{"id":"F2008L03223","name":"AD/EC 225/3 - Main Rotor Blade De-Icing System Harness Connectors","slug":"ad-ec-225-3-main-rotor-blade-de-icing-system-harness-connectors","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":75317,"registerId":"commonwealth-F2008L03223-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Eurocopter EC 225 Series Helicopters","sectionType":"division","heading":"Eurocopter EC 225 Series Helicopters","content":"### Eurocopter EC 225 Series Helicopters\n\n| AD/EC 225/3 | Main Rotor Blade De-IcingSystem Harness Connectors | 11/2008 DM |\n| ----------- | -------------------------------------------------- | ---------- |\n\n| Applicability: | EC 225 LP helicopters, all serial numbers, equipped with main rotor blade de-icing harnesses part number 42994. |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. Check for correct tightness the five main rotor blade de-icing harness connectors on the slip-ring assembly side, in accordance with the accomplishment instructions of the Eurocopter EC 225 LP Alert Service Bulletin (ASB) 05A006 dated 21 December 2006. |\n| | 2. If not previously accomplished in accordance with European Aviation Safety Agency (EASA) Emergency Airworthiness Directive (EAD) 2007-0012-E for each of the five main rotor blade de-icing harness connectors on the slip-ring assembly side, check that the locking system operates correctly and fit the harness connectors with heat-shrinkable sleeves, as instructed in the accomplishment instructions of the ASB 05A006. |\n| | 3. Check for correct tightness the five main rotor blade de-icing harness connectors on the slip-ring assembly side, in accordance with the accomplishment instructions of ASB 05A006. |\n| | 4. Install a heat-shrinkable sleeve on the harness connector, in accordance with the accomplishment instructions of ASB 05A006. |\n| | Later revisions of ASB 05A006, approved by the EASA, are acceptable for compliance with the relevant parts of this Directive. |\n| | Note: EASA EAD 2007-0012-E refers. |\n| Compliance: | For Requirement 1 - Before each flight from 29 August 2008 (the effective date of this Directive) until compliance with Requirement 2 is achieved. |\n| | For Requirement 2 - Within the next 50 hours time in service (TIS) or 3 months, whichever occurs first, after 29 August 2008. |\n| | For Requirement 3 - Within the next 85 hours TIS after initial compliance with Requirement 2 of this Directive or paragraph 2 of EASA EAD 2007-0012-E or the last compliance with paragraph 3 of EASA EAD 2007-0012-E and thereafter at intervals not to exceed 85 hours TIS. |\n\n| | For Requirement 4 - Each time a main rotor blade de-icing harness connector is disconnected and reconnected. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| | This Airworthiness Directive becomes effective on 29 August 2008. |\n| Background: | An occurrence involving the disconnection of a main rotor blade de-icing harness was covered by Direction Générale de l’Aviation Civile of France (DGAC) ADF-2005-214, issued on 1 February 2006. The de-icing harness connector, which is a screwed-type self-locking connector, was affected by an assembly anomaly of its retaining ring which led to the loss of the locking function.Since then, during a flight-related check, another connector of the main rotor blade de-icing harness was found not fully tightened on the slip-ring assembly side. No case of failure of the connector of the same harness on the blade side has been reported so far to EASA.Regarding the latest case of connector disconnection, investigations revealed that the loss of the locking function is due to the failure of a self-locking spring ring inside the connector. In the event of such a situation, the de-icing function on all main rotor blades is lost, which can be detrimental for the safety of the helicopter flying in icing conditions.Therefore, this Directive is issued in order to prevent untimely disconnection of the incriminated de-icing harness connector. |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n25 August 2008","sortOrder":0},{"sectionNumber":"AD/EC 225/3","sectionType":"part","heading":"AD/EC 225/3","content":"## AD/EC 225/3","sortOrder":1},{"sectionNumber":"Main Rotor Blade De-IcingSystem Harness ","sectionType":"part","heading":"Main Rotor Blade De-IcingSystem Harness Connectors","content":"## Main Rotor Blade De-Icing \nSystem Harness Connectors","sortOrder":2},{"sectionNumber":"11/2008 DM","sectionType":"part","heading":"11/2008 DM","content":"## 11/2008 DM","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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive maintaining its original scope: addressing a specific safety-critical defect in a defined helicopter type. The document remains focused on the single issue of de-icing harness connector failures without expansion into broader systems or aircraft types."},"complexity_factors":["Multiple compliance deadlines with cascading conditions (Requirements 1-4 have interdependent timing)","Cross-references to external documents: Eurocopter Alert Service Bulletin 05A006 and EASA Emergency Airworthiness Directive 2007-0012-E","Technical aviation terminology requiring specialist knowledge (TIS = Time in Service, ASB = Alert Service Bulletin, slip-ring assembly)","Conditional logic: Requirement 1 applies only until Requirement 2 is completed; Requirement 3 timing depends on prior compliance with this AD or the EASA directive","Specific part number applicability (42994) requiring technical records verification"],"plain_english_summary":"This mandatory CASA Airworthiness Directive requires owners and operators of Eurocopter EC225 LP helicopters (and their maintenance teams) to inspect and modify the main rotor blade de‑icing electrical connectors because a faulty self‑locking spring ring can let connectors loosen or disconnect. \n\nIt mandates recurring pre‑flight and maintenance checks plus a temporary protective fix until a permanent remedy is installed — preventing in‑flight loss of blade de‑icing that could lead to dangerous icing and loss of control."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive remains narrowly focused on preventing untimely disconnection of the main rotor blade de-icing harness connector on EC 225 LP helicopters fitted with harness P/N 42994. It implements inspection, minor modification (heat-shrink sleeve) and recurring checks consistent with the original safety objective identified in the background. There is no material expansion beyond that original safety remediation purpose."