The Federal Aviation Administration is once again looking into a close call at a major U.S. airport, after two passenger jets narrowly avoided a mid-air collision as they attempted to land in Phoenix.

The two flights, United Airlines Flight 1724 and Delta Air Lines Flight 1070 came too close to each other while arriving at the airport.

The Federal Aviation Administration is investigating a narrowly missed midair collision between a United flight and a Delta flight at Phoenix Sky Harbor International Airport on Saturday, the agency said.