'ATC Zero': Inside the Chicago Center fire

Without warning, the radar scopes went dark and the radio frequencies all fell silent.

In the basement of the Chicago Air Route Air Traffic Control Center shortly after 5 a.m. on Sept. 26, investigators say Brian Howard, a contract employee, severed the main lines of the vast communications network that underpins some of the world’s busiest and most complex airspace, and then set fire to the electronics and slashed his own wrists and neck. He also posted a suicide note on social media.

Howard would survive, but the technological heart of the Chicago air traffic control system had suffered a fatal blow.

“We’ve got primary and backup systems for just about everything,” said Toby Hauck, a Chicago Center air traffic controller and union leader at the 700-employee facility. “But in this case both the primary and backup systems were destroyed. It all went down at once.”

A 911 call at 5:40 a.m., followed by fire alarms, forced all employees to evacuate the FAA facility in suburban Chicago, including about 140 controllers. They had just directed a wave of eastbound red-eye flights high overhead and were prepared to handle a surge of arrivals to O’Hare and Midway, Chicago’s busiest airports.

Within minutes, however, FAA managers had declared an “ATC Zero” situation, meaning that the entire facility was dropping offline. About 40 airplanes on IFR flight plans were over the area when the outage began, and pilots scrambled to reach other air traffic controllers on the emergency frequency, 121.5 MHz. From a timing standpoint, the traffic level was extremely low, but the Friday wave of pre-weekend travel was already rolling and would crest that afternoon.

Around Chicago, IFR departures came to a complete halt. Even at outlying airports far from the city, pilots couldn’t get clearances because they all originate at Chicago Center.

Outside the brick-and-steel FAA building, controllers gathered in a parking lot as dawn broke on a clear, mild fall day. Black smoke billowed from the ground floor of the FAA center. As firefighters and police noisily swarmed the area, controllers used personal cellphones to call and text their peers at other facilities and let them know what was taking place.

James Hall, a controller and union leader at the Chicago Tracon, which coordinates arrivals and departures at the city’s busiest airports, said the 27 controllers on the morning shift got their first sign something was wrong when Chicago Center stopped taking their handoffs and wouldn’t respond to the always-connected telephone “shout line.”

“A few minutes later we learned the center had been evacuated,” Hall said.

Details about what had started the conflagration also began to emerge.

Howard, a contract employee for eight years, knew the communications network and its vulnerabilities. Days later, he would be charged in U.S. District Court with destruction of aircraft facilities, a federal crime with a maximum penalty of 20 years in prison.

For controllers, few of whom knew Howard personally, the most urgent questions had to do with fixing the compromised national air traffic system. A gaping 91,000-square-mile hole had been torn in the center of that network. American, Southwest, and United airlines with hubs in Chicago felt the brunt of the impact with Southwest canceling all of its Midway flights. Thousands of general aviation flights were halted, too. Early estimates predicted it would take many weeks, possibly months, to repair the damaged nerve center.

Without being asked, dozens of Chicago air traffic controllers started driving to distant facilities in Minneapolis, Kansas City, Indianapolis, and Cleveland, which they knew would become inundated with redirected flights as soon as that afternoon.

“They just got in their cars and started driving,” Hauck said. “Some of them didn’t even have a chance to go home and pack their bags. They left with no idea how long they’d be gone.”

A very big mess

Around noon Friday, the day of the fire, police with bomb-sniffing dogs cleared the Chicago Center building, and controllers and FAA managers went back inside. The fire had largely been contained to the basement but the damage to the communications network was extensive.

FAA managers, technicians, and controllers sketched out a plan for getting air traffic moving again although at a vastly reduced rate. Chicago’s Tracon, the approach control facility, was still at full strength. With a redrawn air traffic map, different radio frequencies, and new procedures, the surrounding air route traffic control centers could reach deeply into Chicago Center’s territory and, in some cases, coordinate arrivals and departures directly with the tracon.

“The situation was so unusual and so complex that, in the beginning, we didn’t really know what kind of help to ask for,” Hall said of the tracon, which typically has 27 controllers on each shift. “Everything had to be done manually and coordinated by phone.”

Instead of issuing published standard instrument departures, for example, controllers had to manually write out individual flight plans for every aircraft and read every clearance to all of the controlling agencies before releasing the aircraft. Controller shifts were extended to 10 hours, and most of that time was spent on telephones.

