Application of Cost Index to Fleet Hub Operation

A cost index is used to describe a family of minimum cost flight profiles with a single number expressing the ratio of time cost to fuel cost. A unique cost index for each segment can be used to minimize fuel consumption within the time constraints dictated by hub operation. This paper addresses application of cost index to the fleet of American Airlines aircraft consisting of 727-200, 767, and DC-9-80 -- all equipped with on-board computers which use cost index to compute economic flight profiles. Ground-based flight planning computer programs were modified to determine the most cost-effective index for each segment consistent with company block time objectives for Dallas and Chicago hubs. Flight plans were modified to allow the on-board computer to use the cost index as telemetered to the aircraft at the start of each flight. The cost index may be updated from the ground-based flight planning computer, as the airplane crosses intermediate check points, to account for any unexpected circumstances affecting on-time performance.