CHICAGO (AP) _ The Federal Aviation Administration says it's replacing the entire central computer network at a Chicago-area control center where an act of sabotage brought the city's two international airports to a halt.

The Chicago Department of Aviation says 500 flights were canceled at O'Hare and 50 at Midway on Sunday, though the FAA expects improvements on Monday.

The agency says it's also improving direct communications between other facilities now handling Chicago's air traffic.

At the height of the travel misery Friday, more than 2,000 flights in and out of the airports were canceled, disrupting travel nationwide.

Authorities say a contract employee started a fire in the basement telecommunications room of a regional control center in suburban Aurora and then attempted to commit suicide.

Thirty-six-year-old Brian Howard of Naperville faces felony charges.