February 23, 2012 By Brian Heaton
Frederick Municipal Airport in Maryland is upgrading to a satellite-based air traffic control system that officials hope will improve inefficient flight paths due to spotty radar coverage in the area.
According to Kevin Daugherty, a pilot and airport manager of Frederick Municipal Airport, the location suffers from inadequate radar signals that often require pilots to make adjustments to their flights to and from the airport. Pilots have to fly out of their way in order to stay visible on radar to the Potomac Terminal Radar Approach Control (TRACON), which controls approaches and departures in the airspace surrounding the area.
The new technology — called Automatic Dependent Surveillance-Broadcast (ADS-B) — combines with GPS data to monitor real-time plane location and other flight information on aircraft equipped with ADS-B avionics. Frederick Municipal Airport will build a broadcast station for monitoring ADS-B signals. The signal feed then will be sent to TRACON to improve efficiency.
“If we are flying on a flight plan, a lot of times we’ll have to go west to go east or north to go south because [the tower] can’t ping us on radar until we get to 2,500 to 3,000 feet,” Daugherty said. Planes using ADS-B could fly more direct routes to and from Frederick Municipal Airport and potentially speed up a lot of the flight traffic.
Frederick will be the first general aviation airport — facilities without commercial airlines — and second airfield in Maryland to use the system. Baltimore/Washington International Thurgood Marshall Airport is the other. Construction of the broadcast station will be paid for by the FAA.
Other airports should soon be following suit. By 2020, the Federal Aviation Administration will require most planes to have ADS-B installed as the first step in moving to its Next Generation Air Transportation System (NextGen). The new air traffic control system will eventually replace ground-based radar at airports throughout the United States.
Other planes in the air appear as dots on a radar screen in the cockpit, Daugherty explained. But with ADS-B, a pilot can see in real time the altitude, heading, speed and distance from all other aircraft equipped with ADS-B in the vicinity, instead of relying on that information from the control tower.
Other benefits to pilots include receiving real-time weather briefings, temporary flight rules and notifications. This information should improve safety and situational awareness on the flight deck.
Despite the benefits of ADS-B and satellite based surveillance, don’t expect radar to be decommissioned anytime soon.
Daugherty noted that the ADS-B avionics technology is expensive, likening it to GPS devices for cars when they first came out. But the price tag should lower in time — much like GPS became cheaper. For now, however, the cost is a hurdle.
“The only negative I see is you have to have the avionics for it on your aircraft, and not a lot of them do,” Daugherty said. “I think things will be phased and more airplanes will get it as we get to that mandatory  date.”
The next step, he added, is to incorporate ADS-B into ground vehicles. Daugherty speculated that if ADS-B could be put on trucks and various airfield vehicles, the data would be particularly useful during bad weather, so pilots are fully aware of where everything is as they take off and land.
“[It] increases capacity and safety,” he said, referring to the usefulness of ADS-B. “How can you lose?”
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