{"id":"F2006B07261","name":"AD/TAY/13 - Front Fuel Cut-off Ring","slug":"ad-tay-13-front-fuel-cut-off-ring","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49172,"registerId":"commonwealth-F2006B07261-current","compilationNumber":null,"startDate":"2026-04-02","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 CASR 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\nRolls Royce Turbine Engines \\- Tay Series","sortOrder":0},{"sectionNumber":"AD/TAY/13 Front Fuel Cut-off Ring 12/200","sectionType":"part","heading":"AD/TAY/13 Front Fuel Cut-off Ring 12/2004","content":"# AD/TAY/13 Front Fuel Cut-off Ring 12/2004\n\nApplicability: All TAY611-8 engines prior to engine serial number 16204 that do not have Service Bulletin (SB) TAY-72-1025 standard incorporated.\n\nRequirement: 1. Carry out an inspection of the front fuel cut-off ring in accordance with SB TAY- 72-1644 dated 21 September 2004.\n\n2. Carry out rectification of any defects found during the inspection as detailed in Requirement 1 of this Directive in accordance with SB TAY-72-1644.\n\nNote: LBA AD 2004-426 EASA approval No. 2004-9617 refers.\n\nCompliance: For Requirement 1:\n\nFor engines installed; within 25 flight cycles or 1 month (whichever occurs first) from the effective date of this Directive.\n\nFor uninstalled engines; prior to installation in an aeroplane.\n\nFor Requirement 2: Before further flight.\n\nThis Airworthiness Directive becomes effective on 25 November 2004.\n\nBackground: The installation of post SB TAY-72-1025 low-pressure compressor blade-retaining rings on engines, which do not have SB TAY-72-1025 standard incorporated is incorrect and could lead to the disablement of the emergency fuel shut-off mechanism.\n\n![Signature of James Coyne Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nJames Coyne\n\nDelegate of the Civil Aviation Safety Authority 12 October 2004\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 3 November 2004.","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD remains narrowly targeted to a specific unsafe condition: incorrect installation of post-SB TAY-72-1025 blade-retaining rings on certain Tay 611-8 engines. It does not widen applicability beyond that engine population, nor does it introduce recurring inspection cycles or new regulatory powers. The directive sticks to its original safety-limited purpose (inspect and fix the front fuel cut-off ring on affected engines) rather than expanding scope."},"complexity_factors":["Short text: two operational requirements (inspect and rectify) and a single applicability clause","One engine type and a single serial-number cutoff (TAY611-8 prior to SN 16204)","Two service bulletins referenced: SB TAY-72-1644 (inspection/rectification) and SB TAY-72-1025 (standards incorporation)","Simple compliance timing: installed engines (25 flight cycles or 1 month), uninstalled engines (before installation); defects rectified before further flight","Minor cross-reference to an LBA AD / EASA approval number but no layered conditional exceptions"],"plain_english_summary":"**What this directive does (mechanics first)**\n\n- Requires an inspection of the front fuel cut-off ring on a defined subset of Rolls-Royce Tay 611-8 engines, and repair (rectification) of any defects found, following the procedures in Service Bulletin (SB) TAY-72-1644 (dated 21 September 2004). (See \"Requirement\".)\n- Applies only to TAY611-8 engines with serial numbers before 16204 that have not had SB TAY-72-1025 incorporated. (See \"Applicability\".)\n- Sets the timing for compliance: for engines installed in aircraft, the inspection must be done within 25 flight cycles or 1 month (whichever comes first) from the effective date of the directive; for uninstalled engines, the inspection must be done before installation. Any defects must be rectified before further flight. (See \"Compliance\".)\n\n**Who is affected**\n\n- Aircraft operators and owners who use aircraft powered by Rolls-Royce Tay 611-8 engines with serial numbers earlier than 16204 and which have not had SB TAY-72-1025 incorporated. \n- Maintenance organisations and engineers who perform the inspection and any necessary repairs according to SB TAY-72-1644.