A four engine aircraft has two engines on each side. The probability of an engine failing is independent of the behavior of the others. The time to engine failure has a Weibull Distribution with parameters 3-2 and 0=13.25. If the mission time is three hours, what is the probability of crash: (a) If the plane can fly on any 2 engines? (b) If the plane requires at least 1 engine operating on each side?