The Legend of the Gimli Glider
How a mathematical miscalculation set the stage for disaster, only to be thwarted by the men who miscalculated in the first place.
Flight today is very safe. Every day around the world up to 100,000 flights occur without incident. It is common for an airliner to land at one location, refuel, and be back up in the air in a matter of hours.
In 1983, Air Canada Flight 143, was loading passengers in Montreal. It was preparing to make a run to Edmonton. Only this trip was going to be different.
A Defective Channel
Events were set in motion on July 22, 1983. A Boeing 767 C-CAUN belonging to Air Canada failed a routine check in Edmonton.
A technician discovered a faulty fuel quantity indicating system (FQIS). After making an entry into the logbook, the tech disabled the defective channel. Not an uncommon action in such circumstances.
The next morning, Captain John Weir and his co-pilot Captain Donald Johnson were informed. With the defective channel in the FQIS, the use of a dripstick reading was needed to verify fuel quantity.
Captains Weir and Johnson conducted the math and verified the reading. After passing all other pre-flight checks, the 767 took off. It made its way to Toronto and then to Montreal with no incident.
A Costly Stoichiometry Error
In Montreal, Captain Robert Pearson and First Officer Maurice Quintal took command of the plane. They were to fly to Ottawa and then on to Edmonton.
During the transition, Pearson and Quintal were informed of the faulty FQIS. Pearson then decided to refuel with enough fuel to get to Edmonton without needing to refuel again in Ottawa.
While at the gate, a technician reviewed the logbook in the cockpit. He decided to conduct his own FQIS test. But, as he started the test, a field truck arrived. The tech exited the cockpit and failed to disable the defective FQIS.
When Pearson entered the cockpit, he began doing the calculations to fuel needs. To make this calculation, pilots need to account for the density of jet fuel. Pearson did this in pounds per liter.
He failed to realize that the 767 plane was an all-metric plane. It was a new addition to the fleet. The all-metric plane required that fuel calculations be measured in kilograms per liter.
Trouble Sets In
Flight 143 made its way to Ottawa without incident, but as planned, she didn’t take on fuel while there. To Pearson, the plane had enough fuel onboard to get them to Edmonton.
While flying over Ontario at 41,000 feet, the cockpit warning system alarmed. It indicated there was a problem with fuel pressure on the left side of the plane.
The pilots assumed a fuel pump had gone out and switched off the alarm. The engine could be gravity-fed the fuel it needed during level flight, so there was little cause for concern.
A few seconds after turning off the initial alarm, a second alarm rang. This time it warned the pilots of a fuel pump failure on the right side. Starting to worry, the pilots contacted air traffic control and were instructed to divert to Winnipeg.
When things go wrong, they can go wrong quickly. A few seconds after being re-routed, the left engine failed. As they prepped for a single-engine landing another alarm sounded.
No Engines, No Problem
All engines were out. The alarm associated with this warning was one no one in the cockpit had heard before. Moments later, the 767 lost power.
Pilots undergo rigorous training. They are exposed to a variety of situations and scenarios. Flying a craft with no engines was something training had never considered. The pilots were to solve this for the first time in the real world.
As fate would have it, Pearson was an experienced glider pilot. His experiences in that field provided him with techniques that commercial flight did not use. He and Quintal set to work.
Gliding a maximum distance requires optimum speed. As Pearson settled on the speed, Quintal began calculating distance to Winnipeg.
He then proposed they land at a former Royal Canadian Air Force station - Station Gimli. While it had once served the RCAF, it was now a closed air force base. It seemed to be the godsend answer they needed.
Unbeknownst to Quintal, or his air traffic controller, it was a closed base but not vacant. The Gimli Motorsports Park had converted it into a racetrack. A Winnipeg Sports Car Club had just gotten underway. The area was full of cars and campers.
As the pilots guided the plane downward, the nose wheel failed to drop. As the plane slowed during approach, it became increasingly difficult to control. At that point, the pilots realized they were coming in too high and too fast.
For bystanders attending the race, they couldn’t hear the approaching plane - both its engines were out. There was no warning that an impromptu landing was about to occur.
Pearson and Quintal opted for a forward slip landing. This would increase drag and reduce its altitude. They bore down on the deserted runway, nearly hitting two boys on bikes.
The landing was an immense success. The front landing gear’s failure to deploy resulted in the plane’s nose skidding along the ground. The additional friction slowed the plane enough to keep it from crashing into the race fans.
Seventeen minutes after running out of fuel, Air Canada Flight 143 came to a rest. Of the 61 passengers aboard, no one was seriously injured.
The Gimli Glider
In the aftermath, Captain Pearson suffered a six month demotion. First Officer Quintal received a two week suspension. Several other crews attempted to navigate the same situation in flight simulators. All resulted in major crashes.
Two years later, in 1985, both men were awarded the first ever Federation Aeronautique Internationale Diploma for Outstanding Airmanship. Today, the incident is referred to as the Gimli Glider.
History for the Hurried:
April 6, 1896: After a 1,500 year hiatus, the first Olympics of the modern era was held in Athens, Greece.
April 8, 1952: President Harry S. Truman takes control of America's steel mills to prevent a shutdown by strikers. The seizure of control is ruled unconstitutional by the U.S. District Court. Workers go on strike for nearly two months before scoring a 16 cent per-hour wage increase.