Gimli Glider

Air Canada Flight 143 was a scheduled domestic passenger flight between Montreal and Edmonton that ran out of fuel on July 23, 1983, midway through the flight. The flight crew successfully glided the Boeing 767 from an altitude of 41,000 feet (12,500 m) to an emergency landing at a former Royal Canadian Air Force base in Gimli, Manitoba, which had been converted to a racetrack, Gimli Motorsports Park. It resulted in no serious injuries to passengers or persons on the ground, and only minor damage to the aircraft. The aircraft was repaired and remained in service until its retirement in 2008. This unusual aviation accident earned the aircraft the nickname "Gimli Glider."

The accident was caused by a series of issues, starting with a failed fuel-quantity indicator sensor (FQIS). These had high failure rates in the 767, and the only available replacement was also nonfunctional. The problem was logged, but later, the maintenance crew misunderstood the problem and turned off the backup FQIS. This required the volume of fuel to be manually measured using a dripstick. The navigational computer required the fuel to be entered in kilograms; however, an incorrect conversion from volume to mass was applied, which led the pilots and ground crew to agree that it was carrying enough fuel for the remaining trip. The aircraft was carrying only 45% of its required fuel load. The aircraft ran out of fuel halfway to Edmonton, where maintenance staff were waiting to install a working FQIS that they had borrowed from another airline.

The Board of Inquiry found fault with Air Canada procedures, training, and manuals. It recommended the adoption of fuelling procedures and other safety measures that U.S. and European airlines were already using. The board also recommended the immediate conversion of all Air Canada aircraft from imperial units to SI units, since a mixed fleet was more dangerous than an all-imperial or an all-metric fleet.