{"id":"F2006B04577","name":"AD/BELL 212/45 - Tailboom Upper Longeron Splice","slug":"ad-bell-212-45-tailboom-upper-longeron-splice","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114307,"registerId":"commonwealth-F2006B04577-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 212/45 - Tailboom Upper Longeron Splice","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 212 Series Helicopters\n\n \n\nAD/BELL 212/45 Tailboom Upper Longeron Splice 2/91\n\nApplicability: All model 212 helicopters S/Nos 30501 - 30999, 31101 - 31311, 32101 - 32142 and\n\n35001 - 35022.\n\n \n\nRequirement: Action in accordance with Bell Alert SB No 212-90-63 dated 20 July 1990.\n\n \n\nCompliance: For Part 1: Within 300 hours time in service after 24 January 1991. Repeat the inspections (Part 2) at intervals not to exceed 300 hours time in service.\n\n \n\nBackground: Recent incidents of cracked longeron splices have created a requirement for provision of an inspection opening and repetitive inspection of the upper longeron splices.\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 specifies applicability to a defined set of Model 212 serial numbers and prescribes inspection/modification actions and flight-hour compliance windows. The text does not indicate any change of scope from an original intent; it establishes a targeted inspection requirement in response to reported cracked longeron splices and does not broaden or narrow applicability beyond the listed serial-number ranges. (Applicability; Requirement; Background)"},"complexity_factors":["Narrow technical scope (single component: tailboom upper longeron splice) and limited applicability to specific serial-numbered helicopters (reduces breadth of stakeholders). (Applicability)","Reliance on an external manufacturer document (Bell Alert SB No 212-90-63) for procedural detail increases implementation dependency and requires operators to obtain and interpret that document. (Requirement)","Compliance tied to flight hours (300-hour initial window and 300-hour repeat interval) necessitates operational integration of inspections into maintenance schedules. (Compliance)","AD text is prescriptive on what and when, but omits detailed technical steps and any end condition for recurring inspections, which can create ongoing operational burden until superseded. (Compliance)","Limited regulatory discretion in the AD itself (little room for alternative compliance within the text), but enforcement and interpretation depend on regulator and maintenance providers."],"plain_english_summary":"What this instrument does (mechanical change)\n\n- Requires specified Bell Helicopter Model 212 aircraft to have an inspection opening fitted and to undergo repeated inspections of the tailboom upper longeron splice. (Applicability; Requirement; Background)\n- Directs operators to perform the required work \"in accordance with Bell Alert SB No 212-90-63 dated 20 July 1990.\" (Requirement)\n- Sets timing: the initial action for Part 1 must be done within 300 hours time in service after 24 January 1991, and the inspections in Part 2 must be repeated at intervals not to exceed 300 hours time in service. (Compliance)\n\nWho is covered and who decides\n\n- Covered: all Model 212 helicopters with serial numbers 30501–30999, 31101–31311, 32101–32142 and 35001–35022. (Applicability)\n- The Civil Aviation Safety Authority (CASA) is the issuing regulator listed on the instrument; the technical procedure required is set out by the manufacturer in Bell Alert SB No 212-90-63. (header; Requirement)\n\nWhy the rule exists (official rationale and testing the rationale)\n\n- The stated reason is that recent incidents of cracked longeron splices created a need for an inspection opening and repetitive inspection of the upper longeron splices. (Background)\n- Mechanically, the instrument translates that safety concern into two concrete requirements: (1) implement the inspection opening and initial inspection per the manufacturer’s alert, and (2) continue inspections at specified flight-hour intervals. (Requirement; Compliance)\n\nWho pays and what changes in behaviour\n\n- Operators/owners bear the direct costs: obtaining and following Bell Alert SB No 212-90-63, fitting any inspection opening required by that alert, performing the initial inspection within the specified 300 flight hours after 24 January 1991, and performing ongoing inspections every up to 300 flight hours thereafter. (Requirement; Compliance)\n- Behaviour change: maintenance programs must be updated to include the specified modification/inspection procedure and to schedule and record the recurring inspections. Non-compliance would leave the operator outside the AD’s mandate. (Requirement; Compliance)\n\nCompliance