Aviation Southwest expects normal Chicago Midway operations after harrowing Sunday By Robert Silk / February 12, 2018 Share 1 -- Southwest expects to operate a close-to-normal schedule Monday at its largest base, Chicago Midway, after canceling more than 200 flights Sunday due to difficulties with its de-icing delivery system. "We will continue to work with our customers on their travel plans and apologize for any inconvenience the disruption in service has caused," a Southwest spokeswoman said Monday.The carrier had cancelled six Midway departures as of mid-morning on Monday, according to FlightAware. Midway recorded four inches of snowfall on Sunday, according to Chicago's CBS affiliate, two days after 9 inches of snow fell on the airport. The spokeswoman said Southwest could not access a portion of its de-icing fluid Glycol on Sunday because the pump on one of the Glycol tanks was not working."The pump has been fixed and additional glycol has been delivered to replenish what we used over the weekend," the spokeswoman said. Southwest is scheduled to operate more than 250 flights out of Midway on Monday. Sunday was the second time this winter that Southwest has canceled flights at Midway due to de-icing difficulties. Shortly after Christmas the carrier canceled 90 flights after freezing conditions at the airport slowed de-icing crews, according the Chicago Tribune. The carrier didn't respond to a query about whether it is considering new steps to reduce the chance of similar incidents.