Go to the point where you see the pilot, then go onto the helicopter before the last two Bosses. Enter the god code in the console window, and drop off where the helicopter is located and find the pilot. While he is going onto the helicopter, kill him. Stay near the helicopter. If done correctly the "Your rescuer has died" message will not appear, and you can continue. When you go onto the helicopter, wait until you stop and go out of it. Look at the cockpit of the helicopter; the pilot is there again.