Summary: The Federal Aviation Administration (FAA) is planning to switch from a ground-based civil air navigation system to a satellite-based system using signals generated by the Defense Department's global positioning system. However, the military's system does not satisfy all civil air navigation requirements, such as the one requiring that the system be available virtually all of the time. FAA is acquiring the wide area augmentation system (WAAS)--a network of equipment on the ground and in space--so that the global positioning system can meet civil aviation requirements. Satellite-based navigation, using both WAAS and the global positioning system, should improve the safety of flight operations, allow the fuel-efficient routing of aircraft, increase airport and airspace capacity to meet future air traffic demands, and enable FAA to phase out its costly network of ground-based navigation aids. This testimony discusses (1) the likelihood of WAAS' satisfying key performance requirements within current program cost and schedule estimates; (2) the importance of avoiding delays in FAA's timetable for shutting down ground-based navigation aids; and (3) the potential impact of cost increases and decommissioning delays on the benefit-cost analysis for the WAAS program.
