US aviation regulators, investigating unsettling disclosures of sleeping air traffic controllers, will ban scheduling practices most likely to result in drowsiness at work.
The Federal Aviation Administration also said on Saturday it had suspended a controller in Miami for nodding off on the job, the fifth incident of that type identified in recent weeks and the second at a major centre.
"We will do everything we can to put an end to this," FAA Administrator Randy Babbitt said in a statement.
The string of cases, including one at Washington's Reagan National airport where the lone controller fell asleep on the March 23 midnight shift with two jets en route, have alarmed regulators and safety advocates and raised questions about scheduling.
The FAA official responsible for overseeing the day-to-day operations of 15,000 controllers at more than 400 airports resigned on Thursday.
The agency also ended the practice of staffing overnight shifts with one controller, which had occurred at more than two dozen airports. Those were mainly small centres with very light traffic after midnight.
In addition, the FAA said on Saturday it would by early next week prohibit scheduling practices most likely to result in tired controllers.
Any changes must be negotiated with the union representing controllers, but they could include doing away with midnight schedule swaps, curbing efforts to compress work schedules, or eliminating cases where controllers end one shift and then report for another after a short period.
"We are taking important steps today that will make a real difference in fighting air traffic controller fatigue. But we know we'll need to do more," Babbitt said.
Controller schedule changes would not reduce tower operations, which would affect airline flights.
The biggest centres, such as New York, Chicago and Los Angeles, have more than one controller on duty at all times. This also includes Miami, where the FAA on Saturday said it suspended another controller for sleeping on the job at an air traffic facility that handles aircraft routing.
A preliminary review of the incident showed the controller did not miss any radio contact from aircraft and that no flights were affected. There were 12 controllers on duty at the time, the FAA said.