In the next 24 hours, about 220 Chicago Center controllers dispersed themselves to other centers as well as smaller ATC facilities such as South Bend, Indiana; Milwaukee, Wisconsin; and Moline and Rockford, Illinois, which took over more airspace, higher altitudes, and quadruple their normal traffic volumes. Chicago controllers who had previous experience at regional facilities returned to them so that they could be recertified quickly at familiar locations.

“There have been tornadoes and other events that have caused ATC Zero situations before,” Hauck said. “But they typically last for minutes or a few hours at most. The situation we were facing with Chicago being out was unprecedented. We knew we were in uncharted territory.”

At surrounding centers, FAA managers and air traffic controllers struggled to answer seemingly basic but suddenly imperative questions. How far could their radar see into Chicago airspace? At what altitudes could pilots communicate with controllers on newly activated radio frequencies?

In Kansas City, controllers discovered they could reach aircraft as far north as Joliet, Illinois, and hand them off directly to Chicago Tracon.

“We got out a map and started hand-drawing lines on it,” said Aaron Merrick, a 15-year Kansas City Center controller. “We had some seldom-used radio frequencies that helped us extend our range.”

About 20 Chicago Center controllers and FAA managers showed up at Kansas City Center, and even though some of them were assigned to familiar airspace, many of the procedures and frequencies had changed. Meanwhile, surrounding centers were directing a surge of high-altitude traffic that normally would have gone over Chicago, and ripple effects spread across the continent. Jets coming into Atlanta from the west, for example, were told to fly at far lower altitudes than usual for hundreds of miles because the airspace above them was jammed.

Several radar positions at Kansas City that normally are only used at peak hours were pressed into full-time service, and both Chicago and Kansas City controllers worked side by side.

“The Chicago controllers blended right in—and the collaboration worked better than anyone could have expected,” Merrick said. “In fact, I’ve never seen anything like it. We’re constantly short of staffing, and now we had three entirely new sectors and an entirely new set of procedures. But the teamwork was so phenomenal that we were able to overcome the obstacles. I’ve never been so proud to be a controller.”

At Chicago Center, technical experts determined it would be quicker to replace the damaged network with entirely new equipment than try to repair it—and work continued around the clock for two weeks to do just that. Surprisingly, given the complexity of the project, the new network was fully in place on Oct. 13, just 17 days after the fire.

“When we powered up the new system at midnight on the thirteenth, it worked flawlessly,” said Hauck of Chicago. “In 45 minutes, we assumed control of all of our airspace.”

O’Hare and Midway airports came online first, and the restart would have been a success if it had stopped there. But the system performed so well that they kept expanding it. At the end of the day, Chicago Center had handled 6,847 aircraft.

“That’s about right for a normal 24-hour period,” Hauck said. “But the situation we were dealing with wasn’t normal at all.”

Hauck and Merrick said they and their fellow controllers were so focused on solving problems during the shutdown that there was almost no discussion of Howard, the man accused of setting the fire, or his motivation. News reports said he was upset about an impending job transfer to Honolulu, Hawaii.

“No one really asked about the guy that did this or what his reasons might have been,” Merrick said. “We’re professionals who came together to fix a very big mess—and we all take great pride in what we were able to accomplish.”

Hauck pointed out the irony that a destructive act meant to cause lasting damage had, in fact, done the opposite. New equipment was installed, the Chicago control room got a thorough and overdue cleaning, and controllers who only knew each other as disembodied radio voices worked shoulder to shoulder.

“The positive results that came out of this will endure,” Merrick said. “We’ve got a new appreciation for our fellow controllers in other facilities, and the sense of camaraderie is unbelievable. Managers, controllers, and technical operations specialists have never worked together better.

“It started with a horrible, destructive act,” he said. “But the legacy that comes from this is nothing short of inspiring.”

Hall, of the Chicago Tracon, compared the controllers’ reaction to the citizens of Boston following the 2013 marathon bombing.

“The Boston bombing brought people together, and that’s what this event did for us,” he said. “Everyone stepped up. We did whatever needed to be done.”

Were you flying through Chicago Center’s area when the facility lost communications? If so, please contact AOPA. We’d like to hear your story.