EDMONTON - Investigators have concluded that the cause of a plane crash that killed three Canadians in Antarctica may never be known. The men died in January 2013 when their Twin Otter crashed into the side of a mountain as they were trying to resupply a scientific base on the frozen continent. The Transportation Safety Board says heavy cloud may have prevented the pilot from seeing the slope in front of him. That would have meant that by the time his instruments warned him he was too close, it was too late for him to climb out of trouble. But the board says it's unable to come to a definitive conclusion, because the plane's cockpit voice recorder wasn't working. Officials decided after the crash that it was too dangerous to mount a recovery mission, so the bodies of the men remain on the side of Mount Elizabeth.
