{"id":"F2006B07320","name":"AD/TB20/17 Amdt 1 - Front Seat Safety Belts","slug":"ad-tb20-17-amdt-1-front-seat-safety-belts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49347,"registerId":"commonwealth-F2006B07320-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TB20/17 Amdt 1 - Front Seat Safety Belts","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)  Aerospatiale (Socata) TB20 (Trinidad) Series Aeroplanes\n\n \n\nAD/TB20/17\n\nAmdt 1\n\n\nFront Seat Safety Belts 3/95\n\n \n\nApplicability: All Model TB20 AND TB21 series aircraft.\n\n \n\nRequirement: Action in accordance with SOCATA Mandatory Service Bulletin 10.044.25 Amendment 1.\n\n \n\nNote: DGAC AD 89-097(A)R1 refers.\n\n \n\nCompliance: Prior to 2 March 1996, and thereafter at intervals not to exceed 12 calendar months.\n\n \n\nBackground:  Seat belt anchorage fittings are hidden by aircraft trim and therefore are not readily inspectable for corrosion.\n\n \n\nAmendment 1 is issued to align this Directive with a revision of the Country of Origin AD which reduces the inspection interval.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope (seat belt anchorage inspections for TB20/TB21 aircraft). The only change is tightening the inspection interval to match updated French standards — a refinement within the original safety purpose, not an expansion beyond it."},"complexity_factors":["Single, specific aircraft type (Socata TB20/TB21 series)","One clear compliance action (follow manufacturer's service bulletin)","Simple recurring timeframe (initial deadline + 12-month intervals)","No defined terms section, no cross-references to other legislation beyond the cited service bulletin and French AD","Background explanation provided in plain language","Total length: approximately 150 words of substantive content"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\nOrders owners and operators of **Socata TB20 and TB21 Trinidad series aeroplanes** to inspect the front seat safety belt anchor points for corrosion. These anchor fittings are normally hidden behind interior trim, so corrosion can go unnoticed and potentially weaken the belts in a crash.\n\n**Who must act:**\nAnyone who owns, operates, or maintains these specific French-made single-engine aircraft.\n\n**What must be done:**\nFollow the instructions in **SOCATA Mandatory Service Bulletin 10.044.25 Amendment 1** (the manufacturer's official safety notice). This involves removing trim to inspect the hidden metal fittings that hold the seat belts in place.\n\n**When:**\n- First inspection: before 2 March 1996\n- Repeat inspections: every 12 months thereafter\n\n**Why it matters:**\nCorroded seat belt anchorages could fail in an accident, allowing occupants to be thrown from their seats. This directive was updated (Amendment 1) to require **more frequent inspections** than originally mandated, matching a stricter safety standard from France (the country where these aircraft are built)."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"Amendment 1 reduces the inspection interval and aligns the Australian directive with a revised Country of Origin (DGAC) AD (Amendment 1; Note). The change narrows the time between required inspections to 12 calendar months (Compliance), increasing the frequency of mandatory inspections compared with the previous interval."},"complexity_factors":["Single, well-defined action: inspect front seat belt anchorage fittings per a specified service bulletin (Requirement).","Fixed, short compliance interval (annual) with a clear initial due date (Compliance).","Applicability limited to two aircraft model lines (TB20 and TB21) (Applicability).","Dependency on external document (SOCATA Mandatory Service Bulletin 10.044.25 Amendment 1) for procedural detail (Requirement).","Physical access complexity implied by hidden attachment points behind trim (Background), which may increase labour/time but does not add legal complexity."],"plain_english_summary":"# What this directive changes (mechanical effect)\n\n- The Civil Aviation Safety Authority (CASA) requires all Aerospatiale (SOCATA) TB20 and TB21 series aeroplanes to have their front seat safety-belt anchorage fittings inspected and any required work carried out in the way specified by SOCATA Mandatory Service Bulletin 10.044.25 Amendment 1 (Requirement).\n- The inspection must be done before 2 March 1996 and then no less frequently than every 12 calendar months thereafter (Compliance).\n\n# Who it affects\n\n- Owners and operators of all Model TB20 and TB21 aircraft (Applicability). They must ensure the inspections and any follow-up actions are carried out in accordance with the SOCATA service bulletin (Requirement).\n\n# Why the directive was issued (stated rationale)\n\n- The directive says the anchorage fittings for the front seat belts are concealed by aircraft trim and are not readily inspectable for corrosion (Background). The stated aim is to detect and address corrosion that might otherwise be missed.\n- The amendment aligns the Australian directive with a revised Country of Origin airworthiness directive that reduced the inspection interval (Amendment 1; Note refers to DGAC AD 89-097(A)R1).\n\n# Practical implications, incentives and costs\n\n- Who pays: aircraft owners/operators must procure and arrange the inspections and any repairs required by the service bulletin (Applicability; Requirement; Compliance). Those parties bear labour, parts and aircraft downtime costs.\n- Compliance burden: inspections are mandatory at the stated interval (Compliance). Because the fittings are described as hidden by trim (Background), inspections may require access behind interior panels or partial trim removal, which can increase labour time and complexity.\n- Implementation risk and effectiveness: the directive shifts inspection responsibility into an annual interval and requires the manufacturer’s specified procedures (Requirement). The effectiveness in finding corrosion depends on what the SOCATA service bulletin prescribes; the AD does not reproduce those procedures (Requirement).\n- Bureaucratic discretion and prescriptiveness: CASA prescribes compliance by reference to the manufacturer’s mandatory service bulletin rather than specifying inspection steps itself (Requirement). The AD does not set exceptions or alternative methods in its text.\n- Market effects and private choice: the measure imposes a recurring maintenance obligation on owners/operators (Applicability; Compliance). That will increase recurring maintenance demand; the AD does not specify who must perform the work (the AD requires action in accordance with the service bulletin but does not itself limit who can perform it) (Requirement).\n\n# Trade-offs and opportunity costs\n\n- The directive reduces the interval between inspections (Amendment 1), which increases inspection frequency and the associated costs and aircraft downtime for owners/operators (Compliance; Amendment 1). The intended trade-off is increased likelihood of detecting corrosion earlier (Background). The AD text does not supply cost estimates or alternative risk-mitigation options; those trade-offs must be resolved by the operator when organising compliance.\n\n# Where the details live\n\n- The AD requires actions \"in accordance with SOCATA Mandatory Service Bulletin 10.044.25 Amendment 1\"; the specific inspection techniques, acceptance criteria and repair instructions are contained in that service bulletin, not in the AD text (Requirement)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tb20-17-amdt-1-front-seat-safety-belts","history":"/api/acts/ad-tb20-17-amdt-1-front-seat-safety-belts/history","analysis":"/api/acts/ad-tb20-17-amdt-1-front-seat-safety-belts/analysis","conflicts":"/api/acts/ad-tb20-17-amdt-1-front-seat-safety-belts/conflicts","importantCases":"/api/acts/ad-tb20-17-amdt-1-front-seat-safety-belts/important-cases","documents":"/api/acts/ad-tb20-17-amdt-1-front-seat-safety-belts/documents"}}