GAO hits satellite navigation plan
- By Paula Shaki Trimble
- Jun 19, 2000
It is not clear that the benefits of a satellite-based navigation system
being developed by the Federal Aviation Administration are worth the costs,
according to a General Accounting Office report released last week.
The FAA's Wide-Area Augmentation System, a network of ground-based reference
stations and communications satellites, is being designed to verify and
correct the signal received from the Defense Department's Global Positioning
System satellites before sending the information to pilots.
The FAA had planned to provide initial capabilities by September 2000
but has pushed that back to 2002 and scaled back some of its plans. The
program has suffered from software problems and increasing costs.
GAO estimates the FAA may need three or more years to demonstrate the
requirement that WAAS will virtually never fail to warn pilots of an erroneous
GPS signal — which is known as integrity. That could cost an additional
$200 million to $240 million.
"The difficulties in proving the integrity requirement have occurred
largely because FAA management and the integrated product team underestimated
the complexity of resolving the integrity issue and, as a result, failed
to recognize the seriousness of the problem," according to the GAO report,
"National Airspace System: Persistent Problems in FAA's New Navigation
System Highlight Need for Periodic Evaluation," requested by Sen. Richard
Shelby (R-Ala.), chairman of the Senate Appropriations Committee's Transportation
GAO is pleased with the FAA management's new approach, which allows
time for collecting and evaluating data on system performance, the extent
to which users have purchased equipment and the availability of emerging
new technologies for the new navigation system. However, GAO recommended
the FAA devise a specific plan for reevaluating WAAS at critical points
in development and having the progress of the system independently validated
at the checkpoints before Congress approves additional funding.
In response to the report, the FAA told GAO that users would receive
major benefits from any level of precision approach into airports, and airports
would not necessarily need to upgrade their facilities to take advantage
of the approaches. The FAA also stressed some cost growth resulted from
other factors, such as changes in the way the Transportation Department
calculates project costs.