Since the incident, the FAA has been analyzing what went wrong with its En Route Automation Modernization system. The computer system, known as ERAM, allows air traffic controllers at several dozen "en route centers" around the country to identify and direct planes at high altitudes.
The Los Angeles en route center controls high altitude air traffic over southern and central California, southern Nevada, southwestern Utah and western Arizona — except airspace designated for military use.
In its statement, the FAA said it has adjusted ERAM to require altitude details for flight plans.
"The FAA is confident these steps will prevent a reoccurrence of this specific problem and other potential similar issues going forward," the agency said.
When the system failed, air traffic controllers in Southern California had to call their counterparts at neighboring centers to update them on each plane's flight plan, according to Nate Pair, the president for Los Angeles Center of the National Air Traffic Controllers Association. While that was more onerous than normal operations — when computers automatically pass along updates — the system still worked, Pair said.