activate that. it will go down to that altitude. while you do that you change the rate of descent to 3500. if it was taking off on landing, you probably put that at 18. les could explain that better. >> go ahead l perkses. >> dave is in the right area. you set the altitude and roll down the window to what you want your rate of descent to be or use terminology called flight level change. it will set up own rate of change to that a altitude. something physical has to be done is the whole point. >> that something fizz kalphysical was done after the pilot left. >> exactly. the pilot is seated here. >> co-pilot here. >> co-pilot is there.