(Updates with FAA statement in ninth paragraph.)
June 13 (Bloomberg) -- A work schedule sought by some U.S. air-traffic controllers to get three-day weekends produces severe fatigue because it’s impossible to get adequate rest between duty periods, a Congress-mandated study found.
The report sheds new light on a schedule, known among controllers as the “rattler,” that gained attention in 2011 after at least six controllers fell asleep on the job.
“From a fatigue and safety perspective, this scheduling practice is questionable, and the committee was astonished to find that it is still allowed under current regulations,” the reviewers said in the National Research Council study.
The schedule, which compresses five shifts into four days, causes “reduced cognitive performance” and should be reviewed by the Federal Aviation Administration, the panel said.
After the 2011 sleeping incidents, the FAA allowed the schedule to continue while mandating longer breaks between the shifts.
A 2010 study of the schedule by the National Aeronautics and Space Administration found that it produced less fatigue than other shifts required to cover overnight periods, Doug Church, a spokesman for the National Air Traffic Controllers Association union, said in an e-mail.
The FAA and the union have worked together to take several actions to reduce fatigue, Church said. One such step was to reduce to seven hours the shift during the day that precedes an overnight shift, he said.
“There are ongoing policy changes being studied and implemented that gradually reduce fatigue risk on the midnight shift,” he said.
The FAA is reviewing the report. The agency said in an e- mailed statement that it has taken steps in recent years to reduce the risks of controller fatigue, such as adding a second person to facilities that had been staffed by just one on overnight shifts.
In a typical “rattler” schedule, a controller works five 8-hour shifts starting at 2 p.m. on Monday and ending at 7 a.m. Friday. In the final 24 hours, he or she will work a day shift, take a break during the afternoon and evening, and return for an overnight shift.
The shift’s effects can be more pronounced if a controller has a lengthy commute, further limiting the time for sleep between shifts, according to the report.
Before the final shift of the week, a controller working the schedule must try to sleep during the day when the brain isn’t tired and then work through the night as the body craves slumber, the study found.
“This combination of acute sleep loss and work during the biological night increases the risk for fatigue and for associated errors and accidents,” the study committee said.
The FAA employs about 15,000 controllers to keep the U.S. aviation system functioning around the clock. The controller workforce costs the agency $2.8 billion a year, or about 18 percent of the agency’s $15.8 billion budget, according to the report.
It concluded the FAA could do a better job of determining how many controllers are needed at its towers and radar rooms, and how to best schedule its workforce.
“Taken in its entirety, the staffing process by which FAA determines the total number of controllers can sometimes appear arbitrary, both to this committee and to the organizations and workforce that need to implement the staffing plan within FAA.” the report said.
Bloomberg News reported in 2012 that more than 100 U.S. air-traffic facilities have such little traffic overnight that they should be closed under the agency’s guidelines. Members of Congress from both parties have blocked attempts to cut schedules, according to interviews and documents.
Budget reductions last year under across-the-board cuts in federal spending known as sequestration hindered the FAA’s ability to monitor controllers for signs of fatigue, the report said.
While aviation accidents linked to air-traffic actions make up a small portion of crashes, controller fatigue has arisen in several investigations by the National Transportation Safety Board.
In a 2007 letter, the NTSB wrote that “controllers are sometimes operating in a state of fatigue because of their work schedules and poorly managed utilization of rest periods between shifts and that fatigue has contributed to controller errors.”
The National Research Council study called on the FAA to analyze fatigue hazards among controllers and restart a fatigue- management program that was slowed after budget cuts.