United Airlines flight diverted after co-pilot passes out

The incident comes a day after a pilot fell ill mid-flight and later died

The United Airlines flight was forced to change its course (Getty)

The crew of a domestic US flight have been forced to divert the plane after the co-pilot passed out.

The United Airlines flight heading from Houston, Texas, to San Francisco, California, made an emergency landing in Albuquerque, New Mexico, when the co-pilot lost consciousness.

Air traffic controllers at Albuquerque airport were alerted shortly after 8am that the plane would be landing there, Dan Jiron, a spokesman for Albuquerque airport.

The plane landed safely at the facility at around 8:20am.

The co-pilot, who is second in command, later regained consciousness and was able to walk off the plane. He was then taken to hospital.

The cause of the medical episode and the co-pilot's current condition remain unclear.

United said it was aware of the diversion but did not immediately comment.

The incident comes a day after a flight travelling from Phoenix, Arizona to Boston, Massachusetts was diverted to Sycaruse, New York, when the pilot fell ill mid-flight and later died.

His family later revealed that Michael Johnston, 57, had suffered a heart attack.

In order to keep passengers safe, airline pilots are required to pass annual physical examinations, rising to every six months for captains 40 or older.

Since 1994, only seven pilots for US airlines and one charter pilot have died during flights since 1994, according to the Federal Aviation Administration (FAA).

Steve Wallace, who led the FAA accident-investigations office from 2000 to 2008, said following Mr Johnston's death that it was rare for a pilot to become incapacitated.

Additional reporting by AP