Hello,I understand that the CI can be defined as the ratio between the hourly operating cost of the aircraft and the fuel cost per Lb; that the lower it is, the more cost effective is the flight and that a longer range can be flown. However, what I do not quite understand is, in view of this ratio, a higher fuel cost should on the contrary mean a lower CI and therefore a lower CI should itself mean a lesser cost efficiency ??? Thanks for your enlightment.RegardsEric L.

I think you make one wrong assumption in that a low CI means a mroe cost effective flight. If the fuel cost is low compared to crew salary and such then it

More complicated than I thought, but clear. Thanks for your input.