A preliminary report from the National Transportation Safety Board (NTSB) suggests that a Flexjet pilot was unsure about the identity of runways before a Southwest flight was forced to make a critical go-around to avoid a collision.
The incident on February 25, 2025, currently being investigated, saw a Flexjet Bombardier Challenger 350 cross runway 31C moments before a Southwest Airlines Boeing 737-800 was due to land on the same runway at Chicago Midway International Airport (MDW).
According to the NTSB preliminary report published on March 18, 2025, as the Flexjet aircraft, registered N560FX, cleared the active runway, the Southwest 737, registered N8517F, passed less than 200 feet behind it.
After speaking with the Southwest flight crew, NTSB investigators established that as they continued their authorized approach both the captain, who was flying, and the first officer “noted seeing a general aviation aircraft taxiing on a surface perpendicular to their runway and assumed it would be holding short of runway 31C”.

After hearing the aircraft’s audible 100-foot call, the first officer realized the Flexjet plane was not going to stop and immediately ordered a go-around, which the captain executed.
What the Flexjet flight crew reported
The Flexjet flight crew told investigators after asking for taxiing instructions from the airport ground control the response “did not make sense to them”.
According to the report the flight crew said that “were initially given a clearance” to taxi to runway 22L via F taxiway and to hold short of 4L.
However, after the flight crew requested ground control to clarify the taxi instructions, they were given a new taxi route of taxiway A to taxiway F with a hold short of runway 4L.
“When they were on Taxiway F, ground control instructed them to turn left onto runway 04L, cross runway 31L and then hold short of runway 31C. The flight crew initially read back the instructions incorrectly; however, the ground controller immediately reissued the instructions and received a correct readback,” the NTSB report stated following interviews with the flight crew.
The Flexjet pilots told investigators that as they turned left onto runway 4L the “sun was impeding visibility from the right side of the aircraft”, however they did not recall seeing any hold short line or any other signs for the 31L intersection as they taxied onto runway 4L.

“They stated that taxiway F and runway 13R/31L were in close proximity to each other and by the time the nosewheel had straightened out, they were likely halfway across runway 13R/31L,” the NTSB report said.
According to the Flexjet flight crew runway 31L also had “very similar width to taxiways and that they had not recognized it as a runway”.
“The captain stated that as he approached runway 13C/31C he had thought it was runway 13R/31L. As they approached the runway intersection the crew stated they both looked to the left and to the right and did not observe the SWA airplane on final,” investigators wrote in the report.
The report added that when the Flexjet Bombardier approached the hold short line for runway 31C the ground controller instructed the crew to hold short, but the transmission was not acknowledged.
The cockpit voice recorders (CVRs) from both aircraft were overwritten. The NTSB’s investigation is ongoing.