{"id":"F2006B09328","name":"AD/ECUREUIL/106 - Tail Rotor Blade Trailing Edge Tab","slug":"ad-ecureuil-106-tail-rotor-blade-trailing-edge-tab","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53494,"registerId":"commonwealth-F2006B09328-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\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 CASR 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","sortOrder":0},{"sectionNumber":"AD/ECUREUIL/106 Tail Rotor Blade Trailin","sectionType":"part","heading":"AD/ECUREUIL/106 Tail Rotor Blade Trailing Edge Tab 1/2005","content":"# AD/ECUREUIL/106 Tail Rotor Blade Trailing Edge Tab 1/2005\n\nApplicability: AS 350 helicopters, versions B, BA, BB, B1, B2, B3, and D, fitted with tail rotor blades part number 355A 12.0040 all dash numbers, and part number 355A 12.0050.04, with serial numbers from 8400 through 9224, before incorporation of Repair Sheet FR No. 238 or incorporation of Work Card 64.10.00.872 (Refer to equipment log card (FME)).\n\nNote: Eurocopter AS 350 Alert Service Bulletin No. 64.00.05 corresponds to Repair Sheet FR No. 238.\n\nRequirement: Install additional rivets on the trailing edge tab of blades in accordance with paragraph 2.B. of Eurocopter Alert Service Bulletin No.64.00.05 or later EASA approved revision.\n\nNote: DGAC AD F-2004-178 refers.\n\nCompliance: Within 100 flight hours or 3 months after 20 January 2005, whichever occurs first.\n\nThis Airworthiness Directive becomes effective on 20 January 2005.\n\nBackground: Reports were received of significant tail rotor blade trailing edge tab debonding.\n\nReduced security of the trailing edge tab due to debonding could lead to loss of the tab if it is not monitored, and result in a significant increase in the vibration level.\n\n![Signature of David Villiers, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority 3 December 2004\n\n![](image.001.png)","sortOrder":1}],"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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive addressing a specific unsafe condition in particular helicopter models. The scope remains tightly focused on the tail rotor blade debonding issue described in the background."},"complexity_factors":["Single discrete requirement (install rivets) with clear reference to external technical document","Applicability defined by specific part numbers, serial number ranges, and exclusions for prior repairs","Simple compliance deadline (whichever occurs first of two conditions)","No nested exceptions or conditional logic beyond the applicability criteria","Short document (under 300 words) with minimal cross-referencing to other regulatory instruments"],"plain_english_summary":"This safety order requires operators of Eurocopter AS350 (B, BA, BB, B1, B2, B3 and D) helicopters with specific tail-rotor blade part/serial numbers to fit additional rivets to the trailing-edge tabs to prevent tab debonding. Debonded tabs can induce dangerous vibration and affect flight control. Compliance is required within 100 flight hours or 3 months after 20 Jan 2005 (unless Repair Sheet FR No. 238/Work Card 64.10.00.872 already done) by following Eurocopter Alert Service Bulletin No. 64.00.05."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive is narrowly focused on correcting a specific unsafe condition (trailing edge tab debonding) on a defined subset of AS350 tail rotor blades. It requires a specific corrective action (install additional rivets) and references a particular service bulletin. There is no indication in the text that the scope has been broadened beyond that original safety correction — its applicability, required remedy, and compliance window remain tightly aligned with the stated safety problem."},"complexity_factors":["Short, targeted directive (single corrective action).","Applicability requires matching two part numbers plus a serial number range (8400–9224) and checking for prior incorporation of Repair Sheet FR No. 238 or Work Card 64.10.00.872.","References external technical documents: Eurocopter Alert Service Bulletin No. 64.00.05 (and later EASA‑approved revisions), Repair Sheet FR No. 238, Work Card 64.10.00.872.","Conditional language: applicability excludes blades that have already had the repair/work card incorporated (a before/after condition).","Compliance window has two triggers (100 flight hours OR 3 months), creating a time/usage condition.","Cross‑reference to foreign authority DGAC AD F‑2004‑178 increases traceability requirements but does not add substantive steps."],"plain_english_summary":"**What this instrument does (mechanics)**\n\n- It is an Airworthiness Directive (a legally enforceable safety requirement) that applies to certain Eurocopter AS350 (Ecureuil) helicopters: versions B, BA, BB, B1, B2, B3 and D that have specific tail rotor blade part numbers and serial numbers (part number 355A 12.0040, all dash numbers, and part number 355A 12.0050.04, serials 8400–9224) unless the blade has already had a specified repair/inspection recorded (Repair Sheet FR No. 238 or Work Card 64.10.00.872).