{"id":"F2006B10877","name":"AD/JETSTREAM/1 - Fuselage Drain Holes - Modification","slug":"ad-jetstream-1-fuselage-drain-holes-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56390,"registerId":"commonwealth-F2006B10877-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/JETSTREAM/1 - Fuselage Drain Holes - 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)  British Aerospace BAe 3100 (Jetstream) Series Aeroplanes\n\n \n\nAD/JETSTREAM/1 Fuselage Drain Holes - Modification 8/84\n\nApplicability: All Jetstream Series 3100 aircraft with S/Nos 601, 603, 604, 608 to 624 and 627. Requirement:               British Aerospace Service Bulletin 53-JM7389.\n\nCompliance: Prior to issue of the next Maintenance Release after 31 August 1984.\n\n \n\nBackground: Cases have occurred in service of water draining from the fuselage drain valve at STN 255 onto the flap micro-switches. This water has frozen causing malfunction of the flap operating system.\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\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive’s scope is limited to the listed Jetstream 3100 serial numbers and requires the modification specified in British Aerospace Service Bulletin 53-JM7389 to be carried out by the compliance deadline. The document contains no text indicating any expansion or narrowing of that original scope."},"complexity_factors":["Narrow applicability limited to specific serial numbers (Applicability)","Technical execution delegated to a manufacturer service bulletin rather than detailed in the directive text (Requirement)","Fixed compliance timing tied to the next Maintenance Release after a calendar date, requiring scheduling within maintenance cycles (Compliance)","Safety-critical system involvement (flap micro-switches) increases procedural and qualification requirements for technicians (Background)","Regulatory mandatory nature creates enforcement and certificatory consequences for non-compliance","No cost, parts list or detailed timeline in the AD itself, requiring implementers to seek additional documentation from the manufacturer (Requirement)"],"plain_english_summary":"This mandatory directive from the Civil Aviation Safety Authority requires owners/operators of specified British Aerospace Jetstream 3100 serials to modify the fuselage drain arrangement per Service Bulletin 53‑JM7389 before the next Maintenance Release after 31 August 1984. The change prevents water draining onto flap micro‑switches (which can freeze and impair flap operation). Maintenance organisations must follow the manufacturer’s procedure; owners/operators bear parts, labour and downtime costs."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted airworthiness directive addressing a specific mechanical defect in specific aircraft. It has not expanded beyond its original purpose of mandating a safety modification to prevent flap system failures."},"complexity_factors":["Very short document (approximately 200 words)","Only 3 defined elements: applicability (specific serial numbers), requirement (single service bulletin reference), and compliance deadline","No cross-references to other legislation or regulations beyond the enabling Civil Aviation Regulations 1998","Single, unambiguous requirement with no exceptions, conditions, or alternative compliance methods","Straightforward cause-and-effect background explanation"],"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:**\nRequires owners and operators of certain British Aerospace Jetstream 3100 aircraft to carry out a specific modification to the fuselage (body of the plane) drain holes.\n\n**Who it affects:**\nOwners and operators of Jetstream Series 3100 aircraft with specific serial numbers: 601, 603, 604, 608 through 624, and 627.\n\n**Why it matters:**\nWater was leaking from a drain valve inside the fuselage onto electrical switches that control the flaps (the movable surfaces on the wings that help with takeoff and landing). When this water froze, it caused the flap system to malfunction — a serious flight safety risk. The directive mandates a fix (detailed in British Aerospace Service Bulletin 53-JM7389) before the aircraft's next scheduled maintenance check after 31 August 1984.\n\n**Bottom line:** This is a targeted safety fix to prevent ice-related flap failures on specific Jetstream aircraft."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jetstream-1-fuselage-drain-holes-modification","history":"/api/acts/ad-jetstream-1-fuselage-drain-holes-modification/history","analysis":"/api/acts/ad-jetstream-1-fuselage-drain-holes-modification/analysis","conflicts":"/api/acts/ad-jetstream-1-fuselage-drain-holes-modification/conflicts","importantCases":"/api/acts/ad-jetstream-1-fuselage-drain-holes-modification/important-cases","documents":"/api/acts/ad-jetstream-1-fuselage-drain-holes-modification/documents"}}