Residents in Anne Arundel and Howard counties could hear more - or perhaps less - noise from airplanes rumbling overhead under a plan that the Federal Aviation Administration is considering that would change flight paths at Baltimore-Washington International Airport.
The move, the first change in flight paths at the airport in more than a decade, comes as the FAA consolidates radar control rooms at Washington's three major airports and Andrews Air Force base at a new facility in Virginia.
The agency says none of the three scenarios it proposes for new flight paths would affect the communities within five miles of BWI, where takeoffs and landings are known to rattle windows and sometimes make talking over backyard fences nearly impossible.
But, depending on which plan the FAA chooses, residents in communities such as Severn, Glen Burnie, Laurel and Clarksville in Howard County could see noise levels increase or decrease slightly, according to FAA maps.
The agency might, in the end, make no changes in existing flight paths. It will decide in September which path to pursue.
The FAA has been holding public hearings in Northern Virginia and Washington to discuss the changes, and convened its last one at the BWI Marriott last week. The few residents who attended pored over maps and magenta blips on a computer screen to discern what the changes would mean for their communities.
"We're trying to figure out where we're at, but we can't do that," said Charles Levay, president of Peach Orchard Improvement Association in Severn, as he and a neighbor looked at a map.
Levay said that he still hears airplanes overhead at his home, but said his windows stopped rattling when U.S. Airways discontinued its MetroJet service.
The FAA is mulling the changes in flight paths out of concerns that airspace is becoming too crowded and that the lower and longer flight paths are too expensive for struggling airlines.
When the flight paths were designed in the 1960s, Washington National Airport boasted 1,000 flights a day and was the area's busiest, compared with 250 flights daily from BWI and 100 flights daily from Washington Dulles International.
Forty years later, National's flights remain at the same level. Dulles has eclipsed National with 1,600 daily flights, and BWI has about 1,000.
The last time the FAA altered the airspace was in the late 1980s.
By then, the FAA said in a recent report, it had become clear that the increased demand for air service at fast-growing BWI would result in "unacceptable congestion and delays" to those flying in the entire Washington area, which controls about 2 million flights a year.
With both BWI and Dulles poised to handle yet more traffic, the FAA decided it needed to consolidate each airport's radar rooms - facilities where controllers track planes once they are flying at high altitudes.
"It allows us to be more flexible," said Alan D. Hendry, the FAA's program director for the project and a former air traffic controller in New York's consolidated radar facility. "It will be a great improvement."
About half of the air traffic controllers - who guide the planes through takeoffs and landings - will remain at the airport towers.
The other half will follow the radar controllers to a $93 million facility in Warrington, Va. By next year, controllers from BWI, Andrews Air Force Base, National, Dulles and Richmond International Airport will move into the facility.
The system - known as the Potomac Consolidated Terminal Radar Approach Control, or TRACON - will be in use by 2004.
Under the current system, a BWI radar controller must wait to make contact with a National controller when a flight enters into National airspace to hand it off, and the National controller has to do the same if the flight continues into Dulles' airspace.
With all the controllers looking at the same radar map, Hendry said, the transition will be seamless.
The consolidated system also will allow planes to fly about 1,800 feet higher than they do today, which will save fuel and reduce noise. The changes will save the airline industry between $8 million and $25 million a year, mostly in fuel costs, depending on which flight path scenario the FAA chooses.
Hendry also said security concerns are a motivation for the changes. He declined to elaborate.
The Washington area's airspace, which spans a 75-mile radius from Georgetown, is the nation's third-busiest, behind New York City and Southern California. Those two areas have already consolidated their radar rooms with great success, said FAA spokesman William Shumann.
"This is part of a trend that has been going on for some time in the FAA," he said. "We get significant savings by having these larger facilities. It's also easier to maintain the equipment in one building instead of four."
Attendance has been slim at all the public hearings, at last week's was no exception. About 15 people attended the midday session; even fewer appeared at the evening meeting. Several people said that residents are too busy fighting Maglev, the high-speed train proposed to run through Linthicum.
For maps of the proposed flight paths and other information, visit the FAA's Web site at www.faa.gov/ats/potomac.