The Gimli Glider, Air Canada One Forty-Three, and the Deadstick Landing That Turned a Fuel Blunder Into a Lesson in Best Glide and the Forward Slip

On July 23, 1983, Air Canada Flight 143, a brand-new Boeing 767, ran out of fuel at 41,000 feet over Canada when a unit-conversion error left it loaded with roughly half the fuel the crew believed they had. Both engines flamed out, and Captain Bob Pearson glided the powerless airliner to a deadstick landing at a former air base in Gimli, Manitoba, using best glide airspeed and a forward slip - with no fatalities. The accident is famous as an airline story, but its real value to private pilots is a hands-on lesson in the exact stick-and-rudder skills you already carry in your logbook.

What actually happened to the Gimli Glider?

The airplane was one of the first glass-cockpit airliners Air Canada operated, and one of the first Canadian jets to measure its fuel in kilograms instead of pounds. That detail is the whole story.

On the ground in Montreal, the jet’s fuel-gauging system had a fault, so the crew had to calculate the fuel load by hand. The method is simple: measure the volume in the tanks with a dipstick, then multiply by the fuel’s density to get weight.

But the number they multiplied by was the density in pounds per liter, not kilograms per liter. The airplane needed kilograms, and the difference between those two figures is almost exactly two to one. Every person in the chain cross-checked the math - and every person used the same wrong conversion factor.

The result: they loaded a little more than half the fuel they thought they had. On paper, a full trip to Edmonton with reserves. In reality, not even enough to get there.

Cruising at 41,000 feet, the left engine flamed out first. A couple of minutes later, the right engine quit too. Captain Bob Pearson and First Officer Maurice Quintal were now flying the heaviest glider anyone had ever strapped into.

Why did a careful, experienced crew still run out of fuel?

Nothing about this crew was careless. Pearson and Quintal were good, experienced airline pilots, and that is exactly the point.

A cross-check is only worth something if the people checking each other aren’t all making the same assumption. Five people confirming the same bad number is not five checks - it’s one mistake copied five times.

That trap catches pilots at every level. It’s the same logic when you accept a fuel order, eyeball the tanks, or trust a gauge that reads three-quarters this week just like it read three-quarters last week no matter how long you flew.

The fix is to verify with a source that fails differently. Look in the tank with your own eyes. Stick it. Run the time-and-burn math against the clock. One source is not verification - it’s hope with a number attached.

What is best glide airspeed, and why does it matter so much?

When both engines quit, the 767 lost most of its electrical power and much of its hydraulics. A ram air turbine (RAT) - a small propeller that drops into the slipstream and spins from the passing air - deployed automatically and generated just enough hydraulic pressure to move the flight controls. Pearson still had a control wheel that did something, but he had no thrust, most instruments were dark, and he was coming down.

The first thing he did is the first thing you must do: he flew the airplane. He set a speed and held it. That speed is best glide.

Every airplane has one. It’s the airspeed that gives you the most distance forward for every foot of altitude you give up.

• Fly faster than best glide, and you trade altitude for speed you don’t need.
• Fly slower, and you sink like a brick while creeping toward a stall - with zero power to recover.

Best glide buys you the most time and the most reach, and time and reach are the only two things you have left when the engine quits.

The Airman Certification Standards (ACS) are direct about this. On the emergency approach and landing task, the examiner wants you to establish and maintain the recommended best glide airspeed within tolerance, and to do it promptly - not eventually. Pitch for the number, trim it off so the airplane holds it hands-off, then lift your eyes and go to work on everything else.

Homework: Do you know your best glide number right now, this second, without looking it up, for the airplane you fly most? If not, that’s tonight’s assignment. The moment the engine goes quiet is the worst possible time to go hunting for it.

What flow should I run when the engine quits?

A flow saves you when your brain wants to lock up. A widely taught one walks the alphabet: A-B-C-D-E.

A - Airspeed. Best glide, first, always. Pitch and trim.

