CG 47类咨询NR 08-93 MK 99防火系统有缺陷的天线进料加热器***非活动***非活动***非活动***
Ref / A / Doc / Navsea / - // Ref / B / Doc / Navsea / - // Narr / Ref A技术手册，Navsea SW273-AO-AEG-050。ref b是pms mip 4829/001 .// rmks / 1。该咨询警告Alcon对不起作用的进料加热器的可能性，这可能导致防火系统发生故障。2.背景。对CG 47的RoH事件，Raytheon检查了AS-3444天线的主要和辅助（后参考）进料加热器。发现许多这些加热器失败了。由于这些加热器直接连接到船舶电源并由安装的热敏电阻自动控制，因此失败未被发现。检查了许多其他船舶中的天线并发现也失败了。无效的进巫加热器可能导致进料窗口上的冰积聚，当天线辐射时会导致窗口上的电弧放电。3.行动。 A. CG 47 CLASS SHIPS SHOULD PERFORM AN INSPECTION OF THE FEEDHORN HEATERS TO ENSURE THAT THEY ARE FUNCTIONAL AS FOLLOWS: (1) SECURE POWER TO THE HEATER BEING INSPECTED. (2) OPEN THE INTERCONNECTING BOX ASSEMBLY (REF A, PAGE 7-249, FIND NR 30) AND USE A MULTIMETER TO ENSURE NO VOLTAGE IS PRESENT. (3) REMOVE WIRES FROM THE TERMINAL POST. (4) COOL THE HEATER, USING ICE OR A FREEZE SPRAY. (5) MEASURE THE RESISTANCE ON EACH SET OF LEADS TO EACH HEATER. AN OPEN READING INDICATES THAT THE HEATER IS DEFECTIVE. B. IF DEFECTIVE HEATERS ARE FOUND, PROCURE REPLACEMENTS. ON BOARD ALLOWANCE IS ONE OF EACH (MAIN AND ANCILLARY) TYPE. CURRENT LEAD TIME FOR MAIN HEATERS IS SIX MONTHS. C. HEATERS SHOULD BE ORDERED USING THE FOLLOWING INFORMATION: (1) MAIN FEEDHORN HEATER - PART NUMBER 2912010-1 NSN 4540-01-115-2545. (2) ANCILLARY FEEDHORN HEATER - PART NUMBER 2912012-1 NSN 4540-01-264-7798. 4. FOR COMNAVSURFLANT/COMNAVSURFPAC - RECOMMEND CG 47 CLASS SHIPS BE TASKED TO CARRY OUT THE ACTION IN PARA THREE ABOVE. 5. NSWC/PHD IS DEVELOPING A PMS PROCEDURE FOR REF B WHICH WILL PROVIDE A PERIODIC CHECK OF THE FEEDHORN HEATERS. 6. THIS ADVISORY HAS NO IMPACT ON EOSS, CSOSS, TECHNICAL DOCUMENTATION OR CMP. IT WILL BE CANCELLED WHEN THE PMS PROCEDURE HAS BEEN DEVELOPED AND DISTRIBUTED. 7. POINT OF CONTACT IS MR N S SMITHSON, PMS400F511, DSN: 332-5981 OR COMM (703) 602-5981. TECHNICAL POC IS MR T. PETITO, NSWC/PHD CODE 4C12, DSN: 551-7377 OR COMM (805) 982-7377.//
CG-47.