DUBLIN, Ireland - When an Air Canada co-pilot having a mental breakdown had to be forcibly removed from the cockpit, restrained and sedated in January, a flight attendant helped the pilot make an emergency landing.

The report by the Irish Air Accident Investigation Unit into an incident said the pilot noticed immediately that his co-pilot was not in good professional shape on the day of the flight, arriving late after all the safety checks and paperwork had been completed. He reported that the co-pilot’s behavior worsened once they were airborne. Over the mid-Atlantic, the report said, the co-pilot began talking in a “rambling and disjointed” manner, took another nap, and then refused to buckle his seat belt. The pilot concluded that his colleague couldn’t do his job.