For Immediate Release

Release No. APA 03-98
January 5, 1999
Contact: Paul Takemoto
Phone: 202-267-8521


WASHINGTON, DC — The Federal Aviation Administration (FAA) announced today that it is revising the implementation schedule for the Wide Area Augmentation System (WAAS) to allow more time to complete development of a critical software safety package that monitors, corrects and verifies the performance of the WAAS system.

The original July 1999 commissioning date for Phase 1 of WAAS has been rescheduled to September 2000. WAAS is an augmentation to the Global Positioning System (GPS) that corrects the GPS standard civil signal to provide the accuracy, integrity, and availability needed for civil aviation navigation.

"The FAA remains committed to implementation of WAAS because of its safety benefits for the aviation community and the flying public, and because it is central to our overall efforts to modernize the National Airspace System (NAS)," said FAA Administrator Jane F. Garvey. Garvey noted that the FAA WAAS team is also working in partnership with Europe and Japan to provide a seamless global satellite system for improved aviation safety worldwide.

The revised schedule came after the final and most complex software module proved to be "a much greater challenge than originally anticipated," said Steven Zaidman, associate administrator for Research & Acquisition. "We will not commission Phase I of WAAS until we are satisfied this technical challenge has been resolved," Zaidman said.

All the other major software modules have been completed except for the Correction & Verification (C&V) system, which performs more than 20 critical monitoring, correction, and verification functions. These include determining the precise positions of the GPS and geostationary satellites, the accurate effects of the ionosphere on the GPS/WAAS signal, and the validity of the WAAS messages.

In addition, all the required hardware systems for Phase 1 are in place. These include 25 ground reference stations, two master control stations, two geosynchronous (GEO) satellite uplink stations, and two transponders on GEO satellites leased from Inmarsat that are in orbit and operating successfully.

When Phase 1 is in operation, WAAS will provide pilots with en route navigation and vertical guidance for precision approaches to runways over a limited portion of the continental United States.

The new schedule will provide a navigation signal broadcast in mid 1999. This signal will be broadcast from two Inmarsat satellites already on contract and will be capable of supporting non-safety applications, such as an aid to visual flight rule (VFR) flight. WAAS commissioning, scheduled for the fall of 2000, will support instrument flight rule (IFR) flight.

The Johns Hopkins Applied Physics Laboratory of Laurel, Md., is currently conducting an independent risk assessment of the use of GPS for civil aviation. That assessment, which is expected to be released this month, will help determine whether WAAS is capable of being used as the sole or primary means of navigation for civil aviation. The revised schedule will give the FAA adequate time to redefine future satellite navigation improvements in light of the Hopkins study.

An electronic version of this news release is available via the World Wide Web at: www.faa.gov

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