By RAY MASSEY

Last updated at 08:49 31 January 2008

The co-pilot of a packed Heathrow-bound plane had to be dragged screaming from his cockpit after apparently suffering a mental breakdown in mid-air.

Horrified passengers on the flight from Canada saw the man being pinned down by fellow crew members as he yelled loudly and demanded to "speak to God".

The co-pilot was shackled by his ankles and handcuffed to a seat as the jet was forced to make an emergency landing at the Republic of Ireland's Shannon Airport.

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Passengers then saw him being led off the plane with his feet still bound and muttering to himself.

He was taken by ambulance to a nearby psychiatric ward, and his wife was last night by his side at the hospital as investigators sought to find out what triggered the drama at 35,000ft over the Atlantic.

The incident occurred just an hour from landing at Heathrow and the captain had to take solo command of the controls.

Although the co-pilot would, in the normal course of events, routinely fly and even land the Boeing 767-333, bosses at Air Canada yesterday said that at no point had any of the 146 passengers on board, including three infants, been endangered.

One of the passengers on Flight AC848 from Toronto to Heathrow, Sean Finucane, said the co-pilot was taken into the cabin in restraints in front of business-class passengers 15 minutes before the aircraft began its descent.

He told the Canadian Broadcasting Corporation: "He was very, very distraught. He was yelling loudly.

"His voice was clear so he didn't sound drunk or anything. He was swearing and asking for God and very distressed. He basically said he wanted to talk to God.

"When they tried to put his shoes on later, he swore and threatened people. He was very, very distressed."

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Another passenger, Chris Robson, told how he had woken to the sound of many footsteps hurrying to the front of the plane about fiveanda-half hours into the flight.

He said that one of the crew announced to passengers: "We have a medical emergency."

Mr Robson, a global training adviser, was sitting just yards from the co-pilot as he was being restrained by crew and passengers, including an off-duty member of the Canadian military, outside the galley, just behind the cockpit.

Mr Robson said of the co-pilot: 'He was clearly someone not in control of his senses.

"The captain came on and said the flight was being diverted to Shannon.

"I saw the crew all around a man on the floor outside the galley. It appeared they were restraining him. He was looking around. He was swearing and yelling."

Mr Robson added that others on board said they heard the rambling First Officer say "he wanted to talk to God... that the plane was low on fuel".

He said that later, as the co-pilot was being escorted off the plane by airport police, members of the Irish Garda and two paramedics, he had his eyes closed and was mumbling to no one in particular: "It's OK. You can text me. You can e-mail me."

After the landing at Shannon Airport at 7.30am on Monday, passengers had to wait about seven hours before another flight crew arrived from Heathrow to fly them to London on the same plane.

Air Canada spokesman John Reber said: "It would be inappropriate for us to specify the cause of the illness, whether physical or psychological.

"The captain and crew followed correct operational procedures when the co-pilot fell ill.

"At the time nobody's safety was compromised. He is in the care of health professionals who will determine the extent of his illness. Air Canada has sent a pilot to accompany the man's wife."

Captain Andy Wilson, president of the Air Canada Pilots Association said: "Although the illness of flight crew is rare, pilots are fully trained for such an event."

A spokesman for regulators Transport Canada said they would interview the flight crew and airline.

She said commercial pilots must undergo medical check-ups every six months but a psychiatric evaluation is not done unless it is deemed necessary.