{"id":"F2006B04556","name":"AD/BELL 212/24 Amdt 1 - Main Gear Box Spiral Bevel Gear Inspection and Rotor Brake Quill Shaft Removal","slug":"ad-bell-212-24-amdt-1-main-gear-box-spiral-bevel-gear-inspection-and-rotor-brake-quill-shaft-removal","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114286,"registerId":"commonwealth-F2006B04556-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 212/24 Amdt 1 - Main Gear Box Spiral Bevel Gear Inspection and Rotor Brake Quill Shaft Removal","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\nBell Helicopter Textron 212 Series Helicopters\n\n \n\nAD/BELL 212/24\n\nAmdt 1\n\n\nMain Gear Box Spiral Bevel Gear Inspection and Rotor Brake Quill Shaft Removal\n\n\n1/79\n\n \n\nApplicability: All model 212 helicopters.\n\n \n\nDocument: 1. For helicopters fitted with P/N 204-040-701-3 spiral bevel gear - SB 212-78-8, and after any occurrence of torsional overloading, part 1(B) of SB 212-78-12.\n\n \n\n2. For helicopters fitted with P/N 204-040-701-101 spiral bevel gear - SB 212-78-12. Compliance:              As per the requirement document.\n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is Amendment 1 (Amdt 1) of an existing Airworthiness Directive. The scope remains tightly focused on the original safety issue: main gearbox spiral bevel gear inspection and rotor brake quill shaft removal for Bell 212 helicopters. The amendment appears to update or clarify the reference documents (the service bulletins) rather than expand the scope to new aircraft types, new components, or new operational requirements. The applicability remains 'All model 212 helicopters' — unchanged from the original intent."},"complexity_factors":["Very short document (approximately 150 words)","Only 2 defined part numbers (P/N 204-040-701-3 and P/N 204-040-701-101) creating a simple binary applicability split","Minimal conditional logic — essentially 'if fitted with part A, do X; if fitted with part B, do Y'","Heavy reliance on external documents (Service Bulletins SB 212-78-8 and SB 212-78-12) for actual procedural detail — the AD itself is a pointer rather than a standalone instruction","No nested exceptions or complex cross-referencing within the instrument itself","Single compliance requirement: 'As per the requirement document' — no phased compliance, no repetitive intervals, no alternative methods of compliance (AMOCs) mentioned"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific Bell 212 helicopters.\n\n**What it does:**\n- Requires owners and operators of Bell 212 helicopters to inspect the **main gearbox spiral bevel gear** (a critical component that transfers power from the engine to the rotor) and remove the **rotor brake quill shaft** (part of the braking system that stops the rotor blades).\n\n**Who it affects:**\n- Anyone who owns, operates, or maintains **all model 212 helicopters** — this is a blanket requirement across the entire fleet of this aircraft type in Australia.\n\n**Why it matters:**\n- These inspections are safety-critical. The spiral bevel gear is essential for flight control and power transmission. If it fails due to **torsional overloading** (twisting stress beyond design limits, such as from a hard landing or sudden engine stop), the helicopter could lose rotor power catastrophically. The directive references specific **Service Bulletins (SBs)** — manufacturer-issued technical notices — that detail exactly how to perform these checks.\n\n**Key point:** This isn't optional. Compliance is mandatory \"as per the requirement document\" — meaning operators must follow the referenced Bell Helicopter service bulletins to the letter."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The text supplied is an amendment (Amdt 1) to AD/BELL 212/24, but the document itself does not state any change of applicability or an explicit expansion/reduction of scope. The AD as presented applies to all model 212 helicopters and directs compliance to the named service bulletins for the specified part numbers (Applicability; Document: items 1–2). There is no information in this excerpt indicating that the scope has been changed from the original instrument."},"complexity_factors":["References multiple external technical documents (SB 212‑78‑8 and SB 212‑78‑12) rather than setting procedures in the AD itself (Document: items 1–2; Compliance).","Conditional requirement tied to an operational event (\"after any occurrence of torsional overloading\") which creates event‑detection and recordkeeping burdens (Document: item 1).","Multiple part numbers (P/N 204‑040‑701‑3 and P/N 204‑040‑701‑101) require accurate identification of installed components to determine applicable actions (Document: items 1–2; Applicability).","Short, high‑level AD text with substantive detail externalised to service bulletins increases reliance on obtaining and interpreting additional documents (Document: items 1–2; Compliance).","Compliance timing and exact steps are not stated in the AD (\"As per the requirement document\"), requiring operators to consult the SBs for deadlines and acceptance criteria (Compliance)."],"plain_english_summary":"This AD mandates inspections of main gearbox spiral bevel gears and removal of the rotor‑brake quill shaft on Bell 212 helicopters, but it delegates the detailed steps, timing and criteria to Service Bulletins SB 212‑78‑8 and SB 212‑78‑12. It applies to all Bell 212s, practically to aircraft fitted with P/N 204‑040‑701‑3 or P/N 204‑040‑701‑101; additional SB action is required for P/N 204‑040‑701‑3 after torsional overloading.\n\nCASA issues the directive; owners/operators fund and arrange the mandated inspections/works per the referenced SBs."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-212-24-amdt-1-main-gear-box-spiral-bevel-gear-inspection-and-rotor-brake-quill-shaft-removal","history":"/api/acts/ad-bell-212-24-amdt-1-main-gear-box-spiral-bevel-gear-inspection-and-rotor-brake-quill-shaft-removal/history","analysis":"/api/acts/ad-bell-212-24-amdt-1-main-gear-box-spiral-bevel-gear-inspection-and-rotor-brake-quill-shaft-removal/analysis","conflicts":"/api/acts/ad-bell-212-24-amdt-1-main-gear-box-spiral-bevel-gear-inspection-and-rotor-brake-quill-shaft-removal/conflicts","importantCases":"/api/acts/ad-bell-212-24-amdt-1-main-gear-box-spiral-bevel-gear-inspection-and-rotor-brake-quill-shaft-removal/important-cases","documents":"/api/acts/ad-bell-212-24-amdt-1-main-gear-box-spiral-bevel-gear-inspection-and-rotor-brake-quill-shaft-removal/documents"}}