[Sasino97]

Код:

public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
  new Float:x,Float:y,Float:z;
  GetPlayerPos(playerid,x,y,z);
  if(newkeys == KEY_FIRE && GetPlayerWeapon(playerid) == WEAPON_PARACHUTE && z > /* (MINIMUM HEIGHT)*/)
  {
     OnPlayerOpenParachute(playerid);
  }
  return 1;
}

public OnPlayerOpenParachute(playerid)
{
  [...]
}

Try this, it should work.

EDIT: Wait, if a player is on a high place, and clicks with that weapons there can be errors....
There is no a solution. For what do you need it?