The US National Transportation Safety Board has issued a recommendation to the FAA to prohibit air traffic controllers from providing supervisory oversight while performing operational air traffic duties.

The action is not directly related to this week's admission by a Washington National tower controller that he fell asleep while working alone on the midnight shift, his fourth such consecutive shift.

But the net effect of the recommendation could address the problem by requiring at least two controllers to be on duty.

At National early on the morning of 23 March, several aircraft were attempting to land but could not contact the tower after receiving a handoff from terminal radar approach controllers. Two aircraft ultimately landed at the airport using "uncontrolled airport" procedures before the controller came back on line.

The NTSB lists several examples of recent incidents that occurred when individual controllers were attempting to both perform supervisory and air traffic control duties, leading to errors.

One occurred at Washington Dulles International airport in Setember 2007, when a controller-in-charge (CIC) was also manning all positions in the tower while a second controller was on break.

The CIC cleared a Learjet 35 for takeoff on a closed, unlit runway that had been occupied by a work crew just before the departure.

No one was injured and the aircraft was not damaged in the incursion.

While regulations allow controllers to perform both functions "on a limited basis such as during periods of low activity" the NTSB says it is "unrealistic to expect an ATC team or a lone controller to consistently predict periods of low activity in an ATC environment".

In response to the Washington National incident, FAA administrator Randy Babbitt says the FAA is "instituting an interim plan" to ensure the situation does not happen again while the agency reviews "overnight staffing at selected airports around the country".

The interim plan requires terminal radar approach controllers to contact towers before handing off an incoming aircraft "to confirm that there is a controller prepared to handle the incoming flight".

"In addition, I have reminded all air traffic controllers that proper procedures dictate that they must offer pilots the option to divert to another airport if they do not make contact with the control tower," says Babbitt.

"Finally, I have ordered a nationwide review of the air traffic control system to confirm the appropriate backup procedures and equipment are in place and in use."

Source: Air Transport Intelligence news