LOS ANGELES (AP) - Parts of Los Angeles International Airport lost electrical power for more than an hour, causing backup systems to kick in and delaying some passengers. Officials do not know what caused the outage between 9:25 p.m. and 10:50 p.m. Sunday, said Mary Ann Pierson of the city's Department of Water and Power. At least four terminals were affected, including those serving United, American and Delta airlines. A backup power system kept fight control towers fully functional, airport spokesman Tom Winfrey said. But some passengers were delayed because electrically operated jet bridges that connect planes to the terminal could not be used, he said.