An air traffic control centre worker brought two of America's busiest airports to a halt after staring a fire, authorities have said .
A criminal complaint filed in US District Court in Chicago charges Brian Howard, 36, with one count of destruction of aircraft or aircraft facilities, a felony.
The FBI said Howard was in hospital due to his injuries and that no court date had been scheduled. The court filing said the contract worker was trying to cut his throat w hen paramedics found him.
Delays and cancellations hit the US air travel network from coast to coast after the fire yesterday. The ground stoppage at O'Hare and Midway airports immediately raised questions about whether the Federal Aviation Administration has adequate back-up plans to keep planes moving when a single facility has to shut down.
By today, more than 2,000 flights in and out of Chicago had been cancelled. A few flights resumed after a nearly five-hour gap, but the planes were moving at a much-reduced pace, officials said, and no one could be sure when full service would be restored.
The early-morning fire forced the evacuation of the control centre in Aurora, west of central Chicago - the second unexpected shutdown of a Chicago-area air traffic centre since May.
Howard worked for the FAA contractor that supplies and maintains communications systems at air traffic centres, said Jessica Cigich, a spokeswoman for Professional Aviation Safety Specialists, the union that represents FAA technicians. He was recently told he was being transferred to Hawaii, the court filing said.
According to the complaint, a relative who saw a suicidal Facebook note posted on Howard's account early yesterday alerted authorities. Meanwhile, a 911 call from the control centre brought firefighters to the scene, where paramedics followed a trail of blood past a fuel can, two knives and a lighter.
When they found Howard, he was trying to cut his throat and told the paramedics: "Leave me alone."
Thomas Ahern, a spokesman for the Bureau of Alcohol, Tobacco, Firearms and Explosives, said the man used petrol as an accelerant.
Howard used a key card to enter the centre, according to the complaint, and video surveillance shows him dragging a rolling suitcase as he entered. Authorities do not believe there is any surveillance video of the crime itself.
When the centre was evacuated, management of the region's airspace was transferred to other facilities, FAA spokeswoman Elizabeth Cory said.
The FAA said it was managing the Aurora traffic through centres in Cleveland, Indianapolis, Kansas City and Minneapolis and would continue working with those radar centres over the weekend to reduce disruption.
The shutdown quickly spread travel misery around the country, with airports as close as Milwaukee and as far as Dallas cancelling flights.
Online radar images at one point showed a gaping hole in the nation's air traffic map over the Upper Midwest. Some passengers already in the air heading for Chicago ended up elsewhere. Southwest Airlines said it scrapped all of its flights at Midway and Milwaukee for the day.
"This is a nightmare scenario when we thought systems were in place to prevent it," said aviation analyst Joseph Schwieterman of DePaul University in Chicago.
"Technology is advancing so fast that there's less of a need for air traffic control to be so geographically oriented. I think the FAA's going to find itself under a microscope."
The disruption was also likely to deliver a financial blow to airlines, Mr Schwieterman said.
Brothers Glenn and Gary Campbell, of suburban Chicago, had planned to travel to Orlando, Florida, for their father's 80th birthday party. Instead, they settled for refunds.
"That it is so easy to disrupt the system is disturbing," said Gary Campbell, a carpenter from Crystal Lake, Illinois. "They need to see how to make sure this kind of thing doesn't happen again."
In May, an electrical problem forced a regional radar centre in suburban Elgin to be evacuated for three hours, with more than 1,100 flights cancelled.
The Aurora facility, known as an en-route centre, handles aircraft flying at high altitudes, including those approaching or leaving Chicago airports. Air traffic closer to the airports is handled by a different centre and the control towers located at the airfields.