At the start, when the two pilots exit the simulator, they complain to the simulator examiner about "a dumb set of scenarios" and "an impossible set of conditions, who ever dreamed that up".
The examiner responds with "It isn't a dream, it happened".
He would know, he is the real life Bob Pearson, the actual captain of the Gimli Glider.
The real "Gimli Glider" - a Boeing 767-233 with registration C-GAUN - left the airstrip by its own power a couple of days after the incident, where it continued to fly for Air Canada until January 2008, when it was flown to Mojave Airport in California and used for spare parts.
The real names of three key individuals - Bob Pearson, Maurice Quintal, and Rick Dion - and their families were retained for the movie, but the names of other people as well as the airline and the flight number were changed. It was really Air Canada flight 143.
In real life Pearson did not return to the smoky cockpit alone, requiring Quintal and Dion to rescue him. He and Quintal returned together, did what they could, and left the airplane by the forward slide.
Based fairly closely on an actual incident on July 23, 1983, nicknamed the "Gimli Glider". The actual error made in fueling was in converting the fuel volume to weight; this is necessary because the density varies with temperature. The crew used the familiar density number in pounds per litre rather than the correct one for kilograms per litre.