{"id":"F2006L01047","name":"AD/BELL 427/4 - Hydraulic Solenoid Tee Fitting","slug":"ad-bell-427-4-hydraulic-solenoid-tee-fitting","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":58338,"registerId":"commonwealth-F2006L01047-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Bell Helicopter Textron 427 Series Helic","sectionType":"division","heading":"Bell Helicopter Textron 427 Series Helicopters","content":"### Bell Helicopter Textron 427 Series Helicopters\n\n| AD/BELL 427/4 | Hydraulic Solenoid Tee Fitting | 5/2006 |\n| ------------- | ------------------------------ | ------ |\n\n| Applicability: | Bell Helicopter Textron Canada (BHTC) Model 427 helicopters S/N 56001 through 56031 and 58001 through 58002.                                                                                                                                                                                                                                                                                |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Replace the Tee fitting P/N AS1 003W060404 and tubes P/N 427-080-058-101,427-080-003-101 with Union P/N AS 5230W0606, Tee fitting P/N NAS1763W060404 and tubes P/N 427-080-069-101, 427-080-068-101, as per instructions outlined in Alert Service Bulletin (ASB) 427-01-02 dated 20 August 2001, or later Transport Canada approved revisions.Note: Transport Canada AD CF-2000-11 refers. |\n| Compliance:    | Within 30 days after the effective date of this AD, unless previously accomplished.                                                                                                                                                                                                                                                                                                         |\n|                | This Airworthiness Directive becomes effective on 11 May 2006.                                                                                                                                                                                                                                                                                                                              |\n| Background:    | While performing a regular maintenance activity, there is a possibility of installing the existing Tee fitting (P/N AS1003W060404) in such a way that the hydraulic fluid flow will be significantly restricted. To preclude this possibility, a new Tee fitting installation has been designed.                                                                                            |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n17 March 2006","sortOrder":0},{"sectionNumber":"AD/BELL 427/4","sectionType":"part","heading":"AD/BELL 427/4","content":"## AD/BELL 427/4","sortOrder":1},{"sectionNumber":"Hydraulic Solenoid Tee Fitting","sectionType":"part","heading":"Hydraulic Solenoid Tee Fitting","content":"## Hydraulic Solenoid Tee Fitting","sortOrder":2},{"sectionNumber":"5/2006","sectionType":"part","heading":"5/2006","content":"## 5/2006","sortOrder":3}],"analysis":{"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"},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD’s scope is consistent with its stated intent in the Background: a targeted mandatory replacement of the specified tee fitting and tubes on listed serial-numbered helicopters to prevent potential hydraulic flow restriction. No expansion or narrowing beyond that targeted corrective action is indicated in the instrument text."},"complexity_factors":["Narrow applicability: only specific Bell 427 serial numbers listed (low breadth).","Single, well-defined mechanical remedy: replacement of identified P/Ns (low technical complexity).","Mandatory short compliance window (30 days) creates scheduling and procurement pressure for operators.","Execution depends on following Bell ASB 427-01-02 (work instructions held outside the AD text).","References an external Transport Canada AD (CF-2000-11), creating cross-jurisdictional linkage."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of specified Bell 427 helicopters (S/N 56001–56031 and 58001–58002) to replace a particular hydraulic tee fitting and associated tubes with designated union, tee and tube parts, using the procedures in Bell Alert Service Bulletin 427-01-02. Compliance is mandatory within 30 days of the AD’s effective date (11 May 2006). Operators pay for the parts and installation; the change mechanically prevents a possible hydraulic flow restriction caused by incorrect installation of the original tee fitting."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive targeting a specific mechanical defect in specific aircraft. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific mechanical modification with clear part numbers","No defined terms section or complex interpretation provisions","Straightforward applicability criteria (specific serial number ranges)","Single compliance deadline with one exception clause ('unless previously accomplished')","References external technical document (Alert Service Bulletin) but provides specific part numbers in the text itself","No nested conditions, cross-references to other legislation, or discretionary powers"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to specific Bell 427 helicopters (serial numbers 56001-56031 and 58001-58002).\n\n**What it does:**\n- Requires owners/operators to replace a specific hydraulic \"Tee fitting\" and associated tubes with redesigned parts\n- The old fitting (part number AS1003W060404) could be installed incorrectly during maintenance, dangerously restricting hydraulic fluid flow\n- The new parts eliminate this risk\n\n**Who must comply:**\n- Anyone operating the affected Bell 427 helicopters\n- Must be done within 30 days of the directive taking effect (11 May 2006), unless already completed\n\n**Why it matters:**\nIncorrect installation of the old fitting could cause hydraulic system failure — potentially catastrophic in a helicopter. This AD prevents that risk through a mandatory hardware swap."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-427-4-hydraulic-solenoid-tee-fitting","history":"/api/acts/ad-bell-427-4-hydraulic-solenoid-tee-fitting/history","analysis":"/api/acts/ad-bell-427-4-hydraulic-solenoid-tee-fitting/analysis","conflicts":"/api/acts/ad-bell-427-4-hydraulic-solenoid-tee-fitting/conflicts","importantCases":"/api/acts/ad-bell-427-4-hydraulic-solenoid-tee-fitting/important-cases","documents":"/api/acts/ad-bell-427-4-hydraulic-solenoid-tee-fitting/documents"}}