National Airspace System:
Observations on the Wide Area Augmentation System
T-RCED-98-12: Published: Oct 1, 1997. Publicly Released: Oct 1, 1997.
- Full Report:
GAO discussed the Federal Aviation Administration's (FAA) Wide Area Augmentation System (WAAS) program, focusing on: (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 (decommissioning) ground-based navigation aids; and (3) the potential impact of cost increases and decommissioning delays on the benefit-cost analysis for the WAAS program.
GAO noted that: (1) while the developers of WAAS and outside experts are confident that WAAS is likely to satisfy most key performance requirements within current program cost and schedule estimates, some concerns are worth noting; (2) specifically, FAA may make some procedural changes for aircraft landings if WAAS is not able to deliver the level of service provided by existing ground-based landing systems; (3) also, FAA may add more space-based equipment to meet performance requirements; (4) FAA expects to make decisions on these matters by late 1998 and late 2000, respectively; (5) if the space-based equipment is added, program costs would grow between $71 million and $192 million above the current total program cost estimate of $2.4 billion; (6) the program's schedule can be expected to slip if arrangements are not made immediately to put this equipment in space; (7) to realize the full cost savings from WAAS, FAA will need to avoid delays in decommissioning its ground-based network of navigation aids; (8) FAA estimates that it incurs costs of $166 million annually to maintain this ground-based network; (9) FAA's plans--which envision complete decommissioning of the network by 2010--presume that the full WAAS will become operational (commissioned) in 2001 and that the aviation industry will install the necessary equipment in its aircraft during the remainder of that decade; (10) however, the planned decommissioning could be delayed if the WAAS program's schedule slips or if safety and economic benefits, such as an aircraft's ability to take advantage of more fuel-efficient routes, are not sufficient to cause the industry to switch to satellite-based navigation technology by the end of the next decade; (11) cost increases and decommissioning delays, if they occur, would reduce the net benefits of the WAAS program, but program benefits would still outweigh costs; (12) FAA's July 1997 benefit-cost analysis found that benefits were: (a) more than five times greater than costs when passenger time savings were included and all aircraft gained savings from shorter flights; and (b) more than two times greater than costs when passenger time savings were excluded and 30 percent of all aircraft gained savings from shorter flights; (13) additional analyses done at GAO's request, using pessimistic cost and decommissioning assumptions, found that the WAAS program's benefits are still significantly greater than the costs; and (14) however, if the ground-based navigation network is not decommissioned or must remain in place much longer than expected, the net benefits from WAAS would be substantially reduced.