Release No. APA 03-98
January 5, 1999
Contact: Paul Takemoto
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
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
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