Time Navigation Benefits in En Route Metered ATC

This paper evaluates benefits to be expected from an early use of Time Navigation (TNAV) capabilities now under engineering development for Flight Management Computer Systems (FMS) operating in the U.S. into airports where En Route Metering (ERM) is currently operational or is scheduled to become operational. The benefits estimates are based on the ability to define and fly fuel-efficient, ATC compatible profiles to meet metering objectives into busy terminal areas. Near-term benefits are quantified from simulation studies of two currently metered airports, Denver and Dallas-Ft. Worth, projected to all planned ERM airports. Consideration of frequency of obtaining non-conflicting "TNAV Clearances" is examined. The savings quantified are based on the use of improved delay absorption techniques using an enhanced FMS. Future operation of TNAV may provide additional fuel savings through reduction of system delay levels and the incorporation of optimization methods to maximize fuel savings.