\n\n**Why it matters (official rationale and practical implications)**\n\n- Officially, the directive responds to instances where post-SB TAY-72-1025 blade-retaining rings were installed on engines that had not had SB TAY-72-1025 incorporated, which can incorrectly alter the front fuel cut-off ring and could disable the emergency fuel shut-off mechanism. (See \"Background\".)\n- Practically, a disabled emergency fuel shut-off affects the ability to quickly stop fuel flow in an emergency, which is a safety-critical function. The AD forces an inspection and repair cycle to confirm the correct hardware and operation.\n\n**Who pays and who decides**\n\n- Aircraft owners/operators pay for the inspection and any repairs or part replacements. \n- The CASA delegate issued the AD and the directive requires work to be done in accordance with the specified service bulletin (SB TAY-72-1644), which determines the technical steps. Compliance times are set in the AD.\n\n**Compliance burden and implementation risks**\n\n- Burden: short-term maintenance work (inspection) and potentially immediate repair that can ground the aircraft until fixed. Costs include labour, parts, and any operational disruption while engines are unavailable.\n- Implementation risks: availability of spare parts or qualified maintenance capacity; correctly identifying which engines lack SB TAY-72-1025 incorporation; complying within the short compliance window (25 flight cycles or 1 month for installed engines).\n\n**Trade-offs, incentives and likely behaviour changes**\n\n- The AD imposes a short, mandatory check and repair requirement focused on a finite engine population. Affected operators will either perform the inspection/rectification as required or, where available and permitted, incorporate SB TAY-72-1025 (if that SB is an accepted terminating action) to change the engine's status and avoid repeat actions tied to this AD. \n- Concentration of costs: the financial and operational impacts fall on the relatively small group of operators running the specified engine serial numbers. The safety benefit is distributed (passengers, crew, public).\n\n**Relevant cross-references and notes**\n\n- The AD references SB TAY-72-1644 for the inspection and rectification procedures and SB TAY-72-1025 for the standard that, if incorporated, makes an engine out of the AD's applicability. The AD also notes an LBA AD and EASA approval number.\n\n(References: Applicability; Requirement 1 & 2; Compliance; Background.)"},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive — a targeted safety instrument addressing a specific unsafe condition in a specific engine model. It has not expanded beyond its original purpose of mandating inspection and repair of the fuel cut-off ring defect."},"complexity_factors":["Single-issue directive with only 2 requirements","Limited applicability (one engine model, specific serial number range, with exception for already-modified engines)","References to external technical documents (Service Bulletins) rather than reproducing full instructions in the text","Simple compliance timeline with clear alternatives (25 flight cycles OR 1 month)","No nested definitions or extensive interpretation sections","Straightforward conditional logic (if engine installed, do X; if uninstalled, do Y)"],"plain_english_summary":"The Civil Aviation Safety Authority has issued a safety order for Rolls‑Royce Tay 611‑8 engines (serials <16204, unless updated to SB TAY‑72‑1025) after discovery of an incorrect low‑pressure compressor blade‑retaining ring that can prevent the emergency fuel shut‑off working. Operators and maintainers must inspect the front fuel cut‑off ring per Service Bulletin TAY‑72‑1644 and repair any defects before flight—within 25 flights or 1 month for in‑service engines, and before installation for spares."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tay-13-front-fuel-cut-off-ring","history":"/api/acts/ad-tay-13-front-fuel-cut-off-ring/history","analysis":"/api/acts/ad-tay-13-front-fuel-cut-off-ring/analysis","conflicts":"/api/acts/ad-tay-13-front-fuel-cut-off-ring/conflicts","importantCases":"/api/acts/ad-tay-13-front-fuel-cut-off-ring/important-cases","documents":"/api/acts/ad-tay-13-front-fuel-cut-off-ring/documents"}}