{"id":"F2006B09364","name":"AD/ECUREUIL/58 - Single-Pole Circuit Breakers","slug":"ad-ecureuil-58-single-pole-circuit-breakers","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53632,"registerId":"commonwealth-F2006B09364-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/ECUREUIL/58 - Single-Pole Circuit Breakers","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nEurocopter AS 350 (Ecureuil) Series Helicopters\n\nAD/ECUREUIL/58 Single-Pole Circuit Breakers 3/99\n\nApplicability: Model AS 350 helicopters, versions B, BA, BB, B2, B3 and D equipped with the following single-pole circuit breakers manufactured by Crouzet:\n\n| Location                                       | Rating  | Part Number |\n| ---------------------------------------------- | ------- | ----------- |\n| Emergency Flotation Gear Optional Installation | 5 Amp   | 84 400 032  |\n|                                                | 10 Amp  | 84 400 034  |\n| Other Optional Installations                   | 1 Amp   | 84 400 028  |\n|                                                | 3 Amp   | 84 400 031  |\n|                                                | 7.5 Amp | 84 400 033  |\n|                                                | 15 Amp  | 84 400 035  |\n|                                                | 20 Amp  | 84 400 036  |\n\nTwo types of Crouzet circuit breakers may have been delivered under Eurocopter Part Number (P/N) 704A36-6120-XXX (X indicates any digit). These circuit breakers are either P/N 84 400 XXX or SP4696-XX. This Directive is only applicable to P/N 84 400 XXX circuit breakers.\n\nNote 1: The circuit breakers are known to be installed on helicopters delivered between 24 April 1995 and 31 August 1996. The circuit breakers may also be installed on helicopters delivered prior to 24 April 1995 or after 31 August 1996 if circuit breakers have been replaced on optional installations since 24 April 1995 or if an optional installation was fitted between 24 April 1995 and 31 August 1996.\n\nRequirement: 1. Check the functioning of all circuit breakers, listed in the above table, that are fitted to installations listed in paragraph 1D1 of Eurocopter AS 350 Mandatory Service Bulletin (SB) 01.00.47 date code 98-47.\n\n    2. Apply the procedures detailed in paragraph 2B of the SB to all the circuit breakers for the remaining installations.\n\n    3. Test each circuit breaker held as spares that has a part number listed in this airworthiness directive, by applying a torque load and checking the circuit breaker in accordance with the directions given in paragraphs 2B(1) and 2B(2) of the SB.\n\n    4. The use of circuit breakers bearing the part numbers listed in this Airworthiness Directive is prohibited.\n\nNote: DCAG AD 98-511-074(A) refers.\n\nCompliance: 1. Within 200 hours time in service but no later than 26 June 1999.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n    2. Prior to 1 January 2000.\n\n    3. Prior to installation.\n\n    4. From 31 December 1999.\n\nThis Airworthiness Directive becomes effective on 25 March 1999.\n\nBackground: This AD is issued to check for any loss of electrical continuity for single-pole circuit breakers bearing the part numbers listed. During testing by the OEM a loss of electrical continuity was discovered between the terminals of the circuit breaker in the engaged position. This loss was found to be due to deterioration of the circuit breaker operation brought about by excessive torque loading during installation.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD text does not indicate any change to the original scope. It limits applicability to specified Crouzet P/Ns (84 400 XXX) on listed AS350 variants, notes delivery-date considerations for installations, and prescribes inspections, tests and a prohibition; no expansion or narrowing of scope is stated in the instrument."},"complexity_factors":["Technical specificity: precise part numbers, ratings and helicopter models must be identified for applicability","Cross-references: requires use of Eurocopter Mandatory Service Bulletin (SB 01.00.47) and refers to DCAG AD 98-511-074(A)","Multiple compliance actions and deadlines: in-service checks, SB procedures, spare testing, and a prohibition on use with differing due dates","Identification ambiguity: two circuit-breaker types may share an OEM part number string (704A36-6120-XXX) but only one internal P/N series (84 400 XXX) is subject to the AD","Operational testing requirement: spares must be torque-tested per SB directions, imposing hands-on labour and test-equipment needs"],"plain_english_summary":"This Airworthiness Directive requires operators of Eurocopter AS350 (B/BA/BB/B2/B3/D) helicopters fitted with specified Crouzet single‑pole circuit breakers (listed part numbers) to inspect and function‑test those breakers, apply the Eurocopter service bulletin procedures for remaining installations, test spares under a torque load, and cease using the listed part numbers.\n\nCASA issued the AD after OEM testing found loss of electrical continuity in the engaged position caused by deterioration from excessive installation torque; the AD sets specific compliance deadlines for checks, spare testing and the prohibition of use."},"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":3,"scope_assessment":{"changed":false,"description":"This is a standard, targeted airworthiness directive addressing a specific safety defect in specific aircraft components. The scope remains tightly focused on the identified circuit breaker fault and does not extend beyond the original safety purpose."},"complexity_factors":["Multiple compliance deadlines (4 separate timelines)","Cross-reference to external technical document (Eurocopter Service Bulletin 01.00.47)","Specific part number identification required (distinguishing between two manufacturer part number series)","Conditional applicability based on delivery dates and replacement history","Different procedures required for different installation locations (emergency flotation vs other optional installations)"],"plain_english_summary":"This CASA Airworthiness Directive orders owners/operators of Eurocopter AS350 (B/BA/BB/B2/B3/D) helicopters to inspect, test and replace certain Crouzet single‑pole circuit breakers (installed/replaced Apr 1995–Aug 1996). Required actions (inspections, testing of spares, and eventual removal from service by 31 Dec 1999) address breakers that may fail from over‑tightening and cause unexpected electrical power loss, protecting critical systems in flight."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ecureuil-58-single-pole-circuit-breakers","history":"/api/acts/ad-ecureuil-58-single-pole-circuit-breakers/history","analysis":"/api/acts/ad-ecureuil-58-single-pole-circuit-breakers/analysis","conflicts":"/api/acts/ad-ecureuil-58-single-pole-circuit-breakers/conflicts","importantCases":"/api/acts/ad-ecureuil-58-single-pole-circuit-breakers/important-cases","documents":"/api/acts/ad-ecureuil-58-single-pole-circuit-breakers/documents"}}