SLFinAZ,
you have a correct question. I am a very current captain, who is almost religious in keeping my scanning ability current. I manually fly a lot, because I feel I must keep current because I owe it to my passengers safety. But even I get sometimes somatographic illusions. And it gets really crazy. My whole body is telling me I am in a turn, when in fact I am level. The urge is so strong, than even if I see it on the instruments that I am level, I still put the controls into the turn. But than I correct it quickly. I feel like a Rowan Atkinson in Johny English movie, when he does not want to kill the Chinese prime minister but has to fight himself not to do it.
. The movie is very funny
. But if you have never had somatographic illusions you will not believe how strong it can be. One of my experienced friends once dropped a pen on the floor during IMC and than picked it up. He had to give controls to the FO for the rest of the approach. He felt so screwed up. May be hape had a cold too, or was fatigued. But he said it felt like a violent tumble to him.
You see, I am current on instrument scan and I have to fight this illusions quite hard. And now imagine that most people are not current and cannot be under the existing airline training philosophy, which is just a philisophy and has not much to do in most cases in survival of difficult conditions. And the sim is unable to simulate somatographic illusions.
It is like you get off from marry-go-round and you try to walk straight. You see you are inclined, but you cannot correct it and you fall. But your life does not depend on it.
In flying an aircraft it it a question of life and death, so we have to find the streangth, be trained properly and be well rested. But airlines are prostitudes and the shareholders or owners are the pimps....