Commercial air traffic at Southern California's major airports came to a stop for more than an hour Tuesday after a power blackout at a regional radar facility.
The outage, which delayed hundreds of flights, occurred about 5:38 p.m. at a Federal Aviation Administration air traffic control center in Palmdale. Authorities were checking reports that a vehicle hit a nearby power pole, possibly causing the facility to lose power.
It marks the second time in less than two years that troubles at the Palmdale center caused major a disruption in air service, although authorities said it's too early to know whether the two incidents point to a systemic problem.
Though a backup generator eventually kicked in, the mishap grounded virtually all flights in and out of Southern California's airports. Some flights were diverted to other airports, while passengers at Los Angeles International, John Wayne, Bob Hope and Ontario International airports spent the evening waiting for flights to be rescheduled.
The Palmdale facility handles flights above 13,000 feet, including commercial flights.
Authorities said the shutdown had a ripple effect on fights across the nation and that flight operations would probably not return to normal until this morning. At LAX alone, about 220 flights, mostly departures, and 25,000 passengers were affected, LAX spokesman Paul Haney said.
"All planes headed to LAX from anywhere else in the country were held on the ground until we resolved this issue," FAA spokeswoman Laura Brown said.
Pilots in the air lost radar contact because of the blackout and relied on radio communications with outlying airports to stay on course. Officials said that all airplanes have preset flight paths that they follow in the event of a radar malfunction and that there was no sign of problems.
"Safety is never compromised, but obviously it's caused an inconvenience," said Allen Kenitzer, a regional spokesman for the FAA.
But an air traffic controllers union representative said that for several minutes, safety was compromised.
"The airplanes were allowed to come into the system unguarded for eight minutes," said Garth Koleszar of the National Air Traffic Controller Assn. "My idea of safety is being 100% sure 100% of the time where an aircraft is. We did compromise safety here a bit."
The normal phalanx of airplane lights that could be seen streaming across the sky from nearby freeways toward LAX in the evening was reduced to a trickle.
"It's empty, very empty. That's the first thing we noticed when we got here," said Isabel Vaqueiro, as she waited outside the American Airlines terminal at LAX for her father, arriving from Fort Lauderdale.
"I'm just annoyed," said Kari Montgomery, an 18-year-old student from Scotland. "It's the first time I've been to America, let alone Los Angeles."
Shortly after 9 p.m., passengers began to flock to baggage claim areas as the airport hummed back to life.
The power outage grounded state Treasurer Phil Angelides, the Democratic nominee for governor, as he waited to depart on a Southwest flight from San Diego to Sacramento. After his plane sat on the tarmac for an hour, he returned to the terminal with the rest of the passengers -- and then started shaking hands and campaigning among the stranded.
Outside Orange County's John Wayne Airport, cars began backing up as passengers being dropped off learned that their flights had been delayed. Inside the terminal, meanwhile, other waiting passengers were glued to their cellphones trying to figure out what to do.
"We're fine with staying put," said Donna Berg, 48, a visitor from Janesville, Wis., on the last leg of a seven-day vacation with her 14-year-old daughter, Jamie. "This is a vacation we didn't want to end anyway. We'd be thrilled if we had to stay another night. We'd just call up our friends and have them pick us up."
Sally O'Neal, 32, of Salt Lake City did not share in the good cheer, as she was caught without a change of clothes for her one-day business trip.
"I wasn't a Boy Scout," she said. "And now I've learned my lesson: Be prepared, no matter what."
At Burbank's Bob Hope Airport, Jerri Krippner, 55, of Tujunga sounded a common refrain: "I don't know anything," she said as she waited for her husband and 3-year-old granddaughter to arrive from Dallas. "They should announce what's going on. They said one of the towers went out."
Last she heard, her loved ones were "stuck in Arizona."
At San Jose Airport, teacher Pat Villalobos waited none the wiser for her Southwest flight to Ontario.
"I heard an agent saying, 'If you want to go home, go home,' " Villalobos said. "Nothing has come up on the intercom. If I just came in right now, I wouldn't know anything was going on."
It was the second time in less than two years that problems at the Los Angeles Air Route Traffic Control Center grounded hundreds of flights. In September of 2004, as many as 800 commercial airline flights bound for Southern California were diverted and all takeoffs halted as a result of human errors.
In that case, radio communications went silent with no warning and a little-used backup system failed only minutes after it was turned on. Air traffic controllers were left with no way talk to pilots in planes flying at cruising altitude across about 178,000 square miles spanning Southern California, most of Arizona and Nevada, even as they watched the blips on the screen in some cases getting closer together.
The failure -- later traced to a technician failing to perform routine maintenance at the Palmdale facility -- created dangerous conditions in the region's skies.
Officials said the loss of radio communication led to at least five instances of planes flying closer together than is safe. About 800 flights arriving or departing from Southern California were delayed, canceled or diverted in the hours it took to correct the problem affecting 30,000 passengers at LAX alone.
The head of the FAA, Marion Blakey, recently warned that the nation's air traffic systems are becoming obsolete and that the they will soon be strained beyond their limits, requiring "essentially a new system."
For Jerad Flickner, a 20-year-old UC Riverside student, the situation was double trouble. He was waiting at LAX about 9 p.m. for a friend arriving from Ecuador, and then he needed to go to Long Beach Airport to get his parents, who were coming in from Milwaukee.
His friend, he said, "is on the runway right now. She had to circle for half an hour. The pilot said they were going to run out of fuel so they had to land."
Meanwhile, Flickner said, his parents were delayed in Denver. "I just got off the phone with them, and they're also sitting on the runway, it's so packed."
Times staff writers Stuart Silverstein, Megan Garvey, Robert Salladay, Sara Lin and Ashley Surdin, and the Associated Press contributed to this report.