As you stand in the doorway of the plane, you feel nervous but excited. You are more than 4000 metres above the ground.The parachute on your back is heavy,and the noise of the plane is very loud.Then you jump.Five seconds later you feel like you are flying. You are falling at nearly 200 kilometres an hour,but you are in control. You can change your direction and speed just by moving your body. For around sixty seconds it's just you and the sky.