One of the most infamous incidents in the history of Canadian aviation, second in my mind only to the cancellation of the Avro Arrow, was what happened to Air Canada Flight 143, aka the Gimli Glider.
That plane was bound from Montreal to Edmonton on July 23, 1983.
But at a cruising height of 41,000 feet, the pilot discovered the plane was less than halfway to its destination and out of fuel.
Indeed, Flight 143 was still over Ontario when the aircraft’s cockpit warning system sounded, indicating a fuel-pressure problem on the aircraft’s left side. A few seconds later, the fuel pressure alarm also sounded for the right engine. This prompted the pilots to divert to Winnipeg. The left engine failed moments later and the pilots began preparing for a single-engine landing.
As they were telling Winnipeg about their problems, the right side engine stopped, and the plane lost all power.
Now, this was not something the pilots had trained for, and it knocked out the plane’s transponder, meaning they couldn’t tell what altitude they were at.
The plane they were flying was very new, and the electronic flight instrument system operated on the electricity generated by the aircraft’s jet engines. With both engines stopped, the system went dead, and most screens went blank, leaving only a few basic battery-powered emergency flight instruments.
The crew searched their emergency checklist for the section on flying the aircraft with both engines out, only to find that no such section existed.
But, the passengers on the plane were lucky, as the pilot, Captain Pearson, was an experienced glider pilot, meaning he was familiar with flying techniques rarely used in commercial flight.
It was by guess and by gumbo, but the captain aimed to keep the speed at 220 knots.
But at the rate of altitude loss, they wouldn’t make it to Winnipeg.
Then, a second stroke of luck: the first officer had served at an Air Force Station in Gimli before he started working for Air Canada. While part of the facility had been converted to a race track complex, with a road-race course, a go-kart track, and a drag strip. And, wouldn’t you know, there was a race happening that day and the old airstrip was full of cars and campers.
The whole story reads like a made-for-TV movie, with kids on bicycles on the landing strip, the plane’s wheels blowing out as it skidded to a stop, with no injuries on the ground or on the plane. It was a heroic moment and the pilot and crew have been well feted for their quick thinking and skill in landing the plane.
But here’s the question. Why did the plane crash in the first place?
Well, turns out that the plane tracked fuel in kilograms, which seems perfectly logical these days. But Canada had only adopted the metric system the previous decade, which was slowly rolling out. This meant that Air Canada was tracking fuel in pounds per litre, not kilograms per litre. Since it takes 2.2 pounds to make up one kilogram, that meant the plane had less than half the fuel on board.
This isn’t the first and might not be the last story of its type. For instance, in 1999, NASA crashed the Mars Climate Orbiter right into the actual planet because they were calculating their data in metric, but the spaceship had been programed to calculate in US Customary Units (that’s the American version of Imperial).
Accuracy in measurements becomes increasingly important the more precise the results need to be. Back in the day, you could say a horse was 15 hands high, knowing that meant it would be about five feet high. If it was over or under that by an inch or two? It wouldn’t mean that the horse would plough into Mars at a speed of close to 25,000 kph.
So pardon me if I take this moment to celebrate 150 years of the International System of Units (SI), which brought the meter, the second and the kilogram to the world.
On May 20, 1875, delegates from a group of 17 countries gathered in Paris to sign the Metre Convention.
I make fun of Imperial units, but back then, measurement was a real nightmare.
While the metric system had been a topic of discussion for at least a hundred years before the Metre Convention, there was no consistency in measurements between countries.
Since the time of Charlemagne, the standard of length had been a measure of the body, that from fingertip to fingertip of the outstretched arms of a large man.
In the middle ages, a standard weight was cast to represent the true standard of weight, but these would rust, could be stolen and lost. When a new royal standard had to be cast, it was a different standard than the old one, and replicas of the old standard weight would be in use at the same time as new ones came into existence.
The Metre Convention offered consistency and a system of measurements that transcended politics, tradition and even language, laying the foundation for what was to become the scientific revolution.
Was it perfect? No. Originally, the metre was designated as one ten-millionth of the distance from the equator to the North Pole. But turns out that wasn’t exactly accurate (they thought it was 40,000 km, but turns out they were 7.863 km short), so in 1799, the metre was redefined in terms of a metre bar. The bar used was changed in 1889, and in 1960 the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86, and again in 2019 to reflect an even more accurate measuring of a metre based on how far light can travel in 1/299,792,458 of a second.
The solution for Air Canada was to convert entirely to metric and ditch Imperial entirely. I would love to see the rest of the country follow suit. It’s been 50+ years. Can we finally take the plunge?
Trent is the publisher of Tumbler RidgeLines.
