Super Mario Sunshine - Stuck on ground!

I am going to make a Mario Sunshine game. But I need help. You cannot pump when you are on the ground. I know why but I dont know how to fix it? Source are down in the post. Code is:

onClipEvent(load){
 moveSpeed = 2;
 vel_y = 0;
 dead = false;
 Kright = Key.RIGHT;
 Kleft = Key.LEFT;
 Kup = Key.UP;
 Kdown = Key.DOWN;
 this.stop();
}
onClipEvent(keyUp){
 gotoAndStop("idle");
}
onClipEvent(enterFrame){
 _y-= vel_y;
 vel_y = vel_y - 0.5;
 if (Key.isDown(Kleft)){
  _x-= moveSpeed;
  this.gotoAndStop("walk");
  _xscale = -100;
 } else if (Key.isDown(Kright)){
  _x+= moveSpeed;
  this.gotoAndStop("walk");
  _xscale = 100;
 }
 if (Key.isDown(("A").charCodeAt(0))){
  vel_y = vel_y + 0.7;
  this.gotoAndStop("pump");
 }
 if (_root.ground.hitTest(this)){
  vel_y = 0;
 }
}

Swf: www.crucialclan.1go.dk
Fla: www.crucialclan.1go.dk/game.fla