The crew of a Southwest Airlines Boeing 737 performed a go-around yesterday at about 8:50 a.m. after a Flexjet Bombardier Challenger 300 crossed the active runway at Chicago Midway International Airport (KMDW) in front of the landing 737. According to ATC audio captured by LiveATC.net, the Challenger crew was instructed by ground control to hold short of Runway 31C. A camera at the airport captured video of the Challenger crossing the runway and the 737 initiating the go-around just before touchdown.

The incident occurred after the Midway ground controller cleared the Challenger to “turn left on Runway 4 Left, cross Runway 31 Left, and hold short of Runway 31 Center.” Then, the Challenger crew responded: “Right, left on two, 4 Left, cross two two, er, one three, uh, Center, Flexjet 560.” The controller gave the instruction again: “Flexjet 560, negative. Cross Runway 31 Left, hold short Runway 31 Center.” The Challenger crew responded: “Cross 31 Left, hold short 31 Center, Flexjet 560.”

After the Challenger allegedly crossed the active runway (31C) without clearance, the Southwest 737 crew called the tower and said, “Southwest 2504, going around.”

Next, the tower controller instructed the Southwest crew to climb to 3,000 feet followed by a heading of 220. The crew asked, “Tower, Southwest 2504, how’d that happen?” Not responding to the question, the controller gave the crew a handoff to Chicago Approach.

In the LiveATC.net recording of the ground control frequency around the time of the go-around, after the controller made other calls to various aircraft, a garbled transmission, likely being stepped on by another transmission, can be heard that sounds like someone is saying “Flexjet 560 hold short, Flexjet 560” but it is not clear where that transmission came from. A few seconds later, the ground controller instructed the Challenger crew: “Flexjet 560, hold your position there.”

The crew responded: “Hold position, Flexjet 560.”

Ground: “Flexjet 560, continue, cross the hold-short, hold short of Hotel.”

Flexjet 560: “Cross the hold-short, hold short of Hotel, Flexjet 560.” 

Ground: “Flexjet 560, your instructions were to hold short of Runway 31 Center.” After a few seconds of silence, the ground controller said: “Flexjet 560, hold right there, sir. Don’t move. Flexjet 560, possible pilot deviation, advise you contact Midway Tower at a number when you’re ready to copy.”

“Flexjet 560, ready to copy.”

Ground: “Flexjet 560, it’s [phone number repeated twice].”

After the crew read back the phone number, the ground controller gave an instruction to Flexjet 560 but then amended that because it was supposed to be for another aircraft. He then cleared the Challenger crew “to continue down 22 Right, make a left turn on November, and then November into the triangle, and then you can call the tower there.”

Flexjet released this statement after the incident: "We are aware of the occurrence today in Chicago. Flexjet adheres to the highest safety standards, and we are conducting a thorough investigation. Any action to rectify and ensure the highest safety standards will be taken.”

A few hours after the close call, the NTSB said that it “is investigating Tuesday’s runway incursion that occurred when a Southwest Airlines Boeing 737-800 initiated a go-around after a business jet entered the same runway at Chicago Midway International Airport.”