{"id":"F2006B09378","name":"AD/ECUREUIL/75 - Switching Unit","slug":"ad-ecureuil-75-switching-unit","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53676,"registerId":"commonwealth-F2006B09378-current","compilationNumber":null,"startDate":"2026-04-02","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\nEurocopter AS 350 (Ecureuil) Series Helicopters","sortOrder":0},{"sectionNumber":"AD/ECUREUIL/75 Switching Unit 5/2002","sectionType":"part","heading":"AD/ECUREUIL/75 Switching Unit 5/2002","content":"# AD/ECUREUIL/75 Switching Unit 5/2002\n\nApplicability: Eurocopter AS 350 B3 helicopters incorporating a switching unit part number (P/N) 200192 and delivered prior to 15 October 2001.\n\nRequirement: 1. Carry out a once only inspection for tightness of the wire harness passing through the transmission deck above the switching unit and for the presence of water in the switching unit in accordance with Eurocopter Alert Service Bulletin Number 76.00.16.P5.\n\n2. The requirements of this Directive are to be entered on the aircraft maintenance release as maintenance required and a copy of this Directive is to be attached to the Aircraft Log Book.\n\nCompliance with Requirement 1 of this Directive constitutes terminating action for this Directive, and Requirement 2 can be cancelled when Requirement 1 has been accomplished.\n\nNote: DGAC Airworthiness Directive 2001-548-084 refers.\n\nCompliance: Prior to flight in icing conditions or prior to 100 hours time in service from the effective date of this Directive, whichever occurs first.\n\nThis Airworthiness Directive becomes effective on 16 May 2002.\n\nBackground: This Directive has been issued to address reports of water entering the switching unit and freezing. In the event of water in the switching unit freezing, the twist grip may jam and prevent manual engine governing in the event of the automatic engine governing system failing.\n\n![Signature of Eugene Paul Holzapfel, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 3 April 2002\n\n![](image.001.png)","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument remains narrowly focused on a single unsafe condition (water ingress and freezing in a particular switching unit) affecting a defined set of helicopters (AS350 B3 with switching unit P/N 200192 delivered before 15 October 2001). It imposes a one‑time inspection and a temporary administrative entry. It does not expand beyond that original safety objective or add ongoing operational restrictions, new certification requirements, or broader applicability."},"complexity_factors":["Short, single‑issue instrument (one page length equivalent).","Single helicopter type and a single affected part number (Eurocopter AS350 B3; switching unit P/N 200192).","Two substantive requirements only: one one‑time inspection and an administrative recording requirement.","One conditional timing rule (prior to flight in icing conditions or within 100 hours, whichever occurs first).","Cross‑references to an external manufacturer service bulletin (Eurocopter Alert Service Bulletin No. 76.00.16.P5) and to a DGAC AD (2001-548-084) increase dependency on external documents but do not add internal complexity.","A terminating action clause (Requirement 1 ends the AD) simplifies ongoing compliance.","Few defined terms and no nested exceptions."],"plain_english_summary":"**What this instrument does (mechanics):**\n\n- Applies to Eurocopter AS350 B3 helicopters that have switching unit part number (P/N) 200192 and were delivered before 15 October 2001 (see \"Applicability\").\n- Requires a one‑time inspection, following Eurocopter Alert Service Bulletin No. 76.00.16.P5, to check:\n  - whether the wire harness that passes through the transmission deck above the switching unit is secure (tightness); and\n  - whether there is water inside the switching unit (see \"Requirement 1\").\n- Requires the AD to be recorded on the aircraft maintenance release and a copy attached to the aircraft log book (see \"Requirement 2\").\n- States that carrying out Requirement 1 is \"terminating action\" for the AD (i.e. once the inspection is done, the AD’s substantive mandate is satisfied) and that Requirement 2 can be removed after Requirement 1 is completed.\n- Sets the compliance deadline: the inspection must be done before the helicopter next flies in icing conditions, or within 100 hours time in service from the AD’s effective date, whichever comes first (see \"Compliance\").\n- Effective date: 16 May 2002.\n\n**Who this affects:**\n\n- Owners and operators of Eurocopter AS350 B3 helicopters that contain switching unit P/N 200192 and were delivered prior to 15 October 2001.  Maintenance organisations and technicians who perform inspections and record keeping on those helicopters are also affected.