{"id":"F2006B06807","name":"AD/SC7/7 - Rudder Bar Assembly - Modification","slug":"ad-sc7-7-rudder-bar-assembly-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114667,"registerId":"commonwealth-F2006B06807-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/SC7/7 - Rudder Bar Assembly - 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)  Short SC7 (Skyvan) Series Aeroplanes\n\n \n\nAD/SC7/7 Rudder Bar Assembly - Modification 7/72\n\nApplicability:  All models. Document: Shorts SB No. 27-55.\n\nCompliance: Within 100 hours time in service after 31 August 1972.\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\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The text applies to all models of Short SC7 series aeroplanes and mandates modification of the rudder bar assembly per Shorts SB No. 27-55 within a specified flight-hours window (Applicability; Document; Compliance). The document contains no indication that its scope has been expanded or narrowed from an original intent; it reads as a targeted, single-action directive tied to the cited service bulletin."},"complexity_factors":["Very short and tightly scoped directive: single aircraft type and single modification.","Clear compliance deadline (100 hours after specified date) reduces interpretive complexity.","Technical detail is delegated to a single referenced document (Shorts SB No. 27-55), so legal text is simple but requires consultation of the service bulletin for implementation.","Historic fixed date may create implementation scheduling complexity relative to individual operator flight hours.","Enforcement and alternative-compliance provisions are not present in the text, requiring reference to broader regulatory framework for procedural detail."],"plain_english_summary":"What this directive requires\n\n- The Civil Aviation Safety Authority lists an airworthiness directive for Short SC7 (Skyvan) series aeroplanes titled “Rudder Bar Assembly - Modification” (AD/SC7/7). (header)\n- It applies to all models of that aircraft series. (Applicability)\n- It directs that the rudder bar assembly be modified in accordance with the manufacturer’s instruction: Shorts Service Bulletin No. 27-55. (Document)\n- The modification must be carried out within 100 hours time in service after 31 August 1972. (Compliance)\n\nWho this affects and who decides\n\n- Aircraft owners and operators of Short SC7 (Skyvan) series aeroplanes are the primary parties required to ensure the work is done, because the directive is addressed to those aircraft (Applicability) and sets the compliance time (Compliance).\n- The Civil Aviation Safety Authority issues the directive and thereby establishes the mandatory requirement (header). The technical steps to implement the change are set out in the manufacturer’s service bulletin referenced by the AD (Document).\n\nWho pays and what changes in behaviour\n\n- Owners/operators bear the direct cost of performing the modification (inferred from the requirement to carry out the work within the stated time). They must schedule the aircraft into maintenance, obtain the parts and follow the service bulletin instructions (Document; Compliance).\n- Maintenance organisations (in-house or independent MROs) will perform the work according to Shorts SB No. 27-55 (Document).\n\nPractical trade-offs, incentives and implementation factors\n\n- Costs and timing: The AD fixes a short compliance window (100 flight hours after 31 August 1972). Operators must prioritise that work within normal maintenance planning, creating scheduling and cash-flow effects (Compliance).\n- Supply and capacity: The AD relies on the manufacturer’s service bulletin for the technical solution; availability of parts, tooling or qualified technicians will affect how quickly operators can comply (Document).\n- Concentration of costs and distribution of benefits: The immediate costs fall on each aircraft owner/operator; maintenance providers and any suppliers of modification kits or parts are likely to receive the corresponding revenue (Applicability; Document).\n- Enforcement and discretion: The directive is set out in the Schedule of Airworthiness Directives under the Civil Aviation authority, making compliance mandatory; the AD itself delegates technical detail to the manufacturer’s service bulletin rather than specifying procedure in full (header; Document).\n\nRisks, opportunity costs and substitutability\n\n- If an operator cannot obtain parts or maintenance capacity within the time window, they face operational disruption from deferring the work; the AD does not specify alternative measures or extensions in this text (Compliance; Document).\n- The AD prescribes a single technical remedy (the service bulletin). Operators cannot substitute a different corrective action unless authorised by the regulator or the manufacturer, since the AD ties compliance to Shorts SB No. 27-55 (Document).\n\nWhat the instrument does not state\n\n- The directive text provided does not include the reason for the modification (no description of the unsafe condition is present in this text). It also does not include detailed enforcement procedures, cost estimates, or alternative compliance options in the excerpt supplied (header; Document; Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1972 addressing a specific mechanical modification. It has not expanded beyond its original scope; it remains a narrow safety order targeting one component on one aircraft type."},"complexity_factors":["Extremely short document — only 4 substantive lines of regulatory content","Zero defined terms in the directive itself (relies entirely on external document: Shorts SB No. 27-55)","No cross-references to other legislation beyond the enabling regulation (CAR 1998, Part 39)","Simple, unconditional compliance requirement: single deadline, single action, no exceptions or alternative methods of compliance stated","No nested logic or conditional provisions — applies to 'All models' without qualification"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of **Short SC7 Skyvan aircraft** (a twin-turboprop utility plane) to modify the **rudder bar assembly** — the foot-operated control mechanism that steers the aircraft on the ground and coordinates turns in the air.\n\n**Who must comply:** Anyone operating any model of the Short SC7 Skyvan series.\n\n**How to comply:** Follow the instructions in **Shorts Service Bulletin No. 27-55** (the manufacturer's official technical notice). The modification must be completed within **100 hours of flight time** after 31 August 1972.\n\n**Why it matters:** Airworthiness Directives are legally binding safety fixes. They typically address design defects, wear patterns, or failure modes discovered after an aircraft enters service. Non-compliance grounds the aircraft — it cannot legally fly until the work is done."}},"importantCases":[],"_links":{"self":"/api/acts/ad-sc7-7-rudder-bar-assembly-modification","history":"/api/acts/ad-sc7-7-rudder-bar-assembly-modification/history","analysis":"/api/acts/ad-sc7-7-rudder-bar-assembly-modification/analysis","conflicts":"/api/acts/ad-sc7-7-rudder-bar-assembly-modification/conflicts","importantCases":"/api/acts/ad-sc7-7-rudder-bar-assembly-modification/important-cases","documents":"/api/acts/ad-sc7-7-rudder-bar-assembly-modification/documents"}}