In an effort to reduce the risk of midair collisions, new air traffic control procedures have begun at Chicago’s O’Hare International Airport. This change was prompted by a pair of near missed at the airport in 2011, in which planes came within a few hundred feet of each other during two separate incidents.

Part of the revision includes a warning system for controllers that will alert them if a plane is approaching land while another plane is about to take off on one of the runways that cross the landing plane’s runway. O’Hare has three runways which either physically cross each other or come close enough that air traffic could collide.

Officials have also moved both controllers responsible for the runways to sit next to each other so they can communicate better. Also changed is a workstation for supervisors that was located in the center which forced controllers to actually shout information back and forth and obstructed their views.

Other changes include when an aircraft should abort its final approach and controllers will undergo additional simulator training for these types of situations.

In a statement, the FAA said safety was the agency’s top priority and it “moved swiftly to develop measures that would eliminate similar occurrences.” There have been no similar incidents since then, it said.

A near miss on May 16, 2011, involving a SkyWest plane coming from Michigan nearly collided with an ExpressJet plane taking off for Buffalo, NY.

The ExpressJet captain told investigators his plane began roaring down a runway when he heard a distressed air traffic controller make a “grunting uhh” sound. Seconds later, the captain saw the landing SkyWest plane heading straight for his and frantically told his co-pilot to “stay low.”

After the danger passed and he regained his composure, the captain radioed the tower after “nearly getting killed” and screamed at the air traffic controller, “What the (expletive) was that?” according to the NTSB report. The controller responded, “Sorry about that.”

The second incident happened on Aug 8, 2011, involving a Chautauqua flight from Wisconsin that was landing and almost struck a Trans State flight.

The Trans State’s pilot said he and his co-pilot spotted the incoming plane themselves but it was too late to abort their takeoff and their plane was “running out of pavement.” Had they not taken evasive action on their own by slightly delaying takeoff, the warning from the tower might “have been too late,” the captain told investigators.

O’Hare will also eventually reconfigure the runways to eliminate this problem altogether.

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