Gimli Glider

Name	Air Canada Flight 143
Occurrence type	Accident
Caption	Air Canada flight 143 landed on an auto dragstrip at Gimli, MB
Date	23 July 1983
Type	Fuel exhaustion, Maintenance error
Site	over Quebec, Ontario and Manitoba, Canada
Passengers	61
Crew	8
Aircraft type	Boeing 767-233
Operator	Air Canada
Tail number
Origin	Montreal-Dorval International Airport
Stopover	Ottawa Macdonald-Cartier International Airport
Destination	Edmonton International Airport
Injuries	10
Fatalities	0
Survivors	69 (all)

The Gimli Glider is the nickname of the Air Canada aircraft that was involved in a notable aviation incident. On 23 July 1983, Air Canada Flight 143, a Boeing 767-200 jet, ran out of fuel at altitude, about halfway through its flight from Montreal to Edmonton via Ottawa. The crew was able to glide the aircraft safely to an emergency landing at Gimli Industrial Park Airport, a former Canadian Air Force base at Gimli, Manitoba.

The subsequent investigation revealed corporate failures and a chain of minor human errors that combined to defeat built-in safeguards. In addition, fuel loading was miscalculated through misunderstanding of the recently adopted metric system, which replaced the imperial system.

History

On July 23rd 1983, the day before the incident, Air Canada's Boeing 767 (registration , c/n 22520/47) flew from Toronto to Edmonton where it underwent routine checks. The next day it was flown to Montreal. Following a crew change, it departed Montreal as Flight 143 for the return trip to Edmonton via Ottawa, with Captain Robert (Bob) Pearson and First Officer Maurice Quintal at the controls.

Running out of fuel

At , over Red Lake, Ontario, the aircraft's cockpit warning system sounded, indicating a fuel pressure problem on the aircraft's left side. Assuming a fuel pump had failed, the pilots turned it off, Seconds later, most of the instrument panels in the cockpit went blank as the right-side engine also stopped and the 767 lost all power.

The 767 was one of the first airliners to include an Electronic Flight Instrument System (EFIS), a system that required the electricity generated by the aircraft's jet engines in order to operate. With both engines stopped, the system went dead, leaving only a few basic battery-powered emergency flight instruments. While these provided basic but sufficient information with which to land the aircraft, a vertical speed indicator that would indicate the rate at which the aircraft was sinking and therefore how far it could glide unpowered was not among them.

In airliners the size of the 767, the engines also supply power for the hydraulic systems without which the aircraft cannot be controlled. Such aircraft are therefore required to accommodate this kind of power failure. As with the 767, this is usually achieved through the automated deployment of a ram air turbine, a generator driven by a small propeller, which in turn is driven by the forward motion of the aircraft. As the Gimli pilots were to experience on their landing approach, a decrease in this forward motion means a decrease in the power available to control the aircraft.

Landing at Gimli

In line with their planned diversion to Winnipeg, the pilots were already descending through when the second engine shut down. They immediately 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, however, was an experienced glider pilot, which gave him familiarity with some flying techniques almost never used by commercial pilots. In order to have the maximum range and therefore the largest choice of possible landing site, he needed to fly the 767 at the "best glide ratio speed". Making his best guess as to this speed for the 767, he flew the aircraft at . First Officer Maurice Quintal began making calculations to see if they could reach Winnipeg. He used the altitude from one of the mechanical backup instruments, while the distance traveled was supplied by the air traffic controllers in Winnipeg, measuring the distance the aircraft's echo moved on their radar screens. The aircraft had lost in , giving a glide ratio of approximately 12:1. The controllers and Quintal both calculated that Flight 143 would not make it to Winnipeg. At this point, Quintal proposed landing at the former RCAF Station Gimli, a closed air force base where he had once served as a Canadian Air Force pilot. Unknown to him, however, part of the facility had been converted to a race track complex, now known as Gimli Motorsports Park . It includes a road race course, a go kart track, and a dragstrip which uses part of one of the two parallel, equal length runways. The other runway was used regularly and maintained to a serviceable condition year round. As a result of the conversion to a dragstrip, the runway now had two racing lanes separated by a guard rail running part way down the middle. Furthermore, an SCCA amateur sports car race was underway that day and the area around the decommissioned runway was full of cars and campers. The decommissioned runway itself was being used to stage the race.

Without power, the pilots had to try lowering the aircraft's main landing gear via a gravity drop, but, due to the airflow, the nose wheel failed to lock into position. The decreasing forward motion of the aircraft also reduced the effectiveness of the Ram Air Turbine (RAT), making the aircraft increasingly difficult to control because of the reduced power being generated.

