{"id":"F2006B09834","name":"AD/F50/1 - Central Windshield Post Connection to Pressure Bulkhead","slug":"ad-f50-1-central-windshield-post-connection-to-pressure-bulkhead","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54863,"registerId":"commonwealth-F2006B09834-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/1 - Central Windshield Post Connection to Pressure Bulkhead","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)  Fokker F50 (F27 Mk 50) Series Aeroplanes\n\n \n\n# AD/F50/1 Central Windshield Post Connection to Pressure Bulkhead\n\nApplicability: All model F27 Mk 050 aircraft with serial numbers 20104 to 20107 inclusive. Requirement:              Modify in accordance with Fokker Service Bulletin F 50-53-001.\n\nNote: RLD BLA No 88-18 refers.\n\n \n\nCompliance: Before exceeding 10,000 flights.\n\n# 7/88\n\n \n\nBackground: The lug at the bottom of the central windshield post has broken on the manufacturer’s fatigue test. A modification has been designed to improve the fatigue resistance of this critical structural joint.\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":2,"scope_assessment":{"changed":false,"description":"The directive's scope is confined to the specific Fokker F27 Mk 050 serial numbers listed and requires a single modification per the referenced service bulletin before 10,000 flights. The text supplied gives no indication that the instrument's scope was widened or narrowed from an earlier intent; it establishes a targeted mandatory modification for the identified aircraft. (See: \"Applicability\", \"Requirement\", \"Compliance\".)"},"complexity_factors":["Very narrow applicability: only four serial-numbered airframes (20104–20107).","Single, clear action required: modification per a single referenced manufacturer service bulletin.","Fixed, simple compliance metric: deadline tied to flight count (10,000 flights).","Limited procedural detail in the directive itself — technical steps are delegated to the referenced service bulletin.","Cross-reference to additional document (RLD BLA No 88-18) increases lookup steps but not substantive complexity."],"plain_english_summary":"This directive mandates a preventive structural modification—per Fokker Service Bulletin F 50-53-001—to address a fatigue failure of the central windshield-post lug discovered in testing. The work must be done before the affected airframes reach the specified flight limit.\n\nIt applies only to four Fokker F50 (F27 Mk 050) airframes, serials 20104–20107, making the owners/operators of those aircraft responsible for arranging and completing the modification."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific structural defect identified in fatigue testing. It has not expanded beyond its original purpose of mandating a repair for a known safety issue in a limited fleet."},"complexity_factors":["Very short document (approximately 150 words)","Only 4 specific aircraft affected (narrow applicability)","Single, clear compliance requirement with reference to external technical document","No defined terms section","No cross-references to other legislation beyond a note about a related Dutch airworthiness directive (RLD BLA No 88-18)","Simple conditional logic: one deadline (10,000 flights) with no exceptions or nested conditions"],"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 aircraft.\n\n**What it does:**\nIt requires owners or operators of certain Fokker F50 aeroplanes to carry out a structural modification. Specifically, they must strengthen the connection between the central windshield post and the pressure bulkhead (a critical wall in the aircraft that maintains cabin pressure).\n\n**Who it affects:**\nOnly four specific aircraft: Fokker F27 Mk 050 models with serial numbers 20104, 20105, 20106, and 20107.\n\n**Why it matters:**\nDuring fatigue testing by the manufacturer, the metal lug (a projecting piece used for attachment) at the bottom of the central windshield post broke. This is a serious structural weakness that could lead to failure in flight. The directive mandates a fix designed by Fokker (the manufacturer) before these aircraft complete 10,000 flights.\n\n**Key deadline:**\nThe modification must be done **before the aircraft reaches 10,000 flights**.\n\n**What needs to be done:**\nInstall the modification exactly as described in **Fokker Service Bulletin F 50-53-001** (technical instructions from the manufacturer)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-1-central-windshield-post-connection-to-pressure-bulkhead","history":"/api/acts/ad-f50-1-central-windshield-post-connection-to-pressure-bulkhead/history","analysis":"/api/acts/ad-f50-1-central-windshield-post-connection-to-pressure-bulkhead/analysis","conflicts":"/api/acts/ad-f50-1-central-windshield-post-connection-to-pressure-bulkhead/conflicts","importantCases":"/api/acts/ad-f50-1-central-windshield-post-connection-to-pressure-bulkhead/important-cases","documents":"/api/acts/ad-f50-1-central-windshield-post-connection-to-pressure-bulkhead/documents"}}