{"id":"F2006B04528","name":"AD/BELL 206/76 Amdt 2 - Horizontal Stabiliser - Inspection and Modification or Retirement","slug":"ad-bell-206-76-amdt-2-horizontal-stabiliser-inspection-and-modification-or-retirement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114240,"registerId":"commonwealth-F2006B04528-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 206/76 Amdt 2 - Horizontal Stabiliser - Inspection and Modification or Retirement","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nBell Helicopter Textron Canada (BHTC) 206 and Agusta Bell 206 Series Helicopters\n\nAD/BELL 206/76\n\nAmdt 2\n\n  \n\nHorizontal Stabiliser \\- Inspection and Modification or Retirement\n\n  \n11/81\n\nApplicability: All model 206L and 206L-1 with S/Nos. listed in Bell Alert SB No. 206L-81-23 and fitted with a horizontal stabiliser assembly of affected P/N detailed in that document.\n\nDocument: Bell Alert SB No. 206L-81-23.\n\nCompliance: 1. Inspect at each daily or overnight inspection until modified IAW with Bell Alert SB No. 206L-81-23.\n\nNote: Pilot in command may perform and certify for this inspection.\n\n2. Retire or modify in accordance with the requirements of Bell Alert SB No. 206L-81-23, not later than 31 March 1982.\n\nBackground: Bell Alert SB No. 206L-81-23 extends the requirement to addition P/N stabilisers and provides for mandatory retirement of certain P/N items.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Yes. The background states the Bell Alert Service Bulletin extends the requirement to additional stabiliser part numbers and requires mandatory retirement of certain part numbers. As implemented by this AD, the scope of affected parts and therefore the set of operators required to comply is expanded compared with the earlier requirement (Background; Applicability)."},"complexity_factors":["Limited applicability to specified helicopter models and serial numbers (Applicability).","Two-step compliance regime: frequent interim inspections plus a single hard deadline for retirement/modification (Compliance 1–2).","Permission for pilot-in-command to perform and certify the inspection alters who may carry out compliance tasks (Note).","Dependence on an external technical document (Bell Alert SB No. 206L-81-23) for procedural and parts details increases operational complexity.","A fixed calendar deadline (31 March 1982) creates a time-sensitive compliance obligation (Compliance 2)."],"plain_english_summary":"What this instrument does (mechanical change)\n\n- This is an airworthiness directive issued under the Civil Aviation Safety Authority covering Bell 206L and 206L-1 helicopters with specific serial numbers and with certain part-numbered horizontal stabiliser assemblies (Applicability).  The directive requires operators to:\n  - Inspect the affected horizontal stabiliser at each daily or overnight inspection until the stabiliser is modified in accordance with Bell Alert SB No. 206L-81-23 (Compliance 1); and\n  - Either retire or modify the affected stabiliser assemblies in accordance with Bell Alert SB No. 206L-81-23 no later than 31 March 1982 (Compliance 2).\n\n- The directive explicitly allows the pilot-in-command to perform and certify the required inspection (Note).\n\nWhy this was issued (stated purpose and what the source says)\n\n- The document cites a Bell Alert Service Bulletin (Bell Alert SB No. 206L-81-23). The background to the directive states that the service bulletin extends the inspection/retirement requirement to additional stabiliser part numbers and makes retirement of certain part numbers mandatory (Background). The directive therefore implements the service bulletin’s expanded scope and mandatory retirement schedule.\n\nWho pays, who decides, and what changes in behaviour (concrete mechanics)\n\n- Who decides: The Civil Aviation Safety Authority issued the airworthiness directive and specifies compliance actions; the detailed technical steps are set out in Bell Alert SB No. 206L-81-23 (header; Compliance). \n- Who acts / who pays: Operators or owners of the affected helicopters must carry out the inspections and must either modify or retire the specified stabiliser assemblies by the stated date. Those actions are likely to impose direct costs on owners/operators (Compliance 1–2; Background). \n- Who may perform the inspection: The pilot-in-command may perform and certify the required daily/overnight inspections, which substitutes for a maintenance technician for that specific check (Note).\n\nCosts, incentives, trade-offs, and compliance burdens (mechanisms, not judgments)\n\n- Immediate compliance burden: Operators must add the specified inspection at every daily or overnight check until the stabiliser is modified, which increases inspection tasks and record-keeping (Compliance 1). \n- One-off cost choice by the deadline: By 31 March 1982 operators must either retire the affected parts or pay for modifications in accordance with the Bell Alert SB (Compliance 2). That creates an economic decision: incur modification/retirement costs now or, if not compliant, be non‑conforming to the AD.