I've starting to use my CS B767. I've yet to use the FMC. I'm now reading all the how-to's and think I've got a handle on it, but my questions is do you use the FS-ATC or radar contact when using the FMC?

If I'm right, once you start your takeoff roll, the FMC can fly the plane from that point on, so wouldn't having ATC direct you to a new heading  screw up the works?

If I'm way off base here please let me know.

Bruce