NOTE: The engine cost estimates presented are derived from correlations developed for historical military engines and may not reflect the current fair market prices of commercial engines considered in this study. Engine cost estimates vary widely, and the estimates presented may vary by as much as 100 percent from estimates developed by other independent sources such as the IBA Engine Value Book 2005 as reported by Euromoney Institutional Investor, May 1, 2005.

^aValues corrected after release of the January 31, 2007, prepublication version of the report.

^bThe direct fuel cost component of $5.00 increases at 6 percent per year, and the overhead increases at 3 percent per year.

^cShading indicates a recouping of investment costs in less than 20 years and thus a positive cash flow at the 20-year point.

^dThe fuel savings noted for the C-130 with new or modified engines are based on the aircraft being flown at the optimal altitude and airspeed for the selected engines and propellers. The flexibility exists in most C-130 missions for the aircraft to be operated at the best range or fuel consumption conditions. The other aircraft and engines considered in the study are operated at their prescribed mission conditions.

^eE-8 re-engining already ongoing.

^fC-5 re-engining already ongoing.