Twelve kilometres above the Manitoba countryside, the unthinkable happens: a brand new Air Canada Boeing 767 runs out of fuel. The 120-tonne, $40-million plane becomes a glider, dropping at over 600 metres per minute with no hope of reaching Winnipeg. Amazingly, the powerless plane makes a successful emergency landing at an abandoned airbase in Gimli, Manitoba. Air Canada reveals how the newest plane in their fleet simply ran out of gas...
The 767 boasts an advanced fuel quantity processor that accurately gauges fuel on board - but on this particular plane that fuel computer had never worked properly, and maintenance workers lacked a spare. Because the 767 was a new addition to Air Canada's fleet (the first metric plane to fly in Canada), the written maintenance standards were still being revised. When the ground crew was preparing the plane for departure from Montreal, they realised that the Fuel Quantity Information System computer on flight 143 was malfunctioning. However, a maintenance worker assured the captain, Robert Pearson - incorrectly as it turned out - that the plane was certified to fly without a functioning fuel gauge if the crew manually checked the quantity of fuel in the tanks.
This manual procedure, known as a "drip," is as old as flying itself. Each fuel tank contains a drip stick, which is similar to the dip stick used to check the oil in a car, except that it is mounted upside down. When a mechanic under the wing loosens the drip stick, it falls within the tank until a float at its tip bobs on the surface of the fuel. The mechanic reads the depth of the fuel from markings on the drip stick, then consults a handbook that gives the corresponding volume of fuel in the tank.
Unfortunately for this crew, for years Air Canada pilots had computed the amount of fuel they would need in pounds (there are 1.77 pounds/litre), whereas the new 767's fuel consumption was expressed in kilograms (there are .8 kg/litre). The new metric specifications were in accord with the Canadian government's plan to introduce metric units nationwide. But the drip procedure told the pilots the amount of fuel on board not in pounds or kilograms, but in litres. What's more, on the earlier airplanes, the fuel had been calculated not by the pilot or copilot, but by the third person in the cockpit, the flight engineer. The 767 did not carry a flight engineer because the computers had reduced the cockpit workload. Now, it was unclear whether the ground crew or the pilots were primarily responsible for the fuel calculations. It didn't matter - they both made the same conversion mistake.
Thus, the plane took off with only half the fuel it needed to reach Edmonton. It began to run out of gas near Red Lake, Ontario.
Air Canada flight 143 was ultimately saved by a series of lucky breaks. The pilot, Captain Pearson, was an experienced glider pilot (he co-owned a Blanik L-13 sailplane). First Officer Maurice Quintal had once been stationed at the Royal Canadian Air Force base at Gimli, 225 kilometres away, and was familiar with the landing strips. Unfortunately, the Gimli base had no control tower or fire trucks - and, unbeknownst to the First Officer, it was now being used as a racetrack. It had been divided into various courses, including a drag strip with a steel guardrail down the middle.
The crew and passengers had just finished dinner when the first warning light came on. Flight 143 was outbound at 41,000 feet and going 469 knots at the time. The 767's Engine Indicator and Crew Alerting System beeped four times in quick succession, alerting them to a fuel pressure problem. "At that point" Pearson says, "we believed we had a failed fuel pump in the left wing, and switched it off. We also considered the possibility we were having some kind of a computer problem. Our flight management computer showed more than adequate fuel remaining for the duration of the flight. We'd made fuel checks at two waypoints and had no other indications of a fuel shortage." But when a second fuel pressure warning light came on, Pearson felt this was too much of a coincidence and made a decision to divert to Winnipeg. Flight 143 requested an emergency clearance and began a gradual descent to 28,000 feet. Says Pearson, "Circumstances then began to build fairly rapidly." Pearson and Quintal immediately began making preparations for a one engine landing. Then another fuel light lit up. Two minutes later, just as preparations were being completed, the EICAS issued a sharp bong - indicating the complete and total loss of both engines. Says Quintal "It's a sound that Bob and I had never heard before. It's not in the simulator." After the "bong," things got quiet. Real quite. Starved of fuel, both Pratt & Whitney engines had just flamed out.
At 1:21 GMT, the forty million dollar, state-of-the-art Boeing 767 had become a glider. The APU, designed to supply electrical and pneumatic power under emergency conditions, was no help because it drank from the same fuel tanks as the main engines. The 767's glass cockpit went dark. Pilot Bob Pearson was left with a radio and standby instruments, noticeably lacking a vertical speed indicator - the glider pilot's instrument of choice. Hydraulic pressure was falling fast and the plane's controls were quickly becoming inoperative. But the engineers at Boeing had foreseen even this most unlikely of scenarios and provided one last failsafe - the RAT.
The RAT is the Ram Air Turbine, a propeller-driven hydraulic pump tucked under the belly of the 767. The RAT can supply just enough hydraulic pressure to move the control surfaces and enable a dead-stick landing. The loss of both engines caused the RAT to automatically drop into the airstream and begin supplying hydraulic pressure.
