This 747-400 United uses the default x-plane fmc. As you maybe know the labels of buttons in the x-plane fmc is different than the 747. I could just label each button on the 747 fmc as the x-plane one, but I wanted to do it like the real one, because in future someone could create the programmed FMC for the plane. So I tried to match functions with similar name labels. But that was not easy to find in all the buttons.
If you activate tooltip function, you will be able to see what those buttons are for, just putting the mouse over them. But here are the x-plane fmc functions and 747 FMC labels connections if you want to have them in paper:


Left Function Keys = Keys on left from first to fith.
Right Function Keys = Keys on right from first to fith
Load Flightplan = 6th Left function key
Save Flightplan = 6th Right function key
Init function = Init Ref
NDB function = RTE
Airports function = DEP ARR
Fix function = FIX
Coordinates function = PROG
Direct function = EXEC
Vor function = NAV RAD (The Nav RAD of the middle botton FMC is for selecting the course, in radio aid)
Previous function = PREV PAGE
Next function = NEXT PAGE

0 to 9 = 0 to 9
Sign function = +/-

A to Z = A to Z
Space function = SP
BackSpace function = DEL
Clear = CLR

Labels of the 747 that already has no function:
ATC, VNAV, LEGS, HOLD, FMC COMM, MENU, ".", "/"



Good flight!

Javier Rollon





