Gimli Glider July 23rd, 1983
A Boeing 767-200 - The first model of the 767, launched in 1978 and produced from 1981 to 1994, is normally fuelled using a device known as the Fuel Quantity Information System Processor (FQIS), which operates all of the internal pumps and reports to the pilots on the status of the amount of fuel. Unfortunatly, Flight 143's FQIS was not working properly (later traced to a bad solder joint in the capacitance gauges in the fuel tanks). Instead, the fuel load was measured with a dipstick, to determine the total volume of fuel in the tanks.
When it came time to calculate how much fuel was needed for the flight from Montreal to Edmonton, the error occured. Calculations were based on weight instead of volume, which required a conversion in the measurements. The Boeing 767-200 was the first in the Air Canada fleet that measured fuel in kilograms, all of the other manuals and planes in the Air Canada fleet used pounds. The pilots used a unit conversion factor of 1.77 Pounds/Litre. However, a fuel load measured in kilograms should have used the conversion factor of 0.8 Kilograms/Litre. After using the 1.77 Pounds/Litre factor, the figure 20,400 was entered into the airplane's computer, telling it they had 20,400 pounds of fuel on board. Which, the computer interpreted as 20,400 kilograms and that there was enough fuel based on the incorrect input. Which in fact the airplane only had 9,144kg (20,160Lbs) onboard.
Not sure of the calculations, the pilots and the fuelling crew calculated the figures three times, after coming up with the same number all three times, the pilot, Captain Robert (Bob) Pearson, finally stated, "That's it, we're going". Flight 143 then flew the short distance from Montreal to Ottawa, again the fuel level was remeasured before the flight proceeded to Edmonton.
At 41,000 feet (12 497 m) over Red Lake, Ontario, the cockpit warning system chimed four times and indicated a fuel pressure problem on the left side. Thinking the fuel pump had failed the pilots turned it off; the tanks are above the engines so gravity will take over and feed the engines. The computer said that there was still plenty of fuel, but this was based on the wrong calculations. A few moments later a second fuel pressure alarm sounded, and the pilots decided to divert to Winnipeg. Within seconds the left engine failed and preparations were made for a one-engine landing.
While they attempted to restart the engine and communicate with controllers in Winnipeg for an emergency landing, the warning system sounded again, this time with a long "bong". The sound was the "all engines out" sound, an event that was never simulated during training. Seconds later the right side engine stopped and the 767 lost all power leaving the cockpit suddenly silent and allowing the cockpit voice recorder to easily pick out the words "Oh, f%$#!".
The 767 is based on a "glass cockpit" concept in which mechanical instruments are replaced with display screen monitors. The jet engines also delivered electrical power to the aircraft, so most of the instrumentation suddenly went dead. One of the lost instruments was the vertical-rate indicator, which would let the pilots know how fast they were sinking and therefore how far they could glide.
The engines also supplied power to the hydraulic systems, without which a plane the size of the 767 could not be controlled. However, Boeing actually planned for this possible failure and included a device known as a ram air turbine that automatically popped open on the side of the plane, using some of the plane's residual velocity to spin a propeller-driven generator and provide enough power to the hydraulics to make it controllable.
With nothing in the emergency guide on flying the aircraft with both engines out, Pearson glided the plane at 220 knots (407 km/h), his best guess as to the optimum airspeed. Copilot Maurice Quintal began making calculations to see if they would reach Winnipeg. He used the altitude from one of the mechanical backup instruments, while the distance travelled was supplied by the air traffic controllers in Winnipeg, who measured the distance the plane's echo moved on their radar screens. The controllers and Quintal both calculated that Flight 143 would not make Winnipeg, as the plane had lost 5,000 ft in 10 nautical miles (1.5 km in 19 km) giving a glide ratio of approximately 12:1.
Stationed at the former Royal Canadian Air Force Base, Quintal selected Gimli to be the attempted place of landing. Since his time in the service, Quintal did not know the Gimli airport had become a public airport. Also not knowing one of its parallel runways was now being used for auto racing. To further complicate the situation, there were many cars, campers and families close to the former runway as it was "Family Day" for the Winnipeg Sports Car Club.
As they approached Quintal did a power-off "gravity drop" of the main landing gear, but the nose wheel, despite being built to open by swinging backwards with the force of the wind, would not lock. The ever-reducing speed of the plane also reduced the effectiveness of The "RAT" (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) and the plane became increasingly difficult to control. As they grew nearer it became apparent that they were too high, and Pearson executed a manoeuvre known as a "forward slip" to increase their drag and reduce their altitude. This gave passengers on one side of the aircraft a view of the ground while passengers on the other side of the plane seen blue skies. With the reduction of speed and altitude the 767 silently leveled off and the main gear touched down. Pearson "stood on the brakes" the instant the plane touched the runway, blowing out several of the plane's tires. The plane came to a stop at the end of the runway in a nose-down position due to the unlocked nose gear, only a few hundred feet from spectators of Family Day at the end of the runway.
None of the 61 passengers were hurt during the landing, the only injuries that resulted from the landing of Flight 143 came from passengers exiting the rear emergency slide, a near vertical angle because of the nose down position of the plane. A minor fire in the nose area was quickly put out by course workers, who rushed over with fire extinguishers.
Within two days the aircraft was repaired and flown out of Gimli, after approximately one million dollars worth of repairs, Aircraft #604 the Boeing 767 known as "The Gimli Glider", is to this day still in the Air Canada fleet.
