It was the second time in as many weeks that a medical emergency in mid-air among a member of the flight crew had forced an Alaska Airlines flight to make an emergency landing.
The co-pilot landed Flight 473 safely after declaring an emergency to get priority care for the pilot, spokesman Paul McElroy said. All of the airlines' pilots are trained to fly single-handedly.
The pilot lost consciousness "somewhere over Oregon," McElroy said, then later regained consciousness and left the cockpit. A doctor on board the flight tended to him in the cabin until the plane landed and was met by medical personnel on the runway.
Passengers watched the drama unfold.
"The cockpit door had opened completely, and the pilot had come out, walked through the door and then fell on the aisle," said one woman who was a passenger aboard the plane. "We didn't know who was flying the plane, or if it was going to land or if the computer technology was just going to take over."
Another passenger, Hylan Slobodkin, also saw the pilot pass out.
"Came out of the cockpit and collapsed on the aisle," he said. "Hit his head on something and called doctors, and fortunately there was a young woman who was a fourth-year medical student who ran to his aid."
The pilot, who was not identified, was taken to a hospital after the plane landed,
By Friday morning his condition had significantly improved, according to doctors, who believe he suffered from a bad case of food poisoning or possibly the flu virus. The pilot reported that he felt fine when he reported for work.
The Boeing 737-700 with 116 passengers and five crew members left Los Angeles about 6:30 p.m. and touched down in Portland at about 9 p.m. It had been due to arrive in Seattle at 9:30 p.m.
McElroy says the pilot has been flying for Alaska for 28 years and was current on his six-month medical evaluation. The co-pilot is an 11-year Alaska Air veteran.
On Jan. 22, the co-pilot on an Alaska Airlines flight from Seattle to Las Vegas fainted briefly, and the pilot requested emergency landing priority to get prompt medical assistance for him.
"At this point we do not believe there was a connection between the two incidents," McElvoy said.
Twenty passengers with a tight schedule for connecting flights were put on a Horizon Air shuttle flight to Seattle on Thursday night, the spokesman said.
A new pilot was dispatched to Portland to fly the remaining passengers to Seattle on board the same plane.