{"id":"F2007L00701","name":"AD/A109/55 - Hydraulic Pipe Interference","slug":"ad-a109-55-hydraulic-pipe-interference","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":64289,"registerId":"commonwealth-F2007L00701-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Agusta A109 Series Helicopters","sectionType":"division","heading":"Agusta A109 Series Helicopters","content":"### Agusta A109 Series Helicopters\n\n| AD/A109/55 | Hydraulic Pipe Interference | 4/2007 |\n| ---------- | --------------------------- | ------ |\n\n| Applicability: | Agusta A109E Helicopters up to Serial Number (S/N) 11158 inclusive and S/N 11501 to 11510 inclusive.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Inspect and replace as necessary hydraulic pipes with Part Number (P/N)109-0761-64-103 and P/N 109-0761-65-103 as detailed in Part I and Part II of Agusta “Bollettino Tecnico” (BT) 109EP-73 original issue or later approved revision.2. Replace the hydraulic pipes P/N 109-0761-64-103 and P/N 109-0761-65-103 with new pipes P/N 109-0763-96-101 and P/N 109-0763-97-101 in accordance with Agusta Bollettino Tecnico (BT) 109EP-73 original issue or later approved revision.3. Do not install hydraulic pipes P/N 109-0761-64-103 and P/N 109-0761-65-103 on any Agusta 109E helicopter.Note: EASA AD 2007-0038 dated 21 February 2007 refers. |\n| Compliance:    | 1. Within the next 50 flight hours after the effective date of this AD. Thereafter repeat at intervals not to exceed 100 flight hours.2. No later than 30 November 2007.3. From 30 November 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                        |\n|                | This Airworthiness Directive becomes effective on 12 April 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| Background:    | There has been reported interference between the hydraulic pipe and the tail rotor control rod assembly on some A109E helicopters. This AD requires an inspection for interference between the pipes and introduces a replacement P/N pipe in conjunction with a fixing method for those pipes. This provides for an increase in the clearance between the pipes and tail rotor control assembly.                                                                                                                                                                                                                                                        |\n\n|     | If not corrected damage to the hydraulic pipes could lead to loss of the No. 1 hydraulic system in flight. |\n| --- | ---------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nDavid Punshon  \nDelegate of the Civil Aviation Safety Authority\n\n28 February 2007","sortOrder":0},{"sectionNumber":"AD/A109/55","sectionType":"part","heading":"AD/A109/55","content":"## AD/A109/55","sortOrder":1},{"sectionNumber":"Hydraulic Pipe Interference","sectionType":"part","heading":"Hydraulic Pipe Interference","content":"## Hydraulic Pipe Interference","sortOrder":2},{"sectionNumber":"4/2007","sectionType":"part","heading":"4/2007","content":"## 4/2007","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD targets a defined subset of A109E helicopters and specific part numbers to remedy reported hydraulic pipe interference. It confines regulatory action to inspections, mandated replacements, and a prohibition on reinstalling the old parts, using Agusta service instructions for execution; it does not broaden regulatory scope beyond these corrective measures."},"complexity_factors":["Targeted applicability to specific serial-number ranges (Applicability)","Multiple, explicit part numbers for inspection, replacement and prohibition (Requirement)","Mixed timing obligations: short initial compliance window, recurring inspection interval, and a hard replacement deadline (Compliance)","Dependence on external procedures: work must follow Agusta Bollettino Tecnico original issue or later approved revision (Requirement)","Operational scheduling burden: compliance measured in flight hours, affecting maintenance planning (Compliance)","Safety consequence tied to a critical system (loss of No.1 hydraulic) increases enforcement attention (Background/Note)"],"plain_english_summary":"This Airworthiness Directive requires operators of specified Agusta A109E helicopters (listed serial numbers) to inspect two specific hydraulic pipe part numbers for interference with the tail-rotor control rod, replace them with new part numbers where required, and prohibits reinstalling the old pipes. The AD’s stated purpose is to increase clearance and prevent damage that could cause loss of the No. 1 hydraulic system. Operators must carry out inspections and replacements on the timelines set by the AD and follow Agusta’s Bollettino Tecnico procedures."},"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 mechanical interference issue on a defined subset of Agusta A109E helicopters. The three requirements (inspect, replace, prohibit) form a coherent, time-bound safety intervention without scope creep."},"complexity_factors":["Single, discrete safety issue with clear mechanical remedy","Only 2 specific part numbers affected, with straightforward replacement instructions","Three sequential compliance requirements with explicit deadlines (flight hours and calendar dates)","No nested exceptions, conditional logic, or cross-references to other legislation","Minimal defined terms (only standard aviation abbreviations: S/N, P/N, BT, AD)","Total length: approximately 300 words of substantive content","Single source document referenced (Agusta Bollettino Tecnico 109EP-73)"],"plain_english_summary":"This CASA Airworthiness Directive mandates owners/operators of Agusta A109E helicopters (specific serial numbers up to S/N 11158 and S/N 11501–11510) fix a defect where hydraulic pipes can rub the tail‑rotor control rod, risking main hydraulic failure.  \n\nIt requires immediate and recurring inspections, replacement with redesigned pipes by 30 November 2007, and bans reinstalling the old pipe parts thereafter to prevent catastrophic loss of control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-a109-55-hydraulic-pipe-interference","history":"/api/acts/ad-a109-55-hydraulic-pipe-interference/history","analysis":"/api/acts/ad-a109-55-hydraulic-pipe-interference/analysis","conflicts":"/api/acts/ad-a109-55-hydraulic-pipe-interference/conflicts","importantCases":"/api/acts/ad-a109-55-hydraulic-pipe-interference/important-cases","documents":"/api/acts/ad-a109-55-hydraulic-pipe-interference/documents"}}