The flight management computer (FMC) measures fuel consumption, allowing the crew to keep track of fuel burned as the flight progresses. It is normally updated automatically by the FQIS, but the fuel quantity can also be entered manually. Because the FMC would reset during the stopover in Ottawa, the captain had the fuel tanks measured again with the dripstick. There were 11,430 litres of fuel in the tanks, and the fueler gave the density as 1.78. Repeating the same error, Captain Pearson determined that he had of fuel and entered this number into the FMC. However, he actually had just of fuel.