The pilots immediately opened the emergency guide, looking for the section on flying the aircraft with both engines out, only to find there was no such section. Pearson glided the plane at 220 knots, his best guess as to the optimum airspeed. Copilot Maurice Quintal began making calculations to see if they'd reach Winnipeg, using the altitude from one of the mechanical backup instruments and distance travelled supplied by the air traffic controllers in Winnipeg, then by measuring the distance the plane's echo moved on their radar screens. The plane had lost 5,000 feet in ten nautical miles (18.5 km), giving a glide ratio of approximately 11:1 (which is actually quite good). But the controllers and Quintal both calculated that Flight 143 would not make Winnipeg.
At this point Quintal selected his former RCAF base at Gimli as the landing spot. Unbeknownst to Quintal, since his time in the service Gimli had "gone public" and was now being used for drag racing. To make matters worse, on this particular day the area was covered with cars and campers for "Family Day"
Pearson and Copilot Quintal turned toward Gimli and continued their steep glide. Flight 143 disappeared below Winnipeg's radar screens, the controllers frantically radioing for information about the number of "souls" on board. Approaching Gimli Pearson and Quintal made their next unpleasant discovery: The RAT didn't supply hydraulic pressure to the 767's landing gear. Pearson ordered a "gravity drop" as Pearson thumbed frantically through the Quick Reference Handbook, or QRH. Quintal soon tossed the QRH aside and hit the button to release the gear door pins. They heard the main gear fall and lock in place. But Quintal only got two green lights, not three: the nose gear hadn't gone over centre and locked, despite the "assist" it was given by the wind.
Six miles out, Pearson began his final approach onto what was formerly RCAFB Gimli. Pearson says his attention was totally concentrated on the airspeed indicator from this point on. Approaching runway 32L he realised he was too high and too fast, and slowed to 180 knots. Lacking divebrakes, he did what any sailplane pilot would do: he crossed the controls and threw the 767 into a vicious sideslip. Slips are normally avoided on commercial flights because of the the tremendous buffeting it creates, unnerving passengers. As he put the plane into a slip some of Flight 143's passengers ended up looking at nothing but blue sky, the others straight down at a golf course. Passengers gasped in horror, as they watched the ground grow closer in the windows. Pearson didn't recover from the slip until the very last moment. A passenger reportedly said, "Christ, I can almost see what clubs they are using." Copilot Quintal suspected Pearson hadn't seen the guardrail and the multitude of people and cars down the runway. But at this point it was too late to say anything. A glider only gets one chance at a landing and they were committed. Quintal bit his lip and remained silent.
The 767 silently levelled off and the main gear touched down as spectators, racers, and kids on bicycles fled the runway. The gigantic Boeing was about to become a 132-ton, silver bulldozer. One member of the Winnipeg Sports Car Club reported he was walking down the dragstrip, a 5-gallon can full of hi-octane racing fuel in hand, when he looked up and saw the 767 headed right for him. Pearson stood on the brakes the instant the main gear touched down. An explosion rocked the 767's cabin as two tires blew. The nose gear, which hadn't locked down, collapsed with a bang. The nose slammed against the tarmac, bounced, then began throwing a 300-foot shower of sparks. The right engine nacelle struck the ground. The 767 reached the tail-end of the dragstrip and the nose grazed a few of the guardrail's wooden support poles. (The dragstrip began in the middle of the runway.) Pearson applied extra right brake so the main gear would straddle the guardrail. Would the sports car fans be able to get out of the way, or would Pearson have to veer the big jet off the runway to avoid hitting stragglers? The 767 came to a stop on its nose, mains, and right engine nacelle less than 100 feet from the spectators, barbecues and campers. All of the race fans had managed to flee.
After the landing, a fire in the nose of the plane was extinguished by go-cart racers with hand-held fire extinguishers. The only injuries were to passengers who exited by the plane's rear emergency slide. Because the nose landing gear was not extended, the tail of the plane ended up three stories in the air, causing passengers exiting the rear emergency slide to slam quite hard into the asphalt.
The aircraft was fixed enough to fly at Gimli then flown to Winnipeg. After approximately $1M in repairs consisting primarily of nose gear replacement, skin repairs and replacement of a wiring harness, it re-entered the Air Canada fleet. Flight crews nicknamed the plane, registration C-GAUN, the "Gimli Glider". As of July 2004, it was still flying.
After the landing, the pilot and co-pilot were praised for saving the lives of the 61 passengers on board. But on 4 October 1983, Air Canada disciplined them for allowing the near-tragedy to happen. The pilot was demoted for six months, the co-pilot was suspended for two weeks and three ground workers were also suspended. A 1985 Transport Canada report blamed errors and insufficient training and safety procedures.
Many residents of Gimli credit the incident with putting their town on the map. On 1 July 1986, Pearson, Quintal and the plane's flight attendants were given a place of honour in Gimli's Canada Day parade for making Gimli the site of Air Canada's most famous unscheduled stop. As an amusing side note, the mechanics sent from Winnipeg Airport in a van ran out of fuel on their way to Gimli, and found themselves stranded in the backwoods of Manitoba. Another van had to be sent to pick them up. Now, in Western Canadian slang, "to pull a Gimli Glider" is to make a spectacular foul-up.
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Updated: January 30, 2005
