An air traffic control worker who fell asleep on the job at Ronald Reagan National Airport has been suspended.

The Federal Aviation Administration said the control tower supervisor fell asleep while working alone on an overnight shift. While he was napping, two airliners were forced to land without assistance from the tower.

Both pilots notified other planes in the area that they were going to land without clearance. The planes landed safely, but the episode has led to fierce criticism.

"As a former airline pilot, I am personally outraged that this controller did not meet his responsibility to help land these two airplanes," FAA Administrator Randy Babbitt said.

In response to the incident, Transportation Secretary Ray LaHood directed the FAA to launch a nationwide study of airport tower staffing.

He also said that at least two controllers should be on duty at night at Reagan.  The Washington, D.C., airport is often frequented by U.S. lawmakers.