about the a320. that is a digital fly-by-wire system aircraft which, as opposed to having big control wheels, has side stick controls that are independent of one another, at the co-pilot station and at the pilot station. and it offers something called flight envelope protection. and simply what that means is that the pilot cannot put flight inputs or control inputs that would exceed the par ram meters that are preprogrammed into the computers. when the pilot controls the aircraft with these kind of joy sticks that they have it sends a -- an electronic relay to computers which interpret the pilot's control inputs. then if the software is programmed for those inputs it allows the aircraft to follow