The report by the Irish Air Accident Investigation Unit into an incident in January applauded the decision-making of the pilot and the cockpit skills of the flight attendant, who stepped into the co-pilot's seat for the emergency diversion to Shannon Airport in western Ireland. None of the 146 passengers or other nine crew members on board the Boeing 767 bound from Toronto to London was injured after the 58-year-old co-pilot had to be removed by attendants and sedated by two doctors on board. The report did not identify any of the Air Canada crew by name. Nor did it specify the psychiatric diagnosis for the co-pilot, who was hospitalized for 11 days in Irish mental wards before being flown by air ambulance back to Canada.

It said the co-pilot was a licensed veteran with more than 6,500 hours' flying time, about half on board Boeing 767s, and had recently passed a medical examination. But it said the pilot noticed immediately that his co-pilot was not in good professional shape on the day of the flight, arriving late to the cockpit after all the safety checks and paperwork had been completed. He reported that the co-pilot's behavior worsened once they were airborne. As the aircraft reached the middle of the 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 or observe other safety procedures when he returned to the cockpit. The pilot concluded that his colleague was now so "belligerent and uncooperative" that he couldn't do his job. The report said the pilot summoned several flight attendants to remove the co-pilot from the cockpit, and one flight attendant suffered an injured wrist in the struggle. Doctors from Britain and Canada on board determined that the co-pilot was confused and disoriented. The report did not mention how the co-pilot was restrained.

Departing passengers at the time said his arms and legs had been tied up to keep him under control. The Air Canada pilot then asked flight attendants to find out if any passenger was a qualified pilot. When none was found, one flight attendant admitted she held a current commercial pilot's license but said her license for reading cockpit instruments had expired.