The Federal Aviation Administration (FAA) is working with Harris Corporation on a computer outage that sent U.S. air travelers nationwide scrambling on Nov. 19 after a pre-dawn FAA computer glitch caused widespread cancellations and delays.

The U.S. aviation agency said the problem lasted about four hours and started when a single circuit board in a piece of networking equipment at a computer center in Salt Lake City failed, preventing ATC computers in different parts of the country from talking to each other. Controllers were forced to type flight plans because they could not be transferred automatically from computers in one region of the country to computers in another, slowing down the whole system.

Delays were particularly bad at Hartsfield-Jackson Atlanta International. The glitch also exacerbated delays in the Northeast, with airports in the Chicago, Washington, D.C., and New York metro areas also reporting problems. AirTran Airways canceled at least 22 flights and delayed dozens more. Delta Air Lines was also affected as was Continental Airlines, JetBlue Airways, USAirways.

It was the fourth major system-wide disruption attributed to the FAA Telecommunications Infrastructure (FTI) system provided by Harris, which the aviation agency began putting into service earlier in this decade as a way to cut costs and assure reliability.

According to the FAA, at 5:00 am EST on Nov. 18 a router problem disrupted a number of air traffic management services, including flight plan processing. The problem was resolved at 9:00 am EST. Air traffic control radar and communication with aircraft were not affected during this time and critical safety systems remained up and running, the FAA stated.

The failure was attributed to a software configuration problem within the FAA Telecommunications Infrastructure (FTI) in Salt Lake City. As a result FAA services used primarily for traffic flow and flight planning were unavailable electronically.

The National Airspace Data Interchange Network (NADIN), which processes flight planning, was affected because it relies on the FTI services. During the outage air traffic controllers managed flight plan data manually and safely according to FAA contingency plans.

The FAA said there was no indication that the outage was a result of a cyber attack.

A team of FAA technical and safety experts was formed to investigate the outage and FAA Administrator Randy Babbitt is meeting with representatives from Harris Corp. "to discuss system corrections to prevent similar outages in the future."

The Professional Aviation Safety Specialists (PASS) union, which represents FAA technicians, said the impact from the communication outage should have been minor.

PASS noted that FTI, which provides all telecommunications used to transfer critical data used by the FAA for air traffic control, is owned by Harris, and as such, the system is not maintained by FAA technicians.

"If the FAA owned and maintained this system, the problem could have been corrected within minutes," said Tom Brantley, PASS national president. "This could have reduced delays tremendously and allowed a much quicker resolution to the problem. Meanwhile, because it took so long for Harris to address the problem, delays continue to plague the system."

PASS has issues with FTI and is concerned with entrusting responsibility for such a massive system entirely to an outside vendor.

The union warns that similar issues could follow with Automatic Dependent Surveillance-Broadcast (ADS-B). This system, which is expected to be the basis of the Next Generation Air Transportation System (NextGen), will not be owned or maintained by the FAA and the aviation agency will again entrust responsibility for its safe operation entirely to private contractors.

"The similarities between FTI and ADS-B are startling," said Brantley. "The FAA cannot continue to allow private contractors free reign without involving experienced FAA employees in the process. As we've seen with today's incident, involving FAA employees can result in far less delays and thus less inconvenience to the flying public. If the FAA continues down this path, there will continue to be risks not only to timely air travel but to the safety of the system as well."