One of the problems facing judges in the July Green Flight Challenge the CAFE Foundation is managing for NASA is that of determining fairly who gets the best fuel mileage. Since “fuel” in this case can be traditional aviation gasoline, bio-diesel, electricity from batteries or solar panels, or some other energy storage medium, wildly different energy densities have to be taken into account. If TSA “freedom feels” seem intrusive, the scrutiny applied to GFC entrants and their craft will be even more onerous. Aircraft will be impounded once inspected and registered, and the only contact pilots may have with their planes before taking off will be to “top off” their fuel tanks or batteries just before the start of their flight – all under constant monitoring. The widely and wildly differing energy densities for the different forms of motive power require careful definition of energy equivalencies. One pound of gasoline, for instance, equals about 20,000 BTU, or 5.8 kilowatt hours, …