LOS ANGELES (AP) — Flights to and from airports in the Los Angeles area were grounded for more than an hour Wednesday due to a computer failure at an air traffic control facility in the region, the Federal Aviation Administration said.

The problems rippled nationwide. Dozens of planes heading into the region were diverted elsewhere, and flights scheduled to take off to the Los Angeles area were held on the ground across the country.

The "ground stop" affected airports including Los Angeles International, the nation's third busiest, where more than 200 departing flights were delayed and 23 were canceled, said Nancy Castles, an airport spokeswoman.

Inbound flights closing in on Los Angeles-area airports were allowed to land. But dozens of other planes that were farther away were diverted to Phoenix, Las Vegas, Salt Lake City and elsewhere.

In all, 27 flights to Los Angeles International were canceled, 212 were delayed and 27 were diverted to other airports, Castles reported late Wednesday night. She said "tens of thousands" of passengers were affected.

Fifteen flights bound for Los Angeles landed at Phoenix Sky Harbor Airport, and another five touched down at Salt Lake City International Airport, officials at those airports said.

Officials at Bob Hope Airport in Burbank, near Los Angeles, said flights were held from 1:50 p.m. PDT until 3:20 p.m. PDT.

A notice posted on the FAA website said planes were not allowed to depart Los Angeles because of a failure within the agency's En Route Automation Modernization system, also known as ERAM.

The computer system 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 is located at the Palmdale Regional Airport, about 40 miles north of Los Angeles. It controls high altitude air traffic over southern and central California, southern Nevada, southwestern Utah and western Arizona — except for airspace designated for military use.

Planes flying at lower altitudes are directed by approach control centers and local airport towers.

The ERAM system is critical to the FAA's plans to transition from a radar-based air traffic control system to satellite-based navigation, but its rollout is years behind schedule and hundreds of millions of dollars over budget.

ERAM is replacing another computer system that was so old that most of the technicians who understood its unique computer language have retired.