Fig. 31-1 Air data system
[2] The air data computer is enclosed in a 1/2 ATR long case. On the front of the unit there are two pneumatic connectors, a toggle switch for checking current status or past history data and a display window for showing test results. ADC uses a digital microprocessor to process pitot pressure, static pressure and total air temperature to produce the required air data information. the ADC provides altitude, altitude rate, baro corrected altitude, computed airspeed, mach, true airspeed, total air temperature, static air
temperature, and total and static air pressures to the various indicators and systems. The air data signals are sent to other systems in analog and digital formats. The digital information is transmitted using ARINC 429 buses.
[3] Two tests may be performed using the TEST/HISTORY switch on the front panel of the ADC. Momentarily placing the TEST/HISTORY switch in the TEST position performs a self test of the ADC . The hexadecimal display is tested and the display “88”will appear if the display is operating properly. After the display test, a display of “AA” indicates that the self test is occuring and the display value on the graphic will be displayed in the flight compartment. The output test values will remain for approximately sixty seconds and the display will flash for the last ten seconds of the test. The operator may select TEST again during this ten second period to have the values displayed for another sixty seconds.
[4] If failures are detected in the ADC or with sensor input signals, the display will momentarily show “FF” followed by the faults displayed as “FX” where the “X”will be a digit from 1 to 7. The meaning of the fault codes is defined on the front of ADC . In addition, the air data computer stores in nonvolatile memory any faults that occur during a flight segment for the last ten flights. Momentarily placing the TEST/HISTORY switch to HISTORY will cause the display to show any faults that occurred during the last flight. This information will be displayed as “OX” where“O”is the flight number (last flight ) and “X”is the fault code. All faults for that flight will be displayed in order. Preceding flights may be selected by placing the switch to HISTORY before the display ends. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：第31课 大气数据系统 LESSON 31 AIR DATA SYSTEM(2)
