I remember years ago seeing DC9's (717 ancestor) sitting on the ground with one side of the elevator down and the other side of the elevator up.
I always did wonder about the reason.
DHC8's, and many other aircraft, have systems that can be split but they normally need some failure to occur before they will operate independantly.
Any 717 drivers or old DC9 drivers able to give it to us from the horse's mouth?
SS