[7] The FMC receives digital and discrete inputs from several sensors and other systems in the FMS. The FMC performs the computational, logical, and input/output processing required by the airplane's flight and performance systems. The outputs of the FMC are in ARINC 429 digital format. Digital inputs are as follows:
CDU provide the interface between the flight crew and the FMC.
Each IRS provides present position, heading, attitude, velocity, altitude, ground speed, and vertical speed to the FMC through an ARINC 429 bus.
Air data computer provides altitude, airspeed mach, and temperature information to the FMC through an ARINC 429 bus.
The pilot's clock provides Greenwich Mean Time ((GMT) to the FMC.
Data from the FCC is transmitted to the MCP (Mode Control Panel) and then to the FMC.
The digital flight control system (DFCS) mode control panel (MCD) provides LNAV and VNAV engage mode logic, selected altitude data, and flap position to the FMC.
The fuel summation unit provides fuel quantity through the DAA.
DME interrogators provide distance information to the FMC, through the DAA.
VHF navigation receivers provide deviation and bearing information to the FMC, through the DAA.
In addition, the FMC monitors discrete input signals from the engine bleed air , engine and wing anti-ice, engine fuel control, and air conditioning systems. Turning on the bleed air, anti-ice, or air conditioning may cause an engine thrust reduction. The FMC uses these discrete signals to provide corresponding adjustments to calculated performance values.
[8] The digital outputs of FMC are as follows:
FMC outputs the N1 limit information to N1 indicators on the primary engine display through the DAA.
FMC tunes the VHF NAV systems. Tuning information is sent to both VHF NAV systems through the DAA.
FMC provides latitude and longitude of airplane present position to the IRS. The present position is used to initialize the IRS. Latitude and longitude coordinates are entered at the FMC ANCDU. The FMC also provides set heading for the IRS attitude mode.
FMC provides gross weight to the digital stall management computer
FMC provides the active N1 limit to TMA on the primary engine display.
FMC sends data to the flight recorder system for recording
Either the FMC or the ANCDU can be selected as the source for the digital outputs to the DFCS flight control computer (FCC) and the EFIS symbol generators. the FMC output provides the FCC with target airspeed and mach, target altitude, target vertical speed, and roll command. The ANCDU output provides roll command only. The FMC sends navigation, guidance and navigation background data to the symbol generators for display on the EHSI and EADI. The ANCDU sends navigation and lateral guidance data only to the symbol generators.
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(27)
