In February 2015, Phoenix residents put up signs complaining about increased noise from airplanes along new flight paths. A court ruling in their favor has given hope to residents in Northwest D.C. who say new paths out of Reagan National Airport disturbing their peace. (Ross D. Franklin/AP)

When a federal appeals court found in favor of the city of Phoenix in its battle over airplane noise, it is possible that no group of residents — beyond those in Arizona — cheered as loudly as some in Northwest D.C.

Georgetown, Palisades and Hillandale residents have waged a long-running fight to get the Federal Aviation Administration to alter the flight path over their communities — with little success. Then this summer, a three-judge panel of the U.S. Court of Appeals for the District of Columbia called for the FAA to scrap flight paths enacted in 2014 at Phoenix's Sky Harbor Airport as part of the agency's effort to modernize the air traffic system. The FAA, the panel found, failed to seek proper public input.

FAA officials were quick to say the ruling and agreement in Phoenix would not set a precedent.

"This resolution is unique to Phoenix," the agency said in an emailed statement. "We will continue to work with other communities individually to address their noise concerns."

But that hasn't stopped other communities from hoping they, too, might force a change.

Maryland Gov. Larry Hogan (R) cited the Phoenix ruling in directing state Attorney General Brian E. Frosh (D) to file suit against the FAA in September over redesigned flight paths at Baltimore-Washington International Marshall Airport. The state even hired one of the same law firms that won the Phoenix case, though it has yet to file suit.

Northwest D.C. residents who have pushed to change the flight path said they'll cite the appeals court ruling as they prepare to argue their case before the same court next month.

"I think it's an extremely important opinion in support of our case," said Don Crockett, a Georgetown resident. "We're very encouraged by that precedent."

The FAA began rolling out new flight paths in 2014 as part of a years-long multibillion-dollar modernization effort called NextGen. The goal was to make flying more efficient by shifting from radar to satellite navigation. The changes will allow planes to fly more direct routes, saving fuel and reducing emissions, the agency said.

But the new paths have led to a dramatic increase in complaints from residents, some of whom had never been affected by jet noise. That was the case in Phoenix, where planes began flying over historic portions of the city. After several months of back-and-forth with the FAA, the city and a coalition of neighborhood groups filed suit in June 2015.

[Report says noise complaints are up at National, Dulles airports]

"What happened in Phoenix was one of the most egregious implementation failures out there — one of the most egregious that I've seen in my career in aviation," said Chris Oswald, a vice president at Airports Council International-North America, which advocates for the nation's airports.

In a 2-1 decision, the appeals court agreed with the contention that the FAA was "arbitrary and capricious" in the way it implemented the procedures.

Designing and redesigning airspace is a complex undertaking that can take years — and FAA officials have long told communities that once changes are in place, undoing them is close to impossible.

In fact, despite the panel's ruling, the FAA won't change all the flight paths over Phoenix, arguing in court papers that such an endeavor could take years, increase safety risks and cause delays at the airport.

"If this court were to vacate all of the RNAV departure procedures from Phoenix Sky Harbor Airport, FAA believes that the resulting disruption while the FAA prepares new replacement procedures would far outweigh any possible benefit," the agency wrote in a joint petition to the court outlining an agreement between the parties over how the flight paths will be amended.

The agency did agree to alter enough of the routes to satisfy the community.

"Bottom line: It is good news," said former Arizona attorney general Terry Goddard, who as senior council at the firm Dentons represented the neighborhoods in Phoenix.

"What happened in Phoenix can be a template that can be applied to other communities, hopefully avoiding the legal process," said Jesse Chancellor, a Howard County, Md., resident who has been active in the battle over noise at BWI. "That would be the easiest and common-sense approach. Lawsuits are expensive and uncertain, and who wants to go through that?"

Goddard said the Phoenix decision has also shown the agency that it is better to be open with communities affected by changes.

"I would think that the FAA would be far more interested in making sure they bend over backwards to get input from the neighborhoods," he said. "Hopefully, the agency will change some procedures so that they are more cognizant of problems on the ground."