Does the Flight Management Computer provide autopilot inputs?

In commercial aircraft that are equipped with a Flight Management Computer (FMC) are flight guidance inputs transferred to the auto-pilot?


I have also seen a similar instrument reffered to as a MCDU (Management Control Disply Unit) and it occupies the same space on the control pedestal as the FMC.


I know that these instruments provide and calculate information on ETA's fuel management, flight planning etc. But does it actually provide command to the autopilot? And if so, can an entire course be planned and be used to command the AP?


How does the Pilot know when various waypoints have been reached or other criteria have been met?


I may have confused the FMC and MCDU.

Does the Flight Management Computer provide autopilot inputs?
The FMC (also called FMS - Flight Management System in some installations) is generally a remotely mounted computer, located in the avionics bay along with the radio receiver/transmitter units, TCAS, EGPWS, etc. The MCDU is the actual display screen and keyboard that you see in the flight deck. It's just a "dumb" control panel for the FMC. The radios work the same way; controllers/displays in the flight deck, actual radios in the avionics bay.





The FMC sends guidance commands to the flight director, which drives the autopilot.





Pilots monitor progress by viewing information displayed on the multi-function display (MFD). It's usually set to display a moving map that can be configured to show flight plan waypoints, high or low navigation aids, airports, airways, etc.
Reply:Yes, the FMC sends info to the autopilot to control the aircraft. And yes, the entire flightplan can be (and usually is) programmed into the FMC. The navigation instruments (and moving map display) let the pilots know where they are and where the waypoints are. Most of the time, the pilots make radio calls and check fuel status at each waypoint on long flights, but the autopilot is handling the flying.
Reply:Yes.





Yes.





Yes.





Navigation displays, command bars, annunciators and alarms.
Reply:I can't answer for civilian aircraft, but for military aircraft, the autopilot is tied to information that is displayed on the HSI/CDI.





This way, whenever NAV mode is selected on the autopilot, it uses whatever system is supplying the guidance to the pilots.





Our C130's use SCNS (Self Contained Nav System) as the FMS. So our autopilot can be tied to SCNS, TACAN, VOR, INS, or several other systems, whatever the pilot selects as his source on the HSI.