SANTA ANA, Calif. (AP) — A brief power outage at a Southern California airport's air traffic control tower on Sunday forced controllers to use portable radios to communicate with pilots and caused several flight delays, the Federal Aviation Administration said.

The outage at John Wayne Airport in Orange County lasted a little more than an hour, agency spokesman Ian Gregor said.

The tower had been running on an emergency generator since commercial power failed Friday "due to a power bump," Gregor said.

The backup generator stopped working at 11:42 a.m. Sunday.

FAA technicians responded to the tower and were able to determine what went wrong. As they were fixing the generator, the tower was able to revert back to commercial power by 1 p.m., said Mike Fergus, another FAA spokesman.

During the outage, controllers used radios to guide pilots through landings.

The FAA said around 10 departing flights were delayed by a little over a half-hour.