{"id":"F2006B09362","name":"AD/ECUREUIL/56 Amdt 1 - Tail Boom-to-Aircraft Structure Junction Attachment Screws","slug":"ad-ecureuil-56-amdt-1-tail-boom-to-aircraft-structure-junction-attachment-screws","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53626,"registerId":"commonwealth-F2006B09362-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/ECUREUIL/56 Amdt 1 - Tail Boom-to-Aircraft Structure Junction Attachment Screws","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\nAIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/ECUREUIL/56 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\nEurocopter AS 350 (Ecureuil) Series Helicopters\n\nAD/ECUREUIL/56\n\nAmdt 1\n\n  \n\nTail Boom-to-Aircraft Structure Junction Attachment Screws\n\n  \n3/2002\n\nApplicability: Model AS 350 helicopters, versions B, BA, BB, B1, B2, and D, equipped with tail boom-to-aircraft structure junction attachment screws part number 22201BC060008L (N5103337287). This directive does not apply to new or overhauled aircraft delivered after 15 May 1997, and aircraft on which no tail boom-to-aircraft structure junction attachment screw was replaced since 1 July 1994 (even if these screws are marked with the letter “M”).\n\nRequirement: Check the marking on the heads of the 23 attachment screws which are located above the cargo compartment floor, and scrap all screws which are marked with the letter “M” on the screw head above the designation “BC”, in accordance with the instructions given in paragraph 2.B.1 of Eurocopter AS350 Alert Service Bulletin No. 01.00.46.\n\nNote: DGAC AD 1997-147-072 (A) R1 refers.\n\nCompliance: Unless already accomplished, within 100 hours time in service after 9 October 1997, or before 31 October 1997; whichever occurs first.\n\nThe compliance time for this amendment remains unchanged. This airworthiness directive becomes effective on 21 March 2002.\n\nBackground: This Directive was originally issued in October 1997, as a batch of attachment screws has been found which do not meet the required metallurgical specification.\n\nAmendment 1 has been issued to cover the conversion of the Service Telex into Alert Service Bulletin No. 01.00.46, with no change to technical content.\n\n![Signature of David Villiers, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 5 February 2002\n\n![](image.001.png)\n\nThe above AD is notified in the Commonwealth of Australia Gazette on 27 February 2002.\n\n  \nPage 1 of 1","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment makes no substantive change to scope. It is purely administrative — updating the reference from a 'Service Telex' to an 'Alert Service Bulletin' (document reclassification by the manufacturer) while explicitly stating 'no change to technical content'. The applicability, requirements, and compliance timing remain identical to the original 1997 directive."},"complexity_factors":["Single, specific mechanical issue (tail boom screws) with clear identification criteria (\"M\" marking)","Only 2 exemption categories to track","Straightforward compliance action: visual inspection and replacement","No nested conditional logic or cross-references to other legislation","Short document (1 page) with minimal defined terms","Single compliance deadline with simple 'whichever occurs first' alternative"],"plain_english_summary":"This CASA safety notice warns operators of Eurocopter AS350 (Ecureuil/Squirrel) B/BA/BB/B1/B2/D models that a batch of tail‑boom attachment screws was made from the wrong metal. Screws marked “M” above “BC” must be inspected and scrapped per Eurocopter Alert Service Bulletin instructions.\n\nIt affects owners/operators of those models (with limited delivery/overhaul date exemptions). Faulty screws could cause catastrophic tail separation; the 2002 update only renumbers the manufacturer document, not the requirement or deadline."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Amendment 1 did not broaden or change the substantive scope of the original directive. It only updates the manufacturer reference by converting a Service Telex into Alert Service Bulletin No. 01.00.46; the technical requirement (inspect specified screws and scrap those marked “M”) and the original applicability and compliance requirements remain unchanged."},"complexity_factors":["Short, single-issue directive focused on one part number and one inspection action","Specific list of affected aircraft models (6 variants)","Two narrow applicability exceptions tied to delivery/overhaul and to replacement history (dates 15 May 1997 and 1 July 1994)","Conditional compliance deadline (whichever occurs first between 100 flight hours after 9 Oct 1997 and date 31 Oct 1997)","Cross-reference to manufacturer documentation (Eurocopter AS350 Alert Service Bulletin No. 01.00.46) for procedural steps","Reference to an overseas AD (DGAC AD 1997-147-072 (A) R1)","Amendment is administrative (conversion of Service Telex to Alert Service Bulletin) which adds a small cross-reference layer but no technical complexity"],"plain_english_summary":"**What this directive does (mechanics)**\n\n- It orders owners/operators of certain Eurocopter AS350 (Ecureuil) helicopters to inspect a specific set of 23 screws that attach the tail boom to the aircraft structure (the screws that sit above the cargo compartment floor).