ATLANTA -- Mass flight delays caused by an electronic communication failure at a Federal Aviation Administration facility drew new criticism for an agency that has been scrutinized over air traffic controller staffing levels and inspection standards for its ground-based equipment.

The Northeast was hardest hit by the delays prompted yesterday by a glitch at a Hampton, Ga., facility that processes flight plans for the eastern half of the U.S.

As of this morning, the FAA said that the situation around the country had returned to normal, with most delays from the malfunction being cleared up last night. But spokeswoman Diane Spitaliere said the investigation into what caused the problem is still ongoing, and she did not know when it would be completed.

"It usually takes a while to be quite honest," she said.

At one point, an FAA Web site that tracks airport status showed delays at some three dozen major airports across the country. The site advised passengers to "check your departure airport to see if your flight may be affected."

The FAA said the glitch appeared to have involved a software problem.

-- The Associated Press