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Controller fatigue an ongoing concern
March 28, 2011
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  • By Alan Levin
    March 25, 2011

    Federal aviation safety investigators have worried for years that the fatiguing schedules that air-traffic controllers work could undermine safety, an issue that resurfaced dramatically this week when the tower at Washington’s Reagan National Airport fell silent in the wee hours.

    Two jets landed without clearance from the control tower at the airport that sits just 2 miles from the White House shortly after midnight Wednesday, according to the National Transportation Safety Board (NTSB). The supervisor on duty, the only person staffing the tower on the overnight shift, told investigators the reason he didn’t respond for more than 24 minutes was that he fell asleep.

    Pilots had repeatedly radioed the tower and gotten no response, according to the NTSB and the Federal Aviation Administration (FAA). After controllers at a regional facility that guides jets to National were notified, they tried to reach the tower via telephones and an intercom system.

    The NTSB said Thursday that “human fatigue issues” was one of the areas under investigation.

    The unnamed supervisor has been removed “from all operational duties” while the FAA investigates the incident, FAA Administrator Randy Babbitt said.

    Transportation Secretary Ray LaHood also ordered the Reagan National tower to have at least two people on duty at all times.

    FAA rules require that two controllers work at most mid-size airports because they must mind the tower, as well as guide traffic in a roughly 50-mile band around the airport.
    Controllers oppose solo shifts

    No such rule applies to Reagan National because a separate facility in Virginia oversees traffic in the area outside the airport. The airport usually has only a handful of flights from midnight to 6 a.m., a workload that one controller can easily handle.

    Larger airports with more overnight traffic, such as John F. Kennedy International in New York, always have at least two controllers on duty.

    National Air Traffic Controllers Association (NATCA) President Paul Rinaldi called for an end to allowing a single person to work during quiet overnight shifts.

    “One-person shifts are unsafe. Period,” Rinaldi said in a statement. “NATCA has long been outspoken in its opposition to one-person staffing on any shift. In fact, the NATCA membership, in its strong commitment to aviation safety, adopted language in its formal constitution nearly 20 years ago opposing one-person staffing on a shift. That language remains in effect today.”

    Fatigue is an issue that has come up repeatedly in NTSB investigations involving controllers.

    “Air-traffic controllers have notoriously difficult schedules that are prone to inducing profound levels of impairment associated with sleep deficiency,” says Chuck Czeisler, a Harvard University Medical School professor who specializes in sleep research.

    The issue arose during the NTSB’s investigation of the Aug. 27, 2006, crash in Lexington, Ky., that killed 49 people. A controller on duty when the jet tried to take off on a dark, closed runway at 6 a.m. told investigators that he had only two hours of sleep during the previous 24 hours.

    The controller was on a shift common among FAA air-traffic workers: He had worked during the day the day before the accident, then returned to work at midnight after nine hours off.

    Although some controllers like such schedules because they effectively give workers a three-day weekend, controllers say they are known as the “rattler” because of the way they disturb normal sleep patterns.

    The NTSB ultimately did not find that the controller was at fault in the crash, but was concerned enough to issue recommendations to the FAA and the NATCA urging that they adopt less fatiguing schedules.
    Fatigue a factor in close calls

    The agency said that several other incidents provided “clear and compelling evidence” that fatigue has played a role in controller errors. They were:

    •On March 23, 2006, a controller at Chicago’s O’Hare International mistakenly told pilots on an Airbus A320 to cross a runway and moments later cleared a Boeing 737 to take off on the same runway. The 737 pilots spotted the other plane and aborted their takeoff. The controller said he had slept only four hours the previous night.

    •On Aug. 19, 2004, a controller at Los Angeles International told a 737 to take off as a Boeing 747 was preparing to land on the same runway. The 747 pilots spotted the other plane and aborted their landing. The controller told investigators she had slept five to six hours and attributed the incident to her fatigue.

    •On July 8, 2001, a collision on a runway at Seattle/Tacoma International was narrowly averted after a controller told a Boeing MD-80 crew to taxi across a runway where a Boeing 767 was landing. The controller was working his third shift in two days with only eight hours off between shifts. At the time of the incident, the controller said, he was fatigued because he “had to be up all night long on a double-quick turnaround.”

    Source: USA TODAY
    Date: 2011-03-25