"The airliner dropped about 400 feet before the captain pulled back on the control column. Fourteen passengers and two crew were hurt, and seven needed hospital treatment. None were wearing seat belts, even though the seat-belt sign was on."
The only danger in this situation had been the F.O. napping for 75 minutes instead of the maximum 40, as the disorientation and confusion stemming from deeper sleep was the culprit in this mix-up. However, the Air Canada Pilots Association, quote, "has long pressured authorities to take the stresses of night flying into account when setting the maximum hours a pilot can work," taking into account that North Atlantic night-flights are hardest on an already-fatigued pilot."
Link to Original Source