Anti-g System Maintenance

anti-g valve and remains constant until the g forces change. As the g forces decrease, the downward force on the activating weight diminishes to a point at which the upper spring lifts the weight off the exhaust valve. The pressure in the suit is then vented through the exhaust port (fig. 1-4, view C) into the cockpit. Anti-G System Filter Most anti-g systems use a filter to prevent particles of dust, trash, and other foreign material from entering the regulating valve. This filter may be located in the supply line, as shown in figure 1-2, or it may be attached to the anti-g valve on the inlet side. A typical anti-g system filter is shown in figure 1-5. Quick Disconnects The anti-g suit is connected to the anti-g system by means of a quick-disconnect coupling. This quick disconnect may be either a single unit that connects the anti-g suit only, or it may be a composite quick disconnect that connects the pilot to the various personal service lines (oxygen, ventilating air, anti-g system, and communications). The anti-g system quick disconnect is used on aircraft that are not equipped with a composite quick disconnect attached to the ejection seat. This disconnect is on a hose that protrudes through the pilot’s console. It is attached by a Figure 1-5.—Anti-g system filter. flexible hose to the outlet port of the anti-g pressure regulating valve. This disconnect may be l pulled up to a bumper stop to aid in connecting the anti-g suit hose. A spring-loaded cover on the disconnect prevents the entry of foreign material when the system is not in use. Anti-g System Maintenance Maintenance of the anti-g system consists mainly of removal and installation of valves and lines and servicing the filter. Component repair of the anti-g valve is limited because of the equip- ment necessary to test the valve. Component repair of the dual range anti-g valve is not recommended. The single-stage anti-g valve may be repaired at intermediate maintenance activities that have the necessary test equipment. SERVICING.— Replace the anti-g filter element at periodic intervals, or when the element becomes clogged or dirty. The replacement interval is specified in the applicable maintenance requirement cards. If the filter is removed from the aircraft, ensure the filter is reinstalled properly. The inlet and outlet ports are identified as IN and OUT to facilitate installation for proper direction of airflow. After replacing the filter element, make a thorough check to ensure that no air leaks exist. OPERATIONAL CHECK.— Perform an operational check of the anti-g system with the aircraft engine running by pressing the test button on top of the valve to determine if there is proper airflow from the system. When the test button is depressed, the amount of airflow from the disconnect should be proportional to the amount the button is depressed. Greater airflow with increased button depression indicates that the anti-g valve is operating properly on aircraft with dual range anti-g valves. This test should be performed in both the high (HI) and low (LO) ranges. VENT-AIR SYSTEM Vent-air systems provide a flow of air to the aircraft’s seat or back cushions or to the ventilating air connection of the antiexposure suit when worn by the pilot and/or crew members. The system provides a measure of personal comfort, offsetting the discomfort caused by the wearing of the antiexposure suit or heat created 1-5