\n\n- The required action is to install additional rivets on the trailing edge tab of each affected tail rotor blade following paragraph 2.B. of Eurocopter Alert Service Bulletin No. 64.00.05 (or a later EASA‑approved revision of that service bulletin).\n\n- The work must be done within 100 flight hours or within 3 months of the effective date, whichever comes first.\n\n- The CASA delegate is the enforcing authority and the directive references related foreign authority actions (DGAC) and the Eurocopter service bulletin for the technical instructions.\n\n**Who this affects**\n\n- Owners/operators of the identified AS350 helicopters whose tail rotor blades match the listed part numbers and serial numbers and which have not already had the specified repair/work-card action recorded.\n\n- Maintenance organisations or mechanics who will do the rivet installation according to the Eurocopter service bulletin.\n\n**Why it matters (official rationale, in plain terms)**\n\n- The directive states that reports were received of significant debonding (separation of bonded parts) of the trailing edge tab on the tail rotor blade. If the tab becomes loose or is lost, it can cause substantial vibration and create an unsafe condition for the helicopter. The stated purpose is to restore or increase the secure attachment of the trailing edge tab to prevent debonding and the associated vibration and safety risk.\n\n**Practical effects, incentives and costs**\n\n- Who pays: The operator/owner pays for the inspection/work and the rivets/labour. If a maintenance organisation is contracted, the operator will ultimately bear that cost.\n\n- Who decides: CASA (through its delegate) mandates the action and accepts compliance when performed to the specified Eurocopter service bulletin or later approved revisions. The maintenance provider decides how to schedule and carry out the work within the specified instructions.\n\n- Behaviour changes: Operators must inspect maintenance logs and blade serial numbers, schedule the rivet installation within the stated time window, and record the action in the equipment log card (FME) to show compliance. Some operators may ground aircraft until the work is done if the compliance window is met.\n\n- Compliance burden: The directive is task‑specific (install rivets per the service bulletin). The burden is administrative (confirming applicability, checking records) plus the direct maintenance cost (parts, labour, possible downtime). The service bulletin provides the technical steps, reducing technical uncertainty, but operators must source parts and book maintenance slots.\n\n- Trade-offs and opportunity cost: Money and hangar time spent on this mandatory inspection/repair cannot be used for other maintenance or operational needs during the compliance window.\n\n- Implementation risk and discretion: The AD delegates the technical method to the Eurocopter Alert Service Bulletin; CASA accepts later EASA‑approved revisions, which gives some regulatory flexibility but means operators must ensure they use an approved revision. There is limited room for alternative methods unless separately approved.\n\n- Market effects: The requirement is narrowly targeted at a subset of blades/serials, so effects on competition or supply are minimal and concentrated on affected operators and maintenance suppliers. If many operators require the same rivets/maintenance at once, there could be short‑term demand on parts and maintenance capacity.\n\n**Concentrated benefits vs diffuse costs**\n\n- Benefits (reduced risk of tab loss and vibration) are concentrated on operators flying the affected blades and on passenger/crew safety in those aircraft.\n\n- Costs are also concentrated on those same operators; the directive does not impose costs on unrelated parties.\n\n**Notes on compliance mechanics and evidentiary matters**\n\n- Operators must check the equipment log card (FME) to determine whether Repair Sheet FR No. 238 or Work Card 64.10.00.872 has already been incorporated (that is, whether the rivets are already fitted). If so, no further action is required for that blade.\n\n- The AD explicitly accepts later EASA‑approved revisions of the Eurocopter service bulletin, which provides a clear path to compliance if the manufacturer revises the procedure.\n\n(Reference: Applicability, Requirement, Compliance, Background sections of the AD.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-ecureuil-106-tail-rotor-blade-trailing-edge-tab","history":"/api/acts/ad-ecureuil-106-tail-rotor-blade-trailing-edge-tab/history","analysis":"/api/acts/ad-ecureuil-106-tail-rotor-blade-trailing-edge-tab/analysis","conflicts":"/api/acts/ad-ecureuil-106-tail-rotor-blade-trailing-edge-tab/conflicts","importantCases":"/api/acts/ad-ecureuil-106-tail-rotor-blade-trailing-edge-tab/important-cases","documents":"/api/acts/ad-ecureuil-106-tail-rotor-blade-trailing-edge-tab/documents"}}