{"id":"F2006B09677","name":"AD/F27/108 - Rudder Trim Tab Control Bracket Attachment - Inspection","slug":"ad-f27-108-rudder-trim-tab-control-bracket-attachment-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115817,"registerId":"commonwealth-F2006B09677-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F27/108 - Rudder Trim Tab Control Bracket Attachment - Inspection","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 F27 Series Aeroplanes\n\n \n\nAD/F27/108 Rudder Trim Tab Control Bracket Attachment - Inspection\n\n\n6/86\n\n \n\nApplicability: All Models.\n\n \n\nRequirement: Fokker Service Bulletin F27/55-58.\n\n \n\nNOTE: R.L.D. AD 85-31 refers.\n\n \n\nCompliance: Prior to 15 July 1985.\n\n \n\nBackground:  Investigation into a flutter occurrence revealed that substitute rivets had been installed in the rib skin attachment of the rudder trim tab actuating bracket. The clamping qualities of the installed rivets may substantially reduce stiffness of the tab control attachment.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive focused on a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of mandating an inspection to prevent rudder flutter."},"complexity_factors":["Very short document (under 200 words)","Only one substantive requirement (comply with Service Bulletin F27/55-58)","No defined terms section","No conditional logic or nested exceptions","Single applicability criterion (All Models)","Single compliance deadline with no alternatives","Background provided in plain narrative form rather than technical legalese"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nOrders owners and operators of **Fokker F27 series aircraft** to inspect the rudder trim tab control bracket attachment. Specifically, they must follow instructions in **Fokker Service Bulletin F27/55-58**.\n\n**Why it matters:**\nAn investigation found that wrong rivets had been used in the rudder trim tab mechanism. These substitute rivets don't clamp properly, which reduces stiffness in the control attachment. This could lead to **flutter** — a dangerous vibration that can cause control surfaces to fail or break off in flight.\n\n**Who must comply:**\nAnyone operating any model of Fokker F27 aircraft.\n\n**Deadline:**\nThe inspection had to be completed before **15 July 1985**.\n\n**Cross-reference:**\nThis Australian directive relates to a similar US Federal Aviation Administration directive (R.L.D. AD 85-31)."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD applies to all Fokker F27 models and requires the inspection set out in Fokker Service Bulletin F27/55-58 to be completed by 15 July 1985. The instrument does not expand or narrow applicability beyond that mandate and does not introduce additional unrelated obligations; it implements an inspection requirement based on the investigation described in the Background section. (Applicability; Requirement; Compliance; Background)"},"complexity_factors":["Short, single-subject directive focused on one inspection","Clear applicability to all Fokker F27 models (no model-specific carve-outs)","External technical detail delegated to a specific Fokker service bulletin (requires access to that document)","Fixed compliance deadline (no staged compliance or performance-based alternatives)","Technical judgement and execution left to maintenance organisations following the service bulletin"],"plain_english_summary":"This AD requires owners/operators of Fokker F27 aircraft to complete an inspection (per Fokker Service Bulletin F27/55-58) of the rudder trim‑tab actuating‑bracket attachment before 15 July 1985 to detect substitute/non‑conforming rivets that could reduce clamping and risk flutter. Operators fund inspections and any repairs; maintenance providers must follow the referenced service bulletin."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f27-108-rudder-trim-tab-control-bracket-attachment-inspection","history":"/api/acts/ad-f27-108-rudder-trim-tab-control-bracket-attachment-inspection/history","analysis":"/api/acts/ad-f27-108-rudder-trim-tab-control-bracket-attachment-inspection/analysis","conflicts":"/api/acts/ad-f27-108-rudder-trim-tab-control-bracket-attachment-inspection/conflicts","importantCases":"/api/acts/ad-f27-108-rudder-trim-tab-control-bracket-attachment-inspection/important-cases","documents":"/api/acts/ad-f27-108-rudder-trim-tab-control-bracket-attachment-inspection/documents"}}