Now, working it backwards... Old Smokey made a reference in a different thread related to Max Endurance/Max Range and in that he talked about FMC users and Cost Index. Which Cost Index values will relate to Max Endurance and Max Range? In a round about way, what I am getting to is; can I manually plot different values (altitudes, temperature, cost index etc) to create my own performance charts when I don't have access to the data that the FMS uses to calculate the values? I know I'm reinventing the wheel, but if I can plot this as I'm flying, it will help me to understand the relationship between these values, ie altitude, temperature, weight, etc. Am I making this more difficult than it needs to be???