\n- The inspection is limited to screws with part number 22201BC060008L (manufacturer serial N5103337287). If a screw head is marked with the letter “M” above the letters “BC”, that screw must be scrapped (disposed of) in accordance with Eurocopter AS350 Alert Service Bulletin No. 01.00.46, paragraph 2.B.1.\n- The directive applies to AS350 B, BA, BB, B1, B2 and D versions, except for: (a) new or overhauled aircraft delivered after 15 May 1997, and (b) aircraft on which no such tail-boom attachment screw has been replaced since 1 July 1994 (even if the screw carries the “M” marking).\n- Compliance deadline (as set originally): do the inspection and remove any affected screws within 100 flight hours after 9 October 1997 or before 31 October 1997, whichever came first.\n- Amendment 1 changes only how the manufacturer’s instruction is referenced (converts a Service Telex into Alert Service Bulletin No. 01.00.46); it does not change the technical requirement.\n\n**Who this affects**\n\n- Directly: owners/operators and maintenance organisations responsible for the listed AS350 helicopter variants that have the specified part-number screws installed and that do not meet the two exceptions above.\n- Indirectly: maintenance suppliers who supply replacement screws and perform the removals/inspections.\n\n**Why it matters (stated purpose and practical effect)**\n\n- Stated purpose: a batch of attachment screws was found not to meet required metallurgical specifications. The action aims to remove screws that might be substandard and so could fail under load.\n\n**Costs, incentives and practical trades-offs**\n\n- Who pays: aircraft owners/operators bear the labour and parts cost to inspect, remove and replace scrapped screws, plus any downtime while maintenance is performed.\n- Behaviour change required: operators must inspect the 23 specified screw heads for the “M” marking and scrap/replace marked screws in line with the Eurocopter service instruction.\n- Implementation burden: a one-time physical inspection of 23 screws per affected helicopter and replacement where required. The directive points to the manufacturer’s Alert Service Bulletin for the exact removal/scrapping instructions (paragraph 2.B.1), so maintainers must follow that procedure.\n- Opportunity cost/trade-off: safety mitigation (replacing potentially defective screws) versus the cash and aircraft availability costs of inspection and replacement. The requirement is narrow and targeted (specific part number, specific location, specific marking).\n- Risk and discretion: the AD sets a mandatory inspection/scrap rule; the CASA delegate enforces it under CAR 1998 subregulation 39.1(1). The directive relies on the manufacturer’s Alert Service Bulletin for procedural detail, so maintainers must follow that document; there is limited regulatory discretion beyond that.\n\n**Effects on private enterprise and markets**\n\n- Small, concentrated compliance cost on owners/operators of the affected fleet. Maintenance providers may gain some additional short-term business (inspection and replacement work).\n- No change to ownership, contract freedom or market structure: the AD prescribes a safety action for airworthiness compliance; replacement parts and labour will be procured under normal maintenance arrangements.\n\n**Other practical points and cross-references**\n\n- The AD refers operators to Eurocopter AS350 Alert Service Bulletin No. 01.00.46 (see Requirement) for the detailed procedure. It also notes a related French DGAC airworthiness directive (DGAC AD 1997-147-072 (A) R1).\n- Amendment 1 simply records that the manufacturer’s procedural reference has been converted into an Alert Service Bulletin; no additional technical steps were added.\n\n(Sections cited: Applicability; Requirement; Compliance; Background; Amendment note.)"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-ecureuil-56-amdt-1-tail-boom-to-aircraft-structure-junction-attachment-screws","history":"/api/acts/ad-ecureuil-56-amdt-1-tail-boom-to-aircraft-structure-junction-attachment-screws/history","analysis":"/api/acts/ad-ecureuil-56-amdt-1-tail-boom-to-aircraft-structure-junction-attachment-screws/analysis","conflicts":"/api/acts/ad-ecureuil-56-amdt-1-tail-boom-to-aircraft-structure-junction-attachment-screws/conflicts","importantCases":"/api/acts/ad-ecureuil-56-amdt-1-tail-boom-to-aircraft-structure-junction-attachment-screws/important-cases","documents":"/api/acts/ad-ecureuil-56-amdt-1-tail-boom-to-aircraft-structure-junction-attachment-screws/documents"}}