Originally Posted by TedUnderwood
Which Cost Index values will relate to Max Endurance and Max Range?
Cost index is a feature of FMS which enables the user to specify a ratio between the cost he assigns to the Time necessary to cover a certain distance, and the cost of Fuel to cover that distance. Depending on that ratio, the FMS selects a speed between that for max. range (cost index 0) and the maximum speed attainable (cost index 999). If you plot a diagram of fuel used versus time for a certain distance flown with various speeds, the cost index corresponds to the slope of a local tangent to that line. It will not give you the speed for max. endurance, because that is slower than max. range (i.e it would correspond to a negative cost index, can you enter that?).
regards,
HN39