Dead-Stick to the Dragstrip

Silence at Forty-One Thousand Feet

Eli: July 23rd, 1983, a little after eight in the evening. Air Canada Flight 143, a Boeing 767, is cruising at 41,000 feet over Red Lake, Ontario. It's flying Montreal to Edmonton, by way of Ottawa. Up front are Captain Bob Pearson and First Officer Maurice Quintal. Then, a warning: low fuel pressure in the left fuel pump.

Mara: A listener asked us what happened to the Air Canada jet that ran out of fuel over Canada in 1983 and had to glide down with no engines. It's Monday, October 12th, and today's angle is a civilian glider pilot dead-sticking a passenger jet onto a crowded dragstrip.

Eli: That jet ends up on the ground in Manitoba. Getting there takes a cockpit gone dark, a hunt for anywhere to land, and an inquiry into why the tanks were empty in the first place.

Mara: So far, though, it's one warning, on one pump, on one side.

Eli: Then the engines go. Both Pratt and Whitney engines flame out, starved of fuel. The backup power unit can't help, because it drinks from the same tanks. The cockpit goes quiet, except for a sound neither pilot is used to: the all-engines-out chime. The voice recorder catches the words, “Oh, f%$#!”

Mara: A tone that only sounds when every engine has stopped. Not one. All of them.

Eli: And at that moment the jet is a glider. The following week, Air Canada announced the probable cause. The plane had simply run out of fuel.

Mara: Time magazine called that cause “stunningly prosaic.”

Eli: Prosaic on paper. In the air, two pilots are holding a silent airliner with nothing left to restart. Mara, keeping it in the air is where the mechanics come in.

Calculating the Glide

Mara: Back up a few minutes. When instruments warned of low fuel pressure in the left fuel pump, Pearson began a descent and turned for Winnipeg, about 120 miles away. Then both engines quit, and the main electrical power went with them. The screens went dark. “Now we're powerless… The cockpit went blank,” Pearson said. What came out instead was a ram-air turbine, a little propeller that drops out of the belly and spins in the rushing air to make just a bit of power.

Eli: Enough hydraulic pressure to move the control surfaces, the parts that steer the plane. Barely.

Mara: And enough to keep the standby instruments alive: a compass, an artificial horizon, airspeed, altitude. Pearson said later, “We were put in a new generation airplane with practically no idea of what to do if the computer system failed.”

Eli: Except Pearson happened to be an experienced glider pilot.

Mara: Pearson drew on that to settle on a glide speed of about 220 knots, and hold it, with no computer to hand him one.

Eli: Meanwhile Quintal is working the numbers. The transponder's dark, so Winnipeg controllers are tracking the jet on radar with a cardboard ruler. Quintal remembers the altitudes, keeps asking them for distances, and builds his own descent profile down through 35,000 feet. Pearson said, “I thought we'd make it to Winnipeg.” By AOPA's account, it was Quintal who said it out loud: they would never make Winnipeg. Gimli was the only alternative, a decommissioned air force base where he'd once been stationed as a military pilot.

Mara: Winnipeg was about 85 kilometres south of Gimli. Close, and still too far.

Eli: So Quintal punches in the coordinates for a runway he knew from his air force days. What neither pilot knew was what that runway had become.

Touchdown on the Dragstrip

Mara: Gimli comes up, and they're too high and too fast. No flaps to slow them, no reverse thrust waiting on the ground. So Pearson reaches back to his glider days for a sideslip. He crosses the controls, wheel one way, rudder the other, so the jet flies a little sideways, like a skier turning across a slope to lose height without picking up speed. Drag goes way up. The descent steepens. The 220 knots he'd guarded all the way down now has to go.

Eli: A glider pilot's trick, flown in an airliner full of passengers.

Mara: Pearson called it “a very cold robotic experience.” He had tunnel vision, he said, “trying to aim for the piece of cement at Gimli airport.” That piece of cement wasn't empty. Quintal's old base was a motorsport track now, and that Saturday the Winnipeg Sports Car Club was holding a Family Day: race cars, tents and campers, barbecues, families, and boys on bicycles on the tarmac.

Eli: One teenager there saw it coming “sort of sideways and cockeyed.”

Mara: Which is exactly what a sideslip looks like from the ground.

Eli: Back over Red Lake, Pearson had engines and a full panel of screens. Now he's crossing the threshold, the start of the runway, with neither. The gear had dropped by gravity. The main wheels locked; the nose wheel didn't. Quintal said there was no sound of it going down, “and that was a terrible feeling.” Pearson puts the mains on the concrete, holds the nose up as long as he can, then, in his words, “stood on the brakes.” Tires blow. The nose collapses, and the 767 skids on in sparks and smoke while the crowd scatters.

Mara: That scraping nose became a brake, stopping it short of a steel barrier.

Eli: Pearson only saw the boys once the main gear was down. “When I looked up and saw these boys, that's when my heart starting beating. That was the traumatic part for me.” One of the boys said later they were “like deer in the headlights.” The jet stopped not far from them.

