{"id":"F2006B02188","name":"AD/AC-112/4 - Engine Oil Pressure Line - Replacement","slug":"ad-ac-112-4-engine-oil-pressure-line-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41418,"registerId":"commonwealth-F2006B02188-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AC-112/4 - Engine Oil Pressure Line - Replacement","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-description: CASA Airworthiness Directive\nmeta-generator: Aspose.Words for .NET 22.10.0\nmeta-keywords: Issue 1/1977,Aircraft below 5700 kg,Gulfstream (Rockwell) 112 Series Aeroplanes,Engine Oil Pressure Line - Replacement,4\ntitle: Airworthiness Directive - AD/AC-112/4 - Engine Oil Pressure Line - Replacement\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)  Gulfstream (Rockwell) 112 Series Aeroplanes\n\n \n\nAD/AC-112/4 Engine Oil Pressure Line - Replacement 1/77\n\nApplicability: Model 112 with S/Nos. 3 to 470.\n\n \n\nDocument: Rockwell International SB No. SB-112-46, Part II. Compliance: Within 100 hours’ time in service after 31 January 1977.\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 directive as written applies to a defined set of Model 112 aircraft (S/N 3–470) and mandates replacement of the engine oil pressure line per Rockwell SB-112-46, Part II within a specified timeframe. There is no text in the instrument indicating an expansion or narrowing of scope beyond those explicit limits, so the scope appears unchanged from the instrument's stated operative purpose: to require that replacement for the listed aircraft within the stated compliance period. (Applicability; Document; Compliance.)"},"complexity_factors":["Narrow applicability (single model and serial-number range). (Applicability: Model 112 with S/Nos. 3 to 470.)","Fixed and short compliance window (100 hours after 31 January 1977). (Compliance: Within 100 hours’ time in service after 31 January 1977.)","Reliance on an external service bulletin for technical instructions rather than including step-by-step detail in the AD. (Document: Rockwell International SB No. SB-112-46, Part II.)","No exemptions, alternatives, or procedural detail provided in the AD text (implies operator must follow SB or seek approval). (Document; Compliance.)","Regulatory enforcement under Part 39 but no implementation guidance or logistics in the directive itself. (COMMONWEALTH OF AUSTRALIA ... PART 39.)"],"plain_english_summary":"What this instrument does\n\n- This is an Airworthiness Directive issued under the Civil Aviation Regulations (Part 39) that mandates replacement of a specific aircraft component. (COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY)\n- It applies to Gulfstream (Rockwell) 112 Series aeroplanes, Model 112 with serial numbers 3 to 470. (Applicability: Model 112 with S/Nos. 3 to 470.)\n- The directive requires following Rockwell International Service Bulletin No. SB-112-46, Part II for the replacement. (Document: Rockwell International SB No. SB-112-46, Part II.)\n- The work must be completed within 100 hours' time in service after 31 January 1977. (Compliance: Within 100 hours’ time in service after 31 January 1977.)\n\nWho this affects and who decides\n\n- Aircraft owners/operators of affected Model 112 aeroplanes are the parties who must ensure the replacement occurs, because the directive imposes the maintenance requirement on the listed aircraft. (Applicability; Compliance.)\n- The Civil Aviation Safety Authority issued the directive under the cited regulations, and compliance is defined by reference to the Rockwell service bulletin. (COMMONWEALTH OF AUSTRALIA ... PART 39; Document.)\n\nWhy it matters (mechanics, costs and incentives)\n\n- Mechanically, the AD changes the maintenance obligations for owners/operators of the listed aircraft by replacing the engine oil pressure line according to the referenced service bulletin. (Document; Compliance.)\n- The immediate costs are the parts and labour to carry out the replacement and any aircraft downtime needed to complete the work within the 100-hour window. (Compliance requirement implies timing and work.)\n- The compliance requirement creates a short-term scheduling constraint for operators: the replacement must be done within the specified hours-in-service window after the date given. (Compliance.)\n- The AD ties compliance to an external technical document (Rockwell SB-112-46, Part II). That makes fulfilment dependent on access to that bulletin and any parts or procedures it prescribes. (Document.)\n\nTrade-offs, practical risks and administrative features to note\n\n- The AD prescribes a single technical path by reference to the manufacturer service bulletin, so alternatives or variations are not described in the directive text itself; any deviation would require separate approval under the applicable regulatory framework. (Document.)\n- The directive does not, on its face, list exemptions, cost-sharing arrangements, or compensation mechanisms. Operators bear the direct financial and scheduling impact of compliance. (Applicability; Compliance.)\n- Administrative enforcement and aviation-safety oversight fall to the regulator under Part 39, which establishes the AD as a mandatory airworthiness requirement. (COMMONWEALTH OF AUSTRALIA ... PART 39.)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue safety directive from 1977. It has not expanded beyond its original narrow purpose of mandating a specific mechanical replacement on a specific aircraft type."},"complexity_factors":["Extremely short document (under 200 words)","Only 1 defined term implicitly used ('time in service')","No cross-references to other legislation beyond the enabling regulation (CAR 1998 Part 39)","Single, unconditional mandate with clear applicability criteria (specific model and serial number range)","No exceptions, exemptions, or conditional logic","Simple compliance pathway: follow one referenced manufacturer service bulletin"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by the Civil Aviation Safety Authority (CASA) that requires aircraft owners to fix a specific mechanical problem.\n\n**What it does:** It orders owners of certain **Gulfstream (Rockwell) 112 series aeroplanes** (specifically Model 112 with serial numbers 3 to 470) to **replace the engine oil pressure line**. This is a safety-critical fix — if the oil pressure line fails, the engine could lose oil pressure and fail in flight.\n\n**Who must comply:** Anyone who owns or operates one of these specific aircraft models in Australia.\n\n**How to comply:** Follow the instructions in **Rockwell International Service Bulletin SB-112-46, Part II**. This is the manufacturer's official repair guide.\n\n**Deadline:** The replacement must be done **within 100 hours of flying time** after 31 January 1977. (\"Time in service\" means actual hours the aircraft has been airborne, not just calendar time.)\n\n**Why it matters:** Oil pressure lines carry oil to lubricate the engine. A cracked or faulty line can cause catastrophic engine failure. This AD ensures a known defect gets fixed before it causes an accident."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ac-112-4-engine-oil-pressure-line-replacement","history":"/api/acts/ad-ac-112-4-engine-oil-pressure-line-replacement/history","analysis":"/api/acts/ad-ac-112-4-engine-oil-pressure-line-replacement/analysis","conflicts":"/api/acts/ad-ac-112-4-engine-oil-pressure-line-replacement/conflicts","importantCases":"/api/acts/ad-ac-112-4-engine-oil-pressure-line-replacement/important-cases","documents":"/api/acts/ad-ac-112-4-engine-oil-pressure-line-replacement/documents"}}