FAA Investigating Close Call at Chicago Airport

— -- The Federal Aviation Administration is investigating a close call between two aircraft at Chicago Midway Airport. The incident occurred Tuesday evening just before 7:40 p.m.

According to the FAA, air traffic control cleared Southwest Flight 3828 for takeoff, but then Delta Air Lines Flight 1328 also started to roll onto the runway without the proper clearance.

“Preliminary information indicates that Southwest Airlines Flight 3828 was cleared for takeoff on Runway 31-Center,” the FAA said in a statement. “As that aircraft began its takeoff roll, an air traffic controller noticed that Delta Air Lines Flight 1328 had also begun rolling on Runway 4-Right without proper clearance.”

Once the air traffic controller noticed the Delta flight, the controller immediately alerted that crew to stop. The Southwest flight also decided to stop and both planes halted more than 2,000 feet from the runway intersection, the FAA said.

Air traffic control audio indicates the air traffic controller telling a pilot to “Stop, stop.” Then, one of the pilots says "Stopping."

The Southwest Airlines flight returned to the terminal to complete required checklist items, and later continued to Tulsa.

“Our reports indicate that after being cleared for takeoff at MDW on the evening of Tuesday, June 16, the pilots of Southwest flight #3828 followed FAA Air Traffic Control instructions and safely aborted takeoff,” Southwest Airlines told ABC News in a statement.

“Then, the pilots proceeded to taxi off of the runway to complete required checklist items and returned to the terminal to complete other necessary reports and tasks. The flight later continued onward to Tulsa without further incident. We appreciate the professionalism of our pilots and the FAA air traffic controller.”

Delta did not immediately respond to a request for comment.

FAA safety investigators continue to examine the incident.