{"id":"F2006B09851","name":"AD/F50/25 - Radio Magnetic Indicators Wiring Change","slug":"ad-f50-25-radio-magnetic-indicators-wiring-change","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54920,"registerId":"commonwealth-F2006B09851-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F50/25 - Radio Magnetic Indicators Wiring Change","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/F50/25 Radio Magnetic Indicators Wiring Change 13/89\n\nApplicability: F27 Mark 50 aircraft with Serial Numbers 20103 to 20108 inclusive and 20110 to 20141 inclusive\n\n \n\nRequirement: Modify in accordance with Fokker 50 Service Bulletin SBF 50-34-013.\n\n \n\nNote: RLD Airworthiness Directive BLA 89-097 refers.\n\n \n\nCompliance: Prior to 1 April 1990.\n\n \n\nBackground: Errors of up to 5 degrees are possible on the RMIs due to incorrect wiring. These exceed permissible limits.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive from 1989/1990. It has not expanded beyond its original narrow purpose of fixing a specific wiring defect in specific aircraft. The document represents the complete regulatory instrument — no scope creep is possible or evident."},"complexity_factors":["Extremely short document — approximately 150 words total","Only 1 substantive requirement: comply with manufacturer service bulletin","No defined terms section — all terminology is standard aviation jargon (RMI, serial numbers, service bulletin)","No conditional logic or exceptions — simple applicability rule based on serial number ranges","Single cross-reference to Dutch authority directive (informational only, not a legal dependency)","Clear, fixed compliance deadline with no alternative methods of compliance (AMOC) mentioned"],"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). Think of it as a \"recall notice\" for aircraft, but legally binding.\n\n**What it does:** It requires owners/operators of specific Fokker F50 aircraft to rewire their **Radio Magnetic Indicators (RMIs)** — cockpit instruments that show the direction to radio navigation beacons. The wiring was installed incorrectly at the factory, causing the compass needles to display up to 5 degrees off from the true direction. That's enough to send a pilot off course.\n\n**Who it affects:** Only 46 specific aircraft — Fokker F50s with serial numbers 20103-20108 and 20110-20141. These are regional turboprop airliners (similar to the ones used by airlines like QantasLink or Alliance in Australia).\n\n**What must be done:** Aircraft operators must follow **Fokker Service Bulletin SBF 50-34-013** — a technical instruction manual from the manufacturer detailing exactly how to fix the wiring. The fix had to be completed before **1 April 1990**.\n\n**Why it matters:** Navigation errors of 5 degrees compound over distance. On a 200km flight, that's roughly 17km off track — potentially the difference between finding an airport and flying into restricted airspace or terrain. This AD prevents that by forcing a free factory-authorized repair.\n\n**The Dutch connection:** The note mentions \"RLD Airworthiness Directive BLA 89-097\" — this shows Australia was harmonizing with the Dutch aviation regulator (RLD, since the Fokker is a Dutch aircraft), ensuring consistent safety standards across borders."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD does not change scope from its stated intent. The document identifies the safety problem (RMI errors up to 5 degrees) (Background), limits the affected fleet precisely by serial number (Applicability), prescribes the corrective action by reference to a named service bulletin (Requirement), and sets a compliance date (Compliance). There is no text indicating an expansion or narrowing of the measure beyond correcting the wiring on the listed aircraft."},"complexity_factors":["Narrow applicability: applies only to F27 Mk 50 aircraft with specific serial numbers (Applicability).","Single required action: one technical modification mandated (Requirement).","Prescriptive compliance method: work must follow Fokker Service Bulletin SBF 50-34-013 (Requirement).","Fixed compliance deadline (Prior to 1 April 1990) creates scheduling pressure (Compliance).","Regulatory formality: issued as an Airworthiness Directive under Civil Aviation Regulations, so non-compliance has regulatory consequence (header).","Technical dependency: performing the change requires access to the service bulletin and appropriate maintenance capability (Requirement)."],"plain_english_summary":"Owners/operators of specific Fokker F50s (S/N 20103–20108, 20110–20141) must carry out a mandated wiring modification to their Radio Magnetic Indicators per Fokker Service Bulletin SBF 50‑34‑013 before 1 April 1990. The AD, issued to eliminate RMI heading errors (up to ~5°), prescribes a single corrective method, imposes the compliance cost on operators, and limits operational discretion unless an alternative is approved."}},"importantCases":[],"_links":{"self":"/api/acts/ad-f50-25-radio-magnetic-indicators-wiring-change","history":"/api/acts/ad-f50-25-radio-magnetic-indicators-wiring-change/history","analysis":"/api/acts/ad-f50-25-radio-magnetic-indicators-wiring-change/analysis","conflicts":"/api/acts/ad-f50-25-radio-magnetic-indicators-wiring-change/conflicts","importantCases":"/api/acts/ad-f50-25-radio-magnetic-indicators-wiring-change/important-cases","documents":"/api/acts/ad-f50-25-radio-magnetic-indicators-wiring-change/documents"}}