{"id":"F2006B09855","name":"AD/F50/29 - Elevator and Tab Pulley Bracket - Frame 3100","slug":"ad-f50-29-elevator-and-tab-pulley-bracket-frame-3100","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54931,"registerId":"commonwealth-F2006B09855-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/29 - Elevator and Tab Pulley Bracket - Frame 3100","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\nAD/F50/29 Elevator and Tab Pulley Bracket - Frame 3100 13/89\n\nApplicability: F27 Mk50 aircraft, serial numbers 20103 through 20108 and 20110 through 20152. Requirement:               Action in accordance with Fokker Service Bulletin F50-27-017, dated 1 September\n\n1989.\n\n \n\nNote: RLD BLA 89-106, dated 25 September 1989 refers.\n\n \n\nCompliance: Prior to accumulating 15000 flight cycles.\n\n \n\nBackground: Fatigue tests on a test assembly of the subject pulley bracket revealed insufficient fatigue life. This AD calls for the replacement of the bracket with a redesigned one.\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 confined to replacing the identified pulley bracket on the listed F27 Mk50 serial numbers before 15,000 flight cycles, as set out in the source. There is no indication in the text that the scope has been expanded or otherwise altered from that stated intent (Applicability; Requirement; Compliance; Background)."},"complexity_factors":["Narrow applicability limited to specific aircraft serial numbers (20103–20108, 20110–20152) (Applicability)","Single, well-defined technical action: replacement per a specified service bulletin (Requirement)","Compliance deadline tied to an operational metric (flight cycles), requiring reliable flight-cycle tracking (Compliance)","Dependency on part availability and maintenance scheduling (Requirement; Compliance)","Low regulatory discretion — mandatory action with a prescribed method (Requirement)"],"plain_english_summary":"The directive requires operators of specified Fokker F50 (F27 Mk50) aeroplanes to replace the elevator/tab pulley bracket at frame 3100 with a redesigned part per Fokker Service Bulletin F50‑27‑017, to be done before the aircraft reach 15,000 flight cycles. It affects the listed aircraft owners and maintenance organisations because fatigue testing showed the original bracket didn’t meet required life; operators bear replacement costs and must schedule the work to keep aircraft airworthy."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific airworthiness issue on a defined aircraft population. It has not expanded beyond its original purpose of mandating replacement of a fatigue-critical component."},"complexity_factors":["Single, specific mechanical component addressed","Clear applicability criteria (specific serial number ranges)","Single compliance trigger (15,000 flight cycles)","One referenced technical document (Fokker Service Bulletin)","No nested exceptions, conditional logic, or defined terms section","Background explanation provided in plain language"],"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:**\nOrders owners and operators of certain Fokker F50 aeroplanes to replace a specific part — the **elevator and tab pulley bracket at Frame 3100** — before the aircraft reaches 15,000 flight cycles.\n\n**Why this matters:**\nFatigue testing revealed this bracket doesn't last as long as originally thought. If it fails in flight, it could affect the elevator (the control surface that makes the plane pitch up or down), potentially causing loss of control.\n\n**Who must comply:**\nAnyone operating Fokker F50 aircraft with serial numbers 20103–20108 and 20110–20152. The fix involves following Fokker's official Service Bulletin F50-27-017 from September 1989.\n\n**The bottom line:**\nThis is a **preventive safety measure**. Don't wait for the part to break — replace it proactively before hitting the flight cycle limit."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-29-elevator-and-tab-pulley-bracket-frame-3100","history":"/api/acts/ad-f50-29-elevator-and-tab-pulley-bracket-frame-3100/history","analysis":"/api/acts/ad-f50-29-elevator-and-tab-pulley-bracket-frame-3100/analysis","conflicts":"/api/acts/ad-f50-29-elevator-and-tab-pulley-bracket-frame-3100/conflicts","importantCases":"/api/acts/ad-f50-29-elevator-and-tab-pulley-bracket-frame-3100/important-cases","documents":"/api/acts/ad-f50-29-elevator-and-tab-pulley-bracket-frame-3100/documents"}}