\n- Incentives created by the directive: Allowing the pilot-in-command to perform the inspection reduces the need for professional maintenance labour for the interim inspection task (Note). By contrast, the mandatory retirement/modification requirement shifts more substantial costs to owners/operators (Compliance 2). \n- Trade-offs and opportunity cost: Time and money spent on inspections and on modifying or replacing parts are resources not available for other maintenance, upgrades, or operations. The directive expands the set of affected part numbers (Background), so more owners/operators will face those opportunity costs. \n\nImplementation risk and administrative dependencies\n\n- The AD depends on an external technical document (Bell Alert SB No. 206L-81-23) for the specific modification/retirement procedures and for the list of additional part numbers and serial numbers. That linkage means operators must obtain and follow the service bulletin to satisfy the AD (Applicability; Compliance 2). \n- The AD sets a fixed deadline (31 March 1982) for retirement or modification; meeting that date is the compliance condition (Compliance 2).\n\nEffects on private choice and market actors (concrete pathways)\n\n- Owners/operators: Must choose between modifying or retiring parts by the deadline; either choice imposes a direct cost and operational planning requirement (Compliance 2). \n- Maintenance providers: May see demand for modification work or for part replacement; allowing pilots to do interim inspections may reduce short-term demand for technicians for that specific inspection task (Note). \n- Aircraft availability and operations: Retirement of an affected stabiliser without immediate replacement could take an aircraft out of service until a compliant part or modification is fitted (Compliance 2).\n\nSummary statement\n\n- Mechanically, the directive requires repeated inspections until a modification is performed, and it mandates retirement or modification of certain stabiliser part numbers by a set date. The directive implements and extends the requirements set out in Bell Alert SB No. 206L-81-23 (Background; Compliance). The burden falls on the affected aircraft owners/operators to inspect, modify, or retire parts by the specified deadline; the pilot-in-command is explicitly permitted to perform the routine inspections in the interim (Note; Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"This is Amendment 2 to an existing Airworthiness Directive. The background explicitly states it 'extends the requirement to addition P/N stabilisers' (additional part numbers) and 'provides for mandatory retirement of certain P/N items' — meaning the scope has expanded from the original AD to cover more aircraft parts and to mandate scrapping rather than just repair for some components."},"complexity_factors":["Very short document (under 200 words)","Only 4 defined elements: applicability (specific models/serial numbers), document reference, compliance requirements, and background","Simple conditional structure: inspect daily UNTIL modified, then retire/modify by fixed date","Single cross-reference to external technical document (Bell Alert SB No. 206L-81-23)","No nested exceptions or complex definitional sections","Clear, unambiguous deadline (31 March 1982)"],"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). Think of it as a \"recall notice\" for aircraft parts, but with legal force. If you don't comply, you can't legally fly the aircraft.\n\n**What it does:** This directive targets specific **Bell 206L and 206L-1 helicopters** (including Agusta Bell variants) with particular serial numbers. It requires owners and operators to:\n\n- **Inspect the horizontal stabiliser** (the small wing at the tail that keeps the helicopter level) at every daily or overnight check until the problem is permanently fixed\n- **Either modify or permanently retire (scrap)** certain stabiliser parts by **31 March 1982**\n\n**Who it affects:**\n- Owners and operators of affected Bell/Agusta 206L series helicopters\n- Pilots in command (who are allowed to perform and sign off on the daily inspections)\n- Maintenance engineers (who must do the modifications or retirement)\n\n**Why it matters:** The horizontal stabiliser is critical for flight safety. This AD responds to Bell Alert Service Bulletin 206L-81-23, which identified dangerous defects in certain part numbers and mandated that some stabilisers be taken out of service entirely rather than repaired. The \"Amendment 2\" expands the original directive to cover additional part numbers and clarifies that some stabilisers must be retired, not just fixed.\n\n**Key takeaway:** If you own one of these helicopters, you must check the tail every day until you either modify it or replace it — and you have a hard deadline of March 1982 to finish the job."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-206-76-amdt-2-horizontal-stabiliser-inspection-and-modification-or-retirement","history":"/api/acts/ad-bell-206-76-amdt-2-horizontal-stabiliser-inspection-and-modification-or-retirement/history","analysis":"/api/acts/ad-bell-206-76-amdt-2-horizontal-stabiliser-inspection-and-modification-or-retirement/analysis","conflicts":"/api/acts/ad-bell-206-76-amdt-2-horizontal-stabiliser-inspection-and-modification-or-retirement/conflicts","importantCases":"/api/acts/ad-bell-206-76-amdt-2-horizontal-stabiliser-inspection-and-modification-or-retirement/important-cases","documents":"/api/acts/ad-bell-206-76-amdt-2-horizontal-stabiliser-inspection-and-modification-or-retirement/documents"}}