It happened often enough in the bad old days to cause headlines and to give office workers in Rosslyn a continuing case of the jitters. People on the top floors of the 30-story USA Today building would glance out the window to see huge jetliners whooshing past -- nearby and below them.

Rosslyn and its skyscrapers have become safer as a result of new guidance equipment installed to aid pilots on their approach to National Airport, according to the Federal Aviation Administration.

"Our big problem with the Rosslyn high-rises was not that planes were coming too close horizontally, but too low," said FAA spokesman Fred Farrar. "It scared people. They were coming in lower than the tops of buildings."

Rosslyn's tallest structures are the 390-foot USA Today building and its twin office tower. At the time the new guidance system was installed 17 months ago, only the building that houses the newspaper's headquarters had been built, and the FAA received complaints from workers on its upper floors that they were looking down on the planes flying by.

Although the FAA maintained there was no danger of a plane hitting one of the skyscrapers, it agreed to install new guidance equipment and landing aid lights on the Key, Memorial and 14th Street bridges.

The new equipment -- a "localizer directional aid" system -- shows pilots on a cockpit scope whether their planes are on course and descending at the correct rate, allowing for minute-by-minute corrections.

It replaced a less sophisticated system that simply gave pilots a beam to follow and told them how many miles they were from the airport. The pilot then had to compare that information with paper charts that showed how high the plane should be at each mileage point.

The new equipment is designed to help pilots comply with a policy that they stay at or above 720 feet altitude when making an instrument approach until they are about a half-mile past the USA Today building.

Farrar said that the FAA has received no reports of planes flying close to the buildings since the new equipment was installed. "It's working well," he said.