB 212-55-07R3. The text does not say which technical option is preferable beyond stating the incompatibility. (Background)\n\nImplementation risk, discretion and compliance burden\n\n- Timing and enforcement: the AD requires compliance \"Forthwith,\" signalling immediate effect, but it provides no schedule, no tolerated delay, and no transitional arrangements in the text. That leaves the scope of immediate action and any enforcement discretion to CASA or to referenced documents. (Compliance)\n\n- Detail and delegation: the AD references a service bulletin (S.B. 212-27-25) and another AD (AD/CASA/8) rather than reproducing technical steps, so the exact work required is set out in those external documents. This reduces detail in the AD itself and delegates the technical specification to the service bulletin. The AD does not state who pays for the work, how to certify the work afterwards, or any administrative steps in this text. (Background)\n\nCross-references and administrative status\n\n- The AD explicitly cancels a prior document (Document: CANCELLED). It also cross-references AD/CASA/8 and two service bulletins (S.B. 212-27-25 and S.B. 212-55-07R3), so compliance requires consulting those materials for operative technical details. (Background) (Applicability)\n\nConcise practical takeaway\n\n- CASA-212 operators must, immediately, have the rudder hinge fittings modified in accordance with S.B. 212-27-25 because this AD requires it and declares the present modification state incompatible with another service bulletin. The AD itself is short on technical or cost details and relies on external service bulletins and other ADs to specify the technical work and any further procedural steps. (Applicability) (Compliance) (Background)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a narrow, technical amendment to a specific airworthiness directive. It does not expand beyond the original scope of aircraft safety regulation for CASA-212 series aeroplanes. The cancellation of a conflicting requirement is precisely within the intended purpose of the airworthiness directive system."},"complexity_factors":["Extremely short document (under 150 words)","No defined terms section — relies on external technical references (Service Bulletins, other ADs)","Single operative provision (cancellation) with immediate effect","No conditional logic, exceptions, or nested provisions","Cross-references are minimal and explicit (SB 212-27-25, AD/CASA/8, SB 212-55-07R3)"],"plain_english_summary":"This is a **Civil Aviation Safety Authority (CASA) Airworthiness Directive** — essentially a mandatory safety order for aircraft.\n\n**What it does:**\n- **Cancels** a previous airworthiness directive (AD/CASA/4) that required a specific modification to rudder hinge fittings on CASA-212 series aeroplanes (a type of aircraft).\n- The cancellation is **immediate** (\"Forthwith\").\n\n**Why it matters:**\n- The old modification (required by Service Bulletin 212-27-25) **conflicted** with a newer, more important safety requirement (Service Bulletin 212-55-07R3).\n- Rather than forcing aircraft owners to comply with two incompatible instructions, CASA has cancelled the older one.\n\n**Who it affects:**\n- Owners and operators of **all CASA-212 model aircraft** registered in Australia.\n- Maintenance engineers working on these aircraft.\n\n**The bottom line:** If you own or maintain a CASA-212 plane, you no longer need to follow the old rudder hinge modification from AD/CASA/4. You should follow the newer requirements in AD/CASA/8 and SB 212-55-07R3 instead."}},"importantCases":[],"_links":{"self":"/api/acts/ad-casa-4-amdt-1-rudder-hinge-fittings-modification","history":"/api/acts/ad-casa-4-amdt-1-rudder-hinge-fittings-modification/history","analysis":"/api/acts/ad-casa-4-amdt-1-rudder-hinge-fittings-modification/analysis","conflicts":"/api/acts/ad-casa-4-amdt-1-rudder-hinge-fittings-modification/conflicts","importantCases":"/api/acts/ad-casa-4-amdt-1-rudder-hinge-fittings-modification/important-cases","documents":"/api/acts/ad-casa-4-amdt-1-rudder-hinge-fittings-modification/documents"}}