{"id":"F2006B01823","name":"AD/A109/37 - Tail Rotor Blades P/N 109-8132-01-111","slug":"ad-a109-37-tail-rotor-blades-p-n-109-8132-01-111","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41021,"registerId":"commonwealth-F2006B01823-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 109 Series Helicopters","sortOrder":0},{"sectionNumber":"AD/A109/37 Tail Rotor Blades P/N 109-813","sectionType":"part","heading":"AD/A109/37 Tail Rotor Blades P/N 109-8132-01-111 4/2003","content":"# AD/A109/37 Tail Rotor Blades P/N 109-8132-01-111 4/2003\n\nApplicability: All Agusta A109E helicopters equipped with tail rotor blades part number 109-8132- 01-107 or \\-109, and all tail rotor blades part number 109-8132-01-107 or \\-109 in storage which have accumulated flight hours on the Model 109E helicopter.\n\nRequirement: Remove from service, all tail rotor blades part number 109-8132-01-107 and \\-109, and replace with part number 109-8132-01-111 tail rotor blades.\n\nNote: Tail rotor blade part number 109-8132-01-111 has a retirement life of 1,000 flight hours.\n\nNote: ENAC AD 2001-496 refers.\n\nCompliance: Before further flight after 17 April 2003, unless already accomplished.\n\nThis Airworthiness Directive becomes effective on 17 April 2003.\n\nBackground: Reports were received from operators of the occurrence of cracks on tail rotor blades part number 109-8132-01-107 and \\-109. In response, the manufacturer has developed improved tail rotor blades by modifying the manufacturing process and increasing the thickness of the blade skins; with resultant increased structural strength.\n\n![](image.002.jpeg)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 4 March 2003\n\n![](image.001.png)","sortOrder":1}],"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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with a narrow, specific safety purpose. The scope remains tightly focused on the identified defect in specific helicopter components."},"complexity_factors":["Single, unambiguous requirement with no conditional exceptions","Only 2 defined part numbers in the applicability section","No cross-references to other legislation (only a non-binding note referencing an Italian aviation directive)","Clear, absolute compliance deadline ('before further flight')","Total length under 300 words","No nested definitions or interpretive provisions"],"plain_english_summary":"This CASA safety order grounds specific tail-rotor blades for Agusta A109E helicopters—parts ending -107 and -109—prohibiting their use and requiring replacement with redesigned -111 blades before any flight after 17 April 2003. It also covers stored blades previously used on this helicopter type.\n\nCracks were found in service; failure could cause catastrophic loss of control. Replacement blades are limited to 1,000 flight hours before retirement."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive addresses a safety issue reported for specific tail rotor blade part numbers and requires their replacement with a manufacturer‑improved part. The measure is focused on that single technical problem (cracking) and does not extend the law’s scope beyond correcting that unsafe condition. There is no indication in the text that the Directive expands to unrelated components, aircraft types, or broader regulatory powers; it remains a targeted mandatory equipment-change requirement tied to reports of cracks and the manufacturer’s redesigned blade."},"complexity_factors":["Short, single-action directive (remove specified parts and replace with a single replacement P/N).","Clear applicability limited to one helicopter model (Agusta A109E) and specific part numbers.","One cross-reference to another authority’s AD (ENAC AD 2001-496).","Single timing requirement: ‘before further flight after 17 April 2003’ (urgent, no phased compliance).","One operationally relevant note: replacement part has a fixed retirement life (1,000 flight hours).","Inclusion of stored parts that have accumulated flight hours adds one small conditional element to applicability."],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- It orders the removal from service of specific tail rotor blades used on Agusta A109E helicopters (parts 109-8132-01-107 and 109-8132-01-109) and requires they be replaced with a specific improved part (109-8132-01-111).\n- The replacement must be done for any helicopter that currently has those blades fitted, and for blades of those part numbers in storage if they have accumulated flight hours on an A109E (see “Applicability”).\n- The action must be completed before the helicopter next flies after 17 April 2003 (see “Compliance”).\n- The replacement blade (P/N 109-8132-01-111) is noted to have a retirement life of 1,000 flight hours (a limit after which the part must be removed from service).\n- The directive cross-references ENAC AD 2001-496 as related material.\n\n**Who this affects and who pays**\n\n- Affected parties: owners and operators of Agusta A109E helicopters, maintenance organisations that service those helicopters, and any holders of the specified spare blades in storage that have seen A109E flight hours.\n- Who pays: operators/owners bear the direct costs — buying replacement blades, labour for removal and installation, and any downtime. Maintenance providers will incur work and inventory impacts; suppliers of the new blade may receive increased orders.\n\n**Why the rule was made (official rationale and what that implies mechanically)**\n\n- The directive states it follows reports of cracks in the older blade parts (109-8132-01-107 and -109). The manufacturer produced a redesigned blade (109-8132-01-111) with thicker skins and a changed manufacturing process to increase structural strength. Mechanically, the rule forces fleet-wide replacement of the older parts with the redesigned part to correct the identified unsafe condition.\n\n**Trade-offs, implementation considerations and likely effects**\n\n- Immediate safety action vs. cost and downtime: The requirement to replace before the next flight creates an urgent compliance burden. That reduces operational flexibility but prioritises removal of the potentially cracked components.\n- Direct costs and opportunity costs: Operators must buy the new blades and schedule maintenance time; aircraft will be out of service during the work. There may be lost revenue if helicopters are grounded pending replacement.\n- Inventory and supply risk: If replacement blades are in limited supply, operators may face delays or premium pricing. Independent maintenance organisations can perform the work, but capacity constraints could push work to OEM-authorised repair centres if parts or tooling are restricted.\n- Asset management effect: The new part has a defined retirement life (1,000 flight hours), which changes maintenance planning and future replacement timing for operators.\n- Concentrated benefits, diffuse costs: The safety benefit accrues to all users/passengers and the operator (reduced risk of failure), while the immediate costs fall on current operators and owners of affected spare parts.\n- Regulatory cross-reference: The AD expressly refers to an ENAC (Italian authority) AD, which may mean implementers need to consult that document for further technical details or background.\n\n**Who decides and what discretion exists**\n\n- The directive is issued by the CASA delegate and sets a mandatory action and timeline. There is little operational discretion for operators about whether to comply: replacement is required before further flight. Discretion that remains is about where and how to conduct the replacement (choice of approved maintenance provider), and how to manage replacement scheduling and inventory.\n\n**Source citation of mechanism**\n\n- Requirement: “Remove from service, all tail rotor blades part number 109-8132-01-107 and -109, and replace with part number 109-8132-01-111 tail rotor blades.”\n- Compliance timing: “Before further flight after 17 April 2003.”\n- Background: reports of cracks; manufacturer modified manufacturing process and increased skin thickness to increase structural strength.\n\n"}},"importantCases":[],"_links":{"self":"/api/acts/ad-a109-37-tail-rotor-blades-p-n-109-8132-01-111","history":"/api/acts/ad-a109-37-tail-rotor-blades-p-n-109-8132-01-111/history","analysis":"/api/acts/ad-a109-37-tail-rotor-blades-p-n-109-8132-01-111/analysis","conflicts":"/api/acts/ad-a109-37-tail-rotor-blades-p-n-109-8132-01-111/conflicts","importantCases":"/api/acts/ad-a109-37-tail-rotor-blades-p-n-109-8132-01-111/important-cases","documents":"/api/acts/ad-a109-37-tail-rotor-blades-p-n-109-8132-01-111/documents"}}