AS3 KeyboardEvent błąd 1119.

Nie wiem czemu to nie działa, pisze:
Scene 1, Layer 'menu script', Frame 1, Line 1562, Column 16 1119: Access of possibly undefined property keyCode through a reference with static type Function.

stage.addEventListener(KeyboardEvent.KEY_DOWN, keyEvent);
function keyEvent(e:KeyboardEvent):void{
    if (keyEvent.keyCode == 81) {
        if (health > maxhealth) {
            health = health;
        }
        if (health < maxhealth && mana > 19) {
        health += 20;
        mana -= 20;
    }
  }
}