{"id":"F2006B01825","name":"AD/A109/39 - Hydraulic Pump","slug":"ad-a109-39-hydraulic-pump","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41023,"registerId":"commonwealth-F2006B01825-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\nAgusta A109 Series Helicopters","sortOrder":0},{"sectionNumber":"AD/A109/39 Hydraulic Pump 5/2003","sectionType":"part","heading":"AD/A109/39 Hydraulic Pump 5/2003","content":"# AD/A109/39 Hydraulic Pump 5/2003\n\nApplicability: All A109E helicopters fitted with hydraulic pump part number 109-0760-42-101. Requirement: 1. In accordance with Bolletino Tecnico 109EP-20:\n\n    Check hydraulic fluid level.\n    If an excessive consumption of hydraulic fluid is noted with no sign of external leakage, perform analysis of the transmission fluid for contamination.\n\n2. Replace the hydraulic pump in accordance with Bolletino Tecnico 109EP-20.\n\nNote: Italian AD 2001-286 refers.\n\nCompliance: 1. At intervals not to exceed the basic 25 hour/30 day inspection.\n\n2. Prior to 30 June 2003.\n\nThis Airworthiness Directive becomes effective on 15 May 2003.\n\nBackground: Certain hydraulic pump design do not allow hydraulic fluid to drain from the case if the hydraulic pump shaft seal leaks. Subsequently fluid leakage can degrade the main transmission seal and allow hydraulic fluid to enter the transmission. Contamination of the transmission lubricating oil could lead to transmission failure.\n\n![](image.002.png)  \n\nJames Coyne\n\nDelegate of the Civil Aviation Safety Authority 2 April 2003\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 23 April 2003.","sortOrder":1}],"analysis":{"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 a specific helicopter model's hydraulic pump. The document shows no evidence of scope creep; it targets exactly one unsafe condition with precise applicability criteria."},"complexity_factors":["Very short document (under 300 words)","Only 1 defined term (Bolletino Tecnico 109EP-20 — referenced but not defined inline)","Simple two-part requirement structure with clear sequential steps","Single applicability criterion (specific helicopter model + part number)","No nested exceptions or conditional logic beyond basic 'if/then' in requirement 1","Straightforward compliance timeline with two clear deadlines","Minimal cross-referencing (only one external document referenced: Italian AD 2001-286, marked as 'Note' only)"],"plain_english_summary":"This AD requires owners/operators and maintenance personnel of Agusta A109E helicopters fitted with hydraulic pump P/N 109-0760-42-101 to perform regular fluid checks, investigate unexplained fluid loss (including testing transmission oil for contamination), and replace the faulty pump with the corrected unit. It addresses a leakage path that can contaminate the main transmission and cause complete transmission failure; all replacements must be completed by 30 June 2003."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD stays within the original safety-focused purpose: to prevent hydraulic fluid leaking into the main transmission by mandating inspection, contamination analysis where appropriate, and pump replacement. It does not broaden the scope beyond that mechanical safety objective (applicability limited to A109E helicopters with the specified pump part number; required actions are directly tied to the identified failure mode)."},"complexity_factors":["Short document (single-page AD)","Single, narrowly framed applicability (one helicopter model and one pump part number)","Few actions (two inspection/analysis steps and one replacement requirement)","One external reference to manufacturer technical bulletin (Bolletino Tecnico 109EP-20) and one foreign AD (Italian AD 2001-286)","Clear compliance deadlines (recurring 25 hr/30 day inspection; replacement by specific calendar date)","Minimal cross-referencing within the instrument (only to Bolletino Tecnico and CAR 1998 subregulation 39.1(1))"],"plain_english_summary":"**What this rule does (mechanics)**\n\n- Applies to: Agusta A109E helicopters that have hydraulic pump part number 109-0760-42-101 (see \"Applicability\").\n- Actions required (\"Requirement\"):\n  - At each scheduled basic inspection (no more than every 25 flight hours or every 30 days) check the hydraulic fluid level following the manufacturer technical instructions (Bolletino Tecnico 109EP-20).\n  - If hydraulic fluid is being consumed more than expected and there is no external leak, take a sample of the transmission oil and analyse it for contamination.\n  - Replace the hydraulic pump in accordance with Bolletino Tecnico 109EP-20.\n- Timing (\"Compliance\"): the checks must be done at intervals not exceeding the basic 25 hour/30 day inspection; pumps identified had to be replaced by 30 June 2003. The AD took effect 15 May 2003.\n- Rationale (\"Background\"): the hydraulic pump design can allow leaked hydraulic fluid to remain in the pump case and migrate into the main transmission. If hydraulic fluid contaminates the transmission oil, it could cause transmission failure. The AD adopts the manufacturer technical bulletin and references an Italian AD on the same issue.\n\n**Who is affected**\n\n- Directly affected: owners and operators of Agusta A109E helicopters fitted with hydraulic pump P/N 109-0760-42-101, and the maintenance organisations that service those helicopters.\n- Indirectly affected: passengers and third parties because the actions aim to reduce the risk of transmission failure.\n\n**Who pays and who decides**\n\n- Operators/owners pay for the additional inspections, oil analyses and the cost and downtime of pump replacement (Requirement; Compliance).\n- The CASA delegate issued the AD under aviation safety regulation; the AD requires compliance with the manufacturer’s Bolletino Tecnico (so the manufacturer’s technical instructions determine how to carry out the checks and replacement).\n\n**Why it matters (practical effects and trade-offs)**\n\n- Safety mechanism: forces regular monitoring for hidden hydraulic leaks and removal/replacement of pumps that could allow hydraulic fluid to contaminate transmission oil (Background; Requirement).\n- Costs and operational impact: creates recurring inspection workload (at every basic 25 hr/30 day inspection) and a one-off replacement requirement by the stated deadline for affected pumps; this imposes direct parts and labour costs and aircraft downtime.\n- Dependence on manufacturer instructions: the AD makes the manufacturer’s Bolletino Tecnico the required means of compliance, so operators follow that technical process (Requirement). That concentrates the technical remedy and spare-parts demand around the manufacturer’s specified procedures and parts.\n- Implementation risks and logistics: potential supply or scheduling constraints for replacement pumps, variability in operators’ ability to detect internal leaks (some leaks leave no external evidence), and the risk of false positives or delayed detection if inspections are not thorough.\n- Incentives and behaviour change: operators will increase monitoring of hydraulic fluid consumption and are compelled to replace identified pumps, reducing the risk of continuing to operate with a pump that could contaminate the transmission. This may shift maintenance budgets and hangar time toward addressing this specific vulnerability.\n\n**Distribution of costs and benefits**\n\n- Costs are concentrated on the subset of A109E operators using the specified pump part number (inspection labour, fluid analysis, pump replacement, downtime).\n- Benefits (reduced risk of transmission contamination/failure) accrue to operators, passengers and the broader public as a diffuse safety improvement.\n\n**Concrete implementation notes**\n\n- The AD requires following Bolletino Tecnico 109EP-20 for the inspection method and for pump replacement (Requirement).\n- The AD referenced Italian AD 2001-286 (Note).\n\n(References to the AD sections above: Applicability, Requirement, Compliance, Background.)"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-a109-39-hydraulic-pump","history":"/api/acts/ad-a109-39-hydraulic-pump/history","analysis":"/api/acts/ad-a109-39-hydraulic-pump/analysis","conflicts":"/api/acts/ad-a109-39-hydraulic-pump/conflicts","importantCases":"/api/acts/ad-a109-39-hydraulic-pump/important-cases","documents":"/api/acts/ad-a109-39-hydraulic-pump/documents"}}