SANTA ANA, Calif. >> The Federal Aviation Administration says a brief power outage at a Southern California airport’s air traffic control tower forced controllers to use portable radios to communicate with pilots and caused several flight delays.

Agency spokesman Ian Gregor says the outage Sunday at John Wayne Airport in Orange County lasted a little more than an hour.

Gregor says the tower had been running on an emergency generator since commercial power failed Friday. He says the backup generator stopped working at 11:42 a.m. Sunday, but the tower was able to revert back to commercial power by 1 p.m.

During the outage, controllers used radios to guide pilots through landings. Gregor says around 10 departing flights were delayed by a little over a half-hour.

Gregor says FAA technicians have determined what went wrong with the generator and are fixing it.