planes.
Its all about planes. Its all about hydraulic pressure. Its all about stalling, about falling. About black boxes and flight recorders. But most importantly, its about the Gimli Glider:
While Flight 143 was cruising over Red Lake, Ontario, at 41,000 feet (12,500 m) shortly after 8 pm CDT, the aircraft's cockpit warning system sounded, indicating a fuel-pressure problem on the aircraft's left side. Assuming that a fuel pump had failed, the pilots turned off the alarm, knowing that the engine could be gravity-fed in level flight. A few seconds later, the fuel pressure alarm also sounded for the right engine. This prompted the pilots to divert to Winnipeg.
Within seconds, the left engine failed and the pilots began preparing for a single-engine landing. As they communicated their intentions to controllers in Winnipeg and tried to restart the left engine, the cockpit warning system sounded again with the "all engines out" sound, a sharp "bong" that no one in the cockpit could recall having heard before. Seconds later, the right-side engine also stopped and the 767 lost all power. Flying with all engines out was never expected to occur, so it had never been covered in training. Adding to both the crew's and the controllers' problems, the plane's transponder failed, stopping the altitude reporting function and forcing the controllers to revert to primary radar to track the plane.
The 767 was one of the first airliners to include an electronic flight instrument system, which operated on the electricity generated by the aircraft's jet engines. With both engines stopped, the system went dead and most of the screens went blank, leaving only a few basic battery-powered emergency flight instruments. While these provided sufficient information to land the aircraft, the backup instruments did not include a vertical speed indicator that could be used to determine how far the aircraft could glide.
On the Boeing 767, the control surfaces are so large that the pilots cannot move them with muscle power alone. Instead, hydraulic systems are used to multiply the forces applied by the pilots. Since the engines supply power for the hydraulic systems, in the case of complete power outage, the aircraft was designed with a ram air turbine that swings out from a compartment and drives a hydraulic pump to supply power to hydraulic systems.
In line with their planned diversion to Winnipeg, the pilots had been descending through 35,000 feet (10,700 m) when the second engine shut down. They had searched their emergency checklist for the section on flying the aircraft with both engines out, only to find that no such section existed. Captain Pearson was an experienced glider pilot, so he was familiar with flying techniques almost never used in commercial flight. To have the maximum range and therefore the largest choice of possible landing sites, he needed to fly the 767 at the optimum glide speed. Making his best guess as to this speed for the 767, he flew the aircraft at 220 knots (410 km/h; 250 mph). First Officer Quintal began to calculate whether they could 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, measured by the aircraft's radar echo observed at Winnipeg. In 10 nautical miles (19 km; 12 mi), the aircraft lost 5,000 feet (1,500 m), giving a glide ratio of roughly 12:1 (dedicated glider planes reach ratios of 50:1 to 70:1).
At this point, Quintal proposed landing at the former RCAF Station Gimli, a closed air force base where he had once served as a pilot for the Royal Canadian Air Force. Unbeknownst to Quintal or to the air traffic controller, a part of the facility had been converted to a race track complex, now known as Gimli Motorsports Park. It included a road-race course, a go-kart track, and a dragstrip. A Canadian Automobile Sport Clubs-sanctioned sports-car race hosted by the Winnipeg Sports Car Club was underway at the time of the incident and the area around the decommissioned runway was full of cars and campers. Part of the decommissioned runway was being used to stage the race.
Without main power, the pilots used a gravity drop to lower the landing gear and lock it into place. The main gear locked into position, but the nose wheel did not. The failure of the nose wheel to lock fortuitously turned out to be advantageous after touchdown. As the aircraft slowed on approach to landing, the reduced power generated by the ram air turbine rendered the aircraft increasingly difficult to control.
