In-Game Documentation This is a simulation of a GCA (Ground Controlled Approach.) The glide path is an imaginary line from the end of the runway to the point where the descent should start (usually about 6 miles out at 1500 feet altitude). The program will put you in that position and then you will control the airspeed and rate of descent to keep the aircraft on the glide path. You are flying a big multi-engine airplane - good luck and happy landings!