OK I give up. That's at least 3 or 4 of you who has completely misunderstood my post and I will bow out leaving you to think that I am suggesting pilots could sleep through cruise with no problems. I have already received an informative post via PM which has given me the answer I was seeking. My belief in the in the high intelligence and understanding of the flying community has gone down a couple of points. (I already know that a great number of you can't spell - particularly the pilots
). I will have no more to say in this thread.