How did a bathroom fan bring O'Hare to a grinding halt?

ELGIN, Ill. (WLS) -- A bathroom fan grounded hundreds of planes and thousands of travelers last week. ABC7's exclusive report looks at how a small problem at TRACON, the FAA facility in Elgin, triggered a day of delays.

It would seem unlikely that a faulty motor on a bathroom fan would severely cripple air traffic. But it did one week ago Tuesday. The glitch - though extremely rare - may have its roots in something as simple as deferred maintenance.

Just off to the side of the Air Traffic Control floor at TRACON is the bathroom where a fan motor seized up, filling the control floor with thick, acrid smoke.

That led to what's called ATC0, which means everybody has to get out of the building.

Therefore, inbound and outbound flights for O'Hare and Midway international airports were handed off to controllers at Chicago Center, located in Aurora.

ABC7 Eyewitness News was told that the fan motor in question at TRACON had malfunctioned before, and sources say the motor was not replaced. Instead, sources say, it was left inoperative when a breaker to it was thrown into the off position. Last Tuesday, a contractor at TRACON on unrelated work apparently noticed the breaker in the off position and flipped it on, and the motor overheated.

"It is my understanding that it may have been up to a year that the fan may not have been functioning properly and I do not know whether the FAA knew the degree of the malfunction, but it was such that they turned the breaker to the fan so the power would not allow the fan to come on," Bryan Zilonis, NATCA regional vice president, said.

Few would have anticipated the chain of events that followed. The burned up bathroom fan motor caused hundreds of flights to be postponed or canceled and left thousands of passengers stuck on tarmacs or in other cities.

Controllers left the building as they were supposed to. The plan called for a portion of them to drive to Chicago Center in Aurora and give limited help with air traffic. But TRACON was on lockdown, and that meant controllers couldn't get back in to get their car keys and headsets for some 45 minutes that fire officials say it took to confirm the source of the smoke. Controllers say that part of the emergency protocol needs revisiting.

"I do think we'll be able to sit down and make sure the emergency readiness plan is more effective for all users in the system in the future," Zilonis said.

When asked when the motor went bad and why it wasn't replaced, the FAA said it cannot comment on any specifics until the investigation is complete. FAA officials have not said when that will be.