{"id":"F2006B06496","name":"AD/RAD/36 Amdt 1 - Collins ADF Type ADF-650 - Operation From 27.5 Volt Supply","slug":"ad-rad-36-amdt-1-collins-adf-type-adf-650-operation-from-27-5-volt-supply","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48047,"registerId":"commonwealth-F2006B06496-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RAD/36 Amdt 1 - Collins ADF Type ADF-650 - Operation From 27.5 Volt Supply","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nRadio Communication and Navigation Equipment\n\nAD/RAD/36\n\nAmdt 1\n\n  \n\nCollins ADF Type ADF-650 \\- Operation From 27.5 Volt Supply\n\n  \n11/82\n\nApplicability: Collins RCR-650 receivers installed in aircraft having 27.5 volt electrical systems.\n\nRequirement: The voltage-dropping resistor originally specified for operation of the RCR-650 receiver from a 27.5 volt supply was an 11 ohm, 15 watt type. This has inadequate power rating, resulting in its overheating.\n\nTo overcome this problem either :\n\n    Modify the equipment in accordance with Collins RCR-650 receiver Service Information Letter 1-77 and Collins RCR-650 receiver SB No. 3; or\n\n    2. Install a dropping resistor and mounting hardware capable of adequate power dissipation; or\n\n    3. Modify the system wiring to provide operating power from a 28V/14V converter of an appropriate rating.\n\nWhere a resistor is used it should be mounted in a remote location that does not transfer heat to the avionics equipment.\n\nCompliance: Within 100 hours after 30 November, 1982.\n\nBackground: The RCR-650 ADF receiver is designed for operation from a 14 volt supply but is sometimes used in aircraft with 27.5 volt electrical systems. The voltage dropping resistors originally specified by the manufacturer are inadequately rated and overheat or burn out.\n\nThe problem can be overcome by fitting higher power rated resistors or modifying the electrical wiring to the receiver and using a DC-DC converter.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":3080},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment adds specific requirements for 27.5 volt electrical system configurations, representing a technical refinement to address a specific safety hazard within the existing scope of ADF-650 airworthiness regulation rather than an expansion beyond the original safety intent."},"complexity_factors":["Three alternative compliance methods with specific technical parameters","Cross-references to external manufacturer documents (Collins SIL 1-77 and SB No. 3)","Technical aviation terminology (voltage-dropping resistors, power dissipation, DC-DC converters)","Flight hour-based compliance calculation rather than calendar date"],"plain_english_summary":"This airworthiness directive addresses a fire hazard when Collins ADF‑650 (RCR‑650) receivers designed for 14V systems are operated on 27.5V aircraft using an undersized voltage‑dropping resistor that can overheat. It applies to any operator with an RCR‑650 on a 27.5V system and requires corrective action within 100 flight hours (manufacturer modification, a properly rated resistor mounted clear of other avionics, or a DC‑DC converter) to prevent resistor burn‑out and avionics fire."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rad-36-amdt-1-collins-adf-type-adf-650-operation-from-27-5-volt-supply","history":"/api/acts/ad-rad-36-amdt-1-collins-adf-type-adf-650-operation-from-27-5-volt-supply/history","analysis":"/api/acts/ad-rad-36-amdt-1-collins-adf-type-adf-650-operation-from-27-5-volt-supply/analysis","conflicts":"/api/acts/ad-rad-36-amdt-1-collins-adf-type-adf-650-operation-from-27-5-volt-supply/conflicts","importantCases":"/api/acts/ad-rad-36-amdt-1-collins-adf-type-adf-650-operation-from-27-5-volt-supply/important-cases","documents":"/api/acts/ad-rad-36-amdt-1-collins-adf-type-adf-650-operation-from-27-5-volt-supply/documents"}}