{"id":"F2006B02459","name":"AD/ARRIUS/4 - Fuel Injection","slug":"ad-arrius-4-fuel-injection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41715,"registerId":"commonwealth-F2006B02459-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nTurbomeca Turbine Engines \\- Arrius Series","sortOrder":0},{"sectionNumber":"AD/ARRIUS/4 Fuel Injection 11/2001","sectionType":"part","heading":"AD/ARRIUS/4 Fuel Injection 11/2001","content":"# AD/ARRIUS/4 Fuel Injection 11/2001\n\nApplicability: All Arrius 1A and 1E turboshaft engines.\n\nRequirement: Replace fuel injectors in accordance with Turbomeca Service Bulletin A319 73 0071.\n\nNote: DGAC AD 2000-532(A) refers.\n\nCompliance: 1. Injectors with less than 1200 hours time in service, prior to exceeding 1250 hours time in service.\n\n2. Injectors with more than 1200 hours time in service, within 110 hours time in service from the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 1 November 2001.\n\nBackground: This Directive has been issued to require the periodic replacement of fuel injectors.\n\nThe requirement is in response to reports of fuel injectors being found totally or partially blocked during maintenance. Blockage of fuel injectors may cause engine flame out during engine deceleration or prevent the 2.5 minute one engine inoperative rating being obtained.\n\n![](image.002.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 14 September 2001\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 10 October 2001.","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD stays within its original safety purpose: periodic removal and replacement of potentially blocked fuel injectors on Arrius 1A and 1E engines. It implements a time-based replacement requirement consistent with the stated background (reports of partial or total injector blockage). The AD does not broaden the obligation beyond that objective; it simply prescribes the replacement action, the technical reference (Turbomeca SB A319 73 0071), and two clear compliance windows. The AD also aligns with the referenced DGAC AD rather than expanding scope beyond that coordination."},"complexity_factors":["Single substantive requirement: replace fuel injectors per Turbomeca Service Bulletin A319 73 0071","Applicability limited to two engine models (Arrius 1A and 1E)","Two conditional compliance windows based solely on time-in-service hours (less than 1200 / more than 1200)","References two external documents (Turbomeca service bulletin and DGAC AD) but no additional nested exceptions","Short text with no defined-term section, no multi-part tests, and no administrative discretion clauses"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- This Airworthiness Directive (AD) orders replacement of the fuel injectors on certain Turbomeca Arrius turboshaft engines. (An AD is a mandatory safety instruction issued by the aviation safety regulator.)\n- It applies to all Arrius 1A and 1E engines (Applicability section).\n- The replacement must follow Turbomeca Service Bulletin A319 73 0071 (Requirement section).\n- Two compliance windows are set (Compliance section):\n  - Injectors with less than 1,200 hours time in service must be replaced before they reach 1,250 hours time in service.\n  - Injectors already above 1,200 hours must be replaced within 110 hours time in service from the AD's effective date.\n- The AD became effective on 1 November 2001 (Compliance/effective date).\n\n**Why it was issued (official rationale and mechanical effect)**\n\n- The Background section explains the reason: some injectors were found partially or totally blocked during maintenance. Blocked injectors can cause engine flameout during deceleration or stop the engine from meeting the 2.5 minute one-engine-inoperative rating. The AD’s mechanical purpose is to remove injectors before they reach the hours at which blockage was observed often enough to be a safety concern.\n\n**Who is affected and who decides**\n\n- Who decides: The Civil Aviation Safety Authority (CASA) delegate issued this AD under the aviation regulations (opening paragraph). The AD directs operators to take the specified action.\n- Who pays: Aircraft operators that use Arrius 1A or 1E engines must pay for the replacement parts and labour, and for any associated downtime.\n- Who performs the work: Maintenance organisations or authorised technicians who can comply with the Turbomeca service instructions.\n\n**Practical effects and compliance mechanics**\n\n- Operators must track injector hours and schedule replacements according to the two time-based windows in the Compliance section.\n- The AD points to Turbomeca Service Bulletin A319 73 0071 for the technical procedure; compliance requires following that bulletin's instructions.\n- Non-compliance would expose operators to regulatory enforcement and potential operational restrictions (typical for ADs).\n\n**Costs, incentives and trade-offs to consider**\n\n- Direct costs: replacement injectors, maintenance labour, and aircraft downtime. These costs are concentrated on operators of aircraft using the specified engines.\n- Indirect effects: increased workload for maintenance providers; possible short-term demand pressure for injector parts if many operators act at once.\n- Incentives: operators are incentivised to replace injectors within the windows to stay legally airworthy and avoid safety incidents. Some operators may accelerate replacements to spread maintenance workload.\n- Opportunity costs: time and money spent on early injector replacement cannot be used for other maintenance or upgrades.\n- Implementation risks: availability of replacement injectors and qualified technicians; scheduling difficulty if many injectors reach the replacement threshold simultaneously.\n\n**Reference and coordination**\n\n- The AD references Turbomeca Service Bulletin A319 73 0071 for the replacement procedure (Requirement section).\n- The AD notes a related French DGAC AD (DGAC AD 2000-532(A)), indicating the CASA action aligns with a foreign regulator’s measure (Note/Background).\n\n**Net effect in plain terms**\n\n- Operators of Arrius 1A and 1E engines must replace fuel injectors on a time-in-service basis to reduce the risk of blocked injectors causing engine flameout or a loss of required engine performance, following the manufacturer's service bulletin and within the hours set by the AD (Applicability, Requirement, Compliance, Background sections)."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific mechanical defect in specific engine models. There is no evidence of scope creep; it targets exactly the unsafe condition described in the background (blocked fuel injectors) with precisely tailored applicability and compliance requirements."},"complexity_factors":["Single, clearly defined applicability (two specific engine models)","Straightforward two-tier compliance schedule based on hours-in-service","Only one substantive requirement (replace fuel injectors per specified service bulletin)","Minimal cross-referencing (one French aviation authority AD mentioned in a note, one Turbomeca service bulletin)","No nested exceptions or conditional logic","Short document (approximately 250 words of substantive text)","Plain language background section explaining the safety rationale"],"plain_english_summary":"This mandatory Airworthiness Directive requires operators of Turbomeca Arrius 1A and 1E helicopter engines (commonly in AS350/EC130 types) to replace fuel injectors before specified flight-hour limits. It prevents injector blockage that can cause engine flame-outs or loss of emergency power in twin-engine operations, so operators must proactively swap injectors by the AD’s hour-based deadlines."}},"importantCases":[],"_links":{"self":"/api/acts/ad-arrius-4-fuel-injection","history":"/api/acts/ad-arrius-4-fuel-injection/history","analysis":"/api/acts/ad-arrius-4-fuel-injection/analysis","conflicts":"/api/acts/ad-arrius-4-fuel-injection/conflicts","importantCases":"/api/acts/ad-arrius-4-fuel-injection/important-cases","documents":"/api/acts/ad-arrius-4-fuel-injection/documents"}}