The Federal Aviation Administration (FAA) is investigating a close call involving two commercial planes that were taking off at the same time on intersecting runways at Chicago's Midway International Airport, according to officials, reported Fox News.

Southwest Airlines flight 3828 had been cleared for takeoff and was speeding down the runway when an air traffic controller spotted Delta Air Lines flight 1328 advancing on an intersecting takeoff strip without proper clearance at approximately 7:40 p.m. Tuesday, according to a statement released by the FAA, reported CNN.

Upon noticing the two passenger planes heading towards the intersection, the air traffic controller immediately alerted the Delta crew to stop the aircraft in order to avoid a collision. The Southwest crew also chose to stop their airplane.

Both hit the brakes just in time to avoid disaster as the planes stopped about 2,000 to 3,000 feet from the runway intersection, according to the Chicago Tribune.

Similar-sounding flight numbers may have caused the mix-up between the two aircrafts. Before the incident, a ground controller also warned both pilots about the confusing flight numbers of the two planes waiting for clearance to takeoff.

The FAA is currently investigating the incident, which Delta said it would fully cooperate with.