--- title: "Air Canada 767 ran dry at 41,000 feet over a pounds-for-kilograms error and glided to Gimli, Manitoba" url: https://badiyaa.com/gimli-glider-air-canada-143-pounds-kilograms/ published: 2026-11-07T11:08:00+00:00 modified: 2026-11-07T11:08:00+00:00 section: History publisher: Badiyaa --- # Air Canada 767 ran dry at 41,000 feet over a pounds-for-kilograms error and glided to Gimli, Manitoba Flight 143 carried 45 percent of the fuel it needed in July 1983. A density of 1.77 pounds per liter, read as kilograms, made every fuel figure 2.2 times too big. Two Air Canada pilots once lost both engines of a brand-new Boeing 767 at 41,000 feet over northwestern Ontario, and the cause was a single number on a fueler’s slip: 1.77. It was a density in pounds per liter. The jet counted its fuel in kilograms. That was July 23, 1983. Flight 143, bound for Edmonton by way of Ottawa, carried 61 passengers and eight crew. Seventeen minutes after the second engine quit, Captain Bob Pearson put the powerless airliner down on a disused military runway at Gimli, Manitoba, beside a sports-car race in full swing. Everyone on board walked away. The plane got a nickname for life: the Gimli Glider. ## A number with the wrong label The 767 was one of the first Air Canada jets set up for metric units, at a time when Canadian aviation was halfway through switching from imperial measures. Its fuel gauges were also dead. A faulty fuel-quantity processor had blanked them, so the crew in Montreal had the tanks measured by hand with a dripstick, which gives a volume in liters, and then had to work out the mass themselves. The flight plan called for 22,300 kilograms of fuel for both legs. The dripstick showed 7,682 liters already aboard. The fueler supplied a density of 1.77. Nobody on the ramp or in the cockpit caught that this figure meant pounds per liter, the unit the rest of the fleet used. The airline’s own manuals had not made anyone clearly responsible for the sum; on older three-crew jets, a flight engineer would have owned it. ## The calculation, done both ways Here is the arithmetic the crew needed, next to the arithmetic they actually did. The only difference is the density number. - **Correct (0.803 kg per liter):** 7,682 L × 0.803 = 6,169 kg already aboard. 22,300 − 6,169 = 16,131 kg still needed. 16,131 ÷ 0.803 = about 20,088 liters to pump in. - **What happened (1.77, read as if it were kg per liter):** 7,682 × 1.77 = 13,597, treated as kilograms. 22,300 − 13,597 = 8,703 "kg" still needed. 8,703 ÷ 1.77 = about 4,917 liters pumped in. Now the Badiyaa check. Divide the wrong density by the right one: 1.77 ÷ 0.803 = 2.204. That is almost exactly the number of pounds in a kilogram, 2.2046. So every reading of fuel on board came out about 2.2 times too big, because a pound figure had been written in a kilogram box. Add up what the tanks really held after Montreal: 7,682 + 4,917 = 12,599 liters. At 0.803 kg per liter, that is about 10,117 kilograms, or 45 percent of the 22,300 the trip required. The crew had taken on roughly a quarter of the extra fuel they needed (4,917 of 20,088 liters, or 24.5 percent). The same slip was repeated at Ottawa: 11,430 liters were measured there and logged as 20,400 kg, when the real mass was nearer 9,250 kg. The flight computer believed the second figure and showed plenty of fuel all the way to Edmonton. ## Seventeen silent minutes Shortly after 8 p.m. Central time, over Red Lake, Ontario, a fuel-pressure warning lit up for the left side, then the right. The left engine flamed out, then the right. With no engines, the 767’s glass cockpit went dark, leaving a handful of battery-powered standby instruments and no vertical speed readout. A small ram air turbine dropped into the airstream to keep the hydraulics barely alive. The emergency checklist had no section for losing both engines. Pearson flew gliders on weekends. He picked a glide speed near 220 knots by judgment. First Officer Maurice Quintal timed the descent against distances read out by Winnipeg controllers: the jet sank 5,000 feet for every 10 nautical miles. Ten nautical miles is about 60,760 feet, so the glide ratio was roughly 12 to 1, short of the 767’s best of about 20 to 1. Winnipeg was out of reach. Quintal, who had trained at RCAF Station Gimli, suggested the old base 45 miles away. Nobody in the cockpit knew part of that runway had become a drag strip. Coming in too high, Pearson crossed the controls into a forward slip, a glider-pilot move rarely tried in an airliner, to shed height without gaining speed. Boys on bicycles pedaled clear. The nose gear, which had not locked, folded on touchdown, and the scraping nose plus a center guardrail helped stop the jet short of the crowd. A small fire in the nose was put out by race marshals with hand extinguishers. A few passengers were hurt sliding from the tail-high rear exits; none seriously. ## What changed after Gimli A Canadian board of inquiry reported in April 1985. It faulted Air Canada for gaps in training, manuals, spare parts and fueling procedures, praised both crews’ professionalism, and urged the airline to move its whole fleet to one system of units instead of a mix. Air Canada first demoted Pearson for six months and suspended Quintal for two weeks. In 1985 the pair received the first Diploma for Outstanding Airmanship from the Fédération Aéronautique Internationale. The Gimli Glider, registration C-GAUN, flew for Air Canada for almost 25 more years. Its last revenue flight was on January 1, 2008, and later that month Pearson and Quintal rode along on its trip to retirement in the Mojave Desert. On June 27, 2025, its recovered cockpit went on display at the Gimli Glider Exhibit museum in Gimli, with Pearson there to meet it. ## Further reading - [Wikipedia: Gimli Glider](https://en.wikipedia.org/wiki/Gimli_Glider) *Image: Andrew Thomas from Shrewsbury, UK, CC BY-SA 2.0 via Wikimedia Commons* *This article was produced with AI assistance and reviewed by our Editorial Desk. [How we work](https://badiyaa.com/editorial-policy/).*