As the runway drew nearer, it became apparent that the aircraft was too high and fast, raising the danger of running off the runway before the aircraft could be stopped. The lack of hydraulic pressure prevented flap/slat extension. These devices are used under normal landing conditions to reduce the speed of the aircraft for a safe landing. The pilots briefly considered executing a 360 degree turn to reduce speed and altitude, but came to the conclusion they did not have enough altitude for the maneuver. Pearson decided to execute a forward slip to increase drag and lose altitude. This maneuver is commonly used with gliders and light aircraft to descend more quickly. At the time Pearson executed the slip, the aircraft was flying over a golf course.

As soon as the wheels touched the runway, Pearson "stood on the brakes", 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 scrape along the ground. The plane also slammed into the guard rail now separating the strip, which helped slow it down.

None of the 61 passengers were seriously hurt. A minor fire in the nose area was soon put out by racers and course workers armed with fire extinguishers. As the aircraft's nose had collapsed onto the ground, its tail was elevated and there were some minor injuries when passengers exited the aircraft via the rear slides. These were treated by a doctor who had been about to take off in an aircraft on Gimli's remaining runway.

Investigation

An Air Canada investigation concluded that the pilots and mechanics were at fault.

It was also subsequently investigated by the predecessor of the modern Transportation Safety Board of Canada; while concluding that Air Canada management was responsible for "corporate and equipment deficiencies", the report praised the flight and cabin crews for their "professionalism and skill". It noted that Air Canada "... neglected to assign clearly and specifically the responsibility for calculating the fuel load in an abnormal situation", finding that the airline had failed to reallocate the task of checking fuel load that had been the responsibility of the flight engineer on older (three-crew) aircraft.

Fuel quantity indicator system

Information about the amount of fuel in the tanks of a Boeing 767 is computed by the Fuel Quantity Indicator System (FQIS) and displayed on gauges in the cockpit. The FQIS on the incident aircraft was a dual processor channel, each calculating the fuel independently and cross-checking with the other. In the event of one failing the other could still operate alone, but under these circumstances the indicated quantity was required to be cross-checked against a floatstick measurement before departure. In the event of both channels failing there would be no fuel display in the cockpit, and the aircraft would be considered unserviceable and not authorized to fly.

After inconsistencies were found with the FQIS in other 767s, Boeing issued a service bulletin for the routine checking of this system. An engineer in Edmonton duly did so when the aircraft arrived from Toronto following a trouble-free flight the day before the incident. While conducting this check, the FQIS failed and the cockpit fuel gauges went blank. The engineer had previously encountered the same problem earlier in the month when the same aircraft had arrived, again from Toronto, with an FQIS fault. He found then that disabling the second channel by pulling the circuit breaker in the cockpit restored the fuel gauges to working order albeit with only the single FQIS channel operative. In the absence of any spares he simply repeated this temporary fix by pulling and tagging the circuit breaker.

On the day of the incident, the aircraft flew from Edmonton to Montreal. Before departure the engineer informed the pilot of the problem and confirmed that the tanks would have to be checked with the floatstick. In a misunderstanding however the pilot believed that the aircraft had been flown with the fault from Toronto the previous afternoon. That flight proceeded uneventfully with fuel gauges operating correctly on the single channel.

On arrival at Montreal, there was to be a crew change for the return flight back to Edmonton. The outgoing pilot informed Captain Pearson and First Officer Quintal of the problem with the FQIS and passed on his mistaken belief that the aircraft had flown the previous day with this problem. In a further misunderstanding, Captain Pearson believed that he was also being told that the FQIS had been completely unserviceable since then.

While the aircraft was being prepared for its return to Edmonton, a maintenance worker decided to investigate the problem with the faulty FQIS. In order to test the system he re-enabled the second channel, at which point the fuel gauges in the cockpit went blank. He was called away to perform a floatstick measurement of fuel remaining in the tanks. Distracted, he failed to disable the second channel, leaving the circuit breaker tagged (which masked the fact that it was no longer pulled). The FQIS was now completely unserviceable and the fuel gauges were blank.

A record of all actions and findings was made in the maintenance log, including the entry; "SERVICE CHK – FOUND FUEL QTY IND BLANK – FUEL QTY #2 C/B PULLED & TAGGED...". This reports that the fuel gauges were blank and that the second FQIS channel was disabled, but does not make clear that the latter fixed the former.

