Whatever the failure... DON'T PANIC. Do your best to regain control and put the plane down safely. (as in not hitting anyone.. to heck with the model.)
as someone whos flown home safely a funfly inverted with no tailplane using throttle for pitch control, and also a club trainer with a snapped wing brace during a students roll, wings at 40 degrees and a huge urge to turn, full aileron and rudder to fly straight!. Seen a scale Mustang fly home with NO fin or rudder.
so don't panic, use all your controls, keep it slow but fast enough for control, if you've lost a wing for example fly the fuz home and use what controls you have to first get it away from crowds etc then try to induce a spin or some form of control to lessen the impact