Los Angeles ? An instrument landing system that guides arriving planes onto a runway at Los Angeles International Airport failed Monday for the second time in a week, delaying several flights, officials said.

The system malfunctioned just before 10 a.m. and was out for 42 minutes, said Ian Gregor, spokesman for the Federal Aviation Administration.

The same system on the same runway failed on Aug. 7 for several hours, delaying dozens of flights around the country.

This time, arriving flights were delayed 30 to 45 minutes as air traffic controllers kept some planes circling over Los Angeles and reduced the arrival rate from 60 or 70 planes per hour to 46, Gregor said.

The FAA also ordered Los Angeles-bound flights departing from airports within an hour radius to stay on the ground until the problem was fixed, Gregor said.

A union representative questioned the repeated problems with the instrument landing system.

“We literally run those airplanes in wingtip to wingtip on parallel runways,” said Tony Vella, local president of the National Air Traffic Controllers Assn. “I don’t know what it’s going to take out there – if the airplanes are going to have to trade paint out there – before the FAA gets this thing fixed.”

The airport has four parallel runways, one of which is closed for construction.

It averages 1,800 daily flights and this summer’s passenger total is expected to reach 18.7 million, 200,000 more than last year. In 2005, more than 60 million people passed through the airport.

Earlier Monday at LAX, police evacuated an Alaska Airlines flight after a “suspicious item” was found on board that no one claimed.

Authorities using bomb-sniffing dogs found no explosives inside the plane’s cargo hold or the item, which was similar to a remote control for a toy car or plane.

Airport police were notified at 8:20 a.m. that there was a suspicious item on board a plane that was in the air after leaving Guadalajara, Mexico, said airport spokeswoman Nancy Castles.

The plane landed without incident just before 9 a.m., and all 125 passengers and crew were taken to a terminal in buses after the plane stopped in a remote area of the airport, Castles said.