GPS-WAAS commissioned--new future for ILS-like approaches to airports everywhere

October 7, 2003

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FAA Administrator Marion Blakey (left) is briefed on how the WAAS system will be monitored from the FAA Command Center.
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During the WAAS press conference, AOPA President Boyer holds up a copy of "The Future is Now," a 1990 AOPA report to Congress arguing for civilian access to the GPS system.
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This map shows the more than 200 airports which already have published LNAV/VNAV approaches.
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The FAA Command Center in Herndon Virginia. The large wall monitor, second from the left, shows the coverage area and status of the WAAS system.
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WAAS-enabled receiver shows the system "in use" shortly after the FAA turned the system on at midnight EDT (0400Z).
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AOPA President Phil Boyer demonstrates a WAAS receiver to Dan Hanlon, FAA WAAS program manager, on the first day of system operation.

The FAA today at 12:01 a.m. EDT officially turned on the Wide Area Augmentation System (WAAS) to the GPS system. WAAS will provide ILS-like precision approaches to thousands of general aviation airports that don't have them today.

"This is just the first step," said AOPA President Phil Boyer during a press conference at the FAA Command Center in Herndon, Virginia. "But in the future, just try telling the family of a critically ill person who was picked up by an air ambulance at a community airport in bad weather that the expense and the time spent on developing WAAS was too much."

AOPA has been a strong WAAS advocate since the program's inception in 1995. The association has lobbied for WAAS in Congress and was a key instigator of an independent review of the program in 2000 that determined WAAS was necessary and technically feasible.

"Everywhere I go, GA pilots ask, 'How can we get an ILS at our airport?'" said Boyer. "WAAS is the answer for providing precision approaches to all of those airports where ILS just isn't possible. And we can provide an approach with vertical guidance to each runway end."

FAA Administrator Marion Blakey admitted at the press conference that WAAS took longer and was more expensive than originally forecast.

"But we really are talking about rocket science here," she said. "We were doing things that had never been done before. The general aviation community will be the first to benefit from this system. I know you've been eager for this, and I applaud your patience."

WAAS sensors receive the signal broadcast by Global Positioning System (GPS) satellites, correct any errors, and rebroadcast the corrected signals to WAAS-enabled aircraft receivers, thereby enhancing the integrity, accuracy, reliability, and safety of the already highly accurate GPS signal.

The WAAS signal that was turned on today will give properly equipped aircraft vertical guidance for some 500 published procedures (LNAV/VNAV approaches) at more than 200 airports across the United States. Typical LNAV/VNAV approaches allow pilots to descend to 400 feet above the airport elevation in visibility down to 1.5 miles.

Later this year, when tighter lateral and vertical navigation (LPV) standards are implemented, pilots will be able to descend to minima as low as 250 feet in 3/4-mile visibility. (The lowest minima will require an obstruction-free environment near the airport and ground infrastructure such as approach lights, precision runway markings, and runway-parallel taxiways.)

Currently, two manufacturers of GA avionics—UPSAT and Chelton—have WAAS-certified receivers that can be used for "sole-source" IFR navigation, meaning no other navigation systems are required on the aircraft. UPSAT expects to receive certification for vertical navigation ("glideslope") within two months. Other manufacturers will be offering WAAS receivers soon.

"Now that there is a real, certified, and guaranteed signal in space, the people who build the boxes will invest the research and development into new WAAS receivers," Boyer said. "And the more that enter the market, the better the prices will become."

But Boyer said it was still incumbent on the FAA to spread the benefits of the system so that it will be attractive for pilots to buy WAAS boxes. "Now that the FAA has turned on the signal, the agency has to accelerate charting new approaches at those airports that don't have them now," he said. "At the present rate, it will take 30 years to chart WAAS approaches into all airports. The FAA must take innovative steps such as turning to the private sector to survey and design these approaches."

For the near future, the "gold standard" for approach guidance remains an instrument landing system (ILS). Ultimately though, in perhaps a decade's time, WAAS has the potential to offer ILS-quality information to pilots in a typical four-seat single-engine GA aircraft.

"During the initial operational capability phase, there will frequently be nonprecision approaches that have lower visibility minimums than WAAS will," said Randy Kenagy, AOPA's senior director of advanced technology. "But AOPA stands behind the FAA on the deployment of WAAS. As it ramps up and proves itself, it will offer advantages to pilots that will make them want to upgrade their equipment."

"To borrow an analogy from the computer industry, the WAAS initial operational capability phase is like version 1.0 software," said Kenagy. "It's neat, it's useful, and it will get better from here."

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