You cannot bail whilst on the ground as in IL2 46, just doesn't exist right now even when ditching a burning aircraft you cannot jump out of it so you'll need to hit escape and exit mission or spawn in a new aircraft to continue.
To bail whilst airborne first jettison the canopy, ctrl J by default I believe then hit the bail out and you'll appear next the aircraft having bailed out (no bail out animation of going over the side working ingame as yet) also no matter how low you bail providing your chute opens you'll survive
Hope that helps
V