WAM — It's Making an Impact in Colorado

Signals coming from the mountains below to a plane flying overhead.

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NextGen Infrastructure
Includes: Aeronautical Common Service, Communications Common Service, Flight Common Service, Surveillance Common Service, and Weather Common Service.

Tourism is a multi-billion dollar industry in Colorado and an investment in NextGen technology is helping Steamboat Springs, Colo., live up to its reputation as Ski Town, U.S.A.

The rugged terrain that makes Steamboat Springs in northwest Colorado a popular ski destination also makes it challenging for air traffic control radars to track aircraft in certain areas — radar signals cannot pass through solid objects. Add wintery weather and low visibility to the mix and flight delays and cancellations pile up at the commercial and general aviation airports serving the region. Prior to the installation of NextGen technology, difficult-to-access airports averaged 75 flight delays per day during the November-April ski season, according to the Colorado Department of Transportation (CDOT).

Not anymore.

The FAA is improving safety, reducing delays and enabling more flights at four northwest Colorado airports — commercial airport Yampa Valley Regional in Hayden and general aviation airports Craig-Moffat County in Craig, Steamboat Springs/Bob Adams Field in Steamboat Springs and Garfield County Regional in Rifle — using a technology called Wide Area Multilateration (WAM). "Prior to the WAM system being in place, we had a lot of unhappy passengers because they got delayed due to weather," explained Dave Ruppel, airport manager of Yampa Valley Regional, the only commercial airport in northwest Colorado. "After the system began operating, those complaints went down to zero. People can get in and out of the airport on time now."

Without WAM, "winter weather conditions restricted airport arrivals and departures to four aircraft per hour," said Ruppel. Since radars could not track the aircraft once they descended below the tops of the surrounding mountains, air traffic controllers had to keep planes farther apart in the air than usual in order to provide the appropriate safety margins.

With WAM, controllers can safely use standard separation between aircraft. WAM shows the location of the aircraft by using a network of small sensors deployed in remote areas. The sensors read the transponder signal from the aircraft and triangulate its precise location. "Using WAM, the arrival rate for Yampa Valley Regional increases to 15-20 flights per hour," said Ruppel.

Timely airport access is not just important for skiers and snowboarders, it is an economic driver for northwest Colorado. Winter tourism is key for Routt County, home to Yampa Valley Regional, Colorado's sixth busiest airport, the town of Steamboat Springs and its general aviation airport. Roughly 70 percent of winter vacationers, between 95,000 and 110,000 people, visit northwest Colorado via Yampa Valley Regional during ski season. Those passengers, on average, spend $1,161 during their stay.

Through a cost-sharing agreement between the FAA and CDOT, the FAA installed the WAM sensors, which are more cost efficient and flexible than traditional radar in part because they are smaller and easier to install in mountainous terrain than are large rotating radars.

"Instead of a $10-million radar site, we can take small [less expensive] sensors and network them around the Valley," said Greg Dyer, FAA Traffic Management Officer at the Denver Air Route Traffic Control Center in Longmont, Colo.

Under the agreement inked between the FAA and CDOT in 2006, CDOT paid for the equipment, physical site preparations, power and telecommunications. The FAA commissioned, operates and maintains the system.

WAM is working so well that the FAA and CDOT partnered again to expand usage to another four airports. This second phase uses WAM sensors that are integrated in Automatic Dependent Surveillance – Broadcast (ADS-B) ground stations and began operating at Montrose Regional Airport in September 2012. WAM service at Gunnison-Crested Butte Regional, Telluride Regional and Durango-La Plata County airports is scheduled for Summer 2013.

When the FAA brings ADS-B online in Colorado in late 2013, the system will also provide broadcast services of traffic, weather and aeronautical information to equipped aircraft. WAM will then serve as a backup to ADS-B.