In 1998 the Federal Aviation Administration (FAA) established the Free
Flight Phase 1 program to provide new decision-support systems to a
limited number of facilities in a relatively short time (by the end
of 2002), with the goal of providing increased user benefits and maintaining
current levels of safety. The FAA selected systems that were anticipated
to meet those goals and had demonstrated support within the Air Traffic
community.
The User Request Evaluation Tool (URET) is one of the systems selected
for inclusion in the program. URET was an operational prototype that
had been deployed at two of the 20 Air Route Traffic Control Centers
within the continental United States, Indianapolis and Memphis, in the
1996-97 timeframe. It is a decision-support tool used by the sector
team in an Air Route Traffic Control Center. It is implemented at the
Radar Associate Position to support the strategic operations of the
team in an integrated fashion.
With URET, controllers can provide better service by detecting and
resolving problems earlier, maneuvering aircraft less off their filed
route, and reducing some airspace constraints (such as static altitude
restrictions). URET provides an automated conflict probe and trial-planning
capability that informs the controller of projected conflicts and assists
the controller in evaluating resolutions to determine if they are conflict
free before the issuance of a new clearance and amendment. URET also
provides flight data management capabilities that reduce controller
dependence on paper flight strips.
This paper describes the benefits to users of the National Airspace
System attributable to URET. The metrics and measurements described
are based on the experience with URET at the Indianapolis and Memphis
en route centers. From early May 1999 until the deployment of the production
system in January 2002, data was collected on a daily basis in order
to assess the operational impact of the system. Analysis of the metrics
has demonstrated that savings to airlines and general aviation (GA)
attributable to URET derive most directly from savings in nautical miles
flown from the issuance of lateral amendments by controllers and reduction
in fuel burn from the lifting of static altitude restrictions. The savings
in distance flown measured approximately 7,000 nautical miles daily
for the two Centers. Reduction in fuel burn from the lifting of static
altitude restrictions totaled approximately 950,000 gallons annually.
The demonstrated benefits of URET resulted in the recent decision by
the FAA to deploy URET at all 20 Air Route Traffic Control Centers
within the continental United States.
