{"id":"F2006B06485","name":"AD/RAD/21 - Instrument Landing Systems (ILS) Instrumentation","slug":"ad-rad-21-instrument-landing-systems-ils-instrumentation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48013,"registerId":"commonwealth-F2006B06485-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RAD/21 - Instrument Landing Systems (ILS) Instrumentation","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 - 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Radio Communication and Navigation Equipment\n\n \n\nAD/RAD/21 Instrument Landing Systems (ILS) Instrumentation 3/69\n\nApplicability: Airborne ILS installations completed or modified after 15 April 1969.\n\n \n\nRequirement: Localiser and Glideslope information displayed simultaneously on any one indicator shall always relate to the same Instrument Landing System.\n\n \n\nCompliance: Before 15 April 1969.\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\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1722},"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This 1969 airworthiness directive retains its original narrow scope. It addresses only the specific technical issue of ILS signal pairing in cockpit displays and has not expanded to cover broader avionics integration or other navigation systems."},"complexity_factors":["Single, unqualified operational requirement with no exceptions or nested conditions","No definitions section or interpretation provisions","No cross-references to other legislative instruments","Extremely brief (approximately 50 words of substantive regulatory text)","Only two operative dates to consider (applicability and compliance)"],"plain_english_summary":"**What this does:** This safety rule prevents aircraft navigation displays from mixing up landing signals. It requires that when an instrument shows both horizontal position (localiser) and vertical descent path (glideslope) guidance, both signals must come from the **same** ground-based Instrument Landing System (ILS). This stops the dangerous scenario where a pilot might follow horizontal directions for one runway while following vertical directions for a different one.\n\n**Who it affects:** Aircraft with ILS equipment installed or modified after 15 April 1969.\n\n**Why it matters:** During landing—especially in poor visibility when pilots rely entirely on instruments—mixing signals from different runways could send the aircraft off course or into the ground. This \"cross-system\" error was a known risk in early integrated flight displays."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rad-21-instrument-landing-systems-ils-instrumentation","history":"/api/acts/ad-rad-21-instrument-landing-systems-ils-instrumentation/history","analysis":"/api/acts/ad-rad-21-instrument-landing-systems-ils-instrumentation/analysis","conflicts":"/api/acts/ad-rad-21-instrument-landing-systems-ils-instrumentation/conflicts","importantCases":"/api/acts/ad-rad-21-instrument-landing-systems-ils-instrumentation/important-cases","documents":"/api/acts/ad-rad-21-instrument-landing-systems-ils-instrumentation/documents"}}