Wich is the proceduro for doing a 180º turn correctly?
and is it possible that the car flips and crash if you do it wrong?

thanks

Is it a 180 out of reverse or a forward one?
If it's the reverse one, accelerate hard in reverse gear (in a straight line) turn the wheel full lock whilst dipping the clutch, applying lots of handbrake and changing into a forward gear (1st or 2nd.. 2nd is better) whilst ALSO turning the wheel back to opposite lock, releasing the handbrake and flooring it in the aforementined forward gear. Easy Peasy eh?
Forward one, floor it and bang the handbrake on as hard and fast as you dare whilst turning the wheel lock to your desired direction.
The latter is more likely to make you flip and roll, it all depends on the road conditions, your speed and how high your C of G is... Don't try this in a Land Rover for instance..

BTW if it's rear wheel drive car, always dip the clutch whilst the handbrake is on or you could end up with a rather embarassing stall.

EDIT: DISCLAIMER: Don't try this at home kids, Charlottesdad takes no responsibility for wrecked cars, smashed up bus shelters etc.. 

Or there is the Ozzy method. Find a nice tight corner, cover with Fairy Liquid or Castrol GTX and then drive at it really fast. The tricky part is getting your car out of the hedge/field/wall afterwards

Oh, BTW, if you're trying to take a corner like a 180 hairpin as fast as possible the key is to go slow.  Don't overdrive the car.  It's all too easy to push too hard, make a ton of noise and smoke, and come out really slowly.  The best way is to shed a lot of speed before the corner, turn as tight as possible, and get the car pointed in the proper direction early in the corner so you can (smoothly!) get on the gas as early as possible.  There is no "fast" way to do it.  There are only ways that are "less slow" than others.  Too many drivers over-drive the car on slow corners.