B - Best field. Start the search the instant the noise stops. Favor into the wind, but the first priority is a survivable surface within glide range. Pearson’s field was a problem - he was gliding over sparse country and Edmonton was never going to happen. Quintal, a former Royal Canadian Air Force pilot, remembered a former air base at Gimli, Manitoba, within reach. What the crew didn’t know was that one of its long runways was being used that day for drag racing and go-kart events, with people and cars on the pavement.

C - Checklist. Once trimmed and pointed at your field, run the memory items for a restart if you have altitude and reason to try, then the printed checklist: fuel, mixture, carb heat, mags, boost pump. Many engine failures that aren’t fuel exhaustion are a starvation or ignition problem you can fix in seconds. Try the obvious stuff - but never let the restart steal your eyes off the field.

D - Declare. Tell somebody. Squawk 7700, key the mic, say “Mayday” three times, and give them who you are, what’s wrong, and where you’re going. Pearson got a Mayday out, and ATC worked the problem until the jet dropped below radar and radio in the descent.

E - Execute. Commit to the field and fly the pattern you’ve got, not the one you wish you had.

How did a forward slip save a wide-body airliner?

Turning final for Gimli, Pearson had the opposite of the problem you’d expect. He wasn’t too low - he was too high and too fast. A clean jet with no engines to spin up its normal drag-producing systems was carrying too much energy and was going to overshoot into the people and cars.

He needed to lose altitude without gaining airspeed. Pearson happened to be a glider pilot on weekends, so he reached for a tool no 767 crew is trained to use - and one every pilot learns before solo: the forward slip.

You cross the controls: feed in aileron to bank one way, hold opposite rudder to keep the nose from turning. The airplane tracks the centerline while pointed off to the side, presenting its whole flank to the wind. That big flat side becomes a giant speed brake - you drop like an elevator while your airspeed stays put.

Pearson slipped a wide-body airliner full of passengers, straightened it near the ground, and set it down. The nose gear hadn’t locked, so it folded on touchdown - and the dragging nose actually helped, scrubbing off speed and throwing sparks down the runway. They stopped short of the crowd. There were injuries during evacuation, but not a single person died, on the airplane or on the ground.

What should pilots actually take away from the Gimli Glider?

1. Best glide is a reflex, not a number in a book. When it gets quiet, your hands should pitch for that speed before your conscious mind catches up. Practice pitching to it and trimming it hands-off.

2. Energy is options; altitude is time. The higher you are when it quits, the more ground you can reach and the more choices you have. That’s an argument for cruising a bit higher over rough country and climbing over the airport a little longer before you strike out over the trees.

3. The slip is a real emergency tool, not a checkride trick. When you find yourself high and hot on a power-off approach - and you will, because judging a glide without an engine is genuinely hard - you slip. The ACS lists the forward slip to a landing as its own task for exactly this reason.

4. Cross-check the things that can kill you with sources that fail differently. Fuel especially: the gauge, the dipstick, the tab, the time, the burn rate, the clock. Flight 143 nearly crashed because five careful people agreed on one wrong number. Don’t confirm your assumptions - test them.

The final report came from the Canadian aviation authorities and a formal board of inquiry led by Justice George Lockwood, and it lays out the full technical picture, right down to the density figure entered wrong. Every accident report is a lesson someone paid full price for so you could have it cheap.

Key Takeaways

• Air Canada Flight 143 (a Boeing 767) ran out of fuel at 41,000 feet on July 23, 1983, due to a pounds-vs-kilograms conversion error that left it with about half the fuel needed.
• Captain Bob Pearson flew a deadstick landing at Gimli, Manitoba, using best glide airspeed and a forward slip - with no fatalities.
• Know your airplane’s best glide number cold and be able to trim for it hands-off.
• Use a flow - A-B-C-D-E (Airspeed, Best field, Checklist, Declare, Execute) - to stay organized when the engine quits.
• Verify critical items like fuel with independent sources that fail differently, because agreeing cross-checks can all repeat the same mistake.