DOS Games Discussion

ok, i found out myself: You need to hover above the ground in the target region (i guess under 100 feet will do) and then press x.

I got the game and got addicted like 15 years ago, but like Snake I cannot complete the supply run mission. How the hell do you drop the cargo? I found this: http://takegame.com/simulators/htm/lhx.htm but hitting the x key does not work either. Its driving me insane.