On entering the cockpit, Captain Pearson saw what he was expecting to see; blank fuel gauges and a tagged circuit breaker. He consulted the aircraft's Minimum Equipment List (MEL), which told him that the aircraft could not be flown in this condition. However, the 767 was still a very new aircraft, having flown its maiden flight in September 1981. was the 47th Boeing 767 off the production line, delivered to Air Canada less than 4 months previously. In that time there had been 55 changes to the MEL, and some pages were still blank pending development of procedures.

As a result of this unreliability, it had become practice for flights to be authorised by maintenance personnel. To add to his own misconceptions about the condition the aircraft had been flying in since the previous day, reinforced by what he saw in the cockpit, he now had a signed off maintenance log that it had become custom to prefer above the Minimum Equipment List.

Refueling

At the time of the incident, Canada was converting to the metric system. As part of this process, the new 767s being acquired by Air Canada were the first to be calibrated for the new system, using litres and kilograms instead of gallons and pounds. All other aircraft were still operating with Imperial units (gallons and pounds). For the trip to Edmonton, the pilot calculated a fuel requirement of . A dripstick check indicated that there were already in the tanks. In order to calculate how much more fuel had to be added, the crew needed to convert the quantity in the tanks to a weight, subtract that figure from 22,300 and convert the result back into a volume. (In previous times, this task would have been completed by a flight engineer, but the 767 was the first of a new generation of airliners that made this position redundant.)

A litre of jet fuel weighs 0.803 kg, so the correct calculation was:

7682 litres × 0.803 = 6169 kg
22300 kg − 6169 kg = 16131 kg
16131 kg ÷ 0.803 = 20088 litres of fuel to be transferred

Between the ground crew and flight crew, however, they arrived at an incorrect conversion factor of 1.77, the weight of a litre of fuel in pounds. This was the conversion factor provided on the refueller's paperwork and which had always been used for the rest of the airline's imperial-calibrated fleet. Their calculation produced:

7682 litres × 1.77 = 13597 kg
22300 kg − 13597 kg = 8703 kg
8703 kg ÷ 1.77 = 4916 litres of fuel to be transferred

Instead of 22,300 kg of fuel, they had 22,300 pounds' on board — only a little over 10,000 kg, or less than half the amount required to reach their destination. Knowing the problems with the FQIS, Captain Pearson double-checked their calculations but was given the same incorrect conversion factor. He checked their arithmetic, inevitably coming up with the same erroneous figures.

The Flight Management Computer (FMC) measures fuel consumption, allowing the crew to keep track of fuel burned as the flight progresses. It is normally updated automatically by the FQIS, but in the absence of this facility it can be updated manually. Believing he had 22,300 kg of fuel on board, this is the figure the captain entered.

Because the FMC would reset during the stopover in Ottawa, the captain had the fuel tanks measured again with the dripstick while there. In converting the quantity to kilograms, the same incorrect conversion factor was used, leading him to believe he now had 20,400 kg of fuel; in reality, he had less than half the required amount.

Aftermath

It has been reported that, following Air Canada's internal investigation, Captain Pearson was demoted for six months, and First Officer Quintal was suspended for two weeks. Three maintenance workers were also suspended. Nevertheless, in 1985 the pilots were awarded the first ever Fédération Aéronautique Internationale Diploma for Outstanding Airmanship. Quintal was promoted to Captain in 1989, while Pearson retired in 1993.

, fin 604, was patched at Gimli and flown out two days later. It remained in service with Air Canada until almost a quarter century later. In an ironic replay, Capt. Pearson and F.O. Quintal, once reinstated to flight duty following the successful appeal of their suspensions, found themselves once again assigned as crewmembers aboard another Air Canada flight. As they boarded the aircraft they realized it was the same, exact airplane they'd landed that fateful day at Glimli, and they lightly joked about not repeating the performance. However, during the climbout, to their momentary horror, once again the aircraft blasted the cockpit with a low fuel warning. However, this time it turned out to be only a false warning from a defective warning system, and the flight continued uneventfully to its destination. After 25 years of service, the airplane flew its last revenue flight (AC951 from Port-au-Prince, Haiti to Montreal, Canada) on 1 January 2008. Air Canada still uses Flight 143 for its Montreal-Ottawa-Edmonton route.

Retirement

in February 2008 (C-GAUN Air Canada livery was subsequently removed)]] On 24 January 2008, the Gimli Glider took its final voyage, AC7067, from Montreal Trudeau to Mojave Airport before its retirement in the desert where it was used for parts.

