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曝光台 注意防骗 网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
The 14th-stage isolation valve is pneumatically operated and electrically controlled by the 14th-stage ISOL switch/light on the BLEED AIR panel. Valve status is indicated by a switch/light OPEN annunciation (see Figure 14.10.1). The isolation valve is spring-loaded to the closed position when no 14th-stage bleed air is available, or electrical power control is lost. Thrust Reverser Override Function The 14th-stage bleed air cannot simultaneously supply the demands of the thrust reverser and the wing anti-ice system. Therefore, the wing anti-ice system is automatically disabled upon thrust reverser operation. The EICAS caution messages for wing anti-ice are inhibited during thrust reverser operation. ENGINE COWL ANTI-ICE SYSTEM Description The engine cowl anti-ice system prevents ice formation on the cowl leading edges and the T2 probe at the engine inlet, using pressure-regulated 14th-stage bleed air. The bleed air is ducted to the T2 probe and to the cowl leading edges from the cowl anti-ice valve and the ejector. The ejector circulates the air within the cowl with air ejected from the piccolo tubes onto the inner surfaces of the leading edge. After heating the cowl leading edges, the air is exhausted overboard through a louvered exit at the bottom of the engine nacelle. The L (R) COWL ANTI-ICE switch/lights, located on the ANTI-ICE panel, control the left and right engine cowl anti-ice valves respectively.
Components and Operation
When the COWL switch/light is deselected, the cowl anti-ice valve is commanded to close. Should the cowl anti-ice valve remain in the open position (as sensed by the pressure switch), the L (R) COWL A/ICE caution EICAS message will be displayed, indicating bleed pressure in the system (valve failed to close). |
