A United Airlines flight from Houston to San Francisco had to be diverted to Albuquerque, New Mexico, after the co-pilot passed out.

Albuquerque airport spokesman Dan Jiron says air-traffic controllers got word shortly after 8 a.m. Tuesday that the plane would be landing after the first officer, who is second in command, had a medical episode. The plane landed without incident around 8:20 a.m.

Jiron says the co-pilot regained consciousness and was able to walk off the plane to be transported to a hospital. Jiron had no details about the co-pilot's condition or what may have caused the episode.

United was aware of the diversion but didn't immediately comment.

It comes a day after an American Airlines captain became gravely ill while flying from Phoenix to Boston. He later died.