{"id":"F2006B03258","name":"AD/B747/80 - Equipment Cooling System E30 Cooling Rack Orifice","slug":"ad-b747-80-equipment-cooling-system-e30-cooling-rack-orifice","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42682,"registerId":"commonwealth-F2006B03258-current","compilationNumber":null,"startDate":"2026-04-01","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/80 - Equipment Cooling System E30 Cooling Rack Orifice","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)  Boeing 747 Series Aeroplanes\n\n \n\n# AD/B747/80 Equipment Cooling System E30 Cooling Rack Orifice\n\nApplicability: All Boeing 747-400 as detailed in the Requirement document. Requirement:  Action in accordance with Boeing Alert Service Bulletin 747-21A2285. Compliance:               Prior to 6 December 1990.\n\n# 9/90\n\nBackground: One operator has reported three instances of insufficient equipment cooling system pressure in the E30 rack. Lack of sufficient cooling may cause overheating of the main transformer rectifier units resulting in no DC power output from the main TRU’s. Whilst limited DC power will still be available from the main battery and battery charger, loss of output from the main TRU’s will result in loss of many flight essential systems.\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":1386},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted, single-issue directive addressing a specific safety defect in a specific aircraft type. The scope remains confined to the original equipment cooling issue without expansion into broader regulatory changes."},"complexity_factors":["Very short document (approximately 200 words)","Single, unambiguous requirement","Relies on external technical standard (Boeing Service Bulletin) for implementation details","Clear applicability limited to specific aircraft model","No conditional logic, exceptions, or defined terms"],"plain_english_summary":"**What it is:** A safety order requiring airlines to fix a cooling problem in Boeing 747-400 aircraft.\n\n**The problem:** The E30 equipment cooling rack (which houses electrical components like transformer rectifiers) wasn't getting enough airflow. If these units overheat, they stop producing DC electrical power. While backup batteries provide limited power, many critical flight systems would fail.\n\n**What must be done:** Airlines must follow Boeing's technical instructions in Alert Service Bulletin 747-21A2285 to fix the cooling rack orifice (the opening that allows air to flow through).\n\n**Who it affects:** All operators of Boeing 747-400 series aircraft.\n\n**Deadline:** The fix had to be completed before 6 December 1990."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-80-equipment-cooling-system-e30-cooling-rack-orifice","history":"/api/acts/ad-b747-80-equipment-cooling-system-e30-cooling-rack-orifice/history","analysis":"/api/acts/ad-b747-80-equipment-cooling-system-e30-cooling-rack-orifice/analysis","conflicts":"/api/acts/ad-b747-80-equipment-cooling-system-e30-cooling-rack-orifice/conflicts","importantCases":"/api/acts/ad-b747-80-equipment-cooling-system-e30-cooling-rack-orifice/important-cases","documents":"/api/acts/ad-b747-80-equipment-cooling-system-e30-cooling-rack-orifice/documents"}}