\n\n**Why it matters (safety mechanism):**\n\n- The background explains the safety concern: water can enter the switching unit and freeze. If water freezes inside the switching unit, the helicopter’s twist grip (the pilot control used for manual engine governing) may jam, which could prevent manual engine control if the automatic engine governing system fails. The inspection is intended to detect insecure wiring or water intrusion so corrective action can be taken before flight in icing conditions (see \"Background\").\n\n**Practical effects and what must happen:**\n\n- Operators must schedule and perform a one‑off inspection per the Eurocopter service bulletin. If water or insecure wiring is found, maintenance action (repair, drying, sealing, replacement) will be required per the service bulletin or other approved procedures before the helicopter flies in icing conditions.\n- The operator pays for inspection and any corrective work, and must make the required maintenance record entries.\n- Until the inspection is completed, affected helicopters should not be flown in icing conditions (because the compliance deadline is \"prior to flight in icing conditions\").\n\n**Administrative and compliance details (mechanics to watch):**\n\n- The AD cross‑references an external manufacturer document (Eurocopter Alert Service Bulletin No. 76.00.16.P5) and notes a related DGAC Airworthiness Directive (2001-548-084). Compliance therefore depends on following the procedures in the Eurocopter bulletin and on maintenance personnel interpreting and recording the results correctly (see \"Requirement\" and \"Note\").\n- Recording the AD on the maintenance release and attaching a copy to the log book creates an administrative burden (Requirement 2), but that entry can be removed once the inspection (Requirement 1) is completed.\n\n**Costs, incentives and trade‑offs (briefly):**\n\n- Who pays: the aircraft owner/operator bears inspection and any repair costs, and the cost of aircraft downtime while the work is done.\n- Incentives: operators have a clear incentive to complete the inspection promptly to restore unrestricted operation in icing conditions and to avoid regulatory non‑compliance.\n- Trade‑offs and opportunity costs: scheduled maintenance hours and resources will be spent on the inspection and any repairs; those resources are not available for other maintenance or operations during that time.\n- Implementation risk: the AD relies on the Eurocopter service bulletin for the inspection method and corrective actions; inconsistent interpretation or poor workmanship could reduce the measure’s effectiveness.\n\n**Who decides and how enforcement works:**\n\n- The AD is issued by a CASA delegate under subregulation 39.1(1) of CAR 1998; operators must comply with the AD’s requirements and record compliance as required.\n\n(Referenced sections: Applicability; Requirement 1 and 2; Compliance; Background.)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope: addressing a specific unsafe condition (water ingress and freezing) in a specific component (switching unit P/N 200192) on a specific helicopter model (AS 350 B3). There is no evidence of scope creep; the directive remains tightly focused on the original safety issue identified in the background."},"complexity_factors":["Single, specific aircraft model and part number in applicability section","Two straightforward requirements: one technical inspection, one administrative","Clear terminating condition (compliance with Requirement 1 ends the obligation)","Simple compliance timeframe (binary choice: before icing flight OR 100 hours)","No cross-references to other legislation beyond a single service bulletin and a reference to a French aviation directive (DGAC AD 2001-548-084)","No defined terms section","Single background rationale clearly stated"],"plain_english_summary":"This CASA Airworthiness Directive applies to Eurocopter AS 350 B3 helicopters with electrical switching unit PN 200192 delivered before 15 Oct 2001. It mandates a one‑time inspection of wiring near the transmission deck and for water ingress in the switching unit per Eurocopter ASB 76.00.16.P5 (before flying in icing or within 100 FH of 16 May 2002), and requires recording the maintenance and attaching a copy to the logbook. Water ingress can freeze and jam the twist‑grip throttle, risking loss of control; the inspection is terminating action."},"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-ecureuil-75-switching-unit","history":"/api/acts/ad-ecureuil-75-switching-unit/history","analysis":"/api/acts/ad-ecureuil-75-switching-unit/analysis","conflicts":"/api/acts/ad-ecureuil-75-switching-unit/conflicts","importantCases":"/api/acts/ad-ecureuil-75-switching-unit/important-cases","documents":"/api/acts/ad-ecureuil-75-switching-unit/documents"}}