separated. cruise altitude is very difficult. there is a difference between piloting skills and the automation of today's aircraft. the a-321 is a fully automated plane. pilots don't hand fly at cruise altitude very much. there have been cases in the past. the air france 447 which occurred at cruise altitude. they had technical issues. a speed indicator was off and they could not diagnose it. it will be interesting to see how the cruise, from the voice recorder, addressed whatever problems they had. >> that last point, they may not be able to diagnose it, may explain why you hear a pilot say, technical difficulties as opposed to something very, very specific. >> a relatively modest margin of