For the second time in less than a year, fire-related concerns caused the evacuation of an Elgin air traffic control facility with resulting travel nightmares nationwide.
For about three hours Tuesday, the FAA grounded flights in and out of O'Hare and Midway international airports after smoke filled the Terminal Radar Approach Control (TRACON) center in Elgin at 11:30 a.m.
Limited arrivals and departures were allowed around 2:45 p.m. but more than 600 trips were canceled at O'Hare and about 75 at Midway. Delays at O'Hare averaged more than 60 minutes with a worst-case scenario of nearly three hours.
By late Tuesday, delays were averaging 90 minutes at O'Hare and 2 hours at Midway. O'Hare canceled about 1,000 flights and Midway canceled 120 flights.
Things seemed to be returning to normal Wednesday morning, officials from the Chicago Department of Aviation said at 7:30 a.m. Wednesday. No flights were delayed and no cancellations were announced.
Among those in limbo were members of the Chicago Wolves hockey team en route to a playoff game in Toronto. Wolves public relations director Lindsey Willhite of Naperville described a line "six gates long at the United Airlines customer service desk.
"It's awe-inspiring," he said. "Hundreds of people are all trying to call the same single number (provided by United)."
Elgin Fire Department crews declared the building safe and allowed some air traffic control supervisors back in around 1 p.m. However, the full complement of controllers wasn't back until about 4 p.m. when all residual smoke had been cleared.
That left a significant backlog of flights at both airports and travelers are advised to check with their airlines for any schedules changes.
The smoke was caused by a faulty motor in the heating, ventilation and air conditioning system, fire department officials said.
Insulation around the motor wires in a drop ceiling near a bathroom heated up to the point of emitting smoke that was sucked out through the HVAC system, filling the radar room where controllers work, fire Capt. Robb Cagann said.
It took time to identify the source of the smoke with 20 to 30 HVAC units in the building, Cagann said.
"We understand the impact of (the center) and tried to get it back (in operation) as fast as possible."
On the morning of July 2, 2013, a fire alarm went off at the TRACON building because of sprinkler system issues, causing an evacuation. About 80 flights were late.
The TRACON center handles aircraft about five miles from O'Hare to 40 miles out.
As the evacuation occurred, Elgin controllers' responsibilities were transferred over to the Chicago Center facility in Aurora, which normally handles flights 40 miles or more out from O'Hare.
However, because controllers are trained in specific geographic areas, it's not a seamless transition.
Some Elgin controllers also were dispatched to work at Aurora.
"Limitations of the radar equipment at Chicago Center will prevent normal operations," said Bryan Zilonis, Great Lakes regional vice president with the National Air Traffic Controllers Association.
"There will be delays in all the Chicago airports until they can return and provide service from the TRACON building,"
The Wolves are scheduled to play the Toronto Marlies Wednesday in the Western Conference semifinals and were supposed to be in the host town Tuesday night.
Two out of three team flights Tuesday were canceled. "All the gear, the sticks, the pads are on the canceled flights," Willhite said.
"There are a lot of stone-faces," he said, describing the airport atmosphere.