{"id":"F2006B09365","name":"AD/ECUREUIL/59 Amdt 4 - Tail Rotor Hub Pitch Change Bearings","slug":"ad-ecureuil-59-amdt-4-tail-rotor-hub-pitch-change-bearings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53637,"registerId":"commonwealth-F2006B09365-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/ECUREUIL/59 Amdt 4 - Tail Rotor Hub Pitch Change Bearings","content":"![](image.001.png)\n\n![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/ECUREUIL/59 Amdt 3 and issues the following 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\n![](image.001.png)\n\nEurocopter AS 350 (Ecureuil) Series Helicopters\n\nAD/ECUREUIL/59\n\nAmdt 4\n\n  \nTail Rotor Hub Pitch Change Bearings 13/2002\n\nApplicability: AS 350 helicopters versions B, BA, B1, B2, B3, BB and D fitted with tail rotor pitch change plate, P/N’s 350A33-2004-00/-01/-02/-03/-05 or 350A33-2009-00/-01, and not incorporating Mod 076551 or Eurocopter AS 350 Service Bulletin No.\n\n65.00.38R1.\n\nRequirement: 1. Check the rotational torque of the tail rotor pitch change plate bearing in accordance with paragraph 2.B (1) of Eurocopter Alert Service Bulletin (ASB) No. 05.00.29 Revision 3.\n\n    2. Carry out the axial play, friction point and brinelling check in accordance with paragraph 2.B (2) of Eurocopter Alert Service Bulletin (ASB) No. 05.00.29 Revision 3.\n    3. Before installation of a spare pitch change plate assembly carry out the requirement s of paragraphs 2.B 1 and 2.B 2 of Eurocopter Alert Service Bulletin (ASB) No. 05.00.29 Revision 3.\n\n    4. Disposition of components subject to the inspections as required by Items 1 \\- 3 of this Directive shall be in accordance with paragraph 2.B 3 of Eurocopter Alert Service Bulletin (ASB) No. 05.00.29 Revision 3.\n\nNote 1: DGAC AD 1999-085-076(A) R3 refers.\n\nNote 2: Incorporation of Eurocopter Service Bulletin AS 350 65.00.38.P5 constitutes terminating action for this Directive.\n\nCompliance: 1. Unless previously accomplished within 10 flying hours after 31 October 2002.\n\n    2. At intervals not to exceed 50 flying hours from the previous check (without exceeding 6 months between two checks).\n    3. Prior to installation of a tail rotor pitch change plate assembly or a tail rotor gearbox assembly.\n    4. During compliance with Requirements 1, 2, or 3, as applicable.\n\nThe compliance times of Amendment 3 of this Directive remain unchanged by this issue.\n\nEurocopter AS 350 (Ecureuil) Series Helicopters\n\nAD/ECUREUIL/59 (continued)\n\nThis Amendment becomes effective on 26 December 2002.\n\nBackground: In service reports have revealed deterioration of the tail rotor hub pitch change plate bearing which could have to the seizure of the bearing and loss of control of the aircraft. This Directive introduces measures to check for correct rotational torque, and regular maintenance checks to ensure the integrity of the assembly.\n\nAmendment 1 was issued to correct Compliance Statement 2 to reflect the DGAC repetitive inspection requirements and to include the more stringent compliance requirements of DGAC 1999-085-076(A) R1 dated 14 May 1999.\n\nAmendment 2 provides terminating action for this Directive and adds reference to disposition of components subject to the required inspections.\n\nAmendment 2 of this Airworthiness Directive became effective on 15 June 2000.\n\nAmendment 3 was been issued to reflect replacement of Eurocopter Service Bulletin No. 05.00.29 R2 with Eurocopter Alert Service Bulletin No. 05.00.29 Revision 3.\n\nThe Service Bulletin was updated to Alert status with no change to the technical content of the Service Bulletin.\n\nAmendment 3 of this Airworthiness Directive became effective on 31 October 2002.\n\nAmendment 4 of this Airworthiness Directive is raised to correct a typographical error in Amendment 3.\n\nThe original issue of this Airworthiness Directive became effective on 20 May 1999.\n\n![Signature of James Coyne, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nJames Coyne\n\nDelegate of the Civil Aviation Safety Authority 18 November 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 4 December 2002.