When an employee in an air traffic control facility tests positive for coronavirus, the result can be a chain of airspace-management responses extending far beyond the affected individual’s work area.
During disinfecting, entire ATC facilities can be shut down for hours or longer, shunting airspace coverage to other facilities with delays and changes of expected or customary routings.
When a positive coronavirus test of a worker at the Houston Air Route Traffic Control Center was confirmed, the facility went to ATC zero March 30, putting an operational contingency program in action, said Rune Duke, AOPA senior director of airspace, air traffic, and aviation security.
An advisory from the Air Traffic Control System Command Center, which a pilot would have noted during preflight planning, reported that “ZHU WILL BE ATC ZERO FROM 0400Z-1100Z DUE TO COVID-19/FACILITY CLEANING.” A notam was also issued for Houston Center.
Terminal radar control facilities that handle some of Houston Center’s underlying airspace took over a portion of the workload. “However, in this case, the high-altitude airspace sectors were not available and the tracon’s sectors did not extend to the higher altitudes, so traffic was rerouted or forced to descend,” Duke said.
With a center’s coverage area temporarily designated a “constrained area,” an airspace flow program takes over. Traffic managers develop a real-time list of flights that are filed into the airspace, as explained in Advisory Circular AC 90-102A.
The Air Traffic Control System Command Center advisory referred to above provided guidance on arrival- and departure-route procedures in use during the center’s closure. “Some routes may steer traffic around constrained airspace altogether, while other routes help flow traffic through the tracons, with altitude restrictions because tracons generally don’t go into the flight levels,” Duke said.
An expected departure clearance time may be part of the traffic management initiative—but the absence of an expected departure clearance time does not suggest that you will avoid being rerouted. (And don’t count on picking up your IFR flight plan airborne to beat the system, Duke cautioned.)
Ground delay programs—issued for individual airports—may also be part of operational contingency programs to “meter the flow” of traffic when demand exceeds capacity, according to the advisory circular. Pilots are mostly familiar with ground delay programs regulating traffic during thunderstorm season.
Ground delays will not always be used in ATC zero responses during this pandemic because overall traffic volume is down, Duke said.
For more information about operational contingency programs and a refresh on how to check for ATC delays, review the FAA publication Traffic Flow Management in the National Airspace System.