Jet diverted to Los Angeles after problem with pressurization

PORTLAND, Ore. - An Alaska Airlines jet on a flight from San Diego to Portland had to land in Los Angeles Monday evening because of problems with its pressurization and air conditioning systems, an airline spokeswoman said Tuesday.

Alaska Flight 503, an MD-80 jet with 135 people on board, was climbing after takeoff when the pilot noticed that the airliner was not pressurizing, said Alaska spokewoman Jan Fisher.

The pilot maintained an altitude of 10,000 feet to Los Angeles. Pressurization is not needed at that altitude. The oxygen masks were never needed and never dropped, she said.

''The whole series of events were handled by standard operating procedure,'' Fisher said.

But the plane's cabin got hot because the air conditioning didn't work, she said.

Passengers transferred to a different airplane in Los Angeles which arrived in Portland at 1:15 a.m. Tuesday, nearly four hours after the original flight was scheduled to land.

The original flight had a scheduled departure of 5:04 p.m. but did not leave until 6:15 p.m., Fisher said. It landed in Los Angeles at 6:45 p.m., she said.

Fisher said she didn't know the exact altitude of the plane when the problems were detected.

A valve malfunction and a broken clamp caused the pressurization and air conditioning system problems. But repairs were made in Los Angeles and the jet was put back into service, Fisher said.

Alaska Airlines has been beset by problems this year.

The Jan. 31 crash of Alaska Flight 261 in the Pacific Ocean off Los Angeles killed all 88 passengers and crew.

Late last month, the airline announced it would fire two pilots who continued a flight even though they had failed to properly pressurize the cabin and some of the emergency oxygen system was depleted.

Last Friday, the Federal Aviation Administration proposed to strip Alaska Airlines of its aircraft maintenance authority after finding maintenance work could not be documented in nearly 150 cases.