{"id":"F2006B03480","name":"AD/BAe 146/29 - Seat Rail Bolts","slug":"ad-bae-146-29-seat-rail-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43034,"registerId":"commonwealth-F2006B03480-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAe 146/29 - Seat Rail Bolts","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)  British Aerospace BAe 146 Series Aeroplanes\n\n \n\nAD/BAe 146/29 Seat Rail Bolts 3/91\n\nApplicability: Model BAe 146 series 300 with the following constructors numbers: E3134, E3135, E3137, E3141, E3142, E3143, E3145, E3147, E3149, E3150 and E3151.\n\n \n\nRequirement: Action in accordance with Mandatory BAe 146 SB 53-102. Compliance: As specified in the Requirement Document.\n\nBackground: To ensure that, if a higher density cabin layout is fitted in the future, the JAR and FAR crashworthiness requirements will still be met, it is necessary to ensure that the bolts securing the outer seat rails at frame 28 are changed from 1/4 in. to 5/16 in. diameter.\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\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD’s scope aligns with its stated purpose in the Background: it mandates a specific structural change (bolt size increase at frame 28) on a defined set of BAe 146-300 constructor numbers to preserve compliance with JAR/FAR crashworthiness if higher-density seating is later fitted (Applicability; Background). The instrument does not expand beyond those listed aircraft or introduce additional obligations beyond following the referenced Mandatory Service Bulletin (Requirement; Compliance)."},"complexity_factors":["Narrow and specific applicability limited to a short list of constructor numbers (Applicability).","Technical but straightforward mechanical change: bolt diameter increase from 1/4 in. to 5/16 in. at a single structural location (Background).","Dependence on an external Mandatory Service Bulletin (BAe 146 SB 53-102) for detailed work and timing creates an external-document dependency (Requirement; Compliance).","Regulatory binding: issued as an Airworthiness Directive under Civil Aviation Regulations Part 39, making compliance mandatory rather than advisory (header; Requirement).","Operational impacts (parts, labour, aircraft downtime) that owners/operators must manage, with costs borne by them though the AD itself does not quantify them (Applicability; Requirement)."],"plain_english_summary":"This AD requires owners/operators of eleven specific BAe 146-300 constructor-numbered aeroplanes to replace outer seat-rail bolts at fuselage frame 28 (from 1/4\" to 5/16\") in accordance with Mandatory SB 53-102. Costs and downtime fall to the operators/MROs. The stated purpose is to preserve JAR/FAR crashworthiness if a higher-density cabin layout is later fitted."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific airworthiness concern on a limited fleet. It has not expanded beyond its original purpose of ensuring crashworthiness compliance for potential future cabin reconfigurations."},"complexity_factors":["Very short document (under 200 words)","Only 11 specific aircraft affected by constructor number","Single technical requirement with clear reference to external standard (Service Bulletin 53-102)","No defined terms section","No nested conditions or exceptions","Straightforward compliance mechanism ('as specified in the Requirement Document')"],"plain_english_summary":"This is an **Airworthiness Directive** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\nOrders the replacement of seat rail bolts on certain British Aerospace BAe 146 aeroplanes. Specifically, the bolts holding the outer seat rails at \"frame 28\" must be upgraded from 1/4 inch to 5/16 inch diameter.\n\n**Who it affects:**\nOwners and operators of **11 specific BAe 146-300 series aircraft** (identified by their constructor numbers: E3134, E3135, E3137, E3141, E3142, E3143, E3145, E3147, E3149, E3150, and E3151).\n\n**Why it matters:**\nThe larger bolts are needed to meet crashworthiness safety standards (JAR and FAR — European and American aviation safety rules) if the airline ever installs a higher-density seating layout. Without this fix, passengers could be at greater risk in an accident if the seat rails fail under higher loads.\n\n**What must be done:**\nOperators must follow the instructions in **British Aerospace Service Bulletin 53-102** — a technical document from the manufacturer detailing exactly how to make the bolt change."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-29-seat-rail-bolts","history":"/api/acts/ad-bae-146-29-seat-rail-bolts/history","analysis":"/api/acts/ad-bae-146-29-seat-rail-bolts/analysis","conflicts":"/api/acts/ad-bae-146-29-seat-rail-bolts/conflicts","importantCases":"/api/acts/ad-bae-146-29-seat-rail-bolts/important-cases","documents":"/api/acts/ad-bae-146-29-seat-rail-bolts/documents"}}