{"id":"F2006B09315","name":"AD/EC 135/1 Amdt 1 - Main Rotor Hub-Shaft","slug":"ad-ec-135-1-amdt-1-main-rotor-hub-shaft","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53443,"registerId":"commonwealth-F2006B09315-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/EC 135/1 Amdt 1 - Main Rotor Hub-Shaft","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)  \n![](image.002.png)  \nEurocopter EC 135 Series Helicopters\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/EC 135/1 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.003.png)AD/EC 135/1\n\nAmdt 1\n\n  \nMain Rotor Hub-Shaft 13/2001\n\nApplicability: All Model EC 135 helicopters equipped with main rotor hub-shaft assembly listed in the Requirement document.\n\nRequirement: Inspect in accordance with Eurocopter Deutschland Alert Service Bulletin EC 135- 62A-004 Revision 3.\n\nNote: LBA AD 1999-185/4 refers.\n\nCompliance: Before further flight after 24 December 1999 for the initial visual inspection, unless already accomplished. Thereafter as specified in the Requirement document.\n\nThe compliance times remain unchanged for this issue. This amendment becomes effective on 27 December 2001.\n\nBackground: Following a recent test run, cracks were detected in the main rotor hub-shaft of an affected helicopter. Initial and repeat inspections are introduced that are intended to prevent fracture of the main rotor hub-shaft, which could result in loss of control of the helicopter.\n\nAmendment 1 is issued in response to a revision of the related LBA AD which introduces the latest revision of the Requirement document. This revision corrects the dimension defining the inspection area and limits the components affected.\n\nThe original issue of this Airworthiness Directive became effective on 24 December 1999.\n\n![Signature of David Villiers, Delegate of the Civil Aviation Safety Authority.](image.004.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 8 November 2001\n\n![](image.002.png)\n\nThe above AD is notified in the Commonwealth of Australia Gazette on 5 December 2001.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 1 narrows and clarifies the original AD’s scope. The amendment updates the Requirement document (Eurocopter ASB Revision 3) to correct the dimension that defines the inspection area and to limit which hub‑shaft components are treated as affected. Mechanically, that reduces the set of parts and helicopters subject to the AD compared with the original issue (original AD effective 24 December 1999); compliance timing remains unchanged but the universe of affected components is smaller as a result of the amendment."},"complexity_factors":["Single narrow technical requirement (inspection) rather than multiple obligations","One referenced technical document: Eurocopter Deutschland Alert Service Bulletin EC 135‑62A‑004 Revision 3","Clear, limited applicability: only EC 135 helicopters with listed hub‑shaft assemblies","Simple compliance timing: initial inspection before next flight after a fixed date, then as per ASB","Moderate cross‑references: refers to LBA AD and CAR 1998 subreg 39.1(1) but does not create complex conditional logic or nested exceptions","Amendment modifies a measurement/dimension and list of affected components, adding a minor technical change that requires careful reading of the ASB"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Revokes the earlier AD/EC 135/1 and issues Amendment 1 that requires specific inspections of the main rotor hub‑shaft on certain Eurocopter EC 135 helicopters.\n- The inspections must be carried out in accordance with Eurocopter Deutschland Alert Service Bulletin EC 135‑62A‑004 Revision 3 (the “Requirement document”).\n- Initial visual inspection: must be done before the next flight after 24 December 1999 if it has not already been completed. Repeat inspections are to be done at the intervals and in the manner specified in the Requirement document.\n- Amendment 1 updates the Requirement document by correcting the dimension that defines the inspection area and by narrowing which hub‑shaft components are covered.\n\n**Who this affects**\n\n- Owners and operators of Eurocopter EC 135 helicopters that have the main rotor hub‑shaft assemblies listed in the Requirement document.\n- Maintenance organisations and engineers who perform the required inspections and any necessary repairs or part replacements.\n- Regulators (the Civil Aviation Safety Authority — CASA) in their role enforcing compliance under CAR 1998, subregulation 39.1(1).\n\n**Why it matters (stated purpose and mechanical effect)**\n\n- The AD arises because cracks were found in a main rotor hub‑shaft after a test run. The stated safety objective is to detect cracks early to prevent a hub‑shaft fracture, which could result in loss of helicopter control. (Background section.)