Okay, so I got it working by creating a trigger that is activated repeatedly when condition is: "((fuel (pln1) < 0.3) or (damage (pln1) > 0.4));", "pln1" being name of the plane and On Act. "pln1 landAt 1;". The plane was forced to land so it came back to waypoints automatically. However I don't know how to check the ammunition of the plane or is it possible?