Reagan National Airport officials yesterday recommended a series of changes, including routing planes over water instead of land, to reduce noise over neighborhoods.

Officials also recommended varying the points where planes turn toward or away from the airport, installing the latest technology to monitor noise and establishing a better way to communicate with the public when problems arise.

"We're dealing with issues we really think address the problems," said Jonathan Gaffney, a spokesman for the Metropolitan Washington Airports Authority.

The recommendations are part of a review of federal noise standards. They come four years after officials began studying the issue, because the review was put on hold after the Sept. 11, 2001, terrorist attacks.

In addition to changing air travel around the world, the attacks limited traffic and noise at National for months. Recently, the airport returned to the robust traffic levels of the summer of 2001, and the launching of a slate of new routes has added to concerns over noisy planes.

The most critical recommendation involves keeping planes over the Potomac and Anacostia rivers. Planes are required to fly over the water within 10 miles north of the airport and five miles south of it. But at night or during bad weather, pilots often stray from that path because it is difficult for them to see below, airport officials said.

Gaffney said the airports authority has proposed using technology, such as a global positioning system, so that pilots would always be able to remain over the rivers.

He said almost all planes turn toward or away from the airport at the southern five-mile point, which means they constantly fly over the same Mount Vernon area neighborhoods in Virginia. So the authority has recommended varying the turning point beyond the five-mile mark to spread out the noise.

"I think that'll serve us down south," said Leo T. Powell Jr., a citizen representative for Maryland on the airport noise abatement committee, which was formed to study the issue. But Powell said Marylanders north of the airport are still dissatisfied. "I don't think the people up north are getting a great deal of relief," he said.

Barbara A. Favola, chairman of the Arlington County Board and head of the noise abatement committee, said one of the biggest problems is airport officials' lack of accountability in monitoring noise violations.

"The airport authority has done a very poor job of monitoring noise complaints and monitoring compliance," she said. The recommendations call for the authority to set up a Web page where people can register complaints and where they would be given a reason for violations.

Regardless of the rules, airport officials and residents say noise levels are much better than they used to be because of quieter jet engines and because general aviation operations were halted at the airport after the terrorist attacks.

The recommendations and public comment about them will be forwarded to the Federal Aviation Administration, which will have final say over any changes. That process is expected to take up to nine months.