{"id":"F2006B04482","name":"AD/BELL 206/26 - Engine Firewall Seal - Modification","slug":"ad-bell-206-26-engine-firewall-seal-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44319,"registerId":"commonwealth-F2006B04482-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 206/26 - Engine Firewall Seal - 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)  Bell Helicopter Textron Canada (BHTC) 206 and Agusta Bell 206 Series Helicopters\n\n \n\nAD/BELL 206/26 Engine Firewall Seal - Modification 8/70 Applicability:              All model 206A and AB-206A with S/Nos. referenced in requirement documents. Document:               1. Bell SB 206A-142; or\n\n2. FAA AD 70-14-6; or\n\n \n\n3. Agusta SB BT206-43.\n\n \n\nCompliance: Within 300 hours time in service after 31 August 1970. Background: AD/Agusta 206/18 equivalent.\n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue safety directive from 1970 concerning one specific mechanical modification. It has not expanded beyond its original purpose of mandating firewall seal modifications for specific helicopter models."},"complexity_factors":["Very short document (approximately 150 words)","Only 3 defined compliance paths (the three referenced documents)","Single, unambiguous deadline (300 hours time in service after fixed date)","No nested exceptions or conditional logic","No cross-references to other legislation beyond the parent Civil Aviation Regulations 1998","Clear applicability criteria (specific models and serial numbers)"],"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) that requires specific repairs or modifications to aircraft.\n\n**What it does:** This directive orders owners and operators of certain Bell 206 and Agusta Bell 206 helicopters to **modify the engine firewall seal**. The firewall is a protective barrier between the engine and the rest of the helicopter; the seal prevents fire, smoke, or toxic fumes from leaking through gaps around pipes or wires that pass through this barrier.\n\n**Who it affects:** \n- All **Bell 206A** model helicopters\n- All **Agusta Bell AB-206A** model helicopters\n- **Only those with specific serial numbers** listed in the referenced technical documents (Service Bulletins from Bell and Agusta, plus a US Federal Aviation Administration directive)\n\n**What must be done:**\n- Helicopter owners must carry out the firewall seal modification exactly as described in one of three approved technical documents\n- The work must be completed **within 300 hours of flight time** after 31 August 1970\n\n**Why it matters:** Fire in a helicopter is catastrophic. A compromised firewall seal could allow an engine fire to spread to the cabin or fuel system, endangering everyone on board. This directive closes a known safety gap identified by the manufacturer and US regulators.\n\n**Key point:** This is not optional. Flying without completing this modification (within the time limit) would violate civil aviation law and make the aircraft unairworthy."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive adopts a mandatory requirement for an engine firewall-seal modification for identified 206A and AB-206A helicopters and states it is equivalent to a prior directive (AD/Agusta 206/18). The scope, as expressed, aligns with that earlier directive; this instrument does not indicate an expansion or contraction of applicability within the text provided."},"complexity_factors":["Narrow technical scope limited to a single modification (engine firewall seal).","Applicability limited to specific models and serial numbers referenced in external documents rather than listed in the directive itself.","Mandated compliance timetable (300 hours TIS after a fixed date) creates a clear but time‑bounded obligation.","Dependence on external technical documents (three possible sources) for the precise work and affected serial numbers.","No enforcement, cost, or alternative compliance mechanisms set out in the text, requiring reference to other regulatory material for those details."],"plain_english_summary":"This airworthiness directive mandates an engine firewall‑seal modification on certain Bell/Agusta 206A and AB‑206A helicopters, to be performed per Bell SB 206A‑142, FAA AD 70‑14‑6 or Agusta SB BT206‑43 within 300 hours TIS from 31 Aug 1970. It makes a manufacturer/authority service instruction into a binding regulatory requirement.\n\nAffected owners/operators must schedule and fund the work, using the cited technical documents and qualified maintenance to meet the compliance deadline."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-206-26-engine-firewall-seal-modification","history":"/api/acts/ad-bell-206-26-engine-firewall-seal-modification/history","analysis":"/api/acts/ad-bell-206-26-engine-firewall-seal-modification/analysis","conflicts":"/api/acts/ad-bell-206-26-engine-firewall-seal-modification/conflicts","importantCases":"/api/acts/ad-bell-206-26-engine-firewall-seal-modification/important-cases","documents":"/api/acts/ad-bell-206-26-engine-firewall-seal-modification/documents"}}