{"id":"F2006B10959","name":"AD/JETSTREAM/9 - Wing Attachment to Fuselage Spigot Installation","slug":"ad-jetstream-9-wing-attachment-to-fuselage-spigot-installation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56527,"registerId":"commonwealth-F2006B10959-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/JETSTREAM/9 - Wing Attachment to Fuselage Spigot Installation","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 3100 (Jetstream) Series Aeroplanes\n\n \n\n# AD/JETSTREAM/9 Wing Attachment to Fuselage\n\nSpigot Installation\n\nApplicability: All Jetstream 3100 aircraft with S/Nos 601 to 666.\n\n \n\nRequirement: Action in accordance with British Aerospace Alert SB 57-A-JA 85-941.\n\n# 11/85 T\n\n \n\nCompliance: Within 50 hours time in service after 25 September 1985 or 7 days after 25 September 1985, whichever occurs first.\n\n \n\nBackground: An operator has reported that a Spigot P/No 13781 B7 attaching the wing front spar to fuselage STN 199 had become disengaged from the Spigot housing.\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 as provided sets a single, explicit scope: it applies to Jetstream 3100 aircraft S/Nos 601–666 and mandates action per British Aerospace Alert SB 57-A-JA 85-941 with a defined compliance window. There is no text in the instrument indicating any change to that original scope."},"complexity_factors":["Narrow, specific technical scope (single aircraft type and serial number range) reduces legal complexity (Applicability).","Mandatory compliance with an external manufacturer service bulletin concentrates technical detail outside the AD text, requiring cross-reference to the SB (Requirement).","Short, fixed compliance window creates operational complexity for scheduling and logistics (Compliance).","Limited regulatory discretion in the text (prescriptive command) simplifies legal interpretation but raises practical coordination demands between operators and maintenance providers (Requirement; Compliance).","Sparse factual background and limited procedural detail in the AD itself reduce interpretive ambiguity but require access to the referenced manufacturer alert for actionable steps (Background; Requirement)."],"plain_english_summary":"### What this instrument does (mechanically)\n\nThis Airworthiness Directive (AD) requires operators of specified British Aerospace Jetstream 3100 aeroplanes to carry out the corrective action set out in a manufacturer service document. It directs that the spigot that attaches the wing front spar to the fuselage be inspected/installed in accordance with British Aerospace Alert SB 57-A-JA 85-941 (Requirement). The AD applies to all Jetstream 3100 aircraft with serial numbers 601 to 666 (Applicability). The work must be done within either 50 hours time in service after 25 September 1985 or within 7 days after 25 September 1985, whichever comes first (Compliance).\n\n### Why this AD was issued (stated reason)\n\nThe AD follows a report from an operator that the spigot P/No 13781 B7 attaching the wing front spar to fuselage station 199 had become disengaged from its housing (Background). The AD therefore mandates the manufacturer-specified action to address that condition (Requirement).\n\n### Who pays, who decides, and how behaviour changes (plain terms)\n\n- Who pays: The aircraft operator or owner pays for the inspection/installation, parts and labour required to comply (Requirement; Compliance).\n- Who decides how to do the work: The AD requires compliance with the specific British Aerospace Alert SB 57-A-JA 85-941, so the technical method and steps are set by that manufacturer document (Requirement).\n- How behaviour changes: Operators must schedule and complete the specified work within the short compliance window (50 hours TIS or 7 days) and may need to take aircraft out of service temporarily to perform the work (Compliance).\n\n### Implementation trade-offs, incentives and practical risks\n\n- Time pressure and operational cost: The short compliance window (50 hours or 7 days after 25 Sept 1985) concentrates maintenance activity into a narrow period, creating direct costs in labour, replacement parts and aircraft downtime borne by operators (Compliance).\n- Delegation of technical detail: The AD mandates following a manufacturer alert (Requirement). That concentrates technical authority in the manufacturer document and means operators rely on that SB for the exact procedure and parts specification (Requirement).\n- Supply and execution risk: If parts, trained personnel or facilities are limited, operators may face delays, increased costs, or the need to reallocate aircraft—these are practical consequences of the compliance requirement (Requirement; Compliance).\n- Compliance certainty and limited discretion: The AD prescribes a defined action and fixed compliance window, leaving little discretion to operators about whether or how to comply; the regulator enforces compliance through the AD framework (Header; Requirement; Compliance).\n\n### Concrete effects on private enterprise and choices\n\n- Maintenance providers: Independent maintenance organisations can perform the work but must follow the manufacturer alert specified by the AD; this sets the technical standard they must meet (Requirement).\n- Operational choice: Operators must choose between meeting the AD quickly (incurring immediate cost and downtime) or risk regulatory non-compliance; the AD creates a clear compliance incentive (Compliance).\n\n### Source references\n\nAll citations in this summary are drawn from the AD text provided: the instrument header (Civil Aviation Regulations/AD schedule), the Applicability clause (S/Nos 601–666), the Requirement clause (action in accordance with British Aerospace Alert SB 57-A-JA 85-941), the Compliance clause (within 50 hours TIS or 7 days after 25 Sept 1985), and the Background note (report of spigot disengagement)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of mandating inspection/correction of the wing attachment spigot installation."},"complexity_factors":["Very short document (approximately 150 words)","Only 2 defined applicability criteria (aircraft model and serial number range)","Single requirement referencing an external technical document (Service Bulletin)","Simple binary compliance condition (50 hours OR 7 days, whichever is first)","No nested exceptions, cross-references to other legislation, or conditional logic","Straightforward factual background describing a single mechanical failure mode"],"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) for specific aircraft.\n\n**What it does:** It requires owners and operators of certain British Aerospace Jetstream 3100 aircraft (serial numbers 601 to 666) to inspect and fix a critical safety problem with how the wings attach to the fuselage (the main body of the plane).\n\n**The specific problem:** A metal fitting called a \"spigot\" (part number 13781 B7) that connects the front wing spar to the fuselage had been found disconnected from its housing. This is extremely dangerous — if the wing separates from the fuselage in flight, the aircraft would crash.\n\n**What must be done:** Operators must follow the instructions in British Aerospace Alert Service Bulletin 57-A-JA 85-941 to inspect and correct the installation of this spigot fitting.\n\n**When it must be done:** Within 50 flight hours **or** 7 days after 25 September 1985 — whichever comes first. This tight deadline reflects the urgent safety risk.\n\n**Who it affects:** Anyone operating Jetstream 3100 aircraft with serial numbers 601 through 666 — primarily regional airlines and charter operators using these turboprop aircraft in Australia.\n\n**Why it matters:** This is an emergency safety directive addressing a potentially catastrophic structural failure. The short compliance timeframe (7 days maximum) indicates CASA treated this as an immediate threat to airworthiness."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jetstream-9-wing-attachment-to-fuselage-spigot-installation","history":"/api/acts/ad-jetstream-9-wing-attachment-to-fuselage-spigot-installation/history","analysis":"/api/acts/ad-jetstream-9-wing-attachment-to-fuselage-spigot-installation/analysis","conflicts":"/api/acts/ad-jetstream-9-wing-attachment-to-fuselage-spigot-installation/conflicts","importantCases":"/api/acts/ad-jetstream-9-wing-attachment-to-fuselage-spigot-installation/important-cases","documents":"/api/acts/ad-jetstream-9-wing-attachment-to-fuselage-spigot-installation/documents"}}