The Gimli Glider retires to the desert. On Thursday, 24 January, fin 604, the Boeing 767-200 better known as the Gimli Glider, will undertake its final voyage from Montreal to Mojave Airport (MHV) before it is retired to the desert. Employees and retirees (bring valid employee ID) are invited to come and say goodbye to the aircraft, which has now become part of Canadian aviation history. Fin 604 is set to depart as flight AC7067, at 9 a.m. from the Montreal Line Maintenance hangar - Air Canada Base, 750 Côte Vertu West; Building 7, Bay 8/13 (West end), Gate entrance 5. Captain Robert Pearson and First Officer Maurice Quintal, the flight crew who landed the aircraft to safety in Gimli on 23 July 1983 are expected to be on hand for the aircraft's departure. The hangar will be open to well-wishers from 8:00 a.m.

Flight AC7067 was captained by Jean-Marc Bélanger, a former head of the Air Canada Pilots Association, while Captain Robert Pearson and Maurice Quintal were on board to oversee the flight from Montreal to California's Mojave Airport, its final resting place. Also on board were three of the six original flight attendants who were on Flight 143. Flight tracking services FlightAware and FlightView indicated on 24 January 2008 that 604's initial flight was from Montreal (CYUL) to Tucson International airport (KTUS), having a planned cruise altitude of FL400. According to FlightAware, 604 landed at 12:53 P.M. (MST) at Tucson International airport (KTUS). The Gimli Glider was then scheduled (but delayed) to depart Tucson and make the final flight to the Mojave Airport (KMHV) for retirement.

On the 25th anniversary of the incident in 2008, pilots Pearson and Quintal were celebrated in a parade in Gimli, as a mural was dedicated to commemorate the landing.

Similar incidents

In 1963, Aeroflot Tupolev Tu-124, ran out of fuel and ditched into the Neva River. All survived.

In 1978, United Airlines Flight 173, a DC-8-61 ran out of fuel and crashed on approach to Portland (Oregon) International Airport. Two of eight crew and eight of 181 passengers were killed.

In 1982, British Airways Flight 9, a Boeing 747-236B, had all four engines disabled after flying through a cloud of volcanic ash above Indonesia. All aboard survived.

In 1989, Varig Flight 254, a Boeing 737-241, ran out of fuel and made a forced landing in the Amazon jungle due to a pilot navigational error. 13 passengers died, and many others received serious injuries.

In 1990, Avianca Flight 52, a Boeing 707-321B, ran out of fuel and crashed on approach to John F. Kennedy International Airport; 73 people on board were killed.

In 2000, Hapag-Lloyd Flight 3378, an Airbus A310-304, ran out of fuel and landed 500 metres short of the runway at Vienna International Airport; all aboard survived.

In 2001, Air Transat Flight 236, an Airbus A330-243, ran out of fuel and made an emergency landing in the Azores. The cause was a fuel leak. All survived.

In 2005, Tuninter Flight 1153, an ATR 72, ran out of fuel and ditched into the Mediterranean sea. The cause was a wrong kind of fuel gauge. 16 people died.

In 2008, British Airways Flight 38, a Boeing 777, lost all power on final approach to Heathrow Airport and belly landed short of Runway 27L. The cause was fuel starvation as a result of fuel filters becoming being clogged with ice crystals that had formed in the fuel. Minor injuries.

See also

, TV movie loosely based on this event

Mayday (TV series) (AKA Air Emergency, Air Crash Investigation), incident covered in season 5 episode 6.

Mars Climate Orbiter, which was lost due to a navigation error when a subcontractor used Imperial units (pound-seconds) instead of the metric units (newton-seconds) as specified by NASA.

References

Further reading

Emergency, Crisis on the Flight Deck, Stanley Stewart, Airlife Publishing Ltd., 1992, ISBN 1 85310 348 9

Freefall: From 41,000 feet to zero - a true story, William and Marilyn Hoffer, Simon & Schuster, 1989 ISBN 978-0671696894

Engineering Disasters - Lessons to be Learned, Don Lawson, ASME Press, 2005, ISBN 0-7918-0230-2. Pages 221-9 deal specifically with Gimli Glider.

External links

Damn Interesting: The Gimli Glider

CBC Digital Archives: 'Gimli Glider' lands without fuel

Photo of C-GAUN after the landing

Picture of C-GAUN in storage (airliners.net)

Video of retirement fly-by

Category:1983 in Canada Category:Air Canada Category:Airliner accidents and incidents caused by fuel exhaustion Category:Aviation accidents and incidents in Canada Category:History of Manitoba Category:In-flight airliner loss of all engines Category:Metrication Category:Individual aircraft Category:Aviation accidents and incidents in 1983 Category:Accidents and incidents involving the Boeing 767 Category:Mojave Air & Space Port Category:Air Canada accidents and incidents