The failure of a system controller card at an AT&T office in Memphis, Tenn., Tuesday apparently caused a communications outage that grounded airplane flights and resulted in delays throughout the nation.
The interruption of communications occurred at 11:25 a.m. CDT at one of 20 air traffic centers run by the Federal Aviation Administration (FAA) to control the routes of high-altitude flights, Kathleen Bergen, a spokesperson for the southern region of the FAA, told TechNewsWorld.
The center is near, but not at, Memphis International Airport, and it does not control flights that go in and out of the airport, she said. Instead, it focuses on the long-distance flights that fly overhead.
220 Planes in the Air
All flights that would have flown through the center’s air space of roughly 120,000 square miles were immediately grounded after the outage occurred, Bergen said, and responsibility for the roughly 220 aircraft already in the air was transferred to similar air traffic control centers in Atlanta; Indianapolis; Kansas City, Mo.; and Forth Worth, Texas, she said.
By 12:30 p.m. Central time “the airspace was cleared of all flights,” Bergen said.
“It looked [like] the hours after 9/11,” Doug Church, a spokesperson for the National Air Traffic Controllers Association, told TechNewsWorld. “It was like a giant hole devoid of any aircraft.”
Hundreds of Delays
According to a preliminary report, the failure of a system controller card at AT&T’s Oakville Central office in Memphis was at the heart of the problem, Bergen explained. Although the FAA does have redundant systems, they all flow through that central point in the AT&T network, she added.
Bell South has now replaced the card, but “we are continuing to discuss the problem with AT&T,” Bergen said.
By 2 p.m., the center began accepting flights to and from airports within its airspace, and by 2:25 p.m. it resumed full operations, “with restrictions to gradually handle the backlog,” she added.
Between 500 and 600 flights were delayed Tuesday, but “we haven’t yet separated out those resulting from the outage from those resulting from severe weather that went through Memphis after the outage occurred,” Bergen said.
Air traffic control is about making handoffs between sectors of air space as flights progress through their routes, Church explained. So when the outage occurred, many controllers resorted to using their own, personal cell phones to maintain at least minimal communications, he said.
Three of 11 radar sites that provide data to the Memphis facility had been knocked out of communications, resulting in a situation “like driving with no windshield wipers during a rainstorm,” Church said.
“It was a very, very serious situation,” he added. “That was the only way they could communicate with other facilities to let them know about aircraft in the air. They had to resort to desperate measures to make sure somebody else had an eye on those folks.”
Breaking the Rules
The irony, however, is that controllers are prohibited by the FAA from using cell phones in air traffic centers, Church noted.
“In routine conditions, cell phones are not permitted in air traffic control facilities,” Bergen affirmed, “but in extenuating circumstances they can be used.”
Bergen had not heard first-hand that the devices had been used in the Memphis situation, “but I wouldn’t dispute it,” she said.
Several dozen air controllers used their cell phones for at least an hour during the Memphis outage, Church said, and “that’s happened before at many facilities around the country,” he added. “It’s the dirty little secret the FAA doesn’t want you to know about.”
There needs to be improved layers of redundancy in the system, and “it’s kind of ridiculous that controllers can’t use cell phones,” Church said.
“If those controllers hadn’t had the ability to communicate with other facilities, I don’t know what they would have done,” he concluded. “They should all be given awards for what they did, not made to think what they did was wrong.”