As the plane approached the runway, the pilots realized it was coming in too high and fast, increasing the likelihood that the 767 would run off the runway. The lack of hydraulic pressure prevented flap/slat extension that would have, under normal conditions, reduced the aircraft's stall speed and increased the lift coefficient of the wings, to slow the airliner for a safe landing. The pilots briefly considered a 360° turn to reduce speed and altitude, but they decided that they did not have enough altitude for the manoeuvre. Pearson decided to execute a forward slip to increase drag and reduce altitude. This manoeuvre, performed by "crossing the controls" (applying rudder in one direction and ailerons in the other direction), is commonly used in gliders and light aircraft to descend more quickly without increasing forward speed; it is almost never used in large jet airliners outside of rare circumstances like those of this flight.The forward slip disrupted airflow past the ram air turbine, which decreased the hydraulic power available; the pilots were surprised to find the aircraft slow to respond when straightening after the forward slip.
With both of its engines dead, the plane made hardly any noise during its approach. This gave people on the ground no warning of the impromptu landing and little time to flee. As the gliding plane closed in on the decommissioned runway, the pilots noticed two boys were riding bicycles within 1,000 feet (300 m) of the projected point of impact. Captain Pearson later said that the boys were so close that he could see the looks of sheer terror on their faces as they realized that a large aircraft was bearing down on them.
Two factors helped avert disaster; the failure of the front landing gear to lock into position during the gravity drop and the presence of a guardrail that had been installed along the centre of the repurposed runway to facilitate its use as a drag race track. As soon as the wheels touched down on the runway, Pearson braked hard, skidding and promptly blowing out two of the aircraft's tires. The unlocked nose wheel collapsed and was forced back into its well, causing the aircraft's nose to slam into, bounce off, and then scrape along the ground. This additional friction helped to slow the airplane and kept it from crashing into the crowds surrounding the runway. Pearson applied extra right brake, which caused the main landing gear to straddle the guardrail. Air Canada Flight 143 came to a final stop on the ground 17 minutes after running out of fuel.
No serious injuries occurred among the 61 passengers or the people on the ground. As the aircraft's nose had collapsed onto the ground, its tail was elevated, so some minor injuries happened when passengers exited the aircraft via the rear slides, which were not sufficiently long to accommodate the increased height. A minor fire in the nose area was extinguished by racers and course workers equipped with portable fire extinguishers.
While Flight 143 was cruising over Red Lake, Ontario, at 41,000 feet (12,500 m) shortly after 8 pm CDT, the aircraft's cockpit warning system sounded, indicating a fuel-pressure problem on the aircraft's left side. Assuming that a fuel pump had failed, the pilots turned off the alarm, knowing that the engine could be gravity-fed in level flight. A few seconds later, the fuel pressure alarm also sounded for the right engine. This prompted the pilots to divert to Winnipeg.
Within seconds, the left engine failed and the pilots began preparing for a single-engine landing. As they communicated their intentions to controllers in Winnipeg and tried to restart the left engine, the cockpit warning system sounded again with the "all engines out" sound, a sharp "bong" that no one in the cockpit could recall having heard before. Seconds later, the right-side engine also stopped and the 767 lost all power. Flying with all engines out was never expected to occur, so it had never been covered in training. Adding to both the crew's and the controllers' problems, the plane's transponder failed, stopping the altitude reporting function and forcing the controllers to revert to primary radar to track the plane.
The 767 was one of the first airliners to include an electronic flight instrument system, which operated on the electricity generated by the aircraft's jet engines. With both engines stopped, the system went dead and most of the screens went blank, leaving only a few basic battery-powered emergency flight instruments. While these provided sufficient information to land the aircraft, the backup instruments did not include a vertical speed indicator that could be used to determine how far the aircraft could glide.
On the Boeing 767, the control surfaces are so large that the pilots cannot move them with muscle power alone. Instead, hydraulic systems are used to multiply the forces applied by the pilots. Since the engines supply power for the hydraulic systems, in the case of complete power outage, the aircraft was designed with a ram air turbine that swings out from a compartment and drives a hydraulic pump to supply power to hydraulic systems.