},"complexity_factors":["4 distinct operative requirements with sequencing and conditionality (Requirements 1–4)","Cross-references to external technical documents: Eurocopter ASB 05A006 and EASA EAD 2007-0012-E","Multiple compliance timeframes and recurrence: pre-flight until corrective action, 50 flight hours or 3 months (first corrective window), 85 flight hours recurring interval","Applicability limited to a specific airframe model and a specific part number (EC 225 LP, harness P/N 42994)","Acceptance clause for later ASB revisions approved by EASA (introduces a delegated update path)","Operational conditional: Requirement 2 applies only if Requirement 2 actions were not previously accomplished under the referenced EAD","Action trigger for Requirement 4 tied to connector disconnection/reconnection events (event-driven compliance)"],"plain_english_summary":"**What this directive does**\n\n- Requires inspections and minor modifications to the main rotor blade de-icing harness connectors on certain Eurocopter EC 225 LP helicopters (those fitted with de-icing harness part number 42994). The actions are intended to prevent the harness connector becoming untimely disconnected and the loss of blade de-icing.\n\n**Who it affects**\n\n- Owners and operators of Eurocopter EC 225 LP helicopters with de-icing harness part number 42994. Maintenance organisations and licensed engineers who service those helicopters must carry out the work.\n\n**Key mechanical requirements (how it works)**\n\n1. Before each flight (from the effective date until a one-time corrective action is done) the five de-icing harness connectors on the slip‑ring assembly side must be checked for correct tightness, following the instructions in Eurocopter EC 225 LP Alert Service Bulletin (ASB) 05A006 (dated 21 December 2006).\n\n2. If the corrective action required by the referenced EASA Emergency Airworthiness Directive (EAD 2007-0012-E) has not already been done, then within 50 flight hours or 3 months (whichever is first) each of the five connectors on the slip‑ring assembly side must have their locking system checked and be fitted with heat‑shrinkable sleeves, again following the ASB instructions.\n\n3. After the initial corrective action, a recurring inspection for correct tightness of the same five connectors must be done within 85 flight hours after the initial compliance and thereafter at intervals not to exceed 85 flight hours.\n\n4. Whenever a de-icing harness connector is disconnected and reconnected, a heat‑shrinkable sleeve must be installed on that connector as instructed in the ASB.\n\n- Later revisions of ASB 05A006 approved by EASA are acceptable for compliance with the directive.\n\n**Why it matters (purpose claim and practical test)**\n\n- The directive is issued because investigation found that a self‑locking spring ring inside the screwed-type connector can fail or be assembled incorrectly, causing the connector to lose its locking function and potentially disconnect. If a connector on the slip‑ring assembly side disconnects in flight, the de-icing function for all main rotor blades can be lost. The directive’s stated purpose is to prevent those untimely disconnections (this is the regulator’s claim).\n\n- Mechanisms used to pursue that purpose: repeated tightness checks, an initial fitment of heat‑shrink sleeves and locking‑function checks, and recurring inspections. These are low‑technology mitigations (inspection + simple physical retention sleeves) rather than wholesale replacement of the connector design.\n\n**Who pays and who decides**\n\n- Costs fall on operators/owners (labour for pre‑flight and scheduled inspections, cost and supply of heat‑shrink sleeves, potential grounding time). Approved maintenance organisations and licensed engineers decide and carry out the physical checks and sleeve installations, using the ASB as the technical method. The regulator accepts later ASB revisions approved by EASA, so the technical standard can be updated without changing the directive.\n\n**Compliance burden, risks and trade-offs**\n\n- Compliance imposes recurring labour and some operational downtime (frequent tightness checks until the sleeve/locking check is completed, then 85‑hour recurring checks). There is also a one-time cost and ongoing practice to install heat‑shrink sleeves whenever connectors are disconnected/reconnected.\n\n- The inspections rely on visible/tactile checks of connector tightness and locking function. If the failure mode is an internal spring ring failure not visible without partial disassembly, inspection risk exists (false negatives). If internal replacement of failed components is required, that increases cost, parts demand and potential aircraft downtime.\n\n- The directive targets a specific part number and a specific connector location (slip‑ring assembly side), so the actions are narrowly focused rather than fleet‑wide design changes. That narrows direct costs to affected EC 225 LPs with that harness but concentrates those costs on that operator subset.\n\n**Practical effect on operators and maintenance providers**\n\n- Operators must schedule and resource additional pre‑flight and maintenance checks, ensure availability of heat‑shrink sleeves (and any parts or tooling specified by the ASB), and update maintenance procedures to capture the recurring 85‑hour inspection and sleeve installation on reconnection.\n\n- Independent maintenance organisations that service EC 225 LP helicopters will perform this work under existing maintenance approvals; the directive does not change who may perform the work but does increase billable maintenance activity for affected helicopters.\n\n(Referenced material: Eurocopter EC 225 LP Alert Service Bulletin 05A006 (21 Dec 2006); EASA Emergency Airworthiness Directive EAD 2007-0012-E.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-ec-225-3-main-rotor-blade-de-icing-system-harness-connectors","history":"/api/acts/ad-ec-225-3-main-rotor-blade-de-icing-system-harness-connectors/history","analysis":"/api/acts/ad-ec-225-3-main-rotor-blade-de-icing-system-harness-connectors/analysis","conflicts":"/api/acts/ad-ec-225-3-main-rotor-blade-de-icing-system-harness-connectors/conflicts","importantCases":"/api/acts/ad-ec-225-3-main-rotor-blade-de-icing-system-harness-connectors/important-cases","documents":"/api/acts/ad-ec-225-3-main-rotor-blade-de-icing-system-harness-connectors/documents"}}