{"id":"F2006B10231","name":"AD/GAZELLE/12 - Tail Gearbox - Inspection and Modification","slug":"ad-gazelle-12-tail-gearbox-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55889,"registerId":"commonwealth-F2006B10231-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/GAZELLE/12 - Tail Gearbox - Inspection and Modification","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Eurocopter SA341 and SA342 (Gazelle) Series Helicopters\n\n \n\nAD/GAZELLE/12 Tail Gearbox - Inspection and Modification 10/82\n\nApplicability: All models SA-341 and SA-342. Document:  Aerospatiale Gazelle SB No. 65.22. Compliance:               In accordance with requirement document.\n\nBackground: Cracking of attachment lugs is attributed to surface and edge defects occurring during manufacture.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument, as presented, confines its scope to all Eurocopter SA‑341 and SA‑342 helicopters and to inspection/modification of the tail gearbox attachment lugs; this matches the stated purpose of addressing manufacturing‑related surface and edge defects that have produced cracking (Applicability; Background). The AD delegates technical method to Aerospatiale Gazelle SB No. 65.22 (Document; Compliance) and does not expand beyond that stated scope in the text provided."},"complexity_factors":["Narrow technical scope: applies only to tail gearbox attachment lugs on SA‑341 and SA‑342 models (Applicability; Background).","External dependency: the AD requires compliance with an external service bulletin (Aerospatiale Gazelle SB No. 65.22), so implementers must consult a separate document for procedural detail (Document; Compliance).","Regulatory formality: issued under Part 39 airworthiness directives, which creates a binding compliance obligation even though the technical steps are delegated to the service bulletin (header; Compliance).","Limited procedural detail in the AD itself: timing, allowable alternatives, and approval pathways are not specified in the AD text provided, increasing reliance on CASA administrative processes and the service bulletin for operational detail (Document; Compliance)."],"plain_english_summary":"This AD requires operators of all SA‑341 and SA‑342 Gazelle helicopters to inspect and, where needed, modify the tail gearbox attachment lugs in accordance with Aerospatiale Gazelle Service Bulletin No. 65.22. It responds to observed manufacturing‑related cracking and shifts compliance costs and maintenance planning onto aircraft owners, who must arrange the work and associated downtime."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1982 (as indicated by the \"10/82\" suffix). It addresses a specific known defect in a specific aircraft type. There is no indication of scope creep; it remains tightly focused on tail gearbox attachment lug cracking in Gazelle helicopters."},"complexity_factors":["Extremely short document (under 200 words)","No defined terms section — relies entirely on external reference (Aerospatiale SB No. 65.22)","No conditional logic or exceptions within the text itself","Single, unambiguous applicability clause (\"All models SA-341 and SA-342\")","No cross-references to other legislation beyond the enabling regulations (Part 39)","Content is essentially a pointer to a technical document rather than detailed regulatory text"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of **Eurocopter SA341 and SA342 \"Gazelle\" helicopters** to inspect and modify the **tail gearbox** (the component that transfers power to the tail rotor). The work must follow **Aerospatiale Service Bulletin No. 65.22**.\n\n**Why it matters:** The tail gearbox attachment lugs (the brackets that bolt the gearbox to the helicopter) can develop **cracks due to manufacturing defects** in the surface and edges. If these cracks aren't found and fixed, the gearbox could detach in flight — with potentially catastrophic results.\n\n**Who must comply:** Anyone operating these specific Gazelle helicopter models in Australia. \"Compliance\" means doing exactly what the referenced service bulletin says, when it says to do it.\n\n**Key point:** This isn't optional maintenance advice. It's legally enforceable. Flying without completing this directive can ground the aircraft and expose the operator to penalties."}},"importantCases":[],"_links":{"self":"/api/acts/ad-gazelle-12-tail-gearbox-inspection-and-modification","history":"/api/acts/ad-gazelle-12-tail-gearbox-inspection-and-modification/history","analysis":"/api/acts/ad-gazelle-12-tail-gearbox-inspection-and-modification/analysis","conflicts":"/api/acts/ad-gazelle-12-tail-gearbox-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-gazelle-12-tail-gearbox-inspection-and-modification/important-cases","documents":"/api/acts/ad-gazelle-12-tail-gearbox-inspection-and-modification/documents"}}