In line with their planned diversion to Winnipeg, the pilots had been descending through 35,000 feet (10,700 m) when the second engine shut down. They had searched their emergency checklist for the section on flying the aircraft with both engines out, only to find that no such section existed. Captain Pearson was an experienced glider pilot, so he was familiar with flying techniques almost never used in commercial flight. To have the maximum range and therefore the largest choice of possible landing sites, he needed to fly the 767 at the optimum glide speed. Making his best guess as to this speed for the 767, he flew the aircraft at 220 knots (410 km/h; 250 mph). First Officer Quintal began to calculate whether they could 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, measured by the aircraft's radar echo observed at Winnipeg. In 10 nautical miles (19 km; 12 mi), the aircraft lost 5,000 feet (1,500 m), giving a glide ratio of roughly 12:1 (dedicated glider planes reach ratios of 50:1 to 70:1).
At this point, Quintal proposed landing at the former RCAF Station Gimli, a closed air force base where he had once served as a pilot for the Royal Canadian Air Force. Unbeknownst to Quintal or to the air traffic controller, a part of the facility had been converted to a race track complex, now known as Gimli Motorsports Park. It included a road-race course, a go-kart track, and a dragstrip. A Canadian Automobile Sport Clubs-sanctioned sports-car race hosted by the Winnipeg Sports Car Club was underway at the time of the incident and the area around the decommissioned runway was full of cars and campers. Part of the decommissioned runway was being used to stage the race.
Without main power, the pilots used a gravity drop to lower the landing gear and lock it into place. The main gear locked into position, but the nose wheel did not. The failure of the nose wheel to lock fortuitously turned out to be advantageous after touchdown. As the aircraft slowed on approach to landing, the reduced power generated by the ram air turbine rendered the aircraft increasingly difficult to control.
As the plane approached the runway, the pilots realized it was coming in too high and fast, increasing the likelihood that the 767 would run off the runway. The lack of hydraulic pressure prevented flap/slat extension that would have, under normal conditions, reduced the aircraft's stall speed and increased the lift coefficient of the wings, to slow the airliner for a safe landing. The pilots briefly considered a 360° turn to reduce speed and altitude, but they decided that they did not have enough altitude for the manoeuvre. Pearson decided to execute a forward slip to increase drag and reduce altitude. This manoeuvre, performed by "crossing the controls" (applying rudder in one direction and ailerons in the other direction), is commonly used in gliders and light aircraft to descend more quickly without increasing forward speed; it is almost never used in large jet airliners outside of rare circumstances like those of this flight.The forward slip disrupted airflow past the ram air turbine, which decreased the hydraulic power available; the pilots were surprised to find the aircraft slow to respond when straightening after the forward slip.
With both of its engines dead, the plane made hardly any noise during its approach. This gave people on the ground no warning of the impromptu landing and little time to flee. As the gliding plane closed in on the decommissioned runway, the pilots noticed two boys were riding bicycles within 1,000 feet (300 m) of the projected point of impact. Captain Pearson later said that the boys were so close that he could see the looks of sheer terror on their faces as they realized that a large aircraft was bearing down on them.
Two factors helped avert disaster; the failure of the front landing gear to lock into position during the gravity drop and the presence of a guardrail that had been installed along the centre of the repurposed runway to facilitate its use as a drag race track. As soon as the wheels touched down on the runway, Pearson braked hard, skidding and promptly blowing out two of the aircraft's tires. The unlocked nose wheel collapsed and was forced back into its well, causing the aircraft's nose to slam into, bounce off, and then scrape along the ground. This additional friction helped to slow the airplane and kept it from crashing into the crowds surrounding the runway. Pearson applied extra right brake, which caused the main landing gear to straddle the guardrail. Air Canada Flight 143 came to a final stop on the ground 17 minutes after running out of fuel.
No serious injuries occurred among the 61 passengers or the people on the ground. As the aircraft's nose had collapsed onto the ground, its tail was elevated, so some minor injuries happened when passengers exited the aircraft via the rear slides, which were not sufficiently long to accommodate the increased height. A minor fire in the nose area was extinguished by racers and course workers equipped with portable fire extinguishers.
moschidae
8 months ago