Nimble maneuvers by the Federal Aviation Administration have managed to keep the nation’s air-traffic control system open, despite coronavirus-related problems at nearly half of all centers handling high-altitude flights.

In the past three weeks, nine of 22 such locations have been affected by employees testing positive for Covid-19, along with more than 26 other federal traffic-control facilities that were closed temporarily or otherwise impacted. But by embracing novel staffing arrangements, establishing spare airport towers wherever feasible and relying on swift cleaning procedures across the board, the agency has limited disruptions, according to an FAA document and government and industry officials.

One important strategy the FAA has relied on, some of the officials said, is designating core groups of controllers at each site to work together on the same shift for five days, and then take time off simultaneously. The goal is to reduce spread of the contagion to members of those specific teams in the event someone tests positive.

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Such safeguards make it easier to identify controllers who might have been exposed, and reduce impact on facilities when employees need to self-quarantine. Technicians who maintain and repair traffic-control equipment have embraced the same phased staffing principle while relying on bare-bones crews.

In cooperation with the union representing controllers, the FAA has determined minimum daily staffing levels in light of reduced traffic and social-distancing guidelines, according to a memo that was distributed at the end of March and reviewed by The Wall Street Journal. When one shift ends, the goal is to ensure priority information is passed on “while minimizing contact with employees on other shifts and crews,” the memo said.


Teams are usually scheduled to report over five-day work stretches and can be placed on administrative leave to guarantee full paychecks, according to the memo.

The FAA hasn’t detailed the number of controllers off the job due to the pandemic. It has said contingency plans are in place to shift duties among facilities and that its commitment to safety hasn’t wavered.

An estimated 70% plunge in overall commercial flights has allowed the FAA to reduce staffing levels nearly everywhere, which also makes it easier to alert and isolate employees who might have been infected by co-workers.

At the end of last week, government data showed flights were down by 65% or more at six of the nation’s 10 typically busiest airports. Major hubs such as San Francisco International Airport and New York’s John F. Kennedy International Airport were down more than 75%.


Where possible, FAA managers establish alternate towers—dubbed “clean spares”—to control takeoffs and landings. Sometimes, separate towers that normally control only taxiing planes are converted to that role. The goal is to ensure traffic keeps flowing when the primary tower has to be temporarily closed for disinfecting.

In all cases, the agency has instructed contractors to step up routine cleaning procedures. Some towers have been closed for days, or closed repeatedly, to meet federal health standards or respond to additional employees with suspected or confirmed coronavirus infections.

Temporary closings last month of towers at Chicago’s Midway Airport, New York’s LaGuardia Airport and McCarran International Airport in Las Vegas disrupted hundreds of flights. Controllers have tested positive five different times at the facility controlling departures and arrivals across the New York region. On Saturday, the center controlling high-altitude traffic around Memphis and Louisville, important cargo hubs used by FedEx Corp. and United Parcel Service Inc., respectively, had an employee who tested positive.

On Monday, the FAA’s website showed all major facilities across the country handling air traffic as required.


Despite the FAA’s success at avoiding long-term shutdowns, pilots said dispatchers still routinely warn that after departure, sudden changes in the status of distant traffic-control facilities could force flights to be rerouted or even diverted to an alternate destination.

Write to Andy Pasztor at andy.pasztor@wsj.com