{"id":"F2006B04318","name":"AD/BELL 204/10 Amdt 1 - Tail Rotor Blade Grip","slug":"ad-bell-204-10-amdt-1-tail-rotor-blade-grip","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44133,"registerId":"commonwealth-F2006B04318-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 204/10 Amdt 1 - Tail Rotor Blade Grip","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)  \nBell Helicopter Textron 204 Series Helicopters\n\nAIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/BELL 204/10 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\nAD/BELL 204/10\n\nAmdt 1\n\n  \nTail Rotor Blade Grip 8/2000\n\nApplicability: All models 204 fitted with tail rotor hub P/N 204-011-801-5 or \\-7; or P/N 204-011- 701-11 or -13 or -19.\n\nRequirement: Inspect the P/N 204-011-728 or P/N 204-011-706 tail rotor blade grip assemblies for minimum hardness of:\n\n    Rockwell 79 on \"B\" Scale or\n\n    b. below a conductivity of 39 on the international annealed copper standard.\n\nReading should be taken adjacent top the vibro etched serial number between the blade retention bolts and the grip face.\n\nThe test may be accomplished using a Rockwell Hardness tester or Eddy Current tester Magnates FM120 or equivalent.\n\nNote: FAA AD 70-6-2 refers.\n\nCompliance: Before further flight after 3 March 1970, and before installation on an aircraft.\n\nThis Amendment becomes effective on 10 August 2000.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nBackground: This Directive was initially issued to prevent failure of the Subject grip assemblies.\n\nAmendment 1 is issued to provide the country of manufacture AD reference, and to prevent any existing deficient grips from returning to service. It also follows the re- introduction of the AD Series after sixteen years.\n\nThe original issue of this Airworthiness Directive became effective on 3 March 1970.\n\n![](image.003.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 6 July 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 12 July 2000.","sortOrder":0}],"analysis":{"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"},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"Amendment 1 clarifies and restates the original AD from 1970 — it adds a reference to the country-of-manufacture (FAA) AD and explicitly aims to prevent deficient grips from being returned to service. It does not extend the population of affected parts, add new testing regimes beyond the two authorised methods, or otherwise broaden obligations materially beyond the original safety objective (preventing grip failure). Therefore the scope has not significantly changed from the original purpose; the amendment chiefly clarifies references and re‑issues the directive."},"complexity_factors":["Short, single-subject Airworthiness Directive (one component: tail rotor blade grip)","Limited number of affected part numbers (5 hub P/Ns; 2 grip P/Ns)","Two alternative test methods authorized (Rockwell hardness or eddy‑current conductivity)","Straightforward compliance timing (before next flight / before installation)","One cross-reference to an external FAA AD (FAA AD 70-6-2)","No separate definitions section or nested exceptions","Minor ambiguity in the published conductivity phrasing (\"below a conductivity of 39\"), which may require technical clarification"],"plain_english_summary":"**What this instrument does (mechanically)\n\n- Applies to: Bell Helicopter Textron 204 series helicopters fitted with any of these tail rotor hub part numbers: 204-011-801-5, 204-011-801-7, 204-011-701-11, 204-011-701-13, or 204-011-701-19. (See \"Applicability\".)\n\n- Requires: an inspection of the tail rotor blade grip assemblies (part numbers 204-011-728 or 204-011-706) to verify they meet a specified minimum hardness. The check may be done either with a Rockwell hardness tester (target: Rockwell 79 on the B scale) or by an eddy-current conductivity test (threshold described as \"below a conductivity of 39 on the international annealed copper standard\"). Readings must be taken adjacent to the vibro‑etched serial number between the blade retention bolts and the grip face. (See \"Requirement\".)\n\n- Test equipment authorised: Rockwell Hardness tester or Eddy Current tester Magnates FM120 or equivalent.\n\n- Timing (Compliance): the inspection must be done before the next flight after 3 March 1970, and before any grip is installed on an aircraft. (See \"Compliance\".)\n\n- Administrative detail: this Amending AD (Amendment 1) became effective 10 August 2000 and explicitly references the relevant foreign (manufacturer/country of origin) AD. The stated background purpose is to prevent failure of the grips and to stop any existing deficient grips from returning to service. (See \"Background\".)\n\nWho this affects\n\n- Aircraft operators and owners of Bell 204 helicopters fitted with the listed tail rotor hub part numbers — they must ensure affected grip assemblies are inspected and that non‑compliant grips are not installed.\n\n- Maintenance organisations, repair stations and licensed maintenance personnel — they carry out the hardness/conductivity tests and decide whether a grip is airworthy or must be removed/replaced.