Redeye, your example of engine out scenarios brings up the fact that most of the existing winged UAVs we see in present military applications are single engine aircraft. Obviously there is a limit to the weight such a machine can carry, but up to that point the single engine design solves many problems attending asymmetrical engine failure. Automated controls can be devised to steer a drone with any number of powerplants missing, but cascading failure scenerios may prove to be a limiting factor in drone capacity. One thing that often fazes a computer is the scenario where several options are all about equal in value. That is one thing a human excels at, ie. bringing personal experience to bear in complex situations where several options appear to be equal.