WLDP FAULT LOAD DSPL TEST LOAD DSPL FWC 1 FAULT FWC 2 FAULT TEST TEST BITE DISPLAY INHIB OVER BITE INPUTS INPUTS ECAM EFIS Aircraft systems inputs test button Inhibited warnings override switch Displays switch Signal generator test button Flight warning computer test buttons and annunciation lights parameters and the copilot’s CDU handling navigational  chores. This is optional at the flightcrew’s discretion. If a  main component fails (e.g., an FMC or a CDU), the remaining  operational  units continue to operate with full control and  without system compromise. Each flight of an aircraft has vertical, horizontal, and navigational  components, which are maintained by manipulating the engine  and airframe controls. While doing so, numerous options  are available to the pilot. Rate of climb, thrust settings, EPR  levels, airspeed, descent rates, and other terms can be varied.  Commercial air carriers use the FMC to establish guidelines  by which flights can be flown. Usually, these promote the  company’s goals for fuel and equipment conservation. The  pilot need only enter variables as requested and respond to  suggested alternatives as the FMC presents them.  Figure 10-123.  An ECAM maintenance panel used for testing and  annunciating faults in the ECAM system.  The FMC has stored in its database literally hundreds of flight  plans with predetermined operational parameters that can be  selected and implemented. Integration with NAV-COM aids  allows the FMS to change radio frequencies as the flight plan  is enacted. Internal computations using direct input from  fuel flow and fuel quantity systems allow the FMC to carry  out lean operations or pursue other objectives, such as high  performance operations if making up time is paramount on a  particular flight. Weather and traffic considerations are also  integrated. The FMS can handle all variables automatically  but communicates via the CDU screen to present its planned  action, gain consensus, or ask for an input or decision.  long engine and component life all contribute to profitability.  An FMS helps achieve these results by operating the aircraft  with greater precision than possible by a human pilot alone. A FMS can be thought of as a master computer system  that has control over all other systems, computerized and  otherwise. As such, it coordinates the adjustment of flight,  engine, and airframe parameters either automatically or by  instructing the pilot how to do so. Literally, all aspects of the  flight are considered, from preflight planning to pulling up  to the jet-way upon landing, including in-flight amendments  to planned courses of action. As with the monitoring systems, FMS includes BITE. The  FMC continuously monitors its entire systems and inputs  for faults during operation. Maintenance personal can  retrieve system generated and pilot recorded fault messages.  They may also access maintenance pages that call out line  replaceable units (LRUs) to which faults have been traced  by the BITE system. Follow manufacturers’ procedures for  interfacing with maintenance data information. The main component of an FMS is the flight management  computer (FMC). It communicates with the EICAS or  ECAM, the ADC, the thrust management computer that  controls the autothrottle functions, the EIFIS symbol  generators, the automatic flight control system, the inertial  reference system, collision avoidance systems, and all of  the radio navigational aids via data busses.  [Figure 10-126] The interface to the system is a control display unit (CDU)  that is normally located forward on the center pedestal in the  cockpit. It contains a full alphanumeric keypad, a CRT or  LCD display/work screen, status and condition annunciators,  and specialized function keys.  [Figure 10-127] Instruments are installed for two purposes: to display  current conditions and to notify of unsatisfactory conditions.  Standardized colors are used to differentiate between  visual messages. For example, the color green indicates a  satisfactory condition. Yellow is used to caution of a serious  condition that requires further monitoring. Red is the color  for an unsatisfactory condition which needs immediate  attention or action. Whether part of the instrument face or of  a visual warning system, these colors give quick-reference  information to the pilot. The typical FMS uses two FMS FMCs that operate  independently as the pilot’s unit and the copilot’s unit.  However, they do crosstalk through the data busses. In normal  operation, the pilot and copilot divide the workload, with the  pilot’s CDU set to supervise and interface with operational  10-75 Warnings and Cautions Annunciator Systems