A major communications failure at the Memphis Center disrupted U.S. air traffic control communications and radar operations for three hours on Sept. 25, prompting the Federal Aviation Administration (FAA) to clear all commercial flights over an eight-state area in the Southeast and Midwest while the technical problem was fixed. The FAA said it did not know why the communications gear failed. The National Air Traffic Controllers Association (NATCA) said the outage left controllers without the ability to use most of their radio frequencies and some of their radar feeds as well. They also were not able to make automated “handoffs” of flights to adjacent airspace sectors at other en route facilities that border Memphis Center. “This was a major safety problem, as controllers, at the time of the outage were thrust into an immensely chaotic situation in which they had to use personal cell phones to talk to other air traffic control facilities about specific flights that they could not communicate with themselves,” the controllers union said. Memphis Center’s airspace includes 100,000 square miles of airspace, covering Tennessee, Arkansas, Mississippi, and parts of Alabama and Kentucky. NATCA said the problem appears to have been caused by a failure of the telephone line that hosts the communications feeds to the facility.