Summary
- The Gimli Glider incident occurred 40 years ago when an Air Canada Boeing 767 ran out of fuel at 41,000 feet, but the pilots successfully glided the plane to a former airfield turned race track for a safe landing.
- The plane lost all power, including its electronic instrument system, but the pilots were able to use the ram air turbine for emergency instruments and hydraulic support to maneuver the aircraft.
- The incident was caused by a combination of technical issues, organizational challenges, human error, and a misunderstanding about fuel measurements in the metric system. The pilots were later awarded for their outstanding airmanship.
It has now been 40 years since the legendary event of the Gimli Glider. Due to a combination of technical issues and human error, an Air Canada Boeing 767 ran out of fuel at 41,000 feet. The pilots glided the plane to a former airfield turned race track. Miraculously, they landed without any severe injuries to passengers or crew. Even the aircraft itself went on to serve another 25 years with the airline.
Double alarms at 41,000 feet
On July 23rd, 1983, Air Canada Flight 143 took off from Montreal, Québec, and headed towards Edmonton, Alberta by way of Ottawa. The flight was operated by a five-month-old Boeing 767-200 with registration C-GAUN. Onboard this multi-leg Canadian domestic flight were 61 passengers and eight crew.
Just after 20:00, while the aircraft was cruising at 41,000 feet over Red Lake, Ontario, the crew received a warning of low fuel pressure in the left fuel pump. The pilots assumed the fuel pump had failed, and switched off the alarm.
At the time, the Flight Management Computer (FMC) said there should be plenty of fuel. However, within moments, the right fuel pump alarm also sounded. The crew then decided to divert the aircraft to Winnipeg, 120 miles away.
The below image is of the electronic flight instrument system that went black when the engines lost power:
As they commenced the descent, the left engine failed within minutes. No sooner had plans for a one-engine landing been made than a loud bang could be heard. The cockpit alarm began blaring 'all engines out,' and the jet lost power.
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Instruments gone
As if flying with no engines was not bad enough, the 767 was one of the first jets with an electronic instrument system powered by its engines. This meant that when the engines stopped working, all the instruments went dark.
Thankfully, the ram air turbine (RAT) was enough to power emergency instruments sufficient to land the aircraft. It also provided some hydraulic support for the crew to be able to maneuver the plane, which was not possible by strength alone.
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However, this did not include a vertical speed indicator that could have provided an idea of how far the plane could glide. Gimli, an old Air Force Base, was 20 miles closer to the aircraft's location than Winnipeg.
Experienced glider pilot in the cockpit
The Captain was Robin 'Bob' Pearson, 48 years old, with 15,000 hours of flying time. With him in the cockpit was First Officer Maurice Quintal, aged 36, with 7,000 hours of flying time. By a stroke of luck, Captain Pearson was also an established glider pilot, and First Officer Quintal had trained at Gimli while serving in the army.
Crabbed their way to the runway
Even though the decommissioned base had no emergency services, it was deemed to be the safer option. However, neither of the pilots was aware the base had been turned into a race track, with a race scheduled for that day.
The two heavy landing gears were dropped and locked by gravity, but the lighter nose gear only partially extended. The crew also realized they were coming in too quickly and too high towards their improvised 'runway.' They opted to slip to lose altitude and speed, as noted in the Canadian Board of Inquiry report:
"As they approached Gimli, Captain Pearson and First Officer Quintal discussed the possibility of executing a side-slip to lose height and speed in order to land close to the beginning of the runway. This the Captain did on the final approach and touched down within 800 feet of the threshold."
The nose gear gave out immediately as the plane touched down, but all 61 onboard survived. However, 10 did suffer minor injuries during the evacuation. Investigators found there were only 64 liters of fuel left but no tank leaks.
So how could this have happened? A combination of technical issues, organizational challenges, human error - and the metric system. First of all, there were problems with the plane's Fuel Quantity Indication System (FQIS).
The Boeing 767-200 had a dual processing channel, which meant that the other could operate on its own if one failed. However, that required the quantity to be cross-checked on the ground by a good old floatstick measurement.
