Comment Re:Reasons unknown?? (Score 1) 156
There was an episode on Nova that posited exactly this. Ultimately, pitot tubes iced over and the plane was unable to determine airspeed so kicked out of autopilot, and the human pilots were too slow to respond with the suggested throttle and pitch settings in such a case.
What amazes me is the incredibly thin window they (speedwise) they have to fly in to be safe. +/- 10kts or something like that.