burden, implementation risk and discretion\n\n- Compliance is specified by reference to a manufacturer alert rather than full technical detail in the AD itself, so operators must obtain and follow that external document to implement the work. That creates a dependency on the content and availability of Bell Alert SB No 212-90-63. (Requirement)\n- The AD prescribes specific scheduling based on flight hours (300-hour initial window and 300-hour repeat interval), which requires operators to track flight hours and integrate inspections into operational and maintenance planning. (Compliance)\n- The AD is prescriptive about what must be done and when; it does not, in this text, provide discretionary exemptions or alternative means of compliance. Implementation choices are therefore largely procedural (how to schedule and perform the inspections) rather than regulatory (there is no discretion in the AD text itself). (Requirement; Compliance)\n\nTrade-offs and opportunity costs (mechanical effects)\n\n- Direct costs: labour, any parts or structural work needed to fit the inspection opening, inspection time, and potential repairs or replacements if damage is found. (Requirement; Compliance)\n- Operational cost: aircraft downtime while modification/inspections are carried out and potential removal from service if repairs are required. (Compliance)\n- The AD channels those costs to the listed operators/owners and requires them to prioritise these inspections within the stated flight-hour windows. (Applicability; Compliance)\n\nConcrete limitations of the instrument as presented\n\n- The AD sets applicability, references the manufacturer’s alert for procedure, and imposes a flight-hour based compliance schedule. It does not include the detailed step-by-step technical procedure in the text—operators must consult Bell Alert SB No 212-90-63 to know exactly what to do. (Requirement)\n- The AD does not state a termination condition for the repeated inspections; it requires repeating Part 2 inspections at intervals not to exceed 300 hours, implying an ongoing maintenance requirement until further direction is issued. (Compliance)\n\nSource citations (from the instrument):\n- Applicability: serial-number ranges are listed under \"Applicability.\" (Applicability)\n- Required action: \"Action in accordance with Bell Alert SB No 212-90-63 dated 20 July 1990.\" (Requirement)\n- Timing: initial compliance and repeat intervals are in the \"Compliance\" paragraph. (Compliance)\n- Rationale: \"Recent incidents of cracked longeron splices have created a requirement for provision of an inspection opening and repetitive inspection of the upper longeron splices.\" (Background)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete safety directive addressing a specific airworthiness concern. It has not expanded beyond its original purpose of addressing cracked tailboom longeron splices in the specified helicopter fleet."},"complexity_factors":["Very short document (under 200 words)","Only 4 defined elements: applicability (serial number ranges), requirement (reference to external service bulletin), compliance deadline, and background","No nested conditional logic — simple 'do X by Y date, then repeat every Z hours' structure","Single cross-reference to external document (Bell Alert SB No 212-90-63)","No exceptions, exemptions, or alternative compliance methods stated"],"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/operators of certain Bell 212 helicopters to inspect a specific structural part called the \"tailboom upper longeron splice\" (a joint in the helicopter's tail section that has been cracking)\n- Mandates creating an inspection opening so mechanics can see this area properly\n- Requires repeating these inspections every 300 hours of flight time\n\n**Who it affects:**\n- Operators of Bell 212 helicopters with specific serial numbers (roughly 1970s-era twin Huey helicopters used for firefighting, search and rescue, offshore transport, etc.)\n\n**Why it matters:**\n- Cracked longeron splices could lead to structural failure of the tailboom — potentially catastrophic in flight\n- This AD prevents accidents by catching cracks before they become dangerous\n- Non-compliance grounds the aircraft (illegal to fly until fixed)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-212-45-tailboom-upper-longeron-splice","history":"/api/acts/ad-bell-212-45-tailboom-upper-longeron-splice/history","analysis":"/api/acts/ad-bell-212-45-tailboom-upper-longeron-splice/analysis","conflicts":"/api/acts/ad-bell-212-45-tailboom-upper-longeron-splice/conflicts","importantCases":"/api/acts/ad-bell-212-45-tailboom-upper-longeron-splice/important-cases","documents":"/api/acts/ad-bell-212-45-tailboom-upper-longeron-splice/documents"}}