Crossed wires
Following a flight the day before the incident, an engineer in Edmonton ran a service check on C-GAUN's FQIS, according to Boeing. The system failed, which made the fuel gauges go blank. Drawing on experience from a similar incident with the same aircraft a month prior, the engineer, in lieu of spare parts, fixed the problem by disabling the second channel and tagging the circuit breaker.
He informed the pilot flying out of Edmonton the next day that the fuel would need to be measured with a floatstick. However, there was a misunderstanding, and the information made it to the Montreal crew change in a muddled state.
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System back on, tag remains
To complicate matters more, while the plane was on the ground in Montreal, a technician came into the cockpit and reengaged the second channel of the FQIS. Meanwhile, he was distracted by the fuel tank outside and never removed the tag from the circuit breaker. This caused the fuel gauges to remain completely blank.
That was not all that conspired to cause the Gimli Glider incident. Anyone who works internationally has sometimes come across the vexation of converting between imperial and metric measurements. Although, very rarely has it meant endangering close to one hundred lives.
Measurement transition
The plane had been delivered to Air Canada from Boeing four months earlier. Meanwhile, the type itself had only been introduced into service ten months prior, and C-GAUN was the 47th specimen to roll out from the assembly line.
It was the first aircraft in the Air Canada fleet to use kilograms on the fuel gauges, and the measurements needed to be entered in kg/L. However, the fueler who checked the floatstick reported the density in pounds/L as this was still the standard operating procedure for other Air Canada aircraft.
The cockpit crew then entered the value into the FMC without recalculating it for metric values. So instead of tanking the 20,088 liters of fuel required for the return flight to Edmonton, the plane left with just under 5,000 liters - about half of what was needed to reach their destination. The Captain repeated the same conversion issues after another floatstick test during a stopover in Ottawa.
Suspended and awarded
Two years after the incident, the pilots were awarded the first-ever Fédération Aéronautique Internationale Diploma for Outstanding Airmanship. C-GAUN was patched up in two days and then flew out to Winnipeg for full repairs.
It returned to service with the airline and kept operating until 2008. At this point, it was withdrawn from service and subsequently stored and partially scrapped at the Mojave Air and Space Port in the US federal state of California.
Similar incidents
As it happens, the Gimli Glider is not the only major incident whereby an aircraft has glided to a safe landing following a total power loss. Indeed, last month, Simple Flying took a look at a selection of such instances, with a notable example being British Airways flight 9, just over a year before the Gimli Glider. More recently, Air Transat flight 236 broke the record for the longest airliner glide in 2001.
Looking back
It has now been four decades since Air Canada Flight 143 emergency landed at Gimli Industrial Park Airport. The event has long been remembered as a phenomenal incident across the industry.
Other such incidents include the Miracle on the Hudson, which occurred 14 years ago, on January 15th, 2009. The event saw US Airways Flight 1549 crash-land on the Hudson River after a bird strike. Thanks to the quick thinking of Captain Chesley Sullenberger and First Officer Jeffrey Skiles, all 155 occupants survived. Like Pearson and Quintal's incident, the cause of Sully and Skiles' activities was heavily investigated. However, they also left a positive legacy and became revered as heroes.
When it comes to gliding, other famous affairs across the industry include British Airways Flight 9 in June 1982, which saw a Boeing 747 divert to Jakarta after coming into contact with a Volcanic ash cloud.
Air Transat Flight 236 of August 2001 is another notable example. Here, an Airbus A330 was flying from Toronto to Lisbon as it suffered a fuel exhaustion over the Atlantic. The twinjet then diverted to Lajes Airport in the Azores.
Altogether, these historic moments highlight the abilities and quick reactions of skilled pilots during crucial situations in the skies. The Gimli Glider has undoubtedly left a mark 40 years on.
What are your thoughts about the story of the Gimli Glider? What do you make of the aircraft's overall history? Let us know what you think of the incident that occurred 40 years ago in the comment section.