\n\n- Parts suppliers and overhaul providers — if a grip fails the test it must be replaced; providers must supply grips that meet the specified test criteria.\n\nWhy it matters (stated purpose and operational effects)\n\n- The stated safety purpose is to prevent failure of the tail rotor blade grip assemblies, which are critical for tail rotor integrity (Background and Requirement). The mechanical effect is to create a mandatory inspection gate: grips must be proven to meet a minimum hardness or conductivity standard before a helicopter with the listed hubs flies or before a grip is installed.\n\nPractical implications, costs and incentives\n\n- Who pays: aircraft operators and maintenance providers bear direct costs — the cost of testing (or contracting testing), downtime while inspections are done, and replacement cost if grips fail.\n\n- Who decides: CASA (via the delegate who issued the AD) sets the requirement; operators and qualified maintenance personnel carry out the inspection and decide (based on the test result) whether a grip stays in service.\n\n- Behaviour changes required: routine verification (hardness or conductivity) of affected grips; removal and replacement of any grips that fail the test; recordkeeping to show compliance before next flight or before fitment.\n\n- Trade-offs and implementation risks: the AD imposes a straightforward technical test but requires access to appropriate test equipment (Rockwell hardness tester or an approved eddy‑current tester), trained personnel, and clear interpretation of test results. If grips are scarce, operators face operational disruption and potential aircraft grounding until compliant parts are obtained. The AD cross‑references an FAA AD (70-6-2), which operators may need to consult for further technical detail.\n\nNotes on wording and interpretation\n\n- The AD gives the two alternative test methods (Rockwell hardness or eddy‑current conductivity) but the conductivity threshold language in the published text is terse (\"below a conductivity of 39 on the international annealed copper standard\"). Operators and maintenance organisations will typically treat the requirement as: confirm the grip meets at least the stated hardness standard, using an approved alternative (eddy‑current) measure where indicated. If there is uncertainty about how to interpret the conductivity threshold, maintenance organisations should rely on the FAA reference or manufacturer guidance, or seek CASA clarification.\n\nOfficial purpose claim and testing of that claim\n\n- Official claim: the AD exists to prevent failure of the subject grip assemblies and to stop deficient grips being reinstalled (Background). Mechanically, the AD enforces that claim by creating a mandatory pre‑flight and pre‑installation check of grip hardness/conductivity.\n\n- Testing the claim against costs and incentives: the test is narrow and targeted (single component, fixed test methods). Costs fall on operators and maintenance providers (testing time, replacement parts, possible grounding). The incentive for operators is to avoid groundings and maintain airworthiness by testing or replacing suspect grips. The AD does not create ongoing recurring regulatory obligations beyond the inspection gate (unless grips are replaced or reinstalled), so its burden is concentrated on operators who possess affected grips; the broader fleet is not newly regulated unless it uses the specified parts.\n\nRelevant sections cited: Applicability; Requirement; Compliance; Background; effective date (Amendment 1 effective 10 August 2000)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope of the 1970 directive. The changes are administrative: adding the FAA reference number, ensuring defective grips don't return to service, and reissuing the directive after a 16-year gap in the AD series. The core safety requirement (hardness testing) remains unchanged."},"complexity_factors":["Very short document (approximately 300 words)","Only 2 defined part number ranges in applicability section","Single straightforward requirement with two alternative test methods","No nested exceptions or conditional logic","Clear compliance deadline ('before further flight')","Minimal cross-referencing (only one reference to FAA AD 70-6-2)","Technical but precise language suitable for aircraft mechanics"],"plain_english_summary":"This CASA safety order updates an Airworthiness Directive for Bell 204 series helicopters, requiring hardness testing of specific tail-rotor blade grips before installation or flight. It affects owners, operators and maintenance engineers who handle those grips. The measure ensures grips meet hardness/conductivity limits to prevent tail-rotor failure and potential loss of control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-204-10-amdt-1-tail-rotor-blade-grip","history":"/api/acts/ad-bell-204-10-amdt-1-tail-rotor-blade-grip/history","analysis":"/api/acts/ad-bell-204-10-amdt-1-tail-rotor-blade-grip/analysis","conflicts":"/api/acts/ad-bell-204-10-amdt-1-tail-rotor-blade-grip/conflicts","importantCases":"/api/acts/ad-bell-204-10-amdt-1-tail-rotor-blade-grip/important-cases","documents":"/api/acts/ad-bell-204-10-amdt-1-tail-rotor-blade-grip/documents"}}