\n\n**Costs, incentives and trade‑offs**\n\n- Who pays: Operators bear the direct costs — labour for inspections, potential grounding/downtime, and any parts and replacement work if defects are found.\n- Who decides how to comply: CASA mandates the inspection requirement, but the technical method is specified by the manufacturer’s Alert Service Bulletin (ASB). That delegates the detailed inspection technique and intervals to the manufacturer’s document (Requirement document).\n- Compliance burden: An immediate (pre‑flight) visual inspection obligation for affected units and ongoing repeat inspections according to the ASB. This can disrupt operations and scheduled maintenance.\n- Market effects: Demand for inspection labour and for replacement hub‑shafts/parts will be concentrated on operators of the EC 135 and, where specialised, on suppliers able to meet the ASB requirements. Independent maintenance organisations can perform the work provided they follow the ASB and regulatory approvals.\n- Risks and trade‑offs: Relying on the manufacturer’s ASB centralises technical procedures with the manufacturer’s specification (measurement dimension and affected parts are controlled by the ASB). The amendment narrows the list of affected components and corrects the inspection area, which reduces the number of units treated as at risk compared with the original AD (see Amendment 1). Implementation risk includes possible misinterpretation of the corrected inspection dimension and the operational cost of additional inspections or part replacement if cracks are found.\n\n**Concrete behavioural change required**\n\n- Affected operators must schedule and perform the specified visual inspection before flying the helicopter (if not yet done) and thereafter at the intervals described in the ASB; if cracks or other defects are found, standard maintenance/repair procedures must be followed (which may include grounding and part replacement).\n\n**Source mechanics (where in the AD this is set out)**\n\n- Applicability: identifies the EC 135 helicopters and hub‑shaft assemblies covered.\n- Requirement: mandates inspection in accordance with Eurocopter Alert Service Bulletin EC 135‑62A‑004 Revision 3.\n- Compliance: sets the initial inspection deadline (before next flight after 24 December 1999) and defers repeat interval details to the Requirement document.\n- Background and Amendment 1: explain why the AD was issued (cracks found) and that the amendment corrects the inspection area dimension and narrows affected components.\n\n(Plain factual note: the AD’s stated safety purpose is to prevent hub‑shaft fracture and consequent loss of control. The measure imposes inspection costs and possible repair/replacement costs on operators while delegating the technical inspection procedure and intervals to the manufacturer’s ASB.)"},"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 amendment remains tightly scoped to its original purpose: preventing main rotor hub-shaft fractures in EC 135 helicopters. The amendment narrows rather than expands scope—limiting affected components and correcting inspection dimensions—while maintaining the same safety objective and compliance timeframe as the original 1999 directive."},"complexity_factors":["Short, single-purpose instrument (approximately 250 words)","Only 2 defined applicability criteria (helicopter model + specific assembly)","Single requirement referencing external technical document (Eurocopter Alert Service Bulletin)","Simple compliance structure: one-time initial inspection + recurring inspections per external schedule","No nested exceptions or conditional logic beyond the 'unless already accomplished' clause","Cross-reference to one foreign aviation directive (LBA AD 1999-185/4) and one external technical standard"],"plain_english_summary":"This CASA safety order for Eurocopter EC135 helicopters with a specific main rotor hub‑shaft revokes the earlier AD/EC 135/1 and requires inspections per the Eurocopter service bulletin after cracks were found in testing — an initial visual check was required before any flight after 24 Dec 1999, with repeats per the bulletin. Amendment 1 aligns with the LBA update, refines the inspection area and narrows affected parts. Effective 27 Dec 2001; applies to owners, operators and maintenance engineers."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ec-135-1-amdt-1-main-rotor-hub-shaft","history":"/api/acts/ad-ec-135-1-amdt-1-main-rotor-hub-shaft/history","analysis":"/api/acts/ad-ec-135-1-amdt-1-main-rotor-hub-shaft/analysis","conflicts":"/api/acts/ad-ec-135-1-amdt-1-main-rotor-hub-shaft/conflicts","importantCases":"/api/acts/ad-ec-135-1-amdt-1-main-rotor-hub-shaft/important-cases","documents":"/api/acts/ad-ec-135-1-amdt-1-main-rotor-hub-shaft/documents"}}