The Federal City Council yesterday endorsed the proposed federal policy for National Airport that would reduce commercial airline flights by about 20 percent, ban all late-night flights, admit widebody planes and limit the airport's growth.

The council's policy statement, the result of a study by a 40-member task force of top D.C. business and professional people, will strengthen Transportation Secretary Neil Goldschmidt's hand if he choose to adopt this policy.

It will also anger opponents who believe Goldschmidt's proposal does not go far enough toward reducing the noise and the nuisance the airport generates. g

"The task force believes," the report said, that the "proposed rules for National Airport's operation reasonably accommodate the competing interests at stake." One member of the task force was Paul R. Ignatius, president of the Air Transport Association of America, the airline lobby.

Lawyers for Goldschmidt have promised Federal District Judge Albert V. Bryan Jr. that a final National Airport policy will be published by Aug. 15. The absense of a policy, which has been tied up in lawsuits and administrative actions for years, has meant that the federally owned airport has been unable to move forward on needed improvements in the terminal and roadways.

The council's task force went beyond Goldschmidt's proposals in two important areas.

Goldschmidt proposed that passengers using National Airport be limited to 18 million annually; the council suggested a limit of 16 million to 18 million. The airport had 15 million passengers last year, a record. If the lower council limit were adopted, almost all additional passenger growth would have to take place at Dulles International or Baltimore-Washington International Airports.

The council also proposed that in any future allocation of flights to National Airport, the shorter flights would receive priority. That proposal gets at the heart of concerns from small cities such as Roanoke and Charleston that they would lose nonstop service to National Airport under Goldschmidt's plan.

"National should primarily serve short-haul traffic from relatively nearby cities," the council said.

Congressman have been leaning hard on Goldschmidt in recent hearings to do nothing that would reduce service from National Airport, which is close to Capitol Hill and convenient for a fast Thursday afternoon getaway.

The council agreed with Goldschmidt that the number of commercial airline flights permitted per hour should be cut from to 36, that there should be an absolute ban on all flights between 10:30 p.m. and 7 a.m., and that wide-bodied airplanes such as the A300 or DC10 should be permitted to use National if all safety questions are satisfactorily answered.

National Airport currently has a rule that prohibits nonstop flights from all cities beyond 650 miles, with seven exceptions. Goldschmidt has proposed extending that perimiter to 1,000 miles, with no exceptions.

The council suggested that if the short haul preference proposal were adopted, no perimeter rule would be needed. As a practical matter, National cannot be used for transcontinental flights because its runways are too short for a fully loaded jumbo transport to take off. Planes such as the 727 and DC9, which use National today, do not have transcontinental range.

The council said that the combination of curfews, reduced big-jet operations and the introduction of quieter jumbo jets should provide adequate noise relief to the beleaguered residents of the Potomac River Flight path.

"To the extent practicable," the council said, "consideration should be given to dispersing aircraft departures over more than one flight path so the noise is not concentrated over the same area all of the time."

The Federal City Council is a nonprofit, nonpartisan group of 100 top civic and business leaders that has played an influential role through such actions as lobbying for the completion of the Metro system and financing studies of the region's economic and demographic patterns.