Mara: He aimed for a piece of cement and found a crowd on it.

Eli: Then the slides. Nose down, tail high, so the rear slides are steep, and there are about ten minor injuries getting down them. All 69 people aboard survive. Nobody on the ground is hurt. Smoke is coming from the nose. Pearson went back aboard for an extinguisher and was overcome by smoke. Racers and course marshals ran over with extinguishers of their own, and the fire was out before the fire department got there.

Mara: Sixty-nine aboard, a crowd on the ground, and not one serious injury.

Eli: The day had one more twist. Air Canada sent technicians from Winnipeg to repair the plane, and their vehicle ran out of gas on the way. What nobody at Gimli knew yet was why the jet's tanks were empty. A brand-new airliner had left Montreal fuelled for Edmonton, or so everyone believed, and that belief is where the inquiry started digging.

The Metric Trap

Mara: Start with the fuel gauges. The system feeding them had a fault, later traced to a cold solder joint, basically a bad electrical connection. A technician in Edmonton had found that pulling one circuit breaker got the gauges reading again. Then, in Montreal on the day, another technician reset that breaker to run a test. By the board of inquiry's account, the fuel truck arrived, he was distracted, and he forgot to pull it again. The gauges went blank. That's what Pearson saw when he came aboard.

Eli: Pearson testified mechanics convinced him a manual check was enough. Mechanics denied it.

Mara: That manual check is the dripstick, a rod under the wing that measures how deep the fuel sits in each tank. It gives litres. But the 767 was Air Canada's first metric airplane, counting fuel in kilograms, while the rest of the fleet still ran on pounds. So someone had to turn litres into kilograms. The figure handed to the people doing that math, in Montreal and Ottawa, was 1.77. The board found that converts litres to pounds. For kilograms, the figure is about 0.8.

Eli: So everyone's doing careful arithmetic with the wrong number.

Mara: And careful it was. Pilots and fuellers worked it three times and got the same answer three times, and Pearson said, “That's it, we're going.” Here's the trap. The flight plan called for 22,300 kilograms. Because of that factor, what went in was the same number in pounds, roughly half. So the figure on the scratchpad matched the target exactly. The digits were right. The unit underneath them wasn't.

Eli: So Red Lake, roughly halfway to Edmonton, is where half a load runs out.

Mara: On older jets, a third crew member, the flight engineer, did the fuel sums. The 767 didn't carry one; its computers were meant to take that load. With the gauges dark, the sum fell to whoever was in the cockpit. One mechanic testified he started his own calculation, saw others leaving looking like they knew the number, “so I left my calculations, and that's it.”

Eli: Like the repair van that ran dry on the road to Gimli.

Mara: A number checked three times, sitting right on its target, with the gauges dark the whole way. Eli, whose number that really was is what the inquiry had to decide.

Shared Blame and the Long Glide Home

Eli: The airline's first answer was discipline. Pearson was demoted for six months. Quintal was suspended for two weeks, and so were three ground workers. Then public pressure pushed the government into a yearlong inquiry under Justice George H. Lockwood.

Mara: Air Canada's counsel admitted no one was assigned that calculation in an abnormal situation.

Eli: Which leaves two readings. One runs through the Minimum Equipment List, the rulebook of what has to work before a plane can legally leave. Under it, the board found, taking off from Montreal with blank gauges was “a significant cause of the accident” and “an illegal dispatch.” That's the case against the people in the cockpit and on the ramp. Pearson's answer was that “every single thing that happened in relation to this problem only reinforced my belief that it was legal.”

Mara: The other reading is Justice Lockwood's. Responsibility, his report says, “goes well beyond them into the upper echelons of management within Air Canada,” and the most serious fault was “the failure of communication within the organization.”

Eli: A broken rule, or a company gap?

Mara: The jet itself was repaired and flew for Air Canada another 25 years. In 1985, Pearson and Quintal received the Fédération Aéronautique Internationale's Diploma for Outstanding Airmanship. In 2008 the old 143 made its last trip, to the Mojave Desert, with both of them aboard as passengers, Quintal a captain himself by then. Pearson said four groups had shown interest in the plane: “Hopefully somebody will find a use for it.”

Eli: A track volunteer called it “one in a million.”

Mara: So here's what happened. Flight 143 left with about half the fuel it needed, because a pounds figure was used as kilograms. Both engines quit, and Pearson glided it onto a dragstrip at Gimli with all 69 people alive. That warning over Red Lake, the one Pearson took for a bad pump, was the arithmetic from the ground coming due.

Eli: Two things are still unsettled. The maintenance records don't make clear whether verbal clearance to fly with those gauges was ever confirmed. And accounts still differ on exactly how many people were hurt on the slides.

Mara: For listeners curious about emergency power, look into the ram-air turbine.

Eli: Follow technology for more stories as automated systems meet human error.

Mara: That's all for this one. I'm Mara.

Eli: And I'm Eli. Thanks for listening to Angle. Until next time.