Washington (CNN) -- The rules for takeoffs and landings at Newark Liberty International Airport have changed after two planes came within yards of colliding last month, the Federal Aviation Administration said Tuesday.
United Express Flight 4100, an Embraer ERJ-145 operated by ExpressJet, was cleared to take off on runway 4R at the same time United Airlines Flight 1243, a Boeing 737, was landing on the intersecting runway 29 on April 24.
The 737 flew 135 yards vertically and 50 yards laterally from the smaller regional jet.
"The FAA has investigated the recent air traffic incident at Newark and has taken steps to prevent similar incidents from occurring in the future," according to a statement from the agency. Runway 29 is no longer used for arriving flights when planes are taking off on the intersecting runway 4R.
In the April incident, on air traffic control radio captured by the website LiveATC.net, the tower can be heard telling the pilot of the 737 to "go around" and circle the airport.
The controller told the ERJ to watch out for the larger plane on the right.
"Yeah, we were putting the nose down, and, he was real close," the pilot responds.
Close calls at Newark have happened before, including four in 2008, according to a Department of Transportation inspector general's report.
In one instance, on January 16, 2008, a 737 from Continental Airlines (which has since merged with United) was at risk of hitting an Embraer 145 operating as Continental Express.
It happened at the same intersection and involved the same type of aircraft as April incident, but the planes never got within a mile of each other.
That case was attributed to a mistake by an air traffic controller.
The National Transportation Safety Board will not make a determination of what caused the most recent incident until it releases its final report, which is expected to take months.
United Airlines is working with the agency to investigate the incident, an airline spokeswoman has told CNN.
CNN's Laura Dolan contributed to this report.