Press [Esc] and quit the game after being shot down, but before crashing.
This will prevent the failed mission from being recorded.
Accurate bombing:
Approach the target at an altitude of 1,000 feet when armed with free fall
MK82 and MK84 bombs. Drop the throttle to 30% when the target is one mile
away and switch to the rear external view. Release the bombs when the
target appears between your fighter and the bottom of the screen.