Southwest Airlines says it's cooperating with federal officials investigating a close call on a runway in Chicago last month.
A Southwest plane that had just landed at Midway Airport was preparing to cross a runway when the co-pilot yelled at the pilot to stop to avoid a smaller jet that was taking off.
Federal officials say air traffic controllers didn't cancel the smaller jet's takeoff clearance or tell the Southwest plane to stop.
The planes came within less than 300 feet of each other during the Dec. 1 incident.
The Federal Aviation Administration declined to say whether it took action against any air traffic controllers. The FAA judged the incident to be less serious than a near-collision, instead categorizing it as one in which there was ample distance between planes to avoid a crash.
Southwest spokesman Chris Mainz said Wednesday that the airline was cooperating with the National Transportation Safety Board investigation.
The NTSB said in a preliminary report that air traffic controllers cleared a Learjet for takeoff on Midway's runway 31R and told the Southwest pilot to cross the same runway before contacting ground control.
The Southwest co-pilot saw the Learjet taking off and yelled to the captain to stop, according to the NTSB. The pilot stopped the plane before it reached the runway's edge.
"Air traffic control did not cancel the takeoff clearance of the (Learjet) nor direct the (Southwest plane) to hold short of runway 31R," the safety board said.
The NTSB said that the Southwest pilot claimed that the Learjet flew over his plane. The board said the planes were 287 feet apart as the Learjet passed 62 feet overhead.
Dallas-based Southwest Airlines Co. said there 74 passengers and five crew members on the flight from Minneapolis. The safety board said none were injured. The operator of the Learjet was not identified.