A Southwest Airlines jet lost its navigation system as it approached Los Angeles International Airport last week, forcing air traffic controllers to redirect several flights to clear the airspace as they guided the aircraft to a safe landing, a union representative said Tuesday.
The Federal Aviation Administration issued a statement saying only that it was investigating the flight and that controllers handled the situation professionally.
The Boeing 737 carrying 92 passengers and crew members was coming from San Jose when the navigation system failed around noon on Oct. 20, causing the jet to lose its positioning amid the clouds, said Ron Geyer, union representative for air traffic controllers at the facility that handles planes approaching and leaving Southern California airports.
"The weather was bad. The pilot had no visuals until he was below the clouds," Geyer said.
Geyer said controllers scrambled to redirect several flights so they could clear airspace for the Southwest pilot to get through the clouds until he could see the airport. He said controllers almost never encounter such a scenario.
"It was such a rare occasion, yet there was no impact to the system except we had to turn some planes around to make sure nobody was in jeopardy in case the plane got off course," Geyer said.
A Southwest spokeswoman said the captain's instruments failed but the copilot's remained intact, and emphasized that the plane landed safely and nearly on time.
"An aircraft like this is set up with redundant systems," Ashley Dillon said. "There are backups to backups to backups."
She said the outage occurred because a circuit breaker was flipped on the aircraft. She could not say how common the problem is.
Najmedin Meshkati, a professor who studies aviation safety at the University of Southern California, said he has read few reports of such failures on airliners compared with more frequent incidents like runway incursions. But he said that simply could be because instrument problems are not made public.
"It may not come to the surface that me and you would get to know about it," Meshkati said.