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"Scope has not changed. Amendment 4 corrects a typographical error in Amendment 3 and leaves the substance and compliance times unchanged ('Amendment 4 of this Airworthiness Directive is raised to correct a typographical error'; 'The compliance times of Amendment 3 of this Directive remain unchanged by this issue'). The directive continues to require the inspections and disposition procedures introduced to address bearing deterioration and the risk of seizure."},"complexity_factors":["Multiple external references: Eurocopter Alert Service Bulletin No. 05.00.29 Revision 3 and Eurocopter Service Bulletin AS 350 65.00.38.P5 (terminating action).","Applicability defined by several helicopter sub‑variants and enumerated part numbers, with exclusions (Mod 076551 or AS 350 Service Bulletin No. 65.00.38R1).","Mixture of one‑off and repetitive obligations: initial check within 10 flight hours, recurring checks every 50 flight hours but not exceeding 6 months.","Pre‑installation inspection requirement for spare pitch change plate and tail rotor gearbox assemblies.","Disposition decisions (removal/repair/scrap) are controlled by an external paragraph (2.B.3) of the ASB.","Administrative complexity from successive amendments and cross‑references to prior DGAC ADs and earlier amendment compliance times.","Potential operational impact on maintenance scheduling and spare‑parts management for operators."],"plain_english_summary":"This Airworthiness Directive requires inspections and tests of the tail-rotor pitch-change plate bearing on specified Eurocopter AS350 variants—measuring rotational torque and checking axial play, friction point and brinelling, including checks before installing spare pitch-change plate assemblies. It mandates disposition of suspect components in accordance with Eurocopter Alert Service Bulletin No. 05.00.29 Revision 3 and sets recurring inspection intervals. It applies to operators and maintenance organisations using the listed part numbers, who bear the inspection and remediation costs; CASA states the aim is to prevent bearing seizure and loss of control."},"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 legislation maintains its original narrow scope. It is a technical aviation safety directive focused specifically on tail rotor bearing inspections for one helicopter series. Amendment 4 explicitly states it only corrects a typographical error from Amendment 3, with no expansion of regulatory reach or substantive change to requirements."},"complexity_factors":["Multiple cross-references to external technical documents (Eurocopter Alert Service Bulletin No. 05.00.29 Revision 3) without reproducing their content","Nested applicability conditions: specific helicopter versions AND specific part numbers AND exclusion of modified aircraft","Four distinct compliance timelines with different triggers (flying hours, calendar dates, installation events, and 'as applicable' references)","Technical aviation terminology requiring specialised knowledge (brinelling, axial play, pitch change plate, terminating action)","Amendment history references (Amendments 1-4) that contextualise but don't alter current requirements"],"plain_english_summary":"This CASA safety order forces owners/operators of certain Eurocopter AS350 (Squirrel) helicopters with specified tail‑rotor pitch change plates to inspect and torque‑test the pitch change bearings and perform recurring checks for play, friction and brinelling, plus inspect spares before fitment. It targets aircraft without a specific factory upgrade because bearing failures have caused loss of control. This amendment only corrects a typographical error from the prior update; the safety requirements are unchanged."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ecureuil-59-amdt-4-tail-rotor-hub-pitch-change-bearings","history":"/api/acts/ad-ecureuil-59-amdt-4-tail-rotor-hub-pitch-change-bearings/history","analysis":"/api/acts/ad-ecureuil-59-amdt-4-tail-rotor-hub-pitch-change-bearings/analysis","conflicts":"/api/acts/ad-ecureuil-59-amdt-4-tail-rotor-hub-pitch-change-bearings/conflicts","importantCases":"/api/acts/ad-ecureuil-59-amdt-4-tail-rotor-hub-pitch-change-bearings/important-cases","documents":"/api/acts/ad-ecureuil-59-amdt-4-tail-rotor-hub-pitch-change-bearings/documents"}}