WASHINGTON (03/28/2000) - The U.S. Federal Aviation Administration's satellite navigation system may never reach its goal of providing precision landing capability, FAA officials say.
The cost and time needed to fix safety problems in the FAA's Wide-Area Augmentation System may lead users to decide the program is not worth continuing to a level that would permit landings in low visibility, said Carl McCullough, director of the FAA's Office of Communications, Navigation and Surveillance Systems.
McCullough and members of the WAAS program spoke to reporters Monday about recent problems with the stability and integrity of WAAS, a ground- and space-based system designed to enhance signals from Global Positioning System satellites.
Prime contractor Raytheon Co. is expected to fix some software problems by September. Tests in December also showed that new algorithms are needed in software that indicates to pilots when the GPS signal is unreliable. An independent panel of experts is expected to deliver its recommendations for how to fix the integrity problems in six to nine months.
The FAA is proceeding with plans to offer a navigation capability in 2002 that will allow pilots to use WAAS when their aircraft is 350 feet height above touchdown and have one mile of visibility.
The fate of an even more precise system awaits the independent panel's recommendations. The Global Navigation Satellite Service Landing System reduces the decision height to 200 feet and navigation visibility to a half mile. If the panel's recommendations show that it would be too costly, the agency may shift more resources to another GPS augmentation system, the Local-Area Augmentation System, McCullough said.
LAAS consists of ground stations installed at 143 airports and avionics systems installed on planes that will provide positioning information for pilots to land aircraft despite low visibility.
The agency has requested $113 million for WAAS in its fiscal 2001 budget request.