While most are familiar with the term "asleep at the wheel," how about "asleep in the control tower?"

That was apparently the case as two planes, including an American Airlines Boeing 737 aircraft carrying 91 passengers that had taken off from Dallas, were trying to land at Ronald Reagan Washington National Airport.

There was silence for nearly 40 minutes from the tower around midnight Tuesday at Reagan National Airport. American Airlines Flight 1900 and a United Airway's plane both went in for a landing without any tower control communication from the Washington airport.

The pilots and regional air traffic controllers tried several times to reach the lone on-duty supervisor. Federal investigators are looking into allegations that the supervisor may have fallen asleep.

Aviation expert and pilot Denny Kelly said air controller fatigue is a major concern.

"It's a huge problem, worse now than back then," he said.

The two pilots were in contact with controllers at a regional FAA facility about 40 miles away. Both planes landed safely.

"Our crew did not file a report with us since they were in contact with a regional ATC Center and made a safe, otherwise routine landing," said Andrea Huguely, a spokeswoman with American Airlines.

However, the incident has prompted the federal government to step in, and now tower staffing at airports across the nation will be reviewed. Two controllers will now be required inside the tower during overnight shifts at Reagan.

Kelly said he hopes that becomes procedure at every airport.

"I would hope that they change and that there's always a back up in the tower," he said.