The Alexandria City Council voted unanimously last night to file suit against the Federal Aviation Administration in an attempt to stop the agency from testing the so-called "scatter" plan to distribute aircraft noise from National Airport over a wider area.

Alexandria City Attorney Cyril D. Calley said afterward that he plans to seek a temporary restraining order Monday in U.S. District Court in Alexandria.

The FAA announced last week that the planned test of the new landing and takeoff patterns could begin as early as Sept. 15. Studies indicate that under the plan an additional 450,000 area residents would be affected by noise generated by planes using National Airport. The tests could continue for as long as 90 days, according to the FAA.

Calley said he will ask the court to block the FAA from going ahead with tests because they would harm Alexandria residents.

Calley said if the request is granted, the city would then have an opportunity to argue that the FAA did not thoroughly research the environmental impact that the tests would have on the area.

FAA officials have steadfastly denied that claim.

Although several other local governments, including the District of Columbia and Fairfax and Arlington counties, have opposed the proposed scatter plan tests, Alexandria is the only one that has voted to file suit.

Mayor Charles E. Beatley Jr. invited other area governments to join the city's lawsuit.

"We feel that the scatter plan is hostile to the best interests of people in the city," Beatley said.