Note: The mechanics sent from Winnipeg Airport to repair the aircraft, also ran out of fuel in their van on their way to Gimli.
Gimli Glider crew return on the 25th anniversary.. more
Pearson speaks out again.. more
Boys transfixed by image of plane on silent approach.. more
Crew draw visit to an emotional close.. more
When it came time to calculate how much fuel was needed for the flight from Montreal to Edmonton, the error occured. Calculations were based on weight instead of volume, which required a conversion in the measurements. The Boeing 767-200 was the first in the Air Canada fleet that measured fuel in kilograms, all of the other manuals and planes in the Air Canada fleet used pounds. The pilots used a unit conversion factor of 1.77 Pounds/Litre. However, a fuel load measured in kilograms should have used the conversion factor of 0.8 Kilograms/Litre. After using the 1.77 Pounds/Litre factor, the figure 20,400 was entered into the airplane's computer, telling it they had 20,400 pounds of fuel on board. Which, the computer interpreted as 20,400 kilograms and that there was enough fuel based on the incorrect input. Which in fact the airplane only had 9,144kg (20,160Lbs) onboard.
Not sure of the calculations, the pilots and the fuelling crew calculated the figures three times, after coming up with the same number all three times, the pilot, Captain Robert (Bob) Pearson, finally stated, "That's it, we're going". Flight 143 then flew the short distance from Montreal to Ottawa, again the fuel level was remeasured before the flight proceeded to Edmonton.
At 41,000 feet (12 497 m) over Red Lake, Ontario, the cockpit warning system chimed four times and indicated a fuel pressure problem on the left side. Thinking the fuel pump had failed the pilots turned it off; the tanks are above the engines so gravity will take over and feed the engines. The computer said that there was still plenty of fuel, but this was based on the wrong calculations. A few moments later a second fuel pressure alarm sounded, and the pilots decided to divert to Winnipeg. Within seconds the left engine failed and preparations were made for a one-engine landing.
While they attempted to restart the engine and communicate with controllers in Winnipeg for an emergency landing, the warning system sounded again, this time with a long "bong". The sound was the "all engines out" sound, an event that was never simulated during training. Seconds later the right side engine stopped and the 767 lost all power leaving the cockpit suddenly silent and allowing the cockpit voice recorder to easily pick out the words "Oh, f%$#!".
The 767 is based on a "glass cockpit" concept in which mechanical instruments are replaced with display screen monitors. The jet engines also delivered electrical power to the aircraft, so most of the instrumentation suddenly went dead. One of the lost instruments was the vertical-rate indicator, which would let the pilots know how fast they were sinking and therefore how far they could glide.
The engines also supplied power to the hydraulic systems, without which a plane the size of the 767 could not be controlled. However, Boeing actually planned for this possible failure and included a device known as a ram air turbine that automatically popped open on the side of the plane, using some of the plane's residual velocity to spin a propeller-driven generator and provide enough power to the hydraulics to make it controllable.
With nothing in the emergency guide on flying the aircraft with both engines out, Pearson glided the plane at 220 knots (407 km/h), his best guess as to the optimum airspeed. Copilot Maurice Quintal began making calculations to see if they would reach Winnipeg. He used the altitude from one of the mechanical backup instruments, while the distance travelled was supplied by the air traffic controllers in Winnipeg, who measured the distance the plane's echo moved on their radar screens. The controllers and Quintal both calculated that Flight 143 would not make Winnipeg, as the plane had lost 5,000 ft in 10 nautical miles (1.5 km in 19 km) giving a glide ratio of approximately 12:1.
Stationed at the former Royal Canadian Air Force Base, Quintal selected Gimli to be the attempted place of landing. Since his time in the service, Quintal did not know the Gimli airport had become a public airport. Also not knowing one of its parallel runways was now being used for auto racing. To further complicate the situation, there were many cars, campers and families close to the former runway as it was "Family Day" for the Winnipeg Sports Car Club.
As they approached Quintal did a power-off "gravity drop" of the main landing gear, but the nose wheel, despite being built to open by swinging backwards with the force of the wind, would not lock. The ever-reducing speed of the plane also reduced the effectiveness of The "RAT" (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) and the plane became increasingly difficult to control. As they grew nearer it became apparent that they were too high, and Pearson executed a manoeuvre known as a "forward slip" to increase their drag and reduce their altitude. This gave passengers on one side of the aircraft a view of the ground while passengers on the other side of the plane seen blue skies. With the reduction of speed and altitude the 767 silently leveled off and the main gear touched down. Pearson "stood on the brakes" the instant the plane touched the runway, blowing out several of the plane's tires. The plane came to a stop at the end of the runway in a nose-down position due to the unlocked nose gear, only a few hundred feet from spectators of Family Day at the end of the runway.
None of the 61 passengers were hurt during the landing, the only injuries that resulted from the landing of Flight 143 came from passengers exiting the rear emergency slide, a near vertical angle because of the nose down position of the plane. A minor fire in the nose area was quickly put out by course workers, who rushed over with fire extinguishers.
Within two days the aircraft was repaired and flown out of Gimli, after approximately one million dollars worth of repairs, Aircraft #604 the Boeing 767 known as "The Gimli Glider", is to this day still in the Air Canada fleet.
Note: The mechanics sent from Winnipeg Airport to repair the aircraft, also ran out of fuel in their van on their way to Gimli.
Gimli Glider crew return on the 25th anniversary.. more
Pearson speaks out again.. more
Boys transfixed by image of plane on silent approach.. more
Crew draw visit to an emotional close.. more