FAA certification sought for GPS-based aircraft precision-approach landing system

Leaders of UPS Aviation Technologies in Salem, Ore., say they plan to seek certification this summer for a first-of-its-kind GPS navigation receiver that will use existing signals from the FAA's Wide Area Augmentation System (WAAS) to enable aircraft precision instrument approaches.

By J.R. Wilson

SALEM, Ore. — Leaders of UPS Aviation Technologies in Salem, Ore., say they plan to seek certification this summer for a first-of-its-kind GPS navigation receiver that will use existing signals from the FAA's Wide Area Augmentation System (WAAS) to enable aircraft precision instrument approaches.

First installations would be in the data processing unit of the UPS Aviation Automatic Dependent Surveillance-Broadcast (ADS-B) product line for parent cargo carrier UPS' fleet. Company officials say they plan to introduce stand-alone GPS follow-on products next year.

The receiver would serve first as a short-term solution to problems with a signal integrity monitor that have delayed Federal Aviation Administration (FAA) approval of WAAS itself until late 2002 or early 2003.

Then the receiver would serve as a backup to the WAAS system once it does go online by providing the horizontal/vertical guidance and integrity monitoring needed for precision approaches.

"The WAAS effort has been delayed several times; if it is delayed again, this new development would fill the gap," says Sam Seery, UPS Aviation Technologies' director of sales and marketing. "The new engine also has the same footprint as engines in current C-129-certified products and could go into those and certify them for precision approaches prior to 2002."

Technical standard order (TSO) C-129 prescribes the minimum performance standard airborne supplemental area navigation equipment using GPS must meet.

WAAS uses two satellites in geostationary orbit over the United States to augment the existing global constellation of 26 GPS satellites. Conventional GPS navigation systems provide horizontal guidance accurate to about 10 meters; WAAS improves horizontal and vertical accuracy to about three meters.

The UPS Aviation Technologies WAAS navigation system will provide pilots with continuous horizontal and vertical guidance to runways with a published approach procedure. That will allow them to descend to 250 feet altitude with vertical guidance, a lower approach altitude than allowed by the majority of current approach procedures.

The system also issues a warning if either the vertical or horizontal guidance is out of tolerance or cannot be assured, an element essential to certifying WAAS for precision approaches.

"The airline experience demonstrates that stabilized instrument approaches with vertical guidance are the safest, yet the majority of general aviation airports don't have this precision approach capability," says Phil Boyer, president of the 365,000-member Aircraft Owners and Pilots Association (AOPA) in Frederick, Md.

"This new receiver delivers on the WAAS promise of vertical approach guidance to thousands of GA airports. And it shows the decision to continue WAAS development is a good one," Boyer says.

UPS Aviation Technologies is a wholly owned subsidiary of United Parcel Service Inc. and is closely aligned with UPS Airlines, the ninth largest airline in North America.

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