Five U.S. senators and representatives from Virginia have written to Homeland Security Secretary Tom Ridge seeking a briefing on how the department plans to handle the surge of passengers expected at Dulles International Airport this summer.

With air traffic returning to pre-Sept. 11, 2001, levels and the arrival of two new low-cost carriers, Dulles will go from being the 11th busiest airport in the nation to the seventh in a matter of weeks, the letter said. The airport will need more security screeners, technology and machinery to deal with increasing crowding, lines and flight delays, the letter said.

The letter, dated May 14, was signed by Reps. Thomas M. Davis III (R-Va.), Frank R. Wolf (R-Va.) and James P. Moran Jr. (D-Va.) and Sens. John W. Warner (R-Va.) and George Allen (R-Va.).

The congressmen also requested that "appropriate" numbers of U.S. Customs and Border Patrol personnel be assigned to reduce the existing delays associated with international arrivals and departure at the airport.

The letter said that lines have already gotten so long at Dulles that the terminal is running out of space to accommodate them. The congressmen predicted the situation would worsen with the scheduled launch of Independence Air in June on the heels of Ted, United Airlines' low-cost carrier, starting Dulles flights in April.

"We ask that you provide the necessary TSA [Transportation Security Administration] screening personnel to handle the projected influx of passengers that could cause serious overflow problems, lengthy lines and operational delays," the letter said. "Along with additional personnel, appropriate screening technology and machinery must also be considered where appropriate."

The Department of Homeland Security referred questions about the letter to the Transportation Security Administration.

Chris Rhatigan, a spokeswoman for TSA, said the agency was "fully prepared" for Independence Air and the increased traffic at the airport.

"We're ready for the summer travel at Dulles," Rhatigan said. She said that her department meets regularly with the Metropolitan Washington Airports Authority, which operates and maintains Reagan National and Dulles airports, and with individual airlines and that a news conference was scheduled to be held Wednesday at Dulles to update the public.

This month, TSA announced that Dulles would receive 100 more screeners in June, bringing the number to 645. In addition, administrative staff will work as needed to advise passengers waiting for screening -- reminding them to take out laptops and remove change from their pockets -- to keep the line moving smoothly, Rhatigan said.

In April, Kenneth M. Mead, inspector general of the Department of Transportation, warned a Senate subcommittee that Dulles could see as much as a 50 percent increase in traffic in summer. Mead said the Department of Transportation was concerned about potential flight delays as well as the terminal services needed to process more passengers through security checkpoints.

"The central question is, 'Is what you're going to do at Dulles enough?' " said Robert White, a spokesman for Davis.