(CNN) -- An Alaska Airlines flight was diverted to Portland, Oregon, after the captain lost consciousness and the first officer was forced to take over, an airline spokesman said.
The incident occurred Thursday night on Flight 473 from Los Angeles to Seattle, airline spokesman Paul McElroy said.
When the captain lost consciousness, the first officer took over and piloted the aircraft to the closest airport, he said.
A doctor on board the airplane treated the pilot until it landed in Portland and medical personnel arrived, he said.
The captain was likely suffering from food poisoning or the flu, Alaska Airlines said Friday. The condition of the captain was not immediately available, but he "is doing better today," airline spokeswoman Bobbie Egan said.
There were 116 passengers and five crew members on board the plane, which landed in Portland without incident, according to the airline.
The airline did not release the name of the captain but said he has been flying with Alaska for 28 years. The first officer has been with the airline for 11 years.