{"id":"F2006B07262","name":"AD/TAY/14 - Fuel Cut-off Ring","slug":"ad-tay-14-fuel-cut-off-ring","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49174,"registerId":"commonwealth-F2006B07262-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/14 Fuel Cut-off Ring 12/2004","sectionType":"part","heading":"AD/TAY/14 Fuel Cut-off Ring 12/2004","content":"# AD/TAY/14 Fuel Cut-off Ring 12/2004\n\nApplicability: All TAY620-15 and TAY620-15/20 engines prior to engine serial number 17023 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- 72-1646 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-72-1646.\n\nNote: LBA AD 2004-427 EASA approval No. 2004-9616 refers.\n\nCompliance: For Requirement 1:\n\nFor engines installed; within 500 flight hours 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_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 Airworthiness Directive maintains its original narrow scope — addressing a specific manufacturing/installation error in a defined engine series. There is no evidence of scope creep; it targets exactly the unsafe condition described in the background."},"complexity_factors":["Single, specific mechanical issue with narrow applicability (two engine models, serial number cutoff)","Only two requirements: inspect and repair","Clear compliance deadlines with simple conditions (installed vs uninstalled)","Minimal cross-referencing (one Service Bulletin referenced twice, one note about related German/EASA directive)","No nested exceptions or conditional logic beyond the initial applicability test","Short document (under 300 words of substantive text)"],"plain_english_summary":"The Civil Aviation Safety Authority has issued a safety order for certain Rolls‑Royce Tay 620‑15 and 620‑15/20 engines (serials <17023) because an incorrect low‑pressure compressor blade‑retaining ring can disable the emergency fuel shut‑off. Owners/operators (except engines already modified by SB TAY‑72‑1025) must inspect the front fuel cut‑off ring per Rolls‑Royce SB TAY‑72‑1646 and rectify any defects before flight. In‑service engines: within 500 flight hours of 25 Nov 2004; spares: before installation."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD is narrowly focused on correcting a specific unsafe condition (risk of disabling the emergency fuel shut‑off) for a defined subset of Rolls‑Royce Tay engines. The instrument does not expand obligations beyond inspection and rectification for those engines and associated compliance timing; it therefore does not appear to have grown beyond its original safety‑corrective purpose."},"complexity_factors":["Short, focused instrument (single-page AD) with few provisions","Two engine models specified (TAY620-15 and TAY620-15/20) and a single serial-number cutoff (prior to 17023)","References to two manufacturer service bulletins (SB TAY-72-1646 for inspection/rectification; SB TAY-72-1025 as incorporation status) which contain the technical detail","Different compliance timing depending on engine state (installed: within 500 flight hours; uninstalled: prior to installation)","Rectification requirement is absolute (repairs \"Before further flight\"), adding an operational constraint","Cross-reference to foreign ADs/approvals (LBA AD 2004-427 and EASA approval) but no extensive legal cross-referencing within the text"],"plain_english_summary":"**What this Directive does (mechanically)**\n\n- Requires inspections of the front fuel cut-off ring on specific Rolls-Royce Tay turbofan engines (models TAY620-15 and TAY620-15/20) that are older than serial number 17023 and that have not had Service Bulletin (SB) TAY-72-1025 incorporated (Applicability).\n- Directs maintenance personnel to carry out that inspection using the instructions in Service Bulletin TAY-72-1646 dated 21 September 2004, and to repair any defects found according to the same SB (Requirement 1 and 2).\n- Sets when the inspections must be done: for engines already installed in aircraft, within 500 flight hours of the AD becoming effective; for engines not installed, before they are installed. Any required repairs must be completed before the engine flies again (Compliance).\n\n**Who this affects**\n\n- Owners and operators of aircraft fitted with the affected Rolls‑Royce Tay engines (TAY620‑15 and TAY620‑15/20) with serial numbers prior to 17023 and without SB TAY‑72‑1025 incorporated.\n- Maintenance organisations and engineers who perform inspections and repairs under the referenced service bulletin.\n- Potentially aircraft lessors and insurers with exposure to affected engines while they are being inspected or repaired.\n\n**Why it matters / the safety issue**\n\n- The stated safety concern (Background) is that installing post‑SB TAY‑72‑1025 low‑pressure compressor blade‑retaining rings on engines that do not have SB TAY‑72‑1025 incorporated can incorrectly disable the emergency fuel shut‑off mechanism. The inspection and repair are intended to detect and correct that unsafe condition.\n\n**Who pays and who decides**\n\n- Costs (inspection labour, parts and any repair) fall on the aircraft/engine owner or operator who is responsible for maintaining airworthiness (Requirement & Compliance). The CASA delegate issued the AD (signature block).\n\n**What behaviour changes**\n\n- Operators must schedule and complete the inspection within the stated timeframes and must not return an engine to service for flight if defects covered by the AD remain uncorrected (Compliance & Requirement 2).\n- Maintenance providers must follow the procedures in SB TAY‑72‑1646 when inspecting and rectifying defects.\n\n**Implementation details and trade‑offs**\n\n- The AD orders actions to be taken \"in accordance with\" the named service bulletin (SB TAY‑72‑1646). That makes the SB the technical method for compliance; costs and technical specifics depend on what the SB prescribes.\n- Immediate operational cost is inspection labour and any parts/repairs. There is also potential aircraft downtime while engines are inspected or repaired, which is an opportunity cost for operators.\n- If defects are found, engines cannot fly until repaired (Requirement 2: \"Before further flight\"), which can concentrate costs on individual operators at times of inspection.\n- The AD cross‑references a foreign authority AD (LBA AD 2004‑427) and an EASA approval number; these are administrative cross‑checks that do not alter the mechanical requirements but may affect accepted compliance evidence for regulators or maintenance records.\n\n**Concrete source citations (where to look in the instrument)**\n- Applicability: identifies engine models, serial‑number cutoff (prior to 17023), and excludes engines that have SB TAY‑72‑1025 incorporated.\n- Requirement: inspection and rectification must follow SB TAY‑72‑1646 (dated 21 Sept 2004).\n- Compliance: timing for installed engines (within 500 flight hours) and for uninstalled engines (prior to installation); repairs before further flight.\n- Background: explains the unsafe condition (incorrect installation of post‑SB retaining rings can disable emergency fuel shut‑off).\n\n**Net effect**\n- The AD imposes a targeted inspection-and‑repair obligation on a defined set of Tay engines to protect the emergency fuel shut‑off function. It shifts inspection and repair costs and scheduling burden to the affected operators and requires maintenance actions to be completed according to the manufacturer’s service bulletin before affected engines return to flight service."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tay-14-fuel-cut-off-ring","history":"/api/acts/ad-tay-14-fuel-cut-off-ring/history","analysis":"/api/acts/ad-tay-14-fuel-cut-off-ring/analysis","conflicts":"/api/acts/ad-tay-14-fuel-cut-off-ring/conflicts","importantCases":"/api/acts/ad-tay-14-fuel-cut-off-ring/important-cases","documents":"/api/acts/ad-tay-